1.     Pelvic bones joints. Pelvis. SIZES OF THE FEMALE PELVIS

2.     Hip and knee joints

3.     Leg and foot bones joints

 

Lesson # 7

 

Theme 1. Pelvic bones joints. Pelvis. SIZES OF THE FEMALE PELVIS

 

Articulations of the Pelvis

The ligaments connecting the bones of the pelvis with each other may be divided into four groups:

1. Those connecting the sacrum and ilium.

2. Those passing between the sacrum and ischium.

3. Those uniting the sacrum and coccyx.

4. Those between the two public bones.

  1. Sacroiliac Articulation (articulatio sacroiliaca).The sacroiliac articulation is an amphiarthrodial joint, formed between the auricular surfaces of the sacrum and the ilium. The articular surface of each bone is covered with a thin plate of cartilage, thicker on the sacrum than on the ilium. These cartilaginous plates are in close contact with each other, and to a certain extent are united together by irregular patches of softer fibrocartilage, and at their upper and posterior part by fine interosseous fibers. In a considerable part of their extent, especially in advanced life, they are separated by a space containing a synovia-like fluid, and hence the joint presents the characteristics of a diarthrosis. The ligaments of the joint are:

The Anterior Sacroiliac.

The Posterior Sacroiliac.

The Interosseous.

 

The Anterior Sacroiliac Ligament (ligamentum sacroiliacum anterius) (Fig. 319).The anterior sacroiliac ligament consists of numerous thin bands, which connect the anterior surface of the lateral part of the sacrum to the margin of the auricular surface of the ilium and to the preauricular sulcus.

 

: image319

 

Articulations of pelvis. Anterior view.

  

The Posterior Sacroiliac Ligament (ligamentum sacroiliacum posterius) is situated in a deep depression between the sacrum and ilium behind; it is strong and forms the chief bond of union between the bones. It consists of numerous fasciculi, which pass between the bones in various directions. The upper part (short posterior sacroiliac ligament) is nearly horizontal in direction, and passs from the first and second transverse tubercles on the back of the sacrum to the tuberosity of the ilium. The lower part (long posterior sacroiliac ligament) is obique in direction; it is attached by one extremity to the third transverse tubercle of he back of the sacrum, and by the other to the posterior superior spine of the ilium.

 

: image320

 

Articulatios of pelvis. Posterior view.

 

 The Interosseous Sacroiliac Ligament lies deep to the poserior ligament, and consists of a series of short, strong fibers connecting the tubeosities of the sacrum and ilium. Ligaments Connecting the Sacrum and Ischium. The Sacrotuberous.  The Sacrospinous.

 

The Sacrotuberous Ligament (ligamentum sacrotuberosum; great or posterior sacrosciatic ligament).The sacrotuberous ligament is situated at the lower and back part of the pelvis. It is flat, and triangular in form; narrower in the middle than at the ends; attached by its broad base to the posterior inferior spine of the ilium, to the fourth and fifth transverse tubercles of the sacrum, and to the lower part of the lateral margin of that bone and the coccyx. Passing obliquely downward, forward, and lateralward, it becomes narrow and thick, but at its insertion into the inner margin of the tuberosity of the ischium, it increases in breadth, and is prolonged forward along the inner margin of the ramus, as the falciform process, the free concave edge of which gives attachment to the obturator fascia; one of its surfaces is turned toward the perineum, the other toward the Obturator internus. The lower border of the ligament is directly continuous with the tendon of origin of the long head of the Biceps femoris, and by many is believed to be the proximal end of this tendon, cut off by the projection of the tuberosity of the ischium.

 

Relations.The posterior surface of this ligament gives origin, by its whole extent, to the Glutæus maximus. Its anterior surface is in part united to the sacrospinous ligament. Its upper border forms, above, the posterior boundary of the greater sciatic foramen, and, below, the posterior boundary of the lesser sciatic foramen. Its lower border forms part of the boundary of the perineum. It is pierced by the coccygeal nerve and the coccygeal branch of the inferior gluteal artery.

 

The Sacrospinous Ligament (ligamentum sacrospinosum; small or anterior sacrosciatic ligament).The sacrospinous ligament is thin, and triangular in form; it is attached by its apex to the spine of the ischium, and medially, by its broad base, to the lateral margins of the sacrum and coccyx, in front of the sacrotuberous ligament with which its fibers are intermingled.

 

Relations.It is in relation, anteriorly, with the Coccygeus muscle, to which it is closely connected; posteriorly, it is covered by the sacrotuberous ligament, and crossed by the internal pudendal vessels and nerve. Its upper border forms the lower boundary of the greater sciatic foramen; its lower border, part of the margin of the lesser sciatic foramen.

  These two ligaments convert the sciatic notches into foramina. The greater sciatic foramen is bounded, in front and above, by the posterior border of the hip bone; behind, by the sacrotuberous ligament; and below, by the sacrospinous ligament. It is partially filled up, in the recent state, by the Piriformis which leaves the pelvis through it. Above this muscle, the superior gluteal vessels and nerve emerge from the pelvis; and below it, the inferior gluteal vessels and nerve, the internal pudendal vessels and nerve, the sciatic and posterior femoral cutaneous nerves, and the nerves to the Obturator internus and Quadratus femoris make their exit from the pelvis. The lesser sciatic foramen is bounded, in front, by the tuberosity of the ischium; above, by the spine of the ischium and sacrospinous ligament; behind, by the sacrotuberous ligament. It transmits the tendon of the Obturator internus, its nerve, and the internal pudendal vessels and nerve.

  3. Sacrococcygeal articulation is an amphiarthrodial joint, formed between the oval surface at the apex of the sacrum, and the base of the coccyx. It is homologous with the joints between the bodies of the vertebræ, and is connected by similar ligaments. They are:

The Anterior Sacrococcygeal.

The Posterior Sacrococcygeal.

The Lateral Sacrococcygeal.

The Interposed Fibrocartilage.

The Interarticular

 

The Anterior Sacrococcygeal Ligament (ligamentum sacrococcygeum anterius) consists of a few irregular fibers, which descend from the anterior surface of the sacrum to the front of the coccyx, blending with the periosteum.

 

The Posterior Sacrococcygeal Ligament (ligamentum sacrococcygeum posterius).This is a flat band, which arises from the margin of the lower orifice of the sacral canal, and descends to be inserted into the posterior surface of the coccyx. This ligament completes the lower and back part of the sacral canal, and is divisible into a short deep portion and a longer superficial part. It is in relation, behind, with the Glutæus maximus.

 

The Lateral Sacrococcygeal Ligament (ligamentum sacrococcygeum laterale; intertransverse ligament).The lateral sacrococcygeal ligament exists on either side and connects the transverse process of the coccyx to the lower lateral angle of the sacrum; it completes the foramen for the fifth sacral nerve.

  A disk of fibrocartilage is interposed between the contiguous surfaces of the sacrum and coccyx; it differs from those between the bodies of the vertebræ in that it is thinner, and its central part is firmer in texture. It is somewhat thicker in front and behind than at the sides. Occasionally the coccyx is freely movable on the sacrum, most notably during pregnancy; in such cases a synovial membrane is present.

  The Interarticular Ligaments are thin bands, which unite the cornua of the two bones.

  The different segments of the coccyx are connected together by the extension downward of the anterior and posterior sacrococcygeal ligaments, thin annular disks of fibrocartilage being interposed between the segments. In the adult male, all the pieces become ossified together at a comparatively early period; but in the female, this does not commonly occur until a later period of life. At more advanced age the joint between the sacrum and coccyx is obliterated.

 

Movements.The movements which take place between the sacrum and coccyx, and between the different pieces of the latter bone, are forward and backward; they are very limited. Their extent increases during pregnancy.

  4. The Pubic Symphysis (symphysis ossium pubis; articulation of the pubic bones) between the pubic bones is an amphiarthrodial joint, formed between the two oval articular surfaces of the bones. The ligaments of this articulation are:

The Anterior Pubic.

The Posterior Pubic.

The Superior Pubic.

The Arcuate Pubic.

The Interpubic Fibrocartilaginous Lamina.

: image321

 

The Anterior Pubic Ligament consists of several superimposed layers, which pass across the front of the articulation. The superficial fibers pass obliquely from one bone to the other, decussating and forming an interlacement with the fibers of the aponeuroses of the Obliqui externi and the medial tendons of origin of the Recti abdominis. The deep fibers pass transversely across the symphysis, and are blended with the fibrocartilaginous lamina.

: image319

The Posterior Pubic Ligament.The posterior pubic ligament consists of a few thin, scattered fibers, which unite the two pubic bones posteriorly.

 

The Superior Pubic Ligament (ligamentum pubicum superius).The superior pubic ligament connects together the two pubic bones superiorly, extending laterally as far as the pubic tubercles.

 

The Arcuate Pubic Ligament (ligamentum arcuatum pubis; inferior pubic or subpubic ligament).The arcuate pubic ligament is a thick, triangular arch of ligamentous fibers, connecting together the two pubic bones below, and forming the upper boundary of the pubic arch. Above, it is blended with the interpubic fibrocartilaginous lamina; laterally, it is attached to the inferior rami of the pubic bones; below, it is free, and is separated from the fascia of the urogenital diaphragm by an opening through which the deep dorsal vein of the penis passes into the pelvis.

 

The Interpubic Fibrocartilaginous Lamina (lamina fibrocartilaginea interpubica; interpubic disk).The interpubic fibrocartilaginous lamina connects the opposed surfaces of the pubic bones. Each of these surfaces is covered by a thin layer of hyaline cartilage firmly joined to the bone by a series of nipple-like processes which accurately fit into corresponding depressions on the osseous surfaces. These opposed cartilaginous surfaces are connected together by an intermediate lamina of fibrocartilage which varies in thickness in different subjects. It often contains a cavity in its interior, probably formed by the softening and absorption of the fibrocartilage, since it rarely appears before the tenth year of life and is not lined by synovial membrane. This cavity is larger in the female than in the male, but it is very doubtful whether it enlarges, as was formerly supposed, during pregnancy. It is most frequently limited to the upper and back part of the joint; it occasionally reaches to the front, and may extend the entire length of the cartilage. It may be easily demonstrated when present by making a coronal section of the symphysis pubis near its posterior surface.

 

Mechanism of the Pelvis.The pelvic girdle supports and protects the contained viscera and affords surfaces for the attachments of the trunk and lower limb muscles. Its most important mechanical function, however, is to transmit the weight of the trunk and upper limbs to the lower extremities.

  It may be divided into two arches by a vertical plane passing through the acetabular cavities; the posterior of these arches is the one chiefly concerned in the function of transmitting the weight. Its essential parts are the upper three sacral vertebræ and two strong pillars of bone running from the sacroiliac articulations to the acetabular cavities. For the reception and diffusion of the weight each acetabular cavity is strengthened by two additional bars running toward the pubis and ischium. In order to lessen concussion in rapid changes of distribution of the weight, joints (sacroiliac articulations) are interposed between the sacrum and the iliac bones; an accessory joint (pubic symphysis) exists in the middle of the anterior arch. The sacrum forms the summit of the posterior arch; the weight transmitted falls on it at the lumbosacral articulation and, theoretically, has a component in each of two directions. One component of the force is expended in driving the sacrum downward and backward between the iliac bones, while the other thrusts the upper end of the sacrum downward and forward toward the pelvic cavity.

  The movements of the sacrum are regulated by its form. Viewed as a whole, it presents the shape of a wedge with its base upward and forward. The first component of the force is therefore acting against the resistance of the wedge, and its tendency to separate the iliac bones is resisted by the sacroiliac and iliolumbar ligaments and by the ligaments of the pubic symphysis.

 

: image322

 

Coronal section of anterior sacral segment.

 

 

: image323

 

Coronal section of middle sacra segment.

 

  If a series of coronal sections of the sacroiliac joints be made, it will be found possible to divide the articular portion of the sacrum into three segments: anterior, middle, and posterior. In the anterior segment, which involves the first sacral vertebra, the articular surfaces show slight sinuosities and are almost parallel to one another; the distance between their dorsal margins is, however, slightly greater than that between their ventral margins. This segment therefore presents a slight wedge shape with the truncated apex downward. The middle segment is a narrow band across the centers of the articulations. Its dorsal width is distinctly greater than its ventral, so that the segment is more definitely wedge-shaped, the truncated apex being again directed downward. Each articular surface presents in the center a marked concavity from above downward, and into this a corresponding convexity of the iliac articular surface fits, forming an interlocking mechanism. In the posterior segment the ventral width is greater than the dorsal, so that the wedge form is the reverse of those of the other segmentsi. e., the truncated apex is directed upward. The articular surfaces are only slightly concave.

 

: image324

 

Coronal section of posterior sacral segment.

 

  Dislocation downward and forward of the sacrum by the second component of the force applied to it is prevented therefore by the middle segment, which interposes the resistance of its wedge shape and that of the interlocking mechanism on its surfaces; a rotatory movement, however, is produced by which the anterior segment is tilted downward and the posterior upward; the axis of this rotation passes through the dorsal part of the middle segment. The movement of the anterior segment is slightly limited by its wedge form, but chiefly by the posterior and interosseous sacroiliac ligaments; that of the posterior segment is checked to a slight extent by its wedge form, but the chief limiting factors are the sacrotuberous and sacrospinous ligaments. In all these movements the effect of the sacroiliac and iliolumbar ligaments and the ligaments of the symphysis pubis in resisting the separation of the iliac bones must be recognized.

  During pregnancy the pelvic joints and ligaments are relaxed, and capable therefore of more extensive movements. When the fetus is being expelled the force is applied to the front of the sacrum. Upward dislocation is again prevented by the interlocking mechanism of the middle segment. As the fetal head passes the anterior segment the latter is carried upward, enlarging the antero-posterior diameter of the pelvic inlet; when the head reaches the posterior segment this also is pressed upward against the resistance of its wedge, the movement only being possible by the laxity of the joints and the stretching of the sacrotuberous and sacrospinous ligaments.

 

Pelvis as whole

Hip and sacral bones that joined by sacroiliac joint and pubic symphisis form the pelvis which has upper and lower portions. Upper portion is major pelvis, lower is minor pelvis. Major pelvis separates from minor by terminal line that includes promontorium, arcuate line in iliac bones, pubic crests and upper margin of the symphisis. Major pelvis bordered posteiorly 5th lumbar vertebrae body, laterally - iliac alae. Minor pelvis formed by pubic and ischial bones, it has upper orifice (entrance) and lower orifice (exit). Obturator foramen closed by fibrous plate - obturator membrane. On lateral wall of the minor pelvis found greater and lesser sciatic foramen, that bordered by sacrospinal and sacrotuberal ligaments.

Major pelvis has a transverse size:

Þ          spinarum distance (25-27 cm) between right and left superior anterior iliac spines;

Þ          cristarum distance (28-29 cm) between widest points on right and left iliac crests;

Þ          trochanteric distance (30-32 cm) between greater trochanters of the femurs.

Minor pelvis has a size:

Þ          straight size of the inlet (11 cm) between symphisis and promontorium;

Þ          oblique size of the inlet (12 cm) between sacroiliac joint in one side and iliopubic eminence other side;

Þ          transverse size of the inlet (13 cm) between the widest points of the terminal lines;

Þ          straight size of the outlet from (9 cm) between apex coccyges and lower margin of the pubic symphisis;

Þ          transverse size of the outlet (11 cm) between inner margins of the ischiadic tuber.

Straight size of the entrance to the minor pelvis in female named gynecological conjugate. Generally female has lower and wider pelvic than in male, promontorium extends forward not so much, therefore pelvic aperture more rounded. The sacral bone in female is wider and shorter and angle between inferior pubic rami is much 90o.

In vertical position of the body upper pelvic aperture bent forward with angle to the horizontal plane 55-60o in female and 50-55o in male.

Conducting axis of the lesser pelvis connects the middle points of all straight sizes. Normally conducting axis is the way for occipital fontanelle of the fetus during birth.

 

Theme 2. Hip and knee joints

 

The articulations of the Lower Extremity comprise the following:

 I. Hip.

 

   V. Intertarsal.

 II. Knee.

 

  VI. Tarsometatarsal.

III. Tibiofibular.

 

 VII. Intermetatarsal.

IV. Ankle.

 

VIII. Metatarsophalangeal.

IX. Articulations of the Digits.

 

  

Coxal Articulation or Hip-joint (Articulatio Coxæ)


This articulation is an enarthrodial or ball-and-socket joint, formed by the reception of the head of the femur into the cup-shaped cavity of the acetabulum. The articular cartilage on the head of the femur, thicker at the center than at the circumference, covers the entire surface with the exception of the fovea capitis femoris, to which the ligamentum teres is attached; that on the acetabulum forms an incomplete marginal ring, the lunate surface. Within the lunate surface there is a circular depression devoid of cartilage, occupied in the fresh state by a mass of fat, covered by synovial membrane.
The ligaments of the joint are:

The Articular Capsule.

The Pubocapsular.

The Iliofemoral.

The Ligamentum Teres Femoris.

The Ischiocapsular.

The Glenoidal Labrum.

The Transverse Acetabular

The Articular Capsule (capsula articularis; capsular ligament) is strong and dense. Above, it is attached to the margin of the acetabulum 5 to 6 mm. beyond the glenoidal labrum behind; but in front, it is attached to the outer margin of the labrum, and, opposite to the notch where the margin of the cavity is deficient, it is connected to the transverse ligament, and by a few fibers to the edge of the obturator foramen. It surrounds the neck of the femur, and is attached, in front, to the intertrochanteric line; above, to the base of the neck; behind, to the neck, about 1.25 cm. above the intertrochanteric crest; below, to the lower part of the neck, close to the lesser trochanter. From its femoral attachment some of the fibers are reflected upward along the neck as longitudinal bands, termed retinacula. The capsule is much thicker at the upper and forepart of the joint, where the greatest amount of resistance is required; behind and below, it is thin and loose. It consists of two sets of fibers, circular and longitudinal. The circular fibers, zona orbicularis, are most abundant at the lower and back part of the capsule (Fig. 342), and form a sling or collar around the neck of the femur. Anteriorly they blend with the deep surface of the iliofemoral ligament, and gain an attachment to the anterior inferior iliac spine. The longitudinal fibers are greatest in amount at the upper and front part of the capsule, where they are reinforced by distinct bands, or accessory ligaments, of which the most important is the iliofemoral ligament. The other accessory bands are known as the pubocapsular and the ischiocapsular ligaments. The external surface of the capsule is rough, covered by numerous muscles, and separated in front from the Psoas major and Iliacus by a bursa, which not infrequently communicates by a circular aperture with the cavity of the joint.

 

: image339

 

Right hip-joint from the front

  

The Iliofemoral Ligament (ligamentum iliofemorale; Y-ligament; ligament of Bigelow) is a band of great strength which lies in front of the joint; it is intimately connected with the capsule, and serves to strengthen it in this situation. It is attached, above, to the lower part of the anterior inferior iliac spine; below, it divides into two bands, one of which passes downward and is fixed to the lower part of the intertrochanteric line; the other is directed downward and lateralward and is attached to the upper part of the same line. Between the two bands is a thinner part of the capsule. In some cases there is no division, and the ligament spreads out into a flat triangular band which is attached to the whole length of the intertrochanteric line. This ligament is frequently called the Y-shaped ligament of Bigelow; and its upper band is sometimes named the iliotrochanteric ligament.

 

: image340

 

The hip-joint from behind.

 

The Pubocapsular Ligament (ligamentum pubocapsulare; pubofemoral ligament).This ligament is attached, above, to the obturator crest and the superior ramus of the pubis; below, it blends with the capsule and with the deep surface of the vertical band of the oliofemoral ligament.

 

The Ischiocapsular Ligament (ligamentum ischiocapsulare; ischiocapsular band; ligament of Bertin).The ischiocapsular ligament consists of a triangular band of strong fibers, which spring from the ischium below and behind the acetabulum, and blend with the circular fibers of the capsule

 

The Ligamentum Teres Femoris is a triangular, somewhat flattened band implanted by its apex into the antero-superior part of the fovea capitis femoris; its base is attached by two bands, one into either side of the acetabular notch, and between these bony attachments it blends with the transverse ligament. It is ensheathed by the synovial membrane, and varies greatly in strength in different subjects; occasionally only the synovial fold exists, and in rare cases even this is absent. The ligament is made tense when the thigh is semiflexed and the limb then adducted or rotated outward; it is, on the other hand, relaxed when the limb is abducted. It has, however, but little influence as a ligament.

 

: image341

 

Left hip-joint, opened by removing the floor of the acetabulum from within the pelvis

 

The Glenoidal Labrum (labrum glenoidale; cotyloid ligament).The glenoidal labrum is a fibrocartilaginous rim attached to the margin of the acetabulum, the cavity of which it deepens; at the same time it protects the edge of the bone, and fills up the inequalities of its surface. It bridges over the notch as the transverse ligament, and thus forms a complete circle, which closely surrounds the head of the femur and assists in holding it in its place. It is triangular on section, its base being attached to the margin of the acetabulum, while its opposite edge is free and sharp. Its two surfaces are invested by synovial membrane, the external one being in contact with the capsule, the internal one being inclined inward so as to narrow the acetabulum, and embrace the cartilaginous surface of the head of the femur. It is much thicker above and behind than below and in front, and consists of compact fibers.

 

: image342

 

Hip-joint, front view. The capsular ligament has been largely removed.

 

 

VIDEO

 

 

: image343

 

Capsule of hip-joint (distended). Posterior aspect.

 

 The Transverse Acetabular Ligament (ligamentum transversum acetabuli; transverse ligament).This ligament is in reality a portion of the glenoidal labrum, though differing from it in having no cartilage cells among its fibers. It consists of strong, flattened fibers, which cross the acetabular notch, and convert it into a foramen through which the nutrient vessels enter the joint.

 

Synovial Membrane is very extensive. Commencing at the margin of the cartilaginous surface of the head of the femur, it covers the portion of the neck which is contained within the joint; from the neck it is reflected on the internal surface of the capsule, covers both surfaces of the glenoidal labrum and the mass of fat contained in the depression at the bottom of the acetabulum, and ensheathes the ligamentum teres as far as the head of the femur. The joint cavity sometimes communicates through a hole in the capsule between the vertical band of the iliofemoral ligament and the pubocapsular ligament with a bursa situated on the deep surfaces of the Psoas major and Iliacus.

  The muscles in relation with the joint are, in front, the Psoas major and Iliacus, separated from the capsule by a bursa; above, the reflected head of the Rectus femoris and Glutæus minimus, the latter being closely adherent to the capsule; medially, the Obturator externus and Pectineus; behind, the Piriformis, Gemellus superior, Obturator internus, Gemellus inferior, Obturator externus, and Quadratus femoris (Fig. 344).

 

: image344

 

Structures surrounding right hip-joint.

 

  The arteries supplying the joint are derived from the obturator, medial femoral circumflex, and superior and inferior gluteals.

  The nerves are articular branches from the sacral plexus, sciatic, obturator, accessory obturator, and a filament from the branch of the femoral supplying the Rectus femoris.

Movements.The movements of the hip are very extensive, and consist of flexion, extension, adduction, abduction, circumduction, and rotation.

 

  The length of the neck of the femur and its inclinations to the body of the bone have the effect of converting the angular movements of flexion, extension, adduction, and abduction partially into rotatory movements in the joint. Thus when the thigh is flexed or extended, the head of the femur, on account of the medial inclination of the neck, rotates within the acetabulum with only a slight amount of gliding to and fro. The forward slope of the neck similarly affects the movements of adduction and abduction. Conversely rotation of the thigh which is permitted by the upward inclination of the neck, is not a simple rotation of the head of the femur in the acetabulum, but is accompanied by a certain amount of gliding.

  The hip-joint presents a very striking contrast to the shoulder-joint in the much more complete mechanical arrangements for its security and for the limitation of its movements. In the shoulder, as has been seen, the head of the humerus is not adapted at all in size to the glenoid cavity, and is hardly restrained in any of its ordinary movements by the capsule. In the hip-joint, on the contrary, the head of the femur is closely fitted to the acetabulum for an area extending over nearly half a sphere, and at the margin of the bony cup it is still more closely embraced by the glenoidal labrum, so that the head of the femur is held in its place by that ligament even when the fibers of the capsule have been quite divided. The iliofemoral ligament is the strongest of all the ligaments in the body, and is put on the stretch by any attempt to extend the femur beyond a straight line with the trunk. That is to say, this ligament is the chief agent in maintaining the erect position without muscular fatigue; for a vertical line passing through the center of gravity of the trunk falls behind the centers of rotation in the hip-joints, and therefore the pelvis tends to fall backward, but is prevented by the tension of the iliofemoral ligaments. The security of the joint may be provided for also by the two bones being directly united through the ligamentum teres; but it is doubtful whether this ligament has much influence upon the mechanism of the joint. When the knee is flexed, flexion of the hip-joint is arrested by the soft parts of the thigh and abdomen being brought into contact, and when the knee is extended, by the action of the hamstring muscles; extension is checked by the tension of the iliofemoral ligament; adduction by the thighs coming into contact; adduction with flexion by the lateral band of the iliofemoral ligament and the lateral part of the capsule; abduction by the medial band of the iliofemoral ligament and the pubocapsular ligament; rotation outward by the lateral band of the iliofemoral ligament; and rotation inward by the ischiocapsular ligament and the hinder part of the capsule. The muscles which flex the femur on the pelvis are the Psoas major, Iliacus, Rectus femoris, Sartorius, Pectineus, Adductores longus and brevis, and the anterior fibers of the Glutæi medius and minimus. Extension is mainly performed by the Glutæus maximus, assisted by the hamstring muscles and the ischial head of the Adductor magnus. The thigh is adducted by the Adductores magnus, longus, and brevis, the Pectineus, the Gracilis, and lower part of the Glutæus maximus, and abducted by the Glutæi medius and minimus, and the upper part of the Glutæus maximus. The muscles which rotate the thigh inward are the Glutæus minimus and the anterior fibers of the Glutæus medius, the Tensor fasciæ latæ and the Iliacus and Psoas major; while those which rotate it outward are the posterior fibers of the Glutæus medius, the Piriformis, Obturatores externus and internus, Gemelli superior and inferior, Quadratus femoris, Glutæus maximus, the Adductores longus, brevis, and magnus, the Pectineus, and the Sartorius.

 

 

The Knee-joint (Articulatio Genu)


The knee-joint was formerly described as a ginglymus or hinge-joint, but is really of a much more complicated character. It must be regarded as consisting of three articulations in one: two condyloid joints, one between each condyle of the femur and the corresponding meniscus and condyle of the tibia; and a third between the patella and the femur, partly arthrodial, but not completely so, since the articular surfaces are not mutually adapted to each other, so that the movement is not a simple gliding one. This view of the construction of the knee-joint receives confirmation from the study of the articulation in some of the lower mammals, where, corresponding to these three subdivisions, three synovial cavities are sometimes found, either entirely distinct or only connected together by small communications. This view is further rendered probable by the existence in the middle of the joint of the two cruciate ligaments, which must be regarded as the collateral ligaments of the medial and lateral joints. The existence of the patellar fold of synovial membrane would further indicate a tendency to separation of the synovial cavity into two minor sacs, one corresponding to the lateral and the other to the medial joint.

  The bones are connected together by the following ligaments:

The Articular Capsule.

The Anterior Cruciate.

The Ligamentum Patellæ.

The Posterior Cruciate.

The Oblique Popliteal.

The Medial and Lateral Menisci.

The Tibial Collateral.

The Transverse.

The Fibular Collateral.

The Coronary.

 

VIDEO

 

The Articular Capsule (capsula articularis; capsular ligament) consists of a thin, but strong, fibrous membrane which is strengthened in almost its entire extent by bands inseparably connected with it. Above and in front, beneath the tendon of the Quadriceps femoris, it is represented only by the synovial membrane. Its chief strengthening bands are derived from the fascia lata and from the tendons surrounding the joint. In front, expansions from the Vasti and from the fascia lata and its iliotibial band fill in the intervals between the anterior and collateral ligaments, constituting the medial and lateral patellar retinacula. Behind the capsule consists of vertical fibers which arise from the condyles and from the sides of the intercondyloid fossa of the femur; the posterior part of the capsule is therefore situated on the sides of and in front of the cruciate ligaments, which are thus excluded from the joint cavity. Behind the cruciate ligaments is the oblique popliteal ligament which is augmented by fibers derived from the tendon of the Semimembranosus. Laterally, a prolongation from the iliotibial band fills in the interval between the oblique popliteal and the fibular collateral ligaments, and partly covers the latter. Medially, expansions from the Sartorius and Semimembranosus pass upward to the tibial collateral ligament and strengthen the capsule.

 

The Ligamentum Patellæ (anterior ligament) is the central portion of the common tendon of the Quadriceps femoris, which is continued from the patella to the tuberosity of the tibia. It is a strong, flat, ligamentous band, about 8 cm. in length, attached, above, to the apex and adjoining margins of the patella and the rough depression on its posterior surface; below, to the tuberosity of the tibia; its superficial fibers are continuous over the front of the patella with those of the tendon of the Quadriceps femoris. The medial and lateral portions of the tendon of the Quadriceps pass down on either side of the patella, to be inserted into the upper extremity of the tibia on either side of the tuberosity; these portions merge into the capsule, as stated above, forming the medial and lateral patellar retinacula. The posterior surface of the ligamentum patellæ is separated from the synovial membrane of the joint by a large infrapatellar pad of fat, and from the tibia by a bursa.

 

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Right knee-joint. Anterior view.

  

The Oblique Popliteal Ligament (ligamentum popliteum obliquum; posterior ligament) is a broad, flat, fibrous band, formed of fasciculi separated from one another by apertures for the passage of vessels and nerves. It is attached above to the upper margin of the intercondyloid fossa and posterior surface of the femur close to the articular margins of the condyles, and below to the posterior margin of the head of the tibia. Superficial to the main part of the ligament is a strong fasciculus, derived from the tendon of the Semimembranosus and passing from the back part of the medial condyle of the tibia obliquely upward and lateralward to the back part of the lateral condyle of the femur. The oblique popliteal ligament forms part of the floor of the popliteal fossa, and the popliteal artery rests upon it.

 

The Tibial Collateral Ligament (ligamentum collaterale tibiale; internal lateral ligament) is a broad, flat, membranous band, situated nearer to the back than to the front of the joint. It is attached, above, to the medial condyle of the femur immediately below the adductor tubercle; below, to the medial condyle and medial surface of the body of the tibia. The fibers of the posterior part of the ligament are short and incline backward as they descend; they are inserted into the tibia above the groove for the Semimembranosus. The anterior part of the ligament is a flattened band, about 10 cm. long, which inclines forward as it descends. It is inserted into the medial surface of the body of the tibia about 2.5 cm. below the level of the condyle. It is crossed, at its lower part, by the tendons of the Sartorius, Gracilis, and Semitendinosus, a bursa being interposed. Its deep surface covers the inferior medial genicular vessels and nerve and the anterior portion of the tendon of the Semimembranosus, with which it is connected by a few fibers; it is intimately adherent to the medial meniscus.

 

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Right knee-joint. Posterior view.

 

 

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Right knee-joint, from the front, showing interior ligaments.

 

 

The Fibular Collateral Ligament (ligamentum collaterale fibulare; external lateral or long external lateral ligament) is a strong, rounded, fibrous cord, attached, above, to the back part of the lateral condyle of the femur, immediately above the groove for the tendon of the Popliteus; below, to the lateral side of the head of the fibula, in front of the styloid process. The greater part of its lateral surface is covered by the tendon of the Biceps femoris; the tendon, however, divides at its insertion into two parts, which are separated by the ligament. Deep to the ligament are the tendon of the Popliteus, and the inferior lateral genicular vessels and nerve. The ligament has no attachment to the lateral meniscus.

  An inconstant bundle of fibers, the short fibular collateral ligament, is placed behind and parallel with the preceding, attached, above, to the lower and back part of the lateral condyle of the femur; below, to the summit of the styloid process of the fibula. Passing deep to it are the tendon of the Popliteus, and the inferior lateral genicular vessels and nerve.

 

The Cruciate Ligaments (ligamenta cruciata genu; crucial ligaments).The cruciate ligaments are of considerable strength, situated in the middle of the joint, nearer to its posterior than to its anterior surface. They are called cruciate because they cross each other somewhat like the lines of the letter X; and have received the names anterior and posterior, from the position of their attachments to the tibia.

  The Anterior Cruciate Ligament (ligamentum cruciatum anterius; external crucial ligament) is attached to the depression in front of the intercondyloid eminence of the tibia, being blended with the anterior extremity of the lateral meniscus; it passes upward, backward, and lateralward, and is fixed into the medial and back part of the lateral condyle of the femur.

 

: image348

 

Left knee-joint from behind, showing interior ligaments.

 

  The Posterior Cruciate Ligament (ligamentum cruciatum posterius; internal crucial ligament) is stronger, but shorter and less oblique in its direction, than the anterior. It is attached to the posterior intercondyloid fossa of the tibia, and to the posterior extremity of the lateral meniscus; and passes upward, forward, and medialward, to be fixed into the lateral and front part of the medial condyle of the femur.

 

The Menisci (semilunar fibrocartilages) are two crescentic lamellæ, which serve to deepen the surfaces of the head of the tibia for articulation with the condyles of the femur. The peripheral border of each meniscus is thick, convex, and attached to the inside of the capsule of the joint; the opposite border is thin, concave, and free. The upper surfaces of the menisci are concave, and in contact with the condyles of the femur; their lower surfaces are flat, and rest upon the head of the tibia; both surfaces are smooth, and invested by synovial membrane. Each meniscus covers approximately the peripheral two-thirds of the corresponding articular surface of the tibia.

  The medial meniscus (meniscus medialis; internal semilunar fibrocartilage) is nearly semicircular in form, a little elongated from before backward, and broader behind than in front; its anterior end, thin and pointed, is attached to the anterior intercondyloid fossa of the tibia, in front of the anterior cruciate ligament; its posterior end is fixed to the posterior intercondyloid fossa of the tibia, between the attachments of the lateral meniscus and the posterior cruciate ligament.

 

: image349

 

Head of right tibia seen from above, showing menisci and attachments of ligaments.

 

  The lateral meniscus (meniscus lateralis; external semilunar fibrocartilage) is nearly circular and covers a larger portion of the articular surface than the medial one. It is grooved laterally for the tendon of the Popliteus, which separates it from the fibular collateral ligament. Its anterior end is attached in front of the intercondyloid eminence of the tibia, lateral to, and behind, the anterior cruciate ligament, with which it blends; the posterior end is attached behind the intercondyloid eminence of the tibia and in front of the posterior end of the medial meniscus. The anterior attachment of the lateral meniscus is twisted on itself so that its free margin looks backward and upward, its anterior end resting on a sloping shelf of bone on the front of the lateral process of the intercondyloid eminence. Close to its posterior attachment it sends off a strong fasciculus, the ligament of Wrisberg, which passes upward and medialward, to be inserted into the medial condyle of the femur, immediately behind the attachment of the posterior cruciate ligament. Occasionally a small fasciculus passes forward to be inserted into the lateral part of the anterior cruciate ligament. The lateral meniscus gives off from its anterior convex margin a fasciculus which forms the transverse ligament.

 

The Transverse Ligament (ligamentum transversum genu).The transverse ligament connects the anterior convex margin of the lateral meniscus to the anterior end of the medial meniscus; its thickness varies considerably in different subjects, and it is sometimes absent.

  The coronary ligaments are merely portions of the capsule, which connect the periphery of each meniscus with the margin of the head of the tibia.

 

Synovial Membrane.The synovial membrane of the knee-joint is the largest and most extensive in the body. Commencing at the upper border of the patella, it forms a large cul-de-sac beneath the Quadriceps femoris) on the lower part of the front of the femur, and frequently communicates with a bursa interposed between the tendon and the front of the femur. The pouch of synovial membrane between the Quadriceps and front of the femur is supported, during the movements of the knee, by a small muscle, the Articularis genu, which is inserted into it. On either side of the patella, the synovial membrane extends beneath the aponeuroses of the Vasti, and more especially beneath that of the Vastus medialis. Below the patella it is separated from the ligamentum patellæ by a considerable quantity of fat, known as the infrapatellar pad. From the medial and lateral borders of the articular surface of the patella, reduplications of the synovial membrane project into the interior of the joint. These form two fringe-like folds termed the alar folds; below, these folds converge and are continued as a single band, the patellar fold (ligamentum mucosum), to the front of the intercondyloid fossa of the femur. On either side of the joint, the synovial membrane passes downward from the femur, lining the capsule to its point of attachment to the menisci; it may then be traced over the upper surfaces of these to their free borders, and thence along their under surfaces to the tibia. At the back part of the lateral meniscus it forms a cul-de-sac between the groove on its surface and the tendon of the Popliteus; it is reflected across the front of the cruciate ligaments, which are therefore situated outside the synovial cavity.

 

: image350

 

Sagittal section of right knee-joint.

 

 Bursæ.The bursæ near the knee-joint are the following: In front there are four bursæ: a large one is interposed between the patella and the skin, a small one between the upper part of the tibia and the ligamentum patellæ, a third between the lower part of the tuberosity of the tibia and the skin, and a fourth between the anterior surface of the lower part of the femur and the deep surface of the Quadriceps femoris, usually communicating with the knee-joint. Laterally there are four bursæ: (1) one (which sometimes communicates with the joint) between the lateral head of the Gastrocnemius and the capsule; (2) one between the fibular collateral ligament and the tendon of the Biceps; (3) one between the fibular collateral ligament and the tendon of the Popliteus (this is sometimes only an expansion from the next bursa); (4) one between the tendon of the Popliteus and the lateral condyle of the femur, usually an extension from the synovial membrane of the joint. Medially, there are five bursæ: (1) one between the medial head of the Gastrocnemius and the capsule; this sends a prolongation between the tendon of the medial head of the Gastrocnemius and the tendon of the Semimembranosus and often communicates with the joint; (2) one superficial to the tibial collateral ligament, between it and the tendons of the Sartorius, Gracilis, and Semitendinosus; (3) one deep to the tibial collateral ligament, between it and the tendon of the Semimembranosus (this is sometimes only an expansion from the next bursa); (4) one between the tendon of the Semimembranosus and the head of the tibia; (5) occasionally there is a bursa between the tendons of the Semimembranosus and Semitendinosus.

 

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Capsule of right knee-joint (distended). Lateral aspect.

 

 

Structures Around the Joint.In front, and at the sides, is the Quadriceps femoris; laterally the tendons of the Biceps femoris and Popliteus and the common peroneal nerve; medially, the Sartorius, Gracilis, Semitendinosus, and Semimembranosus; behind, the popliteal vessels and the tibial nerve, Popliteus, Plantaris, and medial and lateral heads of the Gastrocnemius, some lymph glands, and fat.

  The arteries supplying the joint are the highest genicular (anastomotica magna), a branch of the femoral, the genicular branches of the popliteal, the recurrent branches of the anterior tibial, and the descending branch from the lateral femoral circumflex of the profunda femoris.

  The nerves are derived from the obturator, femoral, tibial, and common peroneal.

 

Movements.The movements which take place at the knee-joint are flexion and extension, and, in certain positions of the joint, internal and external rotation. The movements of flexion and extension at this joint differ from those in a typical hinge-joint, such as the elbow, in that (a) the axis around which motion takes place is not a fixed one, but shifts forward during extension and backward during flexion; (b) the commencement of flexion and the end of extension are accompanied by rotatory movements associated with the fixation of the limb in a position of great stability. The movement from full flexion to full extension may therefore be described in three phases:

  1. In the fully flexed condition the posterior parts of the femoral condyles rest on the corresponding portions of the meniscotibial surfaces, and in this position a slight amount of simple rolling movement is allowed.

 

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Capsule of right knee-joint (distended). Posterior aspect.

 

  2. During the passage of the limb from the flexed to the extended position a gliding movement is superposed on the rolling, so that the axis, which at the commencement is represented by a line through the inner and outer condyles of the femur, gradually shifts forward. In this part of the movement, the posterior two-thirds of the tibial articular surfaces of the two femoral condyles are involved, and as these have similar curvatures and are parallel to one another, they move forward equally.

  3. The lateral condyle of the femur is brought almost to rest by the tightening of the anterior cruciate ligament; it moves, however, slightly forward and medialward, pushing before it the anterior part of the lateral meniscus. The tibial surface on the medial condyle is prolonged farther forward than that on the lateral, and this prolongation is directed lateralward. When, therefore, the movement forward of the condyles is checked by the anterior cruciate ligament, continued muscular action causes the medial condyle, dragging with it the meniscus, to travel backward and medialward, thus producing an internal rotation of the thigh on the leg. When the position of full extension is reached the lateral part of the groove on the lateral condyle is pressed against the anterior part of the corresponding meniscus, while the medial part of the groove rests on the articular margin in front of the lateral process of the tibial intercondyloid eminence. Into the groove on the medial condyle is fitted the anterior part of the medial meniscus, while the anterior cruciate ligament and the articular margin in front of the medial process of the tibial intercondyloid eminence are received into the forepart of the intercondyloid fossa of the femur. This third phase by which all these parts are brought into accurate apposition is known as the screwing home, or locking movement of the joint.

  The complete movement of flexion is the converse of that described above, and is therefore preceded by an external rotation of the femur which unlocks the extended joint.

  The axes around which the movements of flexion and extension take place are not precisely at right angles to either bone; in flexion, the femur and tibia are in the same plane, but in extension the one bone forms an angle, opening lateralward with the other.

  In addition to the rotatory movements associated with the completion of extension and the initiation of flexion, rotation inward or outward can be effected when the joint is partially flexed; these movements take place mainly between the tibia and the menisci, and are freest when the leg is bent at right angles with the thigh.

  Movements of Patella.The articular surface of the patella is indistinctly divided into seven facetsupper, middle, and lower horizontal pairs, and a medial perpendicular facet. When the knee is forcibly flexed, the medial perpendicular facet is in contact with the semilunar surface on the lateral part of the medial condyle; this semilunar surface is a prolongation backward of the medial part of the patellar surface. As the leg is carried from the flexed to the extended position, first the highest pair, then the middle pair, and lastly the lowest pair of horizontal facets is successively brought into contact with the patellar surface of the femur. In the extended position, when the Quadriceps femoris is relaxed, the patella lies loosely on the front of the lower end of the femur.

 

VIDEO

 

  During flexion, the ligamentum patellæ is put upon the stretch, and in extreme flexion the posterior cruciate ligament, the oblique popliteal, and collateral ligaments, and, to a slight extent, the anterior cruciate ligament, are relaxed. Flexion is checked during life by the contact of the leg with the thigh. When the knee-joint is fully extended the oblique popliteal and collateral ligaments, the anterior cruciate ligament, and the posterior cruciate ligament, are rendered tense; in the act of extending the knee, the ligamentum patellæ is tightened by the Quadriceps femoris, but in full extension with the heel supported it is relaxed. Rotation inward is checked by the anterior cruciate ligament; rotation outward tends to uncross and relax the cruciate ligaments, but is checked by the tibial collateral ligament. The main function of the cruciate ligament is to act as a direct bond between the tibia and femur and to prevent the former bone from being carried too far backward or forward. They also assist the collateral ligaments in resisting any bending of the joint to either side. The menisci are intended, as it seems, to adapt the surfaces of the tibia to the shape of the femoral condyles to a certain extent, so as to fill up the intervals which would otherwise be left in the varying positions of the joint, and to obviate the jars which would be so frequently transmitted up the limb in jumping or by falls on the feet; also to permit of the two varieties of motion, flexion and extension, and rotation, as explained above. The patella is a great defence to the front of the knee-joint, and distributes upon a large and tolerably even surface, during kneeling, the pressure which would otherwise fall upon the prominent ridges of the condyles; it also affords leverage to the Quadriceps femoris.

 

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Posterior surface of the right patella, showing diagrammatically the areas of contact with the femur in different positions of the knee.

 

  When standing erect in the attitude of attention, the weight of the body falls in front of a line carried across the centers of the knee-joints, and therefore tends to produce overextension of the articulations; this, however, is prevented by the tension of the anterior cruciate, oblique popliteal, and collateral ligaments.

  Extension of the leg on the thigh is performed by the Quadriceps femoris; flexion by the Biceps femoris, Semitendinosus, and Semimembranosus, assisted by the Gracilis, Sartorius, Gastrocnemius, Popliteus, and Plantaris. Rotation outward is effected by the Biceps femoris, and rotation inward by the Popliteus, Semitendinosus, and, to a slight extent, the Semimembranosus, the Sartorius, and the Gracilis. The Popliteus comes into action especially at the commencement of the movement of flexion of the knee; by its contraction the leg is rotated inward, or, if the tibia be fixed, the thigh is rotated outward, and the knee-joint is unlocked.

 

Theme 3. Leg and foot bones joints

 

 

Articulations between the Tibia and Fibula

The articulations between the tibia and fibula are effected by ligaments which connect the extremities and bodies of the bones. The ligaments may consequently be subdivided into three sets: (1) those of the Tibiofibular articulation; (2) the interosseous membrane; (3) those of the Tibiofibular syndesmosis.

 

Tibiofibular Articulation (articulatio tibiofibularis; superior tibiofibular articulation).This articulation is an arthrodial joint between the lateral condyle of the tibia and the head of the fibula. The contiguous surfaces of the bones present flat, oval facets covered with cartilage and connected together by an articular capsule and by anterior and posterior ligaments.

 

The Articular Capsule (capsula articularis; capsular ligament).The articular capsule surrounds the articulation, being attached around the margins of the articular facets on the tibia and fibula; it is much thicker in front than behind.

 

The Anterior Ligament (anterior superior ligament).The anterior ligament of the head of the fibula consists of two or three broad and flat bands, which pass obliquely upward from the front of the head of the fibula to the front of the lateral condyle of the tibia.

 

The Posterior Ligament (posterior superior ligament).The posterior ligament of the head of the fibula is a single thick and broad band, which passes obliquely upward from the back of the head of the fibula to the back of the lateral condyle of the tibia. It is covered by the tendon of the Popliteus.

 

Synovial Membrane.A synovial membrane lines the capsule; it is continuous with that of the knee-joint in occasional cases when the two joints communicate.

 

Interosseous Membrane (membrana interossea cruris; middle tibiofibular ligament).An interosseous membrane extends between the interosseous crests of the tibia and fibula, and separates the muscles on the front from those on the back of the leg. It consists of a thin, aponeurotic lamina composed of oblique fibers, which for the most part run downward and lateralward; some few fibers, however, pass in the opposite direction. It is broader above than below. Its upper margin does not quite reach the tibiofibular joint, but presents a free concave border, above which is a large, oval aperture for the passage of the anterior tibial vessels to the front of the leg. In its lower part is an opening for the passage of the anterior peroneal vessels. It is continuous below with the interosseous ligament of the tibiofibular syndesmosis, and presents numerous perforations for the passage of small vessels. It is in relation, in front, with the Tibialis anterior, Extensor digitorum longus, Extensor hallucis proprius, Peronæus tertius, and the anterior tibial vessels and deep peroneal nerve; behind, with the Tibialis posterior and Flexor hallucis longus.

 

Tibiofibular Syndesmosis (syndesmosis tibiofibularis; inferior tibiofibular articulation).This syndesmosis is formed by the rough, convex surface of the medial side of the lower end of the fibula, and a rough concave surface on the lateral side of the tibia. Below, to the extent of about 4 mm. these surfaces are smooth, and covered with cartilage, which is continuous with that of the ankle-joint. The ligaments are: anterior, posterior, inferior transverse, and interosseous.

 

The Anterior Ligament (ligamentum malleoli lateralis anterius; anterior inferior ligament).The anterior ligament of the lateral malleolus is a flat, triangular band of fibers, broader below than above, which extends obliquely downward and lateralward between the adjacent margins of the tibia and fibula, on the front aspect of the syndesmosis. It is in relation, in front, with the Peronæus tertius, the aponeurosis of the leg, and the integument; behind, with the interosseous ligament; and lies in contact with the cartilage covering the talus.

 

The Posterior Ligament (ligamentum malleoli lateralis posterius; posterior inferior ligament).The posterior ligament of the lateral malleolus, smaller than the preceding, is disposed in a similar manner on the posterior surface of the syndesmosis.

 

The Inferior Transverse Ligament.The inferior transverse ligament lies in front of the posterior ligament, and is a strong, thick band, of yellowish fibers which passes transversely across the back of the joint, from the lateral malleolus to the posterior border of the articular surface of the tibia, almost as far as its malleolar process. This ligament projects below the margin of the bones, and forms part of the articulating surface for the talus.

 

The Interosseous Ligament.The interosseous ligament consists of numerous short, strong, fibrous bands, which pass between the contiguous rough surfaces of the tibia and fibula, and constitute the chief bond of union between the bones. It is continuous, above, with the interosseous membrane.

 

Synovial Membrane.The synovial membrane associated with the small arthrodial part of this joint is continuous with that of the ankle-joint.

 

 

1.      

Name

Shape

Type

Function

Axises of moving

1

Art. genus

condyloid

complex

2 axises

frontal

vertical when bended

2

Art. Tibiofibularis proximal

plane

simple

3 axises

-

3

Art.Talocruralis

trochlear

compound

1 axis

frontal

4

Intertarseal articulations:

a) Art. subtalaris

cylindrical

simple

1 axis

saggital

5

b) Art. Talocolcaneo-navicularis

ball

compound

3 axises

vertical

frontal

6

c) Art. calcaneo-cuboidea

 

plane

simple

3 axises

 

7

d) Art. cuneo-navicularis

plane.

 

Compound

 

 

8

Art. tarsi transversa (Shopara)

 

 

 

 

 

9

Art. tarsometarsea

(Lisfrank)

 

plane.

compound

3 axises

-

10

Artt. intermetatarseae

 

plane.

compound

3 axises

-

11

Art. metatarsophalangea

ball

simple

3 axises

vertical

frontal

12

Art. interphalangea

 

trochlear

simple.

1-axis

frontal

 

 

Articular surfaces

Movement

Ligaments

1

f.a.inferior femoris

f.a.superior tibiae

f.a.patellaris femoris

f.a.patellae

PLICAE: 1.Plicae alares

2.Plicae synoviales, infrapatellaris

 

 

flexion, extension and

rotation when bended

lig. transversum genus

lig. collaterale tibiale

lig. collaterale fibulare

ligg. popliteum obliquum

ligg. popliteum arcuatum

retinacula pattelae laterale, mediale

lig. cruciata anterius et posterius

lig. meniscofemorale anterior

lig. meniscofemorale posterior

2

f.a.capitis fibulae

f.a.fibularis tibiae

limited

ligg.capitis fibulae anterior

et posterior

3

f.a.tibiae inferior

f.a.malleoli medialis

f.a.malleoli lateralis

f.a.superior trochlea

f.a.medialis trochlea

f.a.medialis lateralis trochlea

 

flexion,

extension,

lateral movements when bended

lig. mediale. Parts:

1. tibionavicularis

2. tibiocalcanea

3. tibiotalaris anterior

4. tibiotalaris posterior

lig.talofibulare anterius laterale

lig.talofibulare posterius laterale

lig.calcaneofibulare

4

f.a.calcanei posterior tali

f.a.posterius calcanei

 

supination with

 

lig. plantare longum

5

f.a.calcanei anterior et medii tali et naviculare

f.a.anterior et medii ossis calcanei

f.a.pasteriar ossis navicularis

adduction and plantar flexion,

pronation with abduction and dorsal flexion

lig. calcaneonaviculare plantare

lig. talocaneum interossea

lig. talocaneum med.

lig. talocaneum lat.

6

f.a.cuboiclea ossis calcanei

f.a.pesterior ossis cuboiclei

 

lig. talonaviculare

lig. calcaneocuboideum plantare

7

f. a. cuneidea ossis navicularis

f. a. navicularis ossis cuneidei

 

 

8

f. a. cuboidea ossis calcanei,

f. a. posterior ossis cuboidei

f. a. navicularis tali,

f. a. posterior ossis navicularis

 

 

lig. bifurcatum: lig.calcaneocuboideum

+ lig. calcaneonavicularis

9

f.a. on cuneiform and cuboid bones,

f.a. metetarseal bones

 

limited

 

ligg. tarsometatarsea interossea

ligg. tarsometatarsea mediale

ligg. tarsometatarsea media

ligg. tarsometatarsea laterale

10

 

limited

ligg. metatarsea dorsalia et plantaria

ligg. metatarsea interossea

11

f.a. of the heads (tarsal bones), f.a of the bases (phalanges)

flexion,extension,

slight abduction

ligg. Collateralia, ligg. plantaria

lig.metatars. profundum transvers.

12

f.a. on phalanges

flexion,

extension

ligg. Collateralia

ligg. Plantaria

 

 

 

 

: image354

 

Ligaments of the medial aspect of the foot. (Quain.)

 

 

Talocrural Articulation or Ankle-joint

(Articulatio Talocruralis; Tibiotarsal Articulation)


The ankle-joint is a ginglymus, or hinge-joint. The structures entering into its formation are the lower end of the tibia and its malleolus, the malleolus of the fibula, and the transverse ligament, which together form a mortise for the reception of the upper convex surface of the talus and its medial and lateral facets. The bones are connected by the following ligaments:

The Articular Capsule.

The Anterior Talofibular.

The Deltoid.

The Posterior Talofibular.

The Calcaneofibular.

 

VIDEO

 

The Articular Capsule (capsula articularis; capsular ligament).The articular capsule surrounds the joints, and is attached, above, to the borders of the articular surfaces of the tibia and malleoli; and below, to the talus around its upper articular surface. The anterior part of the capsule (anterior ligament) is a broad, thin, membranous layer, attached, above, to the anterior margin of the lower end of the tibia; below, to the talus, in front of its superior articular surface. It is in relation, in front, with the Extensor tendons of the toes, the tendons of the Tibialis anterior and Peronæus tertius, and the anterior tibial vessels and deep peroneal nerve. The posterior part of the capsule (posterior ligament) is very thin, and consists principally of transverse fibers. It is attached, above, to the margin of the articular surface of the tibia, blending with the transverse ligament; below, to the talus behind its superior articular facet. Laterally, it is somewhat thickened, and is attached to the hollow on the medial surface of the lateral malleolus.

 

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The ligaments of the foot from the lateral aspect.

 

 

The Deltoid Ligament (ligamentum deltoideum; internal lateral ligament).The deltoid ligament is a strong, flat, triangular band, attached, above, to the apex and anterior and posterior borders of the medial malleolus. It consists of two sets of fibers, superficial and deep. Of the superficial fibers the most anterior (tibionavicular) pass forward to be inserted into the tuberosity of the navicular bone, and immediately behind this they blend with the medial margin of the plantar calcaneonavicular ligament; the middle (calcaneotibial) descend almost perpendicularly to be inserted into the whole length of the sustentaculum tali of the calcaneus; the posterior fibers (posterior talotibial) pass backward and lateralward to be attached to the inner side of the talus, and to the prominent tubercle on its posterior surface, medial to the groove for the tendon of the Flexor hallucis longus. The deep fibers (anterior talotibial) are attached, above, to the tip of the medial malleolus, and, below, to the medial surface of the talus. The deltoid ligament is covered by the tendons of the Tibialis posterior and Flexor digitorum longus.

  The anterior and posterior talofibular and the calcaneofibular ligaments were formerly described as the three fasciculi of the external lateral ligament of the ankle-joint.

 

The Anterior Talofibular Ligament. (ligamentum talofibulare anterius the shortest of the three, passes from the anterior margin of the fibular malleolus, forward and medially, to the talus, in front of its lateral articular facet.

 

The Posterior Talofibular Ligament (ligamentum talofibulare posterius the strongest and most deeply seated, runs almost horizontally from the depression at the medial and back part of the fibular malleolus to a prominent tubercle on the posterior surface of the talus immediately lateral to the groove for the tendon of the Flexor hallucis longus.

 

The Calcaneofibular Ligament (ligamentum calcaneofibulare) the longest of the three, is a narrow, rounded cord, running from the apex of the fibular malleolus downward and slightly backward to a tubercle on the lateral surface of the calcaneus. It is covered by the tendons of the Peronæi longus and brevis.

 

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Capsule of left talocrura articulation (distended). Lateral aspect.

 

 

Synovial Membrane invests the deep surfaces of the ligaments, and sends a small process upward between the lower ends of the tibia and fibula.

 

Relations.The tendons, vessels, and nerves in connection with the joint are, in front, from the medial side, the Tibialis anterior, Extensor hallucis proprius, anterior tibial vessels, deep peroneal nerve, Extensor digitorum longus, and Peronæus tertius; behind, from the medial side, the Tibialis posterior, Flexor digitorum longus, posterior tibial vessels, tibial nerve, Flexor hallucis longus; and, in the groove behind the fibular malleolus, the tendons of the Peronæi longus and brevis.

  The arteries supplying the joint are derived from the malleolar branches of the anterior tibial and the peroneal.

  The nerves are derived from the deep peroneal and tibial.

 

Movements.When the body is in the erect position, the foot is at right angles to the leg. The movements of the joint are those of dorsiflexion and extension; dorsiflexion consists in the approximation of the dorsum of the foot to the front of the leg, while in extension the heel is drawn up and the toes pointed downward. The range of movement varies in different individuals from about 50 to 90. The transverse axis about which movement takes place is slightly oblique. The malleoli tightly embrace the talus in all positions of the joint, so that any slight degree of side-to-side movement which may exist is simply due to stretching of the ligaments of the talofibular syndesmosis, and slight bending of the body of the fibula. The superior articular surface of the talus is broader in front than behind. In dorsiflexion, herefore, greater space is required between the two malleoli. This is obtained by a slight outward rotatory movement of the lower end of the fibula and a stretching of the ligaments of the syndesmosis; this lateral movement is facilitated by a slight gliding at the tibiofibular articulation, and possibly also by the bending of the body of the fibula. Of the ligaments, the deltoid is of very great powerso much so, that it usually resists a force which fractures the process of bone to which it is attached. Its middle portion, together with the calcaneofibular ligament, binds the bones of the leg firmly to the foot, and resists displacement in every direction. Its anterior and posterior fibers limit extension and flexion of the foot respectively, and the anterior fibers also limit abduction. The posterior talofibular ligament assists the calcaneofibular in resisting the displacement of the foot backward, and deepens the cavity for the reception of the talus. The anterior talofibular is a security against the displacement of the foot forward, and limits extension of the joint.

  The movements of inversion and eversion of the foot, together with the minute changes in form by which it is applied to the ground or takes hold of an object in climbing, etc., are mainly effected in the tarsal joints; the joint which enjoys the greatest amount of motion being that between the talus and calcaneus behind and the navicular and cuboid in front. This is often called the transverse tarsal joint, and it can, with the subordinate joints of the tarsus, replace the ankle-joint in a great measure when the latter has become ankylosed.

  Extension of the foot upon the tibia and fibula is produced by the Gastrocnemius, Soleus, Plantaris, Tibialis posterior, Peronæi longus and brevis, Flexor digitorum longus, and Flexor hallucis longus; dorsiflexion, by the Tibialis anterior, Peronæus tertius, Extensor digitorum longus, and Extensor hallucis proprius.

 

Intertarsal Articulations (Articulationes Intertarseæ; Articulations of the Tarsus)

 

Talocalcaneal Articulation (articulatio talocalcanea; articulation of the calcaneus and astragalus; calcaneo-astragaloid articulation).The articulations between the calcaneus and talus are two in numberanterior and posterior. Of these, the anterior forms part of the talocalcaneonavicular joint, and will be described with that articulation. The posterior or talocalcaneal articulation is formed between the posterior calcaneal facet on the inferior surface of the talus, and the posterior facet on the superior surface of the calcaneus. It is an arthrodial joint, and the two bones are connected by an articular capsule and by anterior, posterior, lateral, medial, and interosseous talocalcaneal ligaments.

 

The Articular Capsule (capsula articularis).The articular capsule envelops the joint, and consists for the most part of the short fibers, which are split up into distinct slips; between these there is only a weak fibrous investment.

 

The Anterior Talocalcaneal Ligament (ligamentum talocalcaneum anterius; anterior calcaneo-astragaloid ligament) extends from the front and lateral surface of the neck of the talus to the superior surface of the calcaneus. It forms the posterior boundary of the talocalcaneonavicular joint, and is sometimes described as the anterior interosseous ligament.

 

The Posterior Talocalcaneal Ligament (ligamentum talocalcaneum posterius; posterior calcaneo-astragaloid ligament) connects the lateral tubercle of the talus with the upper and medial part of the calcaneus; it is a short band, and its fibers radiate from their narrow attachment to the talus.

 

The Lateral Talocalcaneal Ligament (ligamentum talocalcaneum laterale; external calcaneo-astragaloid ligament) is a short, strong fasciculus, passing from the lateral surface of the talus, immediately beneath its fibular facet to the lateral surface of the calcaneus. It is placed in front of, but on a deeper plane than, the calcaneofibular ligament, with the fibers of which it is parallel.

 

The Medial Talocalcaneal Ligament (ligamentum talocalcaneum mediale; internal calcaneo-astragaloid ligament connects the medial tubercle of the back of the talus with the back of the sustentaculum tali. Its fibers blend with those of the plantar calcaneonavicular ligament.

 

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Coronal section through right talocrural and talocalcaneal joints.

 

 

The Interosseous Talocalcaneal Ligament (ligamentum talocalcaneum interosseum).The interosseous talocalcaneal ligament forms the chief bond of union between the bones. It is, in fact, a portion of the united capsules of the talocalcaneonavicular and the talocalcaneal joints, and consists of two partially united layers of fibers, one belonging to the former and the other to the latter joint. It is attached, above, to the groove between the articular facets of the under surface of the talus; below, to a corresponding depression on the upper surface of the calcaneus. It is very thick and strong, being at least 2.5 cm. in breadth from side to side, and serves to bind the calcaneus and talus firmly together.

 

Synovial Membrane lines the capsule of the joint, and is distinct from the other synovial membranes of the tarsus.

 

Movements.The movements permitted between the talus and calcaneus are limited to gliding of the one bone on the other backward and forward and from side to side.

 

Talocalcaneonavicular Articulation (articulatio talocalcaneonavicularis).This articulation is an arthrodial joint: the rounded head of the talus being received into the concavity formed by the posterior surface of the navicular, the anterior articular surface of the calcaneus, and the upper surface of the planter calcaneonavicular ligament. There are two ligaments in this joint: the articular capsule and the dorsal talonavicular.

 

The Articular Capsule (capsula articularis).The articular capsule is imperfectly developed except posteriorly, where it is considerably thickened and forms, with a part of the capsule of the talocalcaneal joint, the strong interosseous ligament which fills in the canal formed by the opposing grooves on the calcaneus and talus, as above mentioned.

 

The Dorsal Talonavicular Ligament (ligamentum talonaviculare dorsale; superior astragalonavicular ligament) is a broad, thin band, which connects the neck of the talus to the dorsal surface of the navicular bone; it is covered by the Extensor tendons. The plantar calcaneonavicular supplies the place of a plantar ligament for this joint.

 

Synovial Membrane.The synovial membrane lines all parts of the capsule of the joint.

 Movements.This articulation permits of a considerable range of gliding movements, and some rotation; its feeble construction allows occasionally of dislocation of the other bones of the tarsus from the talus.

 Calcaneocuboid Articulation (articulatio calcaneocuboidea; articulation of the calcaneus with the cuboid).The ligaments connecting the calcaneus with the cuboid are five in number, viz., the articular capsule, the dorsal calcaneocuboid, part of the bifurcated, the long plantar, and the plantar calcaneocuboid.

 The Articular Capsule (capsula articularis).The articular capsule is an imperfectly developed investment, containing certain strengthened bands, which form the other ligaments of the joint.

 

The Dorsal Calcaneocuboid Ligament (ligamentum calcaneocuboideum dorsale; superior calcaneocuboid ligament) is a thin but broad fasciculus, which passes between the contiguous surfaces of the calcaneus and cuboid, on the dorsal surface of the joint.

 

The Bifurcated Ligament (ligamentum bifurcatum; internal calcaneocuboid; interosseous ligament) is a strong band, attached behind to the deep hollow on the upper surface of the calcaneus and dividing in front in a Y-shaped manner into a calcaneocuboid and a calcaneonavicular part. The calcaneocuboid part is fixed to the medial side of the cuboid and forms one of the principal bonds between the first and second rows of the tarsal bones. The calcaneonavicular part is attached to the lateral side of the navicular.

 

The Long Plantar Ligament (ligamentum plantare longum; long calcaneocuboid ligament; superficial long plantar ligament).The long plantar ligament is the longest of all the ligaments of the tarsus: it is attached behind to the plantar surface of the calcaneus in front of the tuberosity, and in front to the tuberosity on the plantar surface of the cuboid bone, the more superficial fibers being continued forward to the bases of the second, third, and fourth metatarsal bones. This ligament converts the groove on the plantar surface of the cuboid into a canal for the tendon of the Peronæus longus.

 

The Plantar Calcaneocuboid Ligament (ligamentum calcaneocuboideum plantare; short calcaneocuboid ligament; short plantar ligament).The plantar calcaneocuboid ligament lies nearer to the bones than the preceding, from which it is separated by a little areolar tissue. It is a short but wide band of great strength, and extends from the tubercle and the depression in front of it, on the forepart of the plantar surface of the calcaneus, to the plantar surface of the cuboid behind the peroneal groove.

 

Synovial Membrane.The synovial membrane lines the inner surface of the capsule and is distinct from that of the other tarsal articulations.

 

Movements.The movements permitted between the calcaneus and cuboid are limited to slight gliding movements of the bones upon each other.

  The transverse tarsal joint is formed by the articulation of the calcaneus with the cuboid, and the articulation of the talus with the navicular. The movement which takes place in this joint is more extensive than that in the other tarsal joints, and consists of a sort of rotation by means of which the foot may be slightly flexed or extended, the sole being at the same time carried medially (inverted) or laterally (everted).

 

The Ligaments Connecting the Calcaneus and Navicular.Though the calcaneus and navicular do not directly articulate, they are connected by two ligaments: the calcaneonavicular part of the bifurcated, and the plantar calcaneonavicular.

  The calcaneonavicular part of the bifurcated ligament is described on page 354.

 

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Ligaments of the sole of the foot, with the tendons of the Peronæus longus, Tibialis posterior and Tibialis anterior muscles.

 

 

The Plantar Calcaneonavicular Ligament (ligamentum calcaneonaviculare plantare; inferior or internal calcaneonavicular ligament; calcaneonavicular ligament) is a broad and thick band of fibers, which connects the anterior margin of the sustentaculum tali of the calcaneus to the plantar surface of the navicular. This ligament not only serves to connect the calcaneus and navicular, but supports the head of the talus, forming part of the articular cavity in which it is received. The dorsal surface of the ligament presents a fibrocartilaginous facet, lined by the synovial membrane, and upon this a portion of the head of the talus rests. Its plantar surface is supported by the tendon of the Tibialis posterior; its medial border is blended with the forepart of the deltoid ligament of the ankle-joint.

 

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Talocalcaneal and talocalcaneonavicular articulations exposed from above by removing the talus.

 

  The plantar calcaneonavicular ligament, by supporting the head of the talus, is principally concerned in maintaining the arch of the foot. When it yields, the head of the talus is pressed downward, medialward, and forward by the weight of the body, and the foot becomes flattened, expanded, and turned lateralward, and exhibits the condition known as flat-foot. This ligament contains a considerable amount of elastic fibers, so as to give elasticity to the arch and spring to the foot; hence it is sometimes called the spring ligament. It is supported, on its plantar surface, by the tendon of the Tibialis posterior, which spreads out at its insertion into a number of fasciculi, to be attached to most of the tarsal and metatarsal bones. This prevents undue stretching of the ligament, and is a protection against the occurrence of flat-foot; hence muscular weakness is, in most cases, the primary cause of the deformity.

 Cuneonavicular Articulation (articulatio cuneonavicularis; articulation of the navicular with the cuneiform bones).The navicular is connected to the three cuneiform bones by dorsal and plantar ligaments.

 The Dorsal Ligaments (ligamenta navicularicuneiformia dorsalia).The dorsal ligaments are three small bundles, one attached to each of the cuneiform bones. The bundle connecting the navicular with the first cuneiform is continuous around the medial side of the articulation with the plantar ligament which unites these two bones.

 The Plantar Ligaments (ligamenta navicularicuneiformia plantaria).The plantar ligaments have a similar arrangement to the dorsal, and are strengthened by slips from the tendon of the Tibialis posterior.

 Synovial Membrane.The synovial membrane of these joints is part of the great tarsal synovial membrane.

 Movements.Mere gliding movements are permitted between the navicular and cuneiform bones.

 Cuboideonavicular Articulation.The navicular bone is connected with the cuboid by dorsal, plantar, and interosseous ligaments.

 The Dorsal Ligament (ligamentum cuboideonaviculare dorsale).The dorsal ligament extends obliquely forward and lateralward from the navicular to the cuboid bone.

 

The Plantar Ligament (ligamentum cuboideonaviculare plantare).The plantar ligament passes nearly transversely between these two bones.

 

The Interosseous Ligament.The interosseous ligament consists of strong transverse fibers, and connects the rough non-articular portions of the adjacent surfaces of the two bones.

 

Synovial Membrane.The synovial membrane of this joint is part of the great tarsal synovial membrane.

 

Movements.The movements permitted between the navicular and cuboid bones are limited to a slight gliding upon each other.

 

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Oblique section of left intertarsal and tarsometatarsal articulations, showing the synovial cavities.

 

 

Intercuneiform and Cuneocuboid Articulations.The three cuneiform bones and the cuboid are connected together by dorsal, plantar, and interosseous ligaments.

 

The Dorsal Ligaments (ligamenta intercuneiformia dorsalia).The dorsal ligaments consist of three transverse bands: one connects the first with the second cuneiform, another the second with the third cuneiform, and another the third cuneiform with the cuboid.

 

The Plantar Ligaments (ligamenta intercuneiformia plantaria).The plantar ligaments have a similar arrangement to the dorsal, and are strengthened by slips from the tendon of the Tibialis posterior.

 

The Interosseous Ligaments (ligamenta intercuneiformia interossea).The interosseous ligaments consist of strong transverse fibers which pass between the rough non-articular portions of the adjacent surfaces of the bones.

 

Synovial Membrane.The synovial membrane of these joints is part of the great tarsal synovial membrane

 

 

Tarsometatarsal Articulations (Articulationes Tarsometatarseæ)



These are arthrodial joints. The bones entering into their formation are the first, second, and third cuneiforms, and the cuboid, which articulate with the bases of the metatarsal bones. The first metatarsal bone articulates with the first cuneiform; the second is deeply wedged in between the first and third cuneiforms articulating by its base with the second cuneiform; the third articulates with the third cuneiform; the fourth, with the cuboid and third cuneiform; and the fifth, with the cuboid. The bones are connected by dorsal, plantar, and interosseous ligaments.

 

The Dorsal Ligaments (ligamenta tarsometatarsea dorsalia).The dorsal ligaments are strong, flat bands. The first metatarsal is joined to the first cuneiform by a broad, thin band; the second has three, one from each cuneiform bone; the third has one from the third cuneiform; the fourth has one from the third cuneiform and one from the cuboid; and the fifth, one from the cuboid.

 

The Plantar Ligaments (ligamenta tarsometatarsea plantaria).The plantar ligaments consist of longitudinal and oblique bands, disposed with less regularity than the dorsal ligaments. Those for the first and second metatarsals are the strongest; the second and third metatarsals are joined by oblique bands to the first cuneiform; the fourth and fifth metatarsals are connected by a few fibers to the cuboid.

 

The Interosseous Ligaments (ligamenta cuneometatarsea interossia).

  The interosseous ligaments are three in number. The first is the strongest, and passes from the lateral surface of the first cuneiform to the adjacent angle of the second metatarsal. The second connects the third cuneiform with the adjacent angle of the second metatarsal. The third connects the lateral angle of the third cuneiform with the adjacent side of the base of the third metatarsal.

 Synovial Membrane between the first cuneiform and the first metatarsal forms a distinct sac. The synovial membrane between the second and third cuneiforms behind, and the second and third metatarsal bones in front, is part of the great tarsal synovial membrane. Two prolongations are sent forward from it, one between the adjacent sides of the second and third, and another between those of the third and fourth metatarsal bones. The synovial membrane between the cuboid and the fourth and fifth metatarsal bones forms a distinct sac. From it a prolongation is sent forward between the fourth and fifth metatarsal bones.

 Movements.The movements permitted between the tarsal and metatarsal bones are limited to slight gliding of the bones upon each other.

 

Metatarsophalangeal Articulations (Articulationes Metatarsophalangeæ)


The metatarsophalangeal articulations are of the condyloid kind, formed by the reception of the rounded heads of the metatarsal bones in shallow cavities on the ends of the first phalanges.

  The ligaments are the plantar and two collateral.

 

The Plantar Ligaments (ligamenta accessoria plantaria; glenoid ligaments of Cruveilhier).The plantar ligaments are thick, dense, fibrous structures. They are placed on the plantar surfaces of the joints in the intervals between the collateral ligaments, to which they are connected; they are loosely united to the metatarsal bones, but very firmly to the bases of the first phalanges. Their plantar surfaces are intimately blended with the transverse metatarsal ligament, and grooved for the passage of the Flexor tendons, the sheaths surrounding which are connected to the sides of the grooves. Their deep surfaces form part of the articular facets for the heads of the metatarsal bones, and are lined by synovial membrane.

 

The Collateral Ligaments (ligamenta collateralia; lateral ligaments).The collateral ligaments are strong, rounded cords, placed one on either side of each joint, and attached, by one end, to the posterior tubercle on the side of the head of the metatarsal bone, and, by the other, to the contiguous extremity of the phalanx.

  The place of dorsal ligaments is supplied by the Extensor tendons on the dorsal surfaces of the joints.

 

Movements.The movements permitted in the metatarsophalangeal articulations are flexion, extension, abduction, and adduction.

 

Articulations of the Digits

(Articulationes Digitorum Pedis; Articulations of the Phalanges)


The interphalangeal articulations are ginglymoid joints, and each has a plantar and two collateral ligaments.

  The arrangement of these ligaments is similar to that in the metatarsophalangeal articulations: the Extensor tendons supply the places of dorsal ligaments.

 Movements.The only movements permitted in the joints of the digits are flexion and extension; these movements are more extensive between the first and second phalanges than between the second and third. The amount of flexion is very considerable, but extension is limited by the plantar and collateral ligaments.

Prepared by Reminetskyy B.Y.