Lesson 5

Muscles of the back

Muscles of the thorax and abdomen

MUSCLES OF THE UPPER EXTREMITY

MUSCLES OF THE LOWER EXTREMITY

Muscles of the back subdivide into superficial and deep (proper) groups.

Superficial Back Musculature

1. Trapezius

· Origin:

1. external occipital protuberance

2. along the medial sides of the superior nuchal line

3. ligamentum nuchae (surrounding the cervical spinous processes)

4. spinous processes of C1-T12

· Insertion:

1. posterior, lateral 1/3 of clavicle

2. acromion

3. superior spine of scapula

· Action:

1. elevates scapula

2. upward rotation of the scapula (upper fibers)

3. downward rotation of the scapula (lower fibers)

4. retracts scapula

· Blood: transverse cervical artery

· Nerve:

1. spinal Accessory (XI) (efferent or motor fibers)

2. ventral ramii of C3 & C4 (afferent or sensory fibers)

2. Latissimus dorsi

· Origin:

1. spinous process of T7-L5

2. upper 2-3 sacral segments

3. iliac crest

4. lower 3 or 4 Ribs

· Insertion: lateral lip of the intertubercular groove

· Action:

1. adduction of humerus

2. medial rotation of the humerus

3. extension from flexed position

4. downward rotation of the scapula

· Blood: thoracodorsal artery

· Nerve: thoracodorsal nerve, C6,7,8

3. Rhomboid major

· Origin:

1. spinous processes of T2-T5

2. supraspinous ligament

· Insertion: medial scapula from the scapular spine to the inferior angle

· Action: retract scapula

· Blood:

1. deep branch of transverse cervical artery, OR

2. dorsal scapular artery

· Nerve: dorsal scapular nerve, C5

4. Rhomboid minor

· Origin:

1. spinous process of C7 & T1

2. ligamentum nuchae

3. supraspinous ligament

· Insertion: medial margin of the scapula at the medial angle

· Action: retract scapula

· Blood:

1. deep branch of transverse cervical artery, OR

2. dorsal scapular artery

· Nerve: dorsal scapular nerve, C5, [C4]

5. Levator scapulae

· Origin: transverse processes of C1-C3 or C4

· Insertion: superior angle of scapula toward the scapular spine

· Action:

1. elevates the scapula

2. extends and/or laterally flexes the head

· Blood: transverse cervical artery

· Nerve:

1. nerves off cervical plexus, C3,4

2. dorsal scapular nerve, C5

6. Serratus posterior superior

· Origin: vertebrae C7-Th2

· Insertion: 2-5 ribs

· Action:

1. elevates ribs

· Blood:

1. posterior intercostal art., deep cervical artery upper part

· Nerve: intercostal nernes, Th1-Th4

7. Serratus posterior inferior

· Origin: vertebrae Th11-L2

· Insertion: 8 - 12 ribs

· Action:

1. depresses the ribs

· Blood: posterior intercostal arteries

· Nerve: intercostal nernes, Th9-Th12

Deep Back Musculature

1. Splenius capitis

· Origin:

1. lower portion of ligamentum nuchae

2. spinous processes of C3-T3(4)

· Insertion:

1. superior nuchal line

2. mastoid process of temporal bone

· Action:

1. bilateral contraction: extend head & neck

2. unilateral contraction: rotate and laterally bend head & neck to the contracted (same) side

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

2. Splenius cervicis

· Origin: spinous process of T3-T6

· Insertion: posterior tubercles of transverse processes of C2-C4

· Action:

1. bilateral contraction: extend head & neck

2. unilateral contraction: rotate and laterally bend head & neck to the contracted (same) side

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

3. Erector Spinae Muscles:

Iliocostalis lumborum

· Origin: common tendinous origin: (same for all lower erector spinae)

1. sacrum

2. iliac crest

3. spinous processes of lower thoracic & most lumbar vertebrae

· Insertion: lower border of angles of ribs (5)6-12

· Action: (same for all erector spinae)

1. bilateral:

a. extension of vertebral column

b. maintenance of erect posture

c. stabilization of vertebral column during flexion, acting in contrast to abdominal muscles and the action of gravity

2. unilateral:

a. lateral bend to same side

b. rotation to same side

c. opposite muscles contract eccentrically for stabilization

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Iliocostalis thoracis

· Origin: upper border of ribs 6-12 (medial to I. lumborum's insertion.)

· Insertion: lower border of angles of ribs 1-6 (sometimes transverse process of C7)

· Action: (same for all erector spinae)

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Iliocostalis cervicis

· Origin: angles of ribs 1-6

· Insertion: transverse processes of C4-C6

· Action: (same for all erector spinae)

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Longissimus thoracis

· Origin: common tendinous origin: (same for all lower erector spinae)

1. sacrum

2. iliac crest

3. spinous processes of lower thoracic & most lumbar vertebrae

· Insertion:

1. transverse processes of all thoracic vertebrae

2. all ribs between tubercles and angles

3. transverse processes of upper lumbar vertebrae

· Action: (same for all erector spinae)

1. bilateral:

a. extension of vertebral column

b. maintenance of erect posture (pneumonic = I Like Standing)

c. stabilization of vertebral column during flexion, acting in contrast to abdominal muscles and the action of gravity

2. unilateral:

a. lateral bend to same side

b. rotation to same side

c. opposite muscles contract eccentrically for stabilization

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Longissimus cervicis

· Origin: transverse processes of T1-T5(6)

· Insertion: transverse processes of C2-C6

· Action: (same for all erector spinae)

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Longissimus capitis

· Origin:

1. transverse and articular processes of middle and lower cervical vertebrae

2. transverse processes of upper thoracic vertebrae

· Insertion: posterior aspect of mastoid process of temporal bone

· Action: (same for all erector spinae)

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Spinalis thoracis

· Origin: common tendinous origin: (same for all lower erector spinae)

1. sacrum

2. iliac crest

3. spinous processes of lower thoracic & most lumbar vertebrae

· Insertion: spinous processes T3(4)-T8(9)

· Action: (same for all erector spinae)

1. bilateral:

a. extension of vertebral column

b. maintenance of erect posture (pneumonic = I Like Standing)

c. stabilization of vertebral column during flexion, acting in contrast to abdominal muscles and the action of gravity

2. unilateral:

a. lateral bend to same side

b. rotation to same side

c. opposite muscles contract eccentrically for stabilization

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Spinalis cervicis

· Origin: spinous processes of C6-T2

· Insertion: spinous processes of C2 (and possibly extend to C3 or C4)

· Action: (same for all erector spinae)

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Spinalis capitis

· Origin: spinous processes of lower cervical & upper thoracic vertebrae

· Insertion: between superior & inferior nuchal lines of occipital bone

· Action: (same for all erector spinae)

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

4. Transversospinal Muscles

Semispinalis thoracis

· Origin: transverse processes of T6-T12 vertebrae

· Insertion: spinous processes of upper thoracic & lower cervical vertebrae

· Action:

1. bilaterally extends vertebral column, especially head and neck

2. controls lateral flexion to side opposite contraction (eccentric for stability)

3. maintains head posture

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Semispinalis cervicis

· Origin: transverse processes of T1-T6 vertebrae and can go down to lower thoracic

· Insertion: spinous processes of C2-T5(6)

· Action:

1. bilaterally extends vertebral column, especially head and neck

2. controls lateral flexion to side opposite contraction (eccentric for stability)

3. maintains head posture

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Semispinalis capitus

· Origin:

1. transverse processes of T1-T6

2. articular processes of C4-C7

· Insertion: between superior & inferior nuchal lines of occipital bone

· Action:

1. bilaterally extends vertebral column, especially head and neck

2. controls lateral flexion to side opposite contraction (eccentric for stability)

3. maintains head posture

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Multifidus

· Origin:

· cervical region: from articular processes of lower cervical vertebrae

· thoracic region: from transverse processes of all thoracic vertebrae

· lumbar region:

1. lower portion of dorsal sacrum

2. PSIS

3. deep surface of tendenous origin of erector spinae

4. mamillary processes of all lumbar vertebrae

· Insertion: spinous process of all vertebrae extending from L5 - C2 (skipping 1-3 segments)

· Action:

1. bilaterally extends vertebral column

2. controls lateral flexion to side opposite contraction (eccentric for stability)

3. unilaterally rotate vertebral bodies (column) to opposite side

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Long rotators

· Origin: transverse process of one vertebra

· Insertion: skips one vertebra to insert on the base of spinous process of vertebra above

· Action:

1. rotate to opposite side

2. bilateral extension

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Short rotators

· Origin: transverse process of one vertebra

· Insertion: base of spinous process of vertebra immediately above

· Action:

1. rotate to opposite side

2. bilateral extension

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

Segmental Muscles:

5. Interspinalis

· Origin: spinous processes of each vertebra

· Insertion: to the spinous process of vertebra immediately above

· Action: extension of the vertebrae segments

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

6. Intertransversi

· Origin: (A to A and B to B)

· cervical region:

A. from the anterior tubercle of transverse process

B. from the posterior tubercle of transverse process

· thoracic region: (poorly developed)

· lumbar region:

A. lateral aspect of the transverse process

B. mamillary process

· Insertion:

· cervical region:

· to the anterior tubercle immediately above

· to the posterior tubercle immediately above

· thoracic region: (poorly developed)

· lumber region:

· lateral aspect of the transverse process immediately above

B. to the accessory process on the vertebra immediately above

· Action:

1. laterally flexes each respective pair of vertebrae

2. (also eccentric muscle contraction provides stability)

· Blood: muscular branches of the aorta

· Nerve: dorsal rami of spinal nerves

7. Levators costarum (short and long)

· Origin: cervical and thoracic vertebrae

· Insertion: ribs

· Action: elevates ribs

· Blood: posterior intercostal artaries

· Nerve: intercostal nernes, C8 - Th1-Th10

8. Suboccipital Musculature

Obliquus capitis inferior

• Origin: spinous process of axis (C2) • Insertion: transverse process of atlas (C1) • Action: rotates the head to the contracted side • Blood: muscular branches of vertebral artery • Nerve: suboccipital nerve, (dorsal rami C1)

Obliquus capitis superior

• Origin: transverse process of atlas (C1) • Insertion: between superior and inferior nuchal line of occiput

• Action: 1.bilaterally extends the head 2.laterally flexes to the contracted side

• Blood: muscular branches of vertebral artery • Nerve: suboccipital nerve, (dorsal rami C1)

Rectus capitis posterior major

• Origin: spinous process of axis (C2) • Insertion: inferior nuchal line (lateral to minor) • Action:

1.bilaterally extends the head 2.rotates the head to the contracted side

• Blood: muscular branches of vertebral artery • Nerve: suboccipital nerve, (dorsal rami C1)

Rectus capitis posterior minor • Origin: posterior tubercle of atlas (C1) • Insertion: inferior nuchal line (adjacent to midline) • Action: bilaterally extends the head • Blood: muscular branches of vertebral artery • Nerve: suboccipital nerve, (dorsal rami C1)

They differ some regions in back: vertebral region, sacral region, scapular region, subscapular region, and lumbar region.

Thoracic region. THE MUSCLES OF THE Thorax. Diaphragm

Muscles of the thorax subdivide into superficial and proper (deep) groups.

Pectoral Musculature

1. Pectoralis major

· Origin:

1. medial 1/3 of clavicle

2. anterior aspect of manubrium & length of body of sternum

3. cartilaginous attachments of upper 6 ribs

4. external oblique's aponeurosis

· Insertion:

1. lateral lip of bicipital groove to the crest of the greater tubercle

2. clavicular fibers insert more distally; sternal fibers more proximally

· Action:

1. adducts humerus

2. medially rotates humerus

3. flexion of the arm from extension (clavicular portion)

· Blood:

1. pectoralis branch of thoracoacromial artery (runs with lateral pec. nerve)

2. lateral thoracic artery (lesser supply, and runs with medial pectoral nerve)

· Nerve:

1. lateral pectoral nerve, C5,6,7 to clavicular portion

2. medial pectoral nerve, C8,T1 to sternal portion

2. Pectoralis minor

· Origin: outer surface of ribs 2-5 or 3-5 or 6

· Insertion: medial aspect of coracoid process of the scapula

· Action:

1. depresses & downwardly rotates the scapula

2. assists in scapular protraction from a retracted position

3. stabilizes the scapula

· Blood: lateral thoracic artery

· Nerve: medial pectoral nerve, C8,T1

3. Subclavius · Origin: first rib about the junction of bone and cartilage

· Insertion: lower surface of clavicle

· Action: assists in stabilizing the clavicle

· Blood: clavicular branch of thoracoacromial artery

· Nerve: nerve to the subclavius, C5,6

4. Serratus anterior

· Origin: fleshy slips from the outer surface of upper 8 or 9 ribs

· Insertion: costal aspect of medial margin of the scapula

· Action:

1. protract scapula

2. stabilize scapula

3. assists in upward rotation

· Blood:

1. lateral thoracic artery supplies the upper part

2. thoracodorsal artery supplies the lower part

· Nerve: long thoracic nerve, C5,6,7

Follow muscles belong to Proper (deep) group of the thorax:

1. External intercostal muscles elevate the ribs

2. Internal intercostal muscles lower ribs

3. Subcostal muscles lower the ribs

4. Transversus thoracis muscles lower the ribs

5. Levators costarum (short and long). They originatefrom cervical and thoracic vertebrae, inserte to ribs. Action: elevates ribs.

Diaphragm - muscular and tendon organ that separates thoracic and abdominal cavities. It has muscular portion and the tendon. Muscular part is divided into three parts: sternal part, costal and lumbar parts. There are weak places where diaphragmatic hernia can be happen – lubocostal and sternocostal tringles. The diaphragm is the dome-shaped sheet of muscle that separates the chest from the abdomen. It is attached to the spine, ribs and sternum and plays a very important role in the breathing process. The lungs are enclosed in a kind of cage in which the ribs form the sides and the diaphragm, an upwardly arching sheet of muscle, forms the floor. When we breathe, the diaphragm is drawn downward until it is flat. At the same time, the muscles around the ribs pull them up like a hoop skirt. The chest cavity becomes deeper and larger, making more air space. The muscle fibers of the diaphragm converge on the central tendon, which is a thick, flat plate of dense fibers. There are openings in the diaphragm for the esophagus (esophageal hiatus), the phrenic nerve (which controls the movements of the diaphragm to produce breathing), and the aorta (aortic hiatus) and vena cava blood vessels (foramen venae cavae inferioris), which lead to and from the heart. When air is drawn into the lungs, the muscles in the diaphragm contract, pulling the central tendon down. This enlarges the chest, and air then passes into the lungs to fill the larger space. The diaphragm sometimes contracts involuntarily because the controlling nerves are irritated by eating too fast (or for some other reason). At this time, if air is inhaled, the space between the vocal cords at the back of the throat close suddenly, producing the clicking noise we call "hiccups."

Breathing

The diaphragm contracts and moves downward elongating the thoracic cavity while the external intercostal muscles contract widening the thoracic cavity causing air to fill the lungs through suction (inspiration). The diaphragm and external intercostal then relax, decreasing the thorax size and reducing lung capacity forcing air out of the lungs (expiration).

THE REGIONS OF THE ABDOMEN. THE MUSCLES OF THE ABDOMEN

The muscles of the abdomen may be divided into two groups: (1) the anterolateral muscles; (2) the posterior muscles.

1. the Antero-lateral Muscles of the Abdomen—The muscles of this group are:

Obliquus externus.

Transversus.

Obliquus internus.

Rectus.

Pyramidalis.

The Obliquus externus abdominis.

  The Obliquus externus abdominis (External or descending oblique muscle) situated on the lateral and anterior parts of the abdomen, is the largest and the most superficial of the three flat muscles in this region. It is broad, thin, and irregularly quadrilateral, its muscular portion occupying the side, its aponeurosis the anterior wall of the abdomen. It arises, by eight fleshy digitations, from the external surfaces and inferior borders of the lower eight ribs; these digitations are arranged in an oblique line which runs downward and backward, the upper ones being attached close to the cartilages of the corresponding ribs, the lowest to the apex of the cartilage of the last rib, the intermediate ones to the ribs at some distance from their cartilages. The five superior serrations increase in size from above downward, and are received between corresponding processes of the Serratus anterior; the three lower ones diminish in size from above downward and receive between them corresponding processes from the Latissimus dorsi. From these attachments the fleshy fibers proceed in various directions. Those from the lowest ribs pass nearly vertically downward, and are inserted into the anterior half of the outer lip of the iliac crest; the middle and upper fibers, directed downward and forward, end in an aponeurosis, opposite a line drawn from the prominence of the ninth costal cartilage to the anterior superior iliac spine.

  The aponeurosis of the Obliquus externus abdominis is a thin but strong membranous structure, the fibers of which are directed downward and medialward. It is joined with that of the opposite muscle along the middle line, and covers the whole of the front of the abdomen; above, it is covered by and gives origin to the lower fibers of the Pectoralis major; below, its fibers are closely aggregated together, and extend obliquely across from the anterior superior iliac spine to the public tubercle and the pectineal line. In the middle line, it interlaces with the aponeurosis of the opposite muscle, forming the linea alba, which extends from the xiphoid process to the symphysis pubis.

  That portion of the aponeurosis which extends between the anterior superior iliac spine and the pubic tubercle is a thick band, folded inward, and continuous below with the fascia lata; it is called the inguinal ligament. The portion which is reflected from the inguinal ligament at the pubic tubercle is attached to the pectineal line and is called the lacunar ligament. From the point of attachment of the latter to the pectineal line, a few fibers pass upward and medialward, behind the medial crus of the subcutaneous inguinal ring, to the linea alba; they diverge as they ascend, and form a thin triangular fibrous band which is called the reflected inguinal ligament.

  In the aponeurosis of the Obliquus externus, immediately above the crest of the pubis, is a triangular opening, the subcutaneous inguinal ring, formed by a separation of the fibers of the aponeurosis in this situation.

  The following structures require further description, viz., the subcutaneous inguinal ring, the intercrural fibers and fascia, and the inguinal, lacunar, and reflected inguinal ligaments.

Variations.—The Obliquus externus may show decrease or doubling of its attachments to the ribs; addition slips from lumbar aponeurosis; doubling between lower ribs and ilium or inguinal ligament. Rarely tendinous inscriptions occur.

  The Obliquus internus abdominis (Internal or ascending oblique muscle) thinner and smaller than the Obliquus externus, beneath which it lies, is of an irregularly quadrilateral form, and situated at the lateral and anterior parts of the abdomen. It arises, by fleshy fibers, from the lateral half of the grooved upper surface of the inguinal ligament, from the anterior two-thirds of the middle lip of the iliac crest, and from the posterior lamella of the lumbodorsal fascia. From this origin the fibers diverge; those from the inguinal ligament, few in number and paler in color than the rest, arch downward and medialward across the spermatic cord in the male and the round ligament of the uterus in the female, and, becoming tendinous, are inserted, conjointly with those of the Transversus, into the crest of the pubis and medial part of the pectineal line behind the lacunar ligament, forming what is known as the inguinal aponeurotic falx. Those from the anterior third of the iliac origin are horizontal in their direction, and, becoming tendinous along the lower fourth of the linea semilunaris, pass in front of the Rectus abdominis to be inserted into the linea alba. Those arising from the middle third of the iliac origin run obliquely upward and medialward, and end in an aponeurosis; this divides at the lateral border of the Rectus into two lamellæ, which are continued forward, one in front of and the other behind this muscle, to the linea alba: the posterior lamella has an attachment to the cartilages of the seventh, eighth, and ninth ribs. The most posterior fibers pass almost vertically upward, to be inserted into the inferior borders of the cartilages of the three lower ribs, being continuous with the Intercostales interni.

The Obliquus internus abdominis.

Variations.—Occasionally, tendinous inscriptions occur from the tips of the tenth or eleventh cartilages or even from the ninth; an additional slip to the ninth cartilage is sometimes found; separation between iliac and inguinal parts may occur.

  The Cremaster is a thin muscular layer, composed of a number of fasciculi which arise from the middle of the inguinal ligament where its fibers are continuous with those of the Obliquus internus and also occasionally with the Transversus. It passes along the lateral side of the spermatic cord, descends with it through the subcutaneous inguinal ring upon the front and sides of the cord, and forms a series of loops which differ in thickness and length in different subjects. At the upper part of the cord the loops are short, but they become in succession longer and longer, the longest reaching down as low as the testis, where a few are inserted into the tunica vaginalis. These loops are united together by areolar tissue, and form a thin covering over the cord and testis, the cremasteric fascia. The fibers ascend along the medial side of the cord, and are inserted by a small pointed tendon into the tubercle and crest of the pubis and into the front of the sheath of the Rectus abdominis.

The Cremaster. 

  The Transversus abdominis (Transversalis muscle) so called from the direction of its fibers, is the most internal of the flat muscles of the abdomen, being placed immediately beneath the Obliquus internus. It arises, by fleshy fibers, from the lateral third of the inguinal ligament, from the anterior three-fourths of the inner lip of the iliac crest, from the inner surfaces of the cartilages of the lower six ribs, interdigitating with the diaphragm, and from the lumbodorsal fascia. The muscle ends in front in a broad aponeurosis, the lower fibers of which curve downward and medialward, and are inserted, together with those of the Obliquus internus, into the crest of the pubis and pectineal line, forming the inguinal aponeurotic falx. Throughout the rest of its extent the aponeurosis passes horizontally to the middle line, and is inserted into the linea alba; its upper three-fourths lie behind the Rectus and blend with the posterior lamella of the aponeurosis of the Obliquus internus; its lower fourth is in front of the Rectus.

Variations.—It may be more or less fused with the Obliquus internus or absent. The spermatic cord may pierce its lower border. Slender muscle slips from the ileopectineal line to transversalis fascia, the aponeurosis of the Transversus abdominis or the outer end of the linea semicircularis and other slender slips are occasionally found.

  The inguinal aponeurotic falx (falx aponeurotica inguinalis; conjoined tendon of Internal oblique and Transversalis muscle) of the Obliquus internus and Transversus is mainly formed by the lower part of the tendon of the Transversus, and is inserted into the crest of the pubis and pectineal line immediately behind the subcutaneous inguinal ring, serving to protect what would otherwise be aweak point in the abdominal wall. Lateral to the falx is a ligamentous band connected with the lower margin of the Transversus and extending down in front of the inferior epigastric artery to the superior ramus of the pubis; it is termed the interfoveolar ligament of Hesselbach and sometimes contains a few muscular fibers.

The Transversus abdominis, Rectus abdominis, and Pyramidalis.

  The Rectus abdominis is a long flat muscle, which extends along the whole length of the front of the abdomen, and is separated from its fellow of the opposite side by the linea alba. It is much broader, but thinner, above than below, and arises by two tendons; the lateral or larger is attached to the crest of the pubis, the medial interlaces with its fellow of the opposite side, and is connected with the ligaments covering the front of the symphysis pubis. The muscle is inserted by three portions of unequal size into the cartilages of the fifth, sixth, and seventh ribs. The upper portion, attached principally to the cartilage of the fifth rib, usually has some fibers of insertion into the anterior extremity of the rib itself. Some fibers are occasionally connected with the costoxiphoid ligaments, and the side of the xiphoid process.

  The Rectus is crossed by fibrous bands, three in number, which are named the tendinous inscriptions; one is usually situated opposite the umbilicus, one at the extremity of the xiphoid process, and the third about midway between the xiphoid process and the umbilicus. These inscriptions pass transversely or obliquely across the muscle in a zigzag course; they rarely extend completely through its substance and may pass only halfway across it; they are intimately adherent in front to the sheath of the muscle. Sometimes one or two additional inscriptions, generally incomplete, are present below the umbilicus.

The interfoveolar ligament, seen from in front.

  The Rectus is enclosed in a sheath formed by the aponeuroses of the Obliqui and Transversus, which are arranged in the following manner. At the lateral margin of the Rectus, the aponeurosis of the Obliquus internus divides into two lamellæ, one of which passes in front of the Rectus, blending with the aponeurosis of the Obliquus externus, the other, behind it, blending with the aponeurosis of the Transversus, and these, joining again at the medial border of the Rectus, are inserted into the linea alba. This arrangement of the aponeurosis exists from the costal margin to midway between the umbilicus and symphysis pubis, where the posterior wall of the sheath ends in a thin curved margin, the linea semicircularis, the concavity of which is directed downward: below this level the aponeuroses of all three muscles pass in front of the Rectus. The Rectus, in the situation where its sheath is deficient below, is separated from the peritoneum by the transversalis fascia. Since the tendons of the Obliquus internus and Transversus only reach as high as the costal margin, it follows that above this level the sheath of the Rectus is deficient behind, the muscle resting directly on the cartilages of the ribs, and being covered merely by the tendon of the Obliquus externus.

  The Pyramidalis is a small triangular muscle, placed at the lower part of the abdomen, in front of the Rectus, and contained in the sheath of that muscle. It arises by tendinous fibers from the front of the pubis and the anterior pubic ligament; the fleshy portion of the muscle passes upward, diminishing in size as it ascends, and ends by a pointed extremity which is inserted into the linea alba, midway between the umbilicus and pubis. This muscle may be wanting on one or both sides; the lower end of the Rectus then becomes proportionately increased in size. Occasionally it is double on one side, and the muscles of the two sides are sometimes of unequal size. It may extend higher than the level stated.

Diagram of sheath of Rectus.

  Besides the Rectus and Pyramidalis, the sheath of the Rectus contains the superior and inferior epigastric arteries, and the lower intercostal nerves.

Variations.—The Rectus may insert as high as the fourth or third rib or may fail to reach the fifth. Fibers may spring from the lower part of the linea alba.

Nerves.—The abdominal muscles are supplied by the lower intercostal nerves. The Obliquus internus and Transversus also receive filaments from the anterior branch of the iliohypogastric and sometimes from the ilioinguinal. The Cremaster is supplied by the external spermatic branch of the genitofemoral and the Pyramidalis usually by the twelfth thoracic.

The Linea Alba.—The linea alba is a tendinous raphé in the middle line of the abdomen, stretching between the xiphoid process and the symphysis pubis. It is placed between the medial borders of the Recti, and is formed by the blending of the aponeuroses of the Obliqui and Transversi. It is narrow below, corresponding to the linear interval existing between the Recti; but broader above, where these muscles diverge from one another. At its lower end the linea alba has a double attachment—its superficial fibers passing in front of the medial heads of the Recti to the symphysis pubis, while its deeper fibers form a triangular lamella, attached behind the Recti to the posterior lip of the crest of the pubis, and named the adminiculum lineæ albæ. It presents apertures for the passage of vessels and nerves; the umbilicus, which in the fetus exists as an aperture and transmits the umbilical vessels, is closed in the adult.

Diagram of a transverse section through the anterior abdomina wall, below the linea semicircularis.

The Lineæ Semilunares.—The lineæ semilunares are two curved tendinous lines placed one on either side of the linea alba. Each corresponds with the lateral border of the Rectus, extends from the cartilage of the ninth rib to the pubic tubercle, and is formed by the aponeurosis of the Obliquus internus at its line of division to enclose the Rectus, reinforced in front by that of the Obliquus externus, and behind by that of the Transversus.

Actions.—When the pelvis and thorax are fixed, the abdominal muscles compress the abdominal viscera by constricting the cavity of the abdomen, in which action they are materially assisted by the descent of the diaphragm. By these means assistance is given in expelling the feces from the rectum, the urine from the bladder, the fetus from the uterus, and the contents of the stomach in vomiting.

  If the pelvis and vertebral column be fixed, these muscles compress the lower part of the thorax, materially assisting expiration. If the pelvis alone be fixed, the thorax is bent directly forward, when the muscles of both sides act; when the muscles of only one side contract, the trunk is bent toward that side and rotated toward the opposite side.

  If the thorax be fixed, the muscles, acting together, draw the pelvis upward, as in climbing; or, acting singly, they draw the pelvis upward, and bend the vertebral column to one side or the other. The Recti, acting from below, depress the thorax, and consequently flex the vertebral column; when acting from above, they flex the pelvis upon the vertebral column. The Pyramidales are tensors of the linea alba.

The Transversalis Fascia.—The transversalis fascia is a thin aponeurotic membrane which lies between the inner surface of the Transversus and the extraperitoneal fat. It forms part of the general layer of fascia lining the abdominal parietes, and is directly continuous with the iliac and pelvic fasciæ. In the inguinal region, the transversalis fascia is thick and dense in structure and is joined by fibers from the aponeurosis of the Transversus, but it becomes thin as it ascends to the diaphragm, and blends with the fascia covering the under surface of this muscle. Behind, it is lost in the fat which covers the posterior surfaces of the kidneys. Below, it has the following attachments: posteriorly, to the whole length of the iliac crest, between the attachments of the Transversus and Iliacus; between the anterior superior iliac spine and the femoral vessels it is connected to the posterior margin of the inguinal ligament, and is there continuous with the iliac fascia. Medial to the femoral vessels it is thin and attached to the pubis and pectineal line, behind the inguinal aponeurotic falx, with which it is united; it descends in front of the femoral vessels to form the anterior wall of the femoral sheath. Beneath the inguinal ligament it is strengthened by a band of fibrous tissue, which is only loosely connected to the ligament, and is specialized as the deep crural arch. The spermatic cord in the male and the round ligament of the uterus in the female pass through the transversalis fascia at a spot called the abdominal inguinal ring. This opening is not visible externally, since the transversalis fascia is prolonged on these structures as the infundibuliform fascia.

The Abdominal Inguinal Ring (annulus inguinalis abdominis; internal or deep abdominal ring).—The abdominal inguinal ring is situated in the transversalis fascia, midway between the anterior superior iliac spine and the symphysis pubis, and about 1.25 cm. above the inguinal ligament. It is of an oval form, the long axis of the oval being vertical; it varies in size in different subjects, and is much larger in the male than in the female. It is bounded, above and laterally, by the arched lower margin of the Transversus; below and medially, by the inferior epigastric vessels. It transmits the spermatic cord in the male and the round ligament of the uterus in the female. From its circumference a thin funnel-shaped membrane, the infundibuliform fascia, is continued around the cord and testis, enclosing them in a distinct covering.

The Inguinal Canal (canalis inguinalis; spermatic canal).—The inguinal canal contains the spermatic cord and the ilioinguinal nerve in the male, and the round ligament of the uterus and the ilioinguinal nerve in the female. It is an oblique canal about 4 cm. long, slanting downward and medialward, and placed parallel with and a little above the inguinal ligament; it extends from the abdominal inguinal ring to the subcutaneous inguinal ring. It is bounded, in front, by the integument and superficial fascia, by the aponeurosis of the Obliquus externus throughout its whole length, and by the Obliquus internus in its lateral third; behind, by the reflected inguinal ligament, the inguinal aponeurotic falx, the transversalis fascia, the extraperitoneal connective tissue and the peritoneum; above, by the arched fibers of Obliquus internus and Transversus abdominis; below, by the union of the transversalis fascia with the inguinal ligament, and at its medial end by the lacunar ligament.

Extraperitoneal Connective Tissue.—Between the inner surface of the general layer of the fascia which lines the interior of the abdominal and pelvic cavities, and the peritoneum, there is a considerable amount of connective tissue, termed the extraperitoneal or subperitoneal connective tissue.

  The parietal portion lines the cavity in varying quantities in different situations. It is especially abundant on the posterior wall of the abdomen, and particularly around the kidneys, where it contains much fat. On the anterior wall of the abdomen, except in the public region, and on the lateral wall above the iliac crest, it is scanty, and here the transversalis fascia is more closely connected with the peritoneum. There is a considerable amount of extraperitoneal connective tissue in the pelvis.

  The visceral portion follows the course of the branches of the abdominal aorta between the layers of the mesenterics and other folds of peritoneum which connect the various viscera to the abdominal wall. The two portions are directly continuous with each other.

The abdominal inguinal ring.

The Deep Crural Arch.—Curving over the external iliac vessels, at the spot where they become femoral, on the abdominal side of the inguinal ligaments and loosely connected with it, is a thickened band of fibers called the deep crural arch. It is apparently a thickening of the transversalis fascia joined laterally to the center of the lower margin of the inguinal ligament, and arching across the front of the femoral sheath to be inserted by a broad attachment into the pubic tubercle and pectineal line, behind the inguinal aponeurotic falx. In some subjects this structure is not very prominently marked, and not infrequently it is altogether wanting.

2. The Posterior Muscles of the Abdomen

Quadratus lumborum.

  The Psoas major, the Psoas minor, and the Iliacus, with the fasciæ covering them, will be described with the muscles of the lower extremity (see page 466).

The Fascia Covering the Quadratus Lumborum.—This is a thin layer attached, medially, to the bases of the transverse processes of the lumbar vertebræ; below, to the iliolumbar ligament; above, to the apex and lower border of the last rib. The upper margin of this fascia, which extends from the transverse process of the first lumbar vertebra to the apex and lower border of the last rib, constitutes the lateral lumbocostal arch (page 405). Laterally, it blends with the lumbodorsal fascia, the anterior layer of which intervenes between the Quadratus lumborum and the Sacrospinalis.

  The Quadratus lumborum is irregularly quadrilateral in shape, and broader below than above. It arises by aponeurotic fibers from the iliolumbar ligament and the adjacent portion of the iliac crest for about 5 cm., and is inserted into the lower border of the last rib for about half its length, and by four small tendons into the apices of the transverse processes of the upper four lumbar vertebræ. Occasionally a second portion of this muscle is found in front of the preceding. It arises from the upper borders of the transverse processes of the lower three or four lumbar vertebræ, and is inserted into the lower margin of the last rib. In front of the Quadratus lumborum are the colon, the kidney, the Psoas major and minor, and the diaphragm; between the fascia and the muscle are the twelfth thoracic, ilioinguinal, and iliohypogastric nerves.

Variations.—The number of attachments to the vertebræ and the extent of its attachment to the last rib vary.

Nerve Supply.—The twelfth thoracic and first and second lumbar nerves supply this muscle.

Actions.—The Quadratus lumborum draws down the last rib, and acts as a muscle of inspiration by helping to fix the origin of the diaphragm. If the thorax and vertebral column are fixed, it may act upon the pelvis, raising it toward its own side when only one muscle is put in action; and when both muscles act together, either from below or above, they flex the trunk.

The Inguinal Canal (canalis inguinalis; spermatic canal).—The inguinal canal contains the spermatic cord and the ilioinguinal nerve in the male, and the round ligament of the uterus and the ilioinguinal nerve in the female. It is an oblique canal about 4 cm. long, slanting downward and medialward, and placed parallel with and a little above the inguinal ligament; it extends from the abdominal inguinal ring to the subcutaneous inguinal ring. It is bounded, in front, by the integument and superficial fascia, by the aponeurosis of the Obliquus externus throughout its whole length, and by the Obliquus internus in its lateral third; behind, by the reflected inguinal ligament, the inguinal aponeurotic falx, the transversalis fascia, the extraperitoneal connective tissue and the peritoneum; above, by the arched fibers of Obliquus internus and Transversus abdominis; below, by the union of the transversalis fascia with the inguinal ligament, and at its medial end by the lacunar ligament.

Extraperitoneal Connective Tissue.—Between the inner surface of the general layer of the fascia which lines the interior of the abdominal and pelvic cavities, and the peritoneum, there is a considerable amount of connective tissue, termed the extraperitoneal or subperitoneal connective tissue.

  The parietal portion lines the cavity in varying quantities in different situations. It is especially abundant on the posterior wall of the abdomen, and particularly around the kidneys, where it contains much fat. On the anterior wall of the abdomen, except in the public region, and on the lateral wall above the iliac crest, it is scanty, and here the transversalis fascia is more closely connected with the peritoneum. There is a considerable amount of extraperitoneal connective tissue in the pelvis.

  The visceral portion follows the course of the branches of the abdominal aorta between the layers of the mesenterics and other folds of peritoneum which connect the various viscera to the abdominal wall. The two portions are directly continuous with each other.

The abdominal inguinal ring.

The Deep Crural Arch.—Curving over the external iliac vessels, at the spot where they become femoral, on the abdominal side of the inguinal ligaments and loosely connected with it, is a thickened band of fibers called the deep crural arch. It is apparently a thickening of the transversalis fascia joined laterally to the center of the lower margin of the inguinal ligament, and arching across the front of the femoral sheath to be inserted by a broad attachment into the pubic tubercle and pectineal line, behind the inguinal aponeurotic falx. In some subjects this structure is not very prominently marked, and not infrequently it is altogether wanting.

They differ some regions in abdomen:

In Epigastrium (upper floor) –

Right Hypochondriac Epigastric, Left Hypochondriac regions

In Mesogastrium (middle floor) –

Right Lateral, Umbilical and Left Lateral regions

In Hypogastrium (lower floor) –

Right Inguinal, Pubic and Left Inguinal regions

Fossae and folds on back surface of front abdominal wall

Back surface of front abdominal wall is covered by parietal sheet of peritoneum and carries unpaired median umbilical fold (plicae) and paired – medial and lateral umbilical folds (plicae). Medial umbilical fossa projected into superficial inguinal ring, which positioned between medial and lateral umbilical folds. Straight inguinal herniae can pass through this fossa. Lateral umbilical fossa placed laterally from lateral umbilical fold. It answers the deep inguinal ring and during pathologic cases can contain oblique inguinal herniae. There is supravesical fossa between median and medial umbilical folds.

Musculature of upper limb

Musculature of upper limb divides into muscles of the shoulder girdle and free limb.

Shoulder Girdle Musculature

Deltoid

· Origin:

1. lateral, anterior 1/3 of distal clavicle

2. lateral boarder of the acromion

3. scapular spine

· Insertion: deltoid tuberosity of humerus

· Action:

1. abducts arm

2. flexion and medial rotation (anterior portion)

3. extension and lateral rotation (posterior portion)

· Blood:

1. posterior humeral circumflex artery

2. deltoid branch of thoracoacromial artery

· Nerve: axillary nerve, C5,6

Supraspinatus

· Origin:

1. supraspinous fossa

2. muscle fascia

· Insertion: uppermost of three facets of the greater tubercle of humerus

· Action:

1. abduction of arm (first 15-20°)

2. stabilizes glenohumeral joint

· Blood: suprascapular artery (poorly supplied)

· Nerve: suprascapular nerve, C5,6

Infraspinatus

· Origin:

1. infraspinous fossa

2. muscle fascia

· Insertion: middle facet of greater tubercle of humerus

· Action:

1. external rotation of the humerus

2. stabilizes the glenohumeral joint

· Blood:

1. suprascapular artery

2. scapular circumflex artery

· Nerve: suprascapular nerve, C5,6

Teres minor

· Origin: middle half of the scapula’s lateral margin

· Insertion: lowest of three facets of the greater tubercle of humerus

· Action:

1. lateral rotation of the humerus

2. stabilizes the glenohumeral joint

· Blood: scapular circumflex artery

· Nerve: axillary nerve, C5,6

Teres major

· Origin: inferior, lateral margin of the scapula

· Insertion: crest of lesser tubercle (just medial to the insertion of latissimus dorsi)

· Action:

1. assists in adduction of arm

2. assists in medial rotation of arm

3. assists in extension from an flexed position

· Blood: thoracodorsal artery

· Nerve: lower subscapular nerve, C5,6

Subscapularis

· Origin: subscapular fossa

· Insertion: lesser tubercle of humerus

· Action:

1. medial rotation of the humerus

2. stabilizes the glenohumeral joint

· Blood: Branches of subscapular artery

· Nerve: upper & lower subscapular nerves, C5,6

Brachium (arm) Musculature

ANTERIOR GROUP

Coracobrachialis

• Origin: coracoid process of the scapula • Insertion: medial shaft of the humerus at about its middle • Action:

1.flexes the humerus 2.assists to adduct the humerus

• Blood: muscular branches of the brachial artery • Nerve: musculocutaneous nerve, C5,6,(C7)

Biceps brachii

• Origin:

1.long head- supraglenoid tubercle and glenohumeral labrum 2.short head- tip of the coracoid process of the scapula

• Insertion:

1.radial tuberosity 2.bicipital aponeurosis

• Action:

1.flexes the forearm at the elbow (when supinated) 2.supinates forearm from neutral 3.stabilizes anterior aspect of shoulder 4.flexes shoulder (weak if at all)

• Blood: muscular branches of brachial artery • Nerve: musculocutaneous nerve, C5,6

Brachialis

• Origin:

1.lower 1/2 of anterior humerus 2.both intermuscular septa

• Insertion:

1.ulnar tuberosity 2.coronoid process of ulna slightly

• Action: elbow flexion (major mover) • Blood:

1.muscular branches of brachial artery 2.radial recurrent artery

• Nerve: musculocutaneous nerve, C5,6

POSTERIOR GROUP

Triceps brachii

• Origin:

1.long head - infraglenoid tubercle of the scapula 2.lateral head - upper half of the posterior surface of the shaft of the humerus, and the upper part of the lateral intermuscular septum 3.medial head - posterior shaft of humerus, distal to radial groove and both the medial and lateral intermuscular septum (deep to the long & lateral heads)

• Insertion:

1.posterior surface of the olecranon process of the ulna 2.deep fascia of the antebrachium

• Action:

1.long - adducts the arm, extends at the shoulder, and a little elbow flexion 2.lateral - extends the forearm at the elbow 3.medial - extends the forearm at the elbow

• Blood:

1.muscular branches of the brachial artery 2.superior ulnar collateral artery 3.profunda brachii artery

• Nerve: radial nerve, C6,7

Cross-section through the middle of upper arm. (Eycleshymer and Schoemaker.)

Anconeus

• Origin: posterior surface of the lateral epicondyle of the humerus • Insertion: lateral aspect of olecranon extending to the lateral part of ulnar body • Action:

1.extends the forearm at the elbow 2.supports the elbow when in full extension

• Blood: middle collateral artery from the profunda brachii artery • Nerve: radial nerve, C7,8

Theme 2. THE MUSCLES OF THE FOREARM AND HAND.

The antibrachial or forearm muscles may be divided into a volar and a dorsal group.

The Volar Antibrachial Muscles—These muscles are divided for convenience of description into two groups, superficial and deep.

The Superficial Group

Pronator teres.

Palmaris longus.

Flexor carpi radialis.

Flexor carpi ulnaris.

Flexor digitorum sublimis.

  The muscles of this group take origin from the medial epicondyle of the humerus by a common tendon; they receive additional fibers from the deep fascia of the forearm near the elbow, and from the septa which pass from this fascia between the individual muscles.

  The Pronator teres has two heads of origin—humeral and ulnar. The humeral head, the larger and more superficial, arises immediately above the medial epicondyle, and from the tendon common to the origin of the other muscles; also from the intermuscular septum between it and the Flexor carpi radialis and from the antibrachial fascia. The ulnar head is a thin fasciculus, which arises from the medial side of the coronoid process of the ulna, and joins the preceding at an acute angle. The median nerve enters the forearm between the two heads of the muscle, and is separated from the ulnar artery by the ulnar head. The muscle passes obliquely across the forearm, and ends in a flat tendon, which is inserted into a rough impression at the middle of the lateral surface of the body of the radius. The lateral border of the muscle forms the medial boundary of a triangular hollow situated in front of the elbow-joint and containing the brachial artery, median nerve, and tendon of the Biceps brachii.

Variations.—Absence of ulnar head; additional slips from the medial intermuscular septum, from the Biceps and from the Brachialis anticus occasionally occur.

  The Flexor carpi radialis lies on the medial side of the preceding muscle. It arises from the medial epicondyle by the common tendon; from the fascia of the forearm; and from the intermuscular septa between it and the Pronator teres laterally, the Palmaris longus medially, and the Flexor digitorum sublimis beneath. Slender and aponeurotic in structure at its commencement, it increases in size, and ends in a tendon which forms rather more than the lower half of its length. This tendon passes through a canal in the lateral part of the transverse carpal ligament and runs through a groove on the greater multangular bone; the groove is converted into a canal by fibrous tissue, and lined by a mucous sheath. The tendon is inserted into the base of the second metacarpal bone, and sends a slip to the base of the third metacarpal bone. The radial artery, in the lower part of the forearm, lies between the tendon of this muscle and the Brachioradialis.

Variations.—Slips from the tendon of the Biceps, the lacertus fibrosus, the coronoid, and the radius have been found. Its insertion often varies and may be mostly into the annular ligament, the trapezium, or the fourth metacarpal as well as the second or third. The muscle may be absent.

  The Palmaris longus is a slender, fusiform muscle, lying on the medial side of the preceding. It arises from the medial epicondyle of the humerus by the common tendon, from the intermuscular septa between it and the adjacent muscles, and from the antibrachial fascia. It ends in a slender, flattened tendon, which passes over the upper part of the transverse carpal ligament, and is inserted into the central part of the transverse carpal ligament and lower part of the palmar aponeurosis, frequently sending a tendinous slip to the short muscles of the thumb.

Variations.—One of the most variable muscles in the body. This muscle is often absent about (10 per cent.), and is subject to many variations; it may be tendinous above and muscular below; or it may be muscular in the center with a tendon above and below; or it may present two muscular bundles with a central tendon; or finally it may consist solely of a tendinous band. The muscle may be double. Slips of origin from the coronoid process or from the radius have been seen.Partial or complete insertion into the fascia of the forearm, into the tendon of the Flexor carpi ulnaris and pisiform bone, into the navicular, and into the muscles of the little finger have been observed.

Front of the left forearm. Superficial muscles.

Front of the left forearm. Deep muscles.

  The Flexor carpi ulnaris lies along the ulnar side of the forearm. It arises by two heads, humeral and ulnar, connected by a tendinous arch, beneath which the ulnar nerve and posterior ulnar recurrent artery pass. The humeral head arises from the medial epicondyle of the humerus by the common tendon; the ulnar head arises from the medial margin of the olecranon and from the upper two-thirds of the dorsal border of the ulna by an aponeurosis, common to it and the Extensor carpi ulnaris and Flexor digitorum profundus; and from the intermuscular septum between it and the Flexor digitorum sublimis. The fibers end in a tendon, which occupies the anterior part of the lower half of the muscle and is inserted into the pisiform bone, and is prolonged from this to the hamate and fifth metacarpal bones by the pisohamate and pisometacarpal ligaments; it is also attached by a few fibers to the transverse carpal ligament. The ulnar vessels and nerve lie on the lateral side of the tendon of this muscle, in the lower two-thirds of the forearm.

Variations.—Slips of origin from the coronoid. The Epitrochleo-anconæus, a small muscle often present runs from the back of the inner condyle to the olecranon, over the ulnar nerve.

  The Flexor digitorum is placed beneath the previous muscle; it is the largest of the muscles of the superficial group, and arises by three heads—humeral, ulnar, and radial. The humeral head arises from the medial epicondyle of the humerus by the common tendon, from the ulnar collateral ligament of the elbow-joint, and from the intermuscular septa between it and the preceding muscles. The ulnar head arises from the medial side of the coronoid process, above the ulnar origin of the Pronator teres. The radial head arises from the oblique line of the radius, extending from the radial tuberosity to the insertion of the Pronator teres. The muscle speedily separates into two planes of muscular fibers, superficial and deep: the superficial plane divides into two parts which end in tendons for the middle and ring fingers; the deep plane gives off a muscular slip to join the portion of the superficial plane which is associated with the tendon of the ring finger, and then divides into two parts, which end in tendons for the index and little fingers. As the four tendons thus formed pass beneath the transverse carpal ligament into the palm of the hand, they are arranged in pairs, the superficial pair going to the middle and ring fingers, the deep pair to the index and little fingers. The tendons diverge from one another in the palm and form dorsal relations to the superficial volar arch and digital branches of the median and ulnar nerves. Opposite the bases of the first phalanges each tendon divides into two slips to allow of the passage of the corresponding tendon of the Flexor digitorum profundus; the two slips then reunite and form a grooved channel for the reception of the accompanying tendon of the Flexor digitorum profundus. Finally the tendon divides and is inserted into the sides of the second phalanx about its middle.

Variations.—Absence of radial head, of little finger portion; accessory slips from ulnar tuberosity to the index and middle finger portions; from the inner head to the Flexor profundus; from the ulnar or annular ligament to the little finger.

The Deep Group

Flexor digitorum profundus.

Flexor pollicis longus.

Pronator quadratus.

  The Flexor digitorum profundus is situated on the ulnar side of the forearm, immediately beneath the superficial Flexors. It arises from the upper three-fourths of the volar and medial surfaces of the body of the ulna, embracing the insertion of the Brachialis above, and extending below to within a short distance of the Pronator quadratus. It also arises from a depression on the medial side of the coronoid process; by an aponeurosis from the upper three-fourths of the dorsal border of the ulna, in common with the Flexor and Extensor carpi ulnaris; and from the ulnar half of the interosseous membrane. The muscle ends in four tendons which run under the transverse carpal ligament dorsal to the tendons of the Flexor digitorum sublimis. Opposite the first phalanges the tendons pass through the openings in the tendons of the Flexor digitorum sublimis, and are finally inserted into the bases of the last phalanges. The portion of the muscle for the index finger is usually distinct throughout, but the tendons for the middle, ring, and little fingers are connected together by areolar tissue and tendinous slips, as far as the palm of the hand.

Variations.—The index finger portion may arise partly from the upper part of the radius. Slips from the inner head of the Flexor sublimis, medial epicondyle, or the coronoid are found. Connection with the Flexor pollicis longus.

  Four small muscles, the Lumbricales, are connected with the tendons of the Flexor profundus in the palm. They will be described with the muscles of the hand.

  The Flexor pollicis longus is situated on the radial side of the forearm, lying in the same plane as the preceding. It arises from the grooved volar surface of the body of the radius, extending from immediately below the tuberosity and oblique line to within a short distance of the Pronator quadratus. It arises also from the adjacent part of the interosseous membrane, and generally by a fleshy slip from the medial border of the coronoid process, or from the medial epicondyle of the humerus. The fibers end in a flattened tendon, which passes beneath the transverse carpal ligament, is then lodged between the lateral head of the Flexor pollicis brevis and the oblique part of the Adductor pollicis, and, entering an osseoaponeurotic canal similar to those for the Flexor tendons of the fingers, is inserted into the base of the distal phalanx of the thumb. The volar interosseous nerve and vessels pass downward on the front of the interosseous membrane between the Flexor pollicis longus and Flexor digitorum profundus.

Variations.—Slips may connect with Flexor sublimis, or Profundus, or Pronator teres. An additional tendon to the index finger is sometimes found.

  The Pronator quadratus is a small, flat, quadrilateral muscle, extending across the front of the lower parts of the radius and ulna. It arises from the pronator ridge on the lower part of the volar surface of the body of the ulna; from the medial part of the volar surface of the lower fourth of the ulna; and from a strong aponeurosis which covers the medial third of the muscle. The fibers pass lateralward and slightly downward, to be inserted into the lower fourth of the lateral border and the volar surface of the body of the radius. The deeper fibers of the muscle are inserted into the triangular area above the ulnar notch of the radius—an attachment comparable with the origin of the Supinator from the triangular area below the radial notch of the ulna.

Tendons of forefinger and vincula tendina.

Variations.—Rarely absent; split into two or three layers; increased attachment upward or downward.

Nerves.—All the muscles of the superficial layer are supplied by the median nerve, excepting the Flexor carpi ulnaris, which is supplied by the ulnar. The Pronator teres, the Flexor carpi radialis, and the Palmaris longus derive their supply primarily from the sixth cervical nerve; the Flexor digitorum sublimis from the seventh and eighth cervical and first thoracic nerves, and the Flexor carpi ulnaris from the eighth cervical and first thoracic. Of the deep layer, the Flexor digitorum profundus is supplied by the eighth cervical and first thoracic through the ulnar, and the volar interosseous branch of the median. The Flexor pollicis longus and Pronator quadratus are supplied by the eighth cervical and first thoracic through the volar interosseous branch of the median.

Actions.—These muscles act upon the forearm, the wrist, and hand. The Pronator teres rotates the radius upon the ulna, rendering the hand prone; when the radius is fixed, it assists in flexing the forearm. The Flexor carpi radialis is a flexor and abductor of the wrist; it also assists in pronating the hand, and in bending the elbow. The Flexor carpi ulnaris is a flexor and adductor of the wrist; it also assists in bending the elbow. The Palmaris longus is a flexor of the wrist-joint; it also assists in flexing the elbow. The Flexor digitorum sublimis flexes first the middle and then the proximal phalanges; it also assists in flexing the wrist and elbow. The Flexor digitorum profundus is one of the flexors of the phalanges. After the Flexor sublimis has bent the second phalanx, the Flexor profundus flexes the terminal one; but it cannot do so until after the contraction of the superficial muscle. It also assists in flexing the wrist. The Flexor pollicis longus is a flexor of the phalanges of the thumb; when the thumb is fixed, it assists in flexing the wrist. The Pronator quadratus rotates the radius upon the ulna, rendering the hand prone.

Cross-section through the middle of the forearm.

2. The Dorsal Antibrachial Muscles—These muscles are divided for convenience of description into two groups, superficial and deep.

The Superficial Group

Brachioradialis.

Extensor digitorum communis.

Extensor carpi radialis longus.

Extensor digiti quinti proprius.

Extensor carpi radialis brevis.

Extensor carpi ulnaris.

Anconæus.

  The Brachioradialis (Supinator longus) is the most superficial muscle on the radial side of the forearm. It arises from the upper two-thirds of the lateral supracondylar ridge of the humerus, and from the lateral intermuscular septum, being limited above by the groove for the radial nerve. Interposed between it and the Brachialis are the radial nerve and the anastomosis between the anterior branch of the profunda artery and the radial recurrent. The fibers end above the middle of the forearm in a flat tendon, which is inserted into the lateral side of the base of the styloid process of the radius. The tendon is crossed near its insertion by the tendons of the Abductor pollicis longus and Extensor pollicis brevis; on its ulnar side is the radial artery.

Variations.—Fusion with the Brachialis; tendon of insertion may be divided into two or three slips; insertion partial or complete into the middle of the radius, fasciculi to the tendon of the Biceps, the tuberosity or oblique line of the radius; slips to the Extensor carpi radialis longus or Abductor pollicis longus; absence; rarely doubled.

  The Extensor carpi radialis longus (Extensor carpi radialis longior) is placed partly beneath the Brachioradialis. It arises from the lower third of the lateral supracondylar ridge of the humerus, from the lateral intermuscular septum, and by a few fibers from the common tendon of origin of the Extensor muscles of the forearm. The fibers end at the upper third of the forearm in a flat tendon, which runs along the lateral border of the radius, beneath the Abductor pollicis longus and Extensor pollicis brevis; it then passes beneath the dorsal carpal ligament, where it lies in a groove on the back of the radius common to it and the Extensor carpi radialis brevis, immediately behind the styloid process. It is inserted into the dorsal surface of the base of the second metacarpal bone, on its radial side.

  The Extensor carpi radialis brevis (Extensor carpi radialis brevior) is shorter and thicker than the preceding muscle, beneath which it is placed. It arises from the lateral epicondyle of the humerus, by a tendon common to it and the three following muscles; from the radial collateral ligament of the elbow-joint; from a strong aponeurosis which covers its surface; and from the intermuscular septa between it and the adjacent muscles. The fibers end about the middle of the forearm in a flat tendon, which is closely connected with that of the preceding muscle, and accompanies it to the wrist; it passes beneath the Abductor pollicis longus and Extensor pollicis brevis, then beneath the dorsal carpal ligament, and is inserted into the dorsal surface of the base of the third metacarpal bone on its radial side. Under the dorsal carpal ligament the tendon lies on the back of the radius in a shallow groove, to the ulnar side of that which lodges the tendon of the Extensor carpi radialis, longus, and separated from it by a faint ridge.

  The tendons of the two preceding muscles pass through the same compartment of the dorsal carpal ligament in a single mucous sheath.

Variations.—Either muscle may split into two or three tendons of insertion to the second and third or even the fourth metacarpal. The two muscles may unite into a single belly with two tendons. Cross slips between the two muscles may occur. The Extensor carpi radialis intermedius rarely arises as a distinct muscle from the humerus, but is not uncommon as an accessory slip from one or both muscles to the second or third or both metacarpals. The Extensor carpi radialis accessorius is occasionally found arising from the humerus with or below the Extensor carpi radialis longus and inserted into the first metacarpal, the Abductor pollicis brevis, the First dorsal interosseous, or elsewhere.

  The Extensor digitorum communis arises from the lateral epicondyle of the humerus, by the common tendon; from the intermuscular septa between it and the adjacent muscles, and from the antibrachial fascia. It divides below into four tendons, which pass, together with that of the Extensor indicis proprius, through a separate compartment of the dorsal carpal ligament, within a mucous sheath. The tendons then diverge on the back of the hand, and are inserted into the second and third phalanges of the fingers in the following manner. Opposite the metacarpophalangeal articulation each tendon is bound by fasciculi to the collateral ligaments and serves as the dorsal ligament of this joint; after having crossed the joint, it spreads out into a broad aponeurosis, which covers the dorsal surface of the first phalanx and is reinforced, in this situation, by the tendons of the Interossei and Lumbricalis. Opposite the first interphalangeal joint this aponeurosis divides into three slips; an intermediate and two collateral: the former is inserted into the base of the second phalanx; and the two collateral, which are continued onward along the sides of the second phalanx, unite by their contiguous margins, and are inserted into the dorsal surface of the last phalanx. As the tendons cross the interphalangeal joints, they furnish them with dorsal ligaments. The tendon to the index finger is accompanied by the Extensor indicis proprius, which lies on its ulnar side. On the back of the hand, the tendons to the middle, ring, and little fingers are connected by two obliquely placed bands, one from the third tendon passing downward and lateralward to the second tendon, and the other passing from the same tendon downward and medialward to the fourth. Occasionally the first tendon is connected to the second by a thin transverse band.

Posterior surface of the forearm. Superficial muscles.

Posterior surface of the forearm. Deep muscles.

Variations.—An increase or decrease in the number of tendons is common; an additional slip to the thumb is sometimes present.

  The Extensor digiti quinti proprius (Extensor minimi digiti) is a slender muscle placed on the medial side of the Extensor digitorum communis, with which it is generally connected. It arises from the common Extensor tendon by a thin tendinous slip, from the intermuscular septa between it and the adjacent muscles. Its tendon runs through a compartment of the dorsal carpal ligament behind the distal radio-ulnar joint, then divides into two as it crosses the hand, and finally joins the expansion of the Extensor digitorum communis tendon on the dorsum of the first phalanx of the little finger.

Variations.—An additional fibrous slip from the lateral epicondyle; the tendon of insertion may not divide or may send a slip to the ring finger. Absence of muscle rare; fusion of the belly with the Extensor digitorum communis not uncommon.

  The Extensor carpi ulnaris lies on the ulnar side of the forearm. It arises from the lateral epicondyle of the humerus, by the common tendon; by an aponeurosis from the dorsal border of the ulna in common with the Flexor carpi ulnaris and the Flexor digitorum profundus; and from the deep fascia of the forearm. It ends in a tendon, which runs in a groove between the head and the styloid process of the ulna, passing through a separate compartment of the dorsal carpal ligament, and is inserted into the prominent tubercle on the ulnar side of the base of the fifth metacarpal bone.

Variations.—Doubling; reduction to tendinous band; insertion partially into fourth metacarpal. In many cases (52 per cent.) a slip is continued from the insertion of the tendon anteriorly over the Opponens digiti quinti, to the fascia covering that muscle, the metacarpal bone, the capsule of the metacarpophalangeal articulation, or the first phalanx of the little finger. This slip may be replaced by a muscular fasciculus arising from or near the pisiform.

  The Anconæus is a small triangular muscle which is placed on the back of the elbow-joint, and appears to be a continuation of the Triceps brachii. It arises by a separate tendon from the back part of the lateral epicondyle of the humerus; its fibers diverge and are inserted into the side of the olecranon, and upper fourth of the dorsal surface of the body of the ulna.

The Deep Group

Supinator.

Extensor pollicis brevis.

Abductor pollicis longus.

Extensor pollicis longus.

Extensor indicis proprius.

  The Supinator (Supinator brevis) is a broad muscle, curved around the upper third of the radius. It consists of two planes of fibers, between which the deep branch of the radial nerve lies. The two planes arise in common—the superficial one by tendinous and the deeper by muscular fibers—from the lateral epicondyle of the humerus; from the radial collateral ligament of the elbow-joint, and the annular ligament; from the ridge on the ulna, which runs obliquely downward from the dorsal end of the radial notch; from the triangular depression below the notch; and from a tendinous expansion which covers the surface of the muscle. The superficial fibers surround the upper part of the radius, and are inserted into the lateral edge of the radial tuberosity and the oblique line of the radius, as low down as the insertion of the Pronator teres. The upper fibers of the deeper plane form a sling-like fasciculus, which encircles the neck of the radius above the tuberosity and is attached to the back part of its medial surface; the greater part of this portion of the muscle is inserted into the dorsal and lateral surfaces of the body of the radius, midway between the oblique line and the head of the bone.

  The Abductor pollicis longus (Extensor oss. metacarpi pollicis) lies immediately below the Supinator and is sometimes united with it. It arises from the lateral part of the dorsal surface of the body of the ulna below the insertion of the Anconæus, from the interosseous membrane, and from the middle third of the dorsal surface of the body of the radius. Passing obliquely downward and lateralward, it ends in a tendon, which runs through a groove on the lateral side of the lower end of the radius, accompanied by the tendon of the Extensor pollicis brevis, and is inserted into the radial side of the base of the first metacarpal bone. It occasionally gives off two slips near its insertion: one to the greater multangular bone and the other to blend with the origin of the Abductor pollicis brevis.

Variations.—More or less doubling of muscle and tendon with insertion of the extra tendon into the first metacarpal, the greater multangular, or into the Abductor pollicis brevis or Opponens pollicis.

The Supinator.

  The Extensor pollicis brevis (Extensor primi internodii pollicis) lies on the medial side of, and is closely connected with, the Abductor pollicis longus. It arises from the dorsal surface of the body of the radius below that muscle, and from the interosseous membrane. Its direction is similar to that of the Abductor pollicis longus, its tendon passing the same groove on the lateral side of the lower end of the radius, to be inserted into the base of the first phalanx of the thumb.

Variations.—Absence; fusion of tendon with that of the Extensor pollicis longus.

  The Extensor pollicis longus (Extensor secundi internodii pollicis) is much larger than the preceding muscle, the origin of which it partly covers. It arises from the lateral part of the middle third of the dorsal surface of the body of the ulna below the origin of the Abductor pollicis longus, and from the interosseous membrane. It ends in a tendon, which passes through a separate compartment in the dorsal carpal ligament, lying in a narrow, oblique groove on the back of the lower end of the radius. It then crosses obliquely the tendons of the Extensores carpi radialis longus and brevis, and is separated from the Extensor brevis pollicis by a triangular interval, in which the radial artery is found; and is finally inserted into the base of the last phalanx of the thumb. The radial artery is crossed by the tendons of the Abductor pollicis longus and of the Extensores pollicis longus and brevis.

  The Extensor indicis proprius (Extensor indicis) is a narrow, elongated muscle, placed medial to, and parallel with, the preceding. It arises, from the dorsal surface of the body of the ulna below the origin of the Extensor pollicis longus, and from the interosseous membrane. Its tendon passes under the dorsal carpal ligament in the same compartment as that which transmits the tendons of the Extensor digitorum communis, and opposite the head of the second metacarpal bone, joins the ulnar side of the tendon of the Extensor digitorum communis which belongs to the index finger.

Variations.—Doubling; the ulnar part may pass beneath the dorsal carpal ligament with the Extensor digitorum communis; a slip from the tendon may pass to the index finger.

Nerves.—The Brachioradialis is supplied by the fifth and sixth, the Extensores carpi radialis longus and brevis by the sixth and seventh, and the Anconæus by the seventh and eighth cervical nerves, through the radial nerve; the remaining muscles are innervated through the deep radial nerve, the Supinator being supplied by the sixth, and all the other muscles by the seventh cervical.

Actions.—The muscles of the lateral and dorsal aspects of the forearm, which comprise all the Extensor muscles and the Supinator, act upon the forearm, wrist, and hand; they are the direct antagonists of the Pronator and Flexor muscles. The Anconæus assists the Triceps in extending the forearm. The Brachioradialis is a flexor of the elbow-joint, but only acts as such when the movement of flexion has been initiated by the Biceps brachii and Brachialis. The action of the Supinator is suggested by its name; it assists the Biceps in bringing the hand into the supine position. The Extensor carpi radialis longus extends the wrist and abducts the hand. It may also assist in bending the elbow-joint; at all events it serves to fix or steady this articulation. The Extensor carpi radialis brevis extends the wrist, and may also act slightly as an abductor of the hand. The Extensor carpi ulnaris extends the wrist, but when acting alone inclines the hand toward the ulnar side; by its continued action it extends the elbow-joint. The Extensor digitorum communis extends the phalanges, then the wrist, and finally the elbow. It acts principally on the proximal phalanges, the middle and terminal phalanges being extended mainly by the Interossei and Lumbricales. It tends to separate the fingers as it extends them. The Extensor digiti quinti proprius extends the little finger, and by its continued action assists in extending the wrist. It is owing to this muscle that the little finger can be extended or pointed while the others are flexed. The chief action of the Abductor pollicis longus is to carry the thumb laterally from the palm of the hand. By its continued action it helps to extend and abduct the wrist. The Extensor pollicis brevis extends the proximal phalanx, and the Extensor pollicis longus the terminal phalanx of the thumb; by their continued action they help to extend and abduct the wrist. The Extensor indicis proprius extends the index finger, and by its continued action assists in extending the wrist.

2. The Medial Volar Muscles

Palmaris brevis.

Flexor digiti quinti brevis.

Abductor digiti quinti.

Opponens digiti quinti.

  The Palmaris brevis is a thin, quadrilateral muscle, placed beneath the integument of the ulnar side of the hand. It arises by tendinous fasciculi from the transverse carpal ligament and palmar aponeurosis; the fleshy fibers are inserted into the skin on the ulnar border of the palm of the hand.

FIG. 427– The muscles of the left hand. Palmar surface. (See enlarged image)

  The Abductor digiti quinti (Abductor minimi digiti) is situated on the ulnar border of the palm of the hand. It arises from the pisiform bone and from the tendon of the Flexor carpi ulnaris, and ends in a flat tendon, which divides into two slips; one is inserted into the ulnar side of the base of the first phalanx of the little finger; the other into the ulnar border of the aponeurosis of the Extensor digiti quinti proprius.

  The Flexor digiti quinti brevis (Flexor brevis minimi digiti) lies on the same plane as the preceding muscle, on its radial side. It arises from the convex surface of the hamulus of the hamate bone, and the volar surface of the transverse carpal ligament, and is inserted into the ulnar side of the base of the first phalanx of the little finger. It is separated from the Abductor, at its origin, by the deep branches of the ulnar artery and nerve. This muscle is sometimes wanting; the Abductor is then, usually, of large size.

  The Opponens digiti quinti (Opponens minimi digiti) (Fig. 426) is of a triangular form, and placed immediately beneath the preceding muscles. It arises from the convexity of the hamulus of the hamate bone, and contiguous portion of the transverse carpal ligament; it is inserted into the whole length of the metacarpal bone of the little finger, along its ulnar margin.

Variations.—The Palmaris brevis varies greatly in size. The Abductor digiti quinti may be divided into two or three slips or united with the Flexor digiti quinti brevis. Accessory head from the tendon of the Flexor carpi ulnaris, the transverse carpal ligament, the fascia of the forearm or the tendon of the Palmaris longus. A portion of the muscle may insert into the metacarpal, or separate slips the Pisimetacarpus, Pisiuncinatus or the Pisiannularis muscle may exist.

Nerves.—All the muscles of this group are supplied by the eighth cervical nerve through the ulnar nerve.

Actions.—The Abductor and Flexor digiti quinti brevis abduct the little finger from the ring finger and assist in flexing the proximal phalanx. The Opponens digiti quinti draws forward the fifth metacarpal bone, so as to deepen the hollow of the palm. The Palmaris brevis corrugates the skin on the ulnar side of the palm.

3. The Intermediate Muscles

Lumbricales.

Interossei.

  The Lumbricales (Fig. 427) are four small fleshy fasciculi, associated with the tendons of the Flexor digitorum profundus. The first and second arise from the radial sides and volar surfaces of the tendons of the index and middle fingers respectively; the third, from the contiguous sides of the tendons of the middle and ring fingers; and the fourth, from the contiguous sides of the tendons of the ring and little fingers. Each passes to the radial side of the corresponding finger, and opposite the metacarpophalangeal articulation is inserted into the tendinous expansion of the Extensor digitorum communis covering the dorsal aspect of the finger.

Variations.—The Lumbricales vary in number from two to five or six and there is considerable variation in insertions.

  The Interossei (Figs. 428, 429) are so named from occupying the intervals between the metacarpal bones, and are divided into two sets, a dorsal and a volar.

  The Interossei dorsales (Dorsal interossei) are four in number, and occupy the intervals between the metacarpal bones. They are bipenniform muscles, each arising by two heads from the adjacent sides of the metacarpal bones, but more extensively from the metacarpal bone of the finger into which the muscle is inserted. They are inserted into the bases of the first phalanges and into the aponeuroses of the tendons of the Extensor digitorum communis. Between the double origin of each of these muscles is a narrow triangular interval; through the first of these the radial artery passes; through each of the other three a perforating branch from the deep volar arch is transmitted.

  The first or Abductor indicis is larger than the others. It is flat, triangular in form, and arises by two heads, separated by a fibrous arch for the passage of the radial artery from the dorsum to the palm of the hand. The lateral head arises from the proximal half of the ulnar border of the first metacarpal bone; the medial head, from almost the entire length of the radial border of the second metacarpal bone; the tendon is inserted into the radial side of the index finger. The second and third are inserted into the middle finger, the former into its radial, the latter into its ulnar side. The fourth is inserted into the ulnar side of the ring finger.

The Interossei volares (Palmar interossei), three in number, are smaller than the Interossei dorsales, and placed upon the volar surfaces of the metacarpal bones, rather than between them. Each arises from the entire length of the metacarpal bone of one finger, and is inserted into the side of the base of the first phalanx and aponeurotic expansion of the Extensor communis tendon to the same finger.

  The first arises from the ulnar side of the second metacarpal bone, and is inserted into the same side of the first phalanx of the index finger. The second arises from the radial side of the fourth metacarpal bone, and is inserted into the same side of the ring finger. The third arises from the radial side of the fifth metacarpal bone, and is inserted into the same side of the little finger. From this account it may be seen that each finger is provided with two Interossei, with the exception of the little finger, in which the Abductor takes the place of one of the pair.

  As already mentioned (p. 461), the medial head of the Flexor pollicis brevis is sometimes described as the Interosseus volaris primus.

The Interossei dorsales of left hand.

The Interossei volares of left hand.

Nerves.—The two lateral Lumbricales are supplied by the sixth and seventh cervical nerves, through the third and fourth digital branches of the median nerve; the two medial Lumbricales and all the Interossei are supplied by the eighth cervical nerve, through the deep palmar branch of the ulnar nerve. The third Lumbricalis frequently receives a twig from the median.

Actions.—The Interossei volares adduct the fingers to an imaginary line drawn longitudinally through the center of the middle finger; and the Interossei dorsales abduct the fingers from that line. In addition to this the Interossei, in conjunction with the Lumbricales, flex the first phalanges at the metacarpophalangeal joints, and extend the second and third phalanges in consequence of their insertions into the expansions of the Extensor tendons. The Extensor digitorum communis is believed to act almost entirely on the first phalanges.

References:

TEXTBOOKS REQUIRED

1.Author David Shier, Jackie Butler, Ricki Lewis Number Of Pages 640 pages Format Hardcover Publication Date 2011-01-11 Language English PublisherMcGraw-Hill Higher Education

2.Synopses of Human Anatomy and Physiology.

Author: Elaine N. Marieb, Katja N. Hoehn Anatomy, Physiology Edition Description: Revised Special Attributes: International Edition, Brand New, College Textbook, Publication Year: 2011

3.Human Anatomy & Physiology (9th Edition) [Hardcover]

Elaine N. Marieb (Author), Katja N Hoehn (Author), Publication Date: January 16, 2012

4.Hole’s essentials of human anatomy and physiology. - 7th edition / David Shier, Jackie, Ricki Lewis. McGraw-Hill Companies, 2000.

5.Human Anatomy and Physiology, 6th edition / Elaine Marieb Seeley, Stephens, and Tate. Anatomy and Physiology, 5th edition, McGraw-Hill Publishing, 2000.

6.Functional Human Anatomy / Edition 1, by David T. Lindsay, Carol D. Rodgers, Jaci Vanheest, 1996 or newest edition

7.Synopsis of Human Anatomy And Physiology / Kent M. Van De Graaff , Stuart Ira Fox , Karen M. Lafleur // Mcgraw-Hill College (December 10, 1996)

Optional Textbook Supplements:

Miller-Keane. Encyclopedia and Dictionary of Medicine, Nursing, & Allied Health, 6th edition, W. B. Saunders Company, 1997. Accompanying CD Rom is REQUIRED.