1. THE SHEATH OF THE RECTUS muscle. LINEA ALBA. PRELUM
ABDOMINALE. THE INGUINAL CANAL AND THE OTHER WEAK PLACES OF THE ABDOMINAL WALL
2. THE MUSCLES OF THE HEAD AND NECK.
3. THE TOPOGRAPHY AND
FASCIAE OF THE HEAD AND NECK
Lesson ¹ 9
Theme 1. THE SHEATH OF THE RECTUS muscle. LINEA
ALBA. PRELUM ABDOMINALE. THE INGUINAL CANAL AND THE OTHER WEAK PLACES OF
THE ABDOMINAL WALL
The Superficial Fascia.—The superficial fascia of the abdomen consists, over the
greater part of the abdominal wall, of a single layer containing a variable
amount of fat; but near the groin it is easily divisible into two layers,
between which are found the superficial vessels and nerves and the superficial
inguinal lymph glands.
The superficial layer (fascia of
Camper) is thick, areolar in texture, and contains in its meshes a varying
quantity of adipose tissue. Below, it passes over the inguinal ligament, and is
continuous with the superficial fascia of the thigh. In the male, Camper’s
fascia is continued over the penis and outer surface of the spermatic cord to
the scrotum, where it helps to form the dartos. As it
passes to the scrotum it changes its characteristics, becoming thin, destitute
of adipose tissue, and of a pale reddish color, and
in the scrotum it acquires some involuntary muscular fibers.
From the scrotum it may be traced backward into continuity with the superficial
fascia of the perineum. In the female, Camper’s fascia is continued from the
abdomen into the labia majora.
The deep layer (fascia of Scarpa) is thinner and more membranous in character
than the superficial, and contains a considerable quantity of yellow elastic fibers. It is loosely connected by areolar tissue to the aponeurosis of the Obliquus externus abdominis, but in the middle
line it is more intimately adherent to the linea alba
and to the symphysis pubis, and is prolonged on to
the dorsum of the penis, forming the fundiform
ligament; above, it is continuous with the superficial fascia over the rest of
the trunk; below and laterally, it blends with the fascia lata
of the thigh a little below the inguinal ligament; medially and below, it is
continued over the penis and spermatic cord to the scrotum, where it helps to
form the dartos. From the scrotum it may be traced
backward into continuity with the deep layer of the superficial fascia of the
perineum (fascia of Colles). In the female, it
is continued into the labia majora and thence to the
fascia of Colles.
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.
The Subcutaneous Inguinal Ring (annulus inguinalis subcutaneus; external
abdominal ring) is an interval in the aponeurosis of the Obliquus externus, just above and lateral to the crest of the pubis.
The aperture is oblique in direction, somewhat triangular in form, and
corresponds with the course of the fibers of the aponeurosis. It usually measures from base to apex about
The subcutaneous inguinal ring gives
passage to the spermatic cord and ilioinguinal nerve
in the male, and to the round ligament of the uterus and the ilioinguinal nerve in the female; it is much larger in men
than in women, on account of the large size of the spermatic cord.
The Intercrural Fibers (fibræ intercrurales; intercolumnar fibers).—The intercrural fibers are a series
of curved tendinous fibers,
which arch across the lower part of the aponeurosis
of the Obliquus externus,
describing curves with the convexities downward. They have received their name
from stretching across between the two crura of the
subcutaneous inguinal ring, and they are much thicker and stronger at the
inferior crus, where they are connected to the inguinal ligament, than
superiorly, where they are inserted into the linea
alba. The intercrural fibers
increase the strength of the lower part of the aponeurosis,
and prevent the divergence of the crura from one
another; they are more strongly developed in the male than in the female.
As they pass across the subcutaneous
inguinal ring, they are connected together by delicate fibrous tissue, forming
a fascia, called the intercrural fascia.
This intercrural fascia is continued down as a
tubular prolongation around the spermatic cord and testis, and encloses them in
a sheath; hence it is also called the external spermatic fascia. The
subcutaneous inguinal ring is seen as a distinct aperture only after the intercrural fascia has been removed.
The subcutaneous inguinal ring.
The Inguinal Ligament (ligamentum
inguinale [Pouparti];
Poupart’s ligament) is the lower border of the aponeurosis of the Obliquus externus, and extends
from the anterior superior iliac spine to the pubic tubercle. From this latter
point it is reflected backward and lateralward to be
attached to the pectineal line for about
The Lacunar Ligament (ligamentum
lacunare [Gimbernati];
Gimbernat’s ligament) is that part of the aponeurosis of the Obliquus externus which is
reflected backward and lateralward, and is attached
to the pectineal line. It is about
The Reflected Inguinal Ligament (ligamentum
inguinale reflexum [Collesi]; triangular fascia).—The reflected inguinal ligament is a layer of tendinous
fibers of a triangular shape, formed by an expansion
from the lacunar ligament and the inferior crus of the subcutaneous inguinal
ring. It passes medialward behind the spermatic cord,
and expands into a somewhat fan-shaped band, lying behind the superior crus of
the subcutaneous inguinal ring, and in front of the inguinal aponeurotic falx, and interlaces
with the ligament of the other side of the linea
alba.
Ligament of Cooper.—This
is a strong fibrous band, which was first described by Sir Astley
Cooper. It extends lateralward from the base of the
lacunar ligament along the pectineal line, to which
it is attached. It is strengthened by the pectineal
fascia, and by a lateral expansion from the lower attachment of the linea alba (adminiculum
lineæ albæ).
The inguinal and lacunar ligaments.
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 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
The
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.
Theme 2. THE MUSCLES OF THE HEAD AND NECK
The Fasciæ and Muscles
of the Head. a. The Muscles of the Scalp
Epicranius
The Skin of the Scalp.—This
is thicker than in any other part of the body. It is intimately adherent to the
superficial fascia, which attaches it firmly to the underlying aponeurosis and muscle. Movements of the muscle move the
skin. The hair follicles are very closely set together, and extend throughout
the whole thickness of the skin. It also contains a
number of sebaceous glands.
The superficial fascia in the cranial region is
a firm, dense, fibro-fatty layer, intimately adherent to the integument, and to
the Epicranius and its tendinous
aponeurosis; it is continuous, behind, with the
superficial fascia at the back of the neck; and, laterally, is continued over
the temporal fascia. It contains between its layers the superficial vessels and
nerves and much granular fat.
The Epicranius
(Occipitofrontalis) is a broad, musculofibrous layer, which covers the whole of one side of
the vertex of the skull, from the occipital bone to the eyebrow. It consists of
two parts, the Occipitalis and the Frontalis, connected by an intervening tendinous
aponeurosis, the galea
aponeurotica.
The Occipitalis,
thin and quadrilateral in form, arises by tendinous
fibers from the lateral two-thirds of the superior
nuchal line of the occipital bone, and from the mastoid part of the temporal.
It ends in the galea aponeurotica.
Muscles of the head, face, and neck.
The Frontalis
is thin, of a quadrilateral form, and intimately adherent to the superficial
fascia. It is broader than the Occipitalis and its fibers are longer and paler in color.
It has no bony attachments. Its medial fibers are
continuous with those of the Procerus; its immediate fibers blend with the Corrugator and Orbicularis oculi; and
its lateral fibers are also blended with the latter
muscle over the zygomatic process of the frontal
bone. From these attachments the fibers are directed
upward, and join the galea aponeurotica
below the coronal suture. The medial margins of the Frontales
are joined together for some distance above the root of the nose; but between
the Occipitales there is a considerable, though
variable, interval, occupied by the galea aponeurotica.
The galea
aponeurotica (epicranial
aponeurosis) covers the upper part of the
cranium; behind, it is attached, in the interval between its union with the Occipitales, to the external occipital protuberance and
highest nuchal lines of the occipital bone; in front, it forms a short and
narrow prolongation between its union with the Frontales.
On either side it gives origin to the Auriculares
anterior and superior; in this situation it loses its aponeurotic
character, and is continued over the temporal fascia to the zygomatic
arch as a layer of laminated areolar tissue. It is closely connected to the
integument by the firm, dense, fibro-fatty layer which forms the superficial
fascia of the scalp: it is attached to the pericranium
by loose cellular tissue, which allows the aponeurosis,
carrying with it the integument to move through a considerable distance.
Variations.—Both
Frontalis and Occipitalis
vary considerably in size and in extent of attachment; either may be absent;
fusion of Frontalis to skin has been noted.
Nerves.—The Frontalis is supplied by the temporal branches of the
facial nerve, and the Occipitalis by the posterior
auricular branch of the same nerve.
Actions.—The Frontales
raise the eyebrows and the skin over the root of the nose, and at the same time
draw the scalp forward, throwing the integument of the forehead into transverse
wrinkles. The Occipitales draw the scalp backward. By
bringing alternately into action the Frontales and Occipitales the entire scalp may be moved forward and
backward. In the ordinary action of the muscles, the eyebrows are elevated, and
at the same time the aponeurosis is fixed by the Occipitales, thus giving to the face the expression of
surprise; if the action be exaggerated, the eyebrows are still further raised,
and the skin of the forehead thrown into transverse wrinkles, as in the
expression of fright or horror.
A thin muscular slip, the Transversus nuchæ,
is present in a considerable proportion (25 per cent.) of cases; it arises
from the external occipital protuberance or from the superior nuchal line,
either superficial or deep to the Trapezius; it is frequently inserted
with the Auricularis posterior, but may join the
posterior edge of the Sternocleidomastoideus.
Muscles of the Head subdivided
into
Mastication and Facial Expression (mimetic) groups
Muscles of Mastication
Masseter
•
Origin:
•
Superficial: 1.zygomatic process of the maxilla 2.inferior border of zygomatic arch
• Intermediate:
inner surface of zygomatic arch • Deep: posterior
aspect of inferior border of zygomatic arch
•
Insertion:
•
Superficial: 1.angle of mandible 2.lateral surface of mandibular ramus
•
Intermediate: ramus of mandible • Deep: 1.superior ramus of mandible 2.coronoid
process of mandible
•
Action: 1.closes the lower jaw (clenches the teeth) 2.may deviate mandible to
opposite side of contraction
•
Blood: masseteric artery • Nerve: masseteric
nerve
Medial
pterygoid
•
Origin:
1.medial
surface of lateral pterygoid plate of the sphenoid
2.palatine bone 3.pterygoid fossa
•
Insertion:
1.inner
surface of mandibular ramus 2.angle of the mandible
•
Action:
1.closes
the lower jaw (clenches the teeth) 2.can protrude the mandible in combination
with the lateral pterygoid
•
Blood: medial pterygoid artery • Nerve: medial pterygoid nerve
Lateral
pterygoid
•
Origin:
1.Superior
head: lateral surface of the greater wing of the sphenoid 2.Inferior head:
lateral surface of the lateral pterygoid plate
•
Insert together:
1.neck
of the mandibular condyle 2.articular disk of the TMJ
•
Action:
1.deviates
mandible to side opposite of contraction (during chewing) 2.opens mouth by
protruding mandible (inferior head) 3.closes the mandible (superior head)
•
Blood: lateral pterygoid artery • Nerve: lateral pterygoid nerve
Temporalis
•
Origin:
•
Temporal fossa
•
Insertion: coronoid process of the mandible
•
Action:
1.closes
the lower jaw (clenches the teeth) 2.retraction, pulles
back
Muscles of Facial Expression (mimetic
muscles) have such peculiarities:
1.
Originate in bones of face and insert
into skin
2.
Do not throw over joints
3.
Do not have proper fasciae (exception
is buccinator muscle)
4.
Placed round natural orifices of the
face (eyes, nostrils, ears and mouth)
5.
They have an antagonists – elastic
skin
Muscles of Facial Expression
(mimetic)
Orbicularis
oculi
•
Origin:
1.orbital
portion: nasal process of frontal bone 2.palpebral portion: palpebral ligament
3.lacrimal portion: lacrimal crest of lacrimal bone
• Insertion:
circumferentially around orbit meeting in palpebral raphe
•
Action: powerfully closes the eye • Blood: ophthalmic artery • Nerve: zygomatic branch of facial nerve
Corrugator
supercilii
•
Origin: frontal bone just above the nose • Insertion: skin of the medial
portion of the eyebrows • Action: draws the eyebrows downward and medially •
Blood: ophthalmic artery • Nerve: zygomatic branch of
facial nerve
Orbicularis oris
Scheme showing arrangement of fibers of Orbicularis oris.
•
Origin:
1.alveolar
border of maxilla 2.lateral to midline of mandible
•
Insertion:
1.circumferentially
around mouth 2.blends with other muscles
•
Action:
1.closes
the lips 2.protrudes the lips
•
Blood: facial artery • Nerve: buccal branch of facial
nerve
Levator labii superioris
•
Action: 1.elevates the upper lip 2.flares the nostrils
Zygomaticus minor
•
Action: elevates the upper lip
Zygomaticus major
•
Action: lifts and draws back the angle(s) of the mouth (as in smiling)
Risorius (may be
absent)
•
Action: draws the mouth laterally (as in smiling)
Levator anguli oris
•
Action: lifts the angle(s) of the mouth (as in smiling)
Buccinator
• Action:
compresses the cheek(s)
Depressor
anguli oris
•
Action: lowers the angle(s) of the mouth (as in frowning)
Depressor
labii inferioris
•
Action: draws the lower lip downward and laterally
Epicranial Musculature
Occipitalis (2 bellies)
•
Origin:
1.lateral
2/3 of superior nuchal line 2.external occipital protuberance
•
Insertion: galea aponeurosis,
over the occipital bone • Action: draws back the scalp to raise the eyebrows
and wrinkle the brow • Blood: occipital artery • Nerve: posterior auricular
branch of facial nerve
Frontalis (2 bellies)
•
Origin: galea aponeurosis,
anterior to the vertex • Insertion: skin above the nose and eyes • Action:
draws back the scalp to raise the eyebrows and wrinkle the brow • Blood:
ophthalmic artery • Nerve: temporal branch of facial nerve
Anterior, posterior and superior auricularis muscles
•
Action: draws the auricle
There are parotid
fascia, masseteric fascia and boccopharyngeal fascia in head region.
Regions of head:
frontal, parietal, occipital, temporal, auditory, mastoid and facial regions.
Facial area has orbital, infraorbital, parotidomasseteric, zygomatic,
nasal, oral and mental regions.
Neck Musculature
Subdivides
into superficial and deep groups
Superficial Neck Musculature
Platysma
•
Origin: subcutaneous skin over delto-pectoral region
• Insertion: invests in the skin widely over the mandible • Action: 1.depress
mandible and lower lip 2.tenses the skin over the lower neck
•
Blood: superficial vessels of the neck • Nerve: cervical branch of facial nerve
(VII cranial)
Sternocleidomastoid
•
Origin: (two heads)
1.manubrium
of sternum 2.medial portion of clavicle
•
Insertion: mastoid process of temporal bone • Action:
1.rotates
to side opposite of contraction 2.laterally flexes to the contracted side
3.bilaterally flexes the neck
•
Blood:
1.occipital
artery 2.superior thyroid artery
•
Nerve:
1.motor:
spinal accessory (XI cranial) 2.sensory: ventral rami of C2,(C3)
1.
Stylohyoid
•
Origin: styloid process of temporal bone • Insertion:
lateral margin of hyoid (near greater horn) • Action:
1.pulls
the hyoid superiorly & posteriorly during swallowing 2.fixes the hyoid bone
for infrahyoid action
•
Blood: facial & occipital artery • Nerve: facial nerve (VII cranial)
2.
Digastric
•
Attachments:
1.post
belly: mastoid process of temporal bone 2.anterior belly: digastric fossa of
internal mandible
•
both bellies meet and attach at the lateral aspect of body of hyoid by a pulley
tendon • Action:
Suprahyoid group
1.open
mouth by depressing mandible 2.fixes hyoid bone for infrahyoid
action
•
Blood: branches of the external carotid • Nerve:
1.posterior
belly: facial nerve (VII cranial) 2.anterior belly: mylohyoid
nerve
3.
Mylohyoid
•
Origin: inner surface of mandible off the mylohyoid
line • Insertion:
1.body
of hyoid 2.along midline at mylohyoid raphe
•
Action:
1.elevates
the hyoid bone 2.raises floor of mouth (for swallowing) 3.depresses mandible
when hyoid is fixed
•
Blood: lingual artery • Nerve: mylohyoid nerve
(branch of mandibular division, V3 cranial)
4.
Geniohyoid
•
Origin: inner surface of the mandible
•
Insertion: body of hyoid (paired muscles)
•
Action:
1.pulles
the tongue 2.depress the mandible 3.works with mylohyoid
•
Blood: lingual artery • Nerve:
Infrahyoid group
1.
Sternohyoid
•
Origin:
1.posterior
aspect of manubrium 2.sternal end of clavicle
•
Insertion: body of hyoid • Action:
1.depresses
hyoid & larynx 2.acts eccentrically with the suprahyoid
muscles to provide them a stable base
•
Blood:
1.inferior
thyroid artery (primary) 2.superior thyroid artery
•
Nerve:
1.upper
portions: superior root of ansa cervicalis,
C2 2.lower portions: inferior root of ansa cervicalis, C2,3
2.
Omohyoid
•
Attachments:
1.superior
belly: hyoid bone (lateral to sternohyoid) 2.inferior
belly: superior scapular border (medial to suprascapular
notch)
•
both bellies meet at the clavicle & are held to the clavicle by a pulley
tendon • Action:
1.depresses
hyoid & larynx 2.acts eccentrically with the suprahyoid
muscles to provide them a stable base
•
Blood:
1.inferior
thyroid artery (primary) 2.superior thyroid artery
•
Nerve:
1.upper
portions: superior root of ansa cervicalis,
C2 2.lower portions: inferior root of ansa cervicalis, C2,3
3.
Sternothyroid
•
Origin: posterior aspect of manubrium • Insertion: oblique line of thyroid
cartilage • Action:
1.depresses
hyoid & larynx 2.acts eccentrically with the suprahyoid
muscles to provide them a stable base
•
Blood:
1.inferior
thyroid artery (primary) 2.superior thyroid artery
•
Nerve:
1.upper
portions: superior root of ansa cervicalis,
C2 2.lower portions: inferior root of ansa cervicalis, C2,3
4.
Thyrohyoid
•
Origin: oblique line of thyroid cartilage • Insertion: body of hyoid • Action:
1.depresses
hyoid 2.may assist in larynx elevation
•
Blood:
1.inferior
thyroid artery (primary) 2.superior thyroid artery
•
Nerve:
1.upper
portions: superior root of ansa cervicalis,
C2 2.lower portions: inferior root of ansa cervicalis, C2,3
Deep Neck Muscles
have lateral, medial groups
Deep Lateral Neck Musculature
Anterior scalene
•
Attachment A: anterior tubercles of transverse processes of C3-C6 • Attachment
B: 1st rib • Action:
if
transverse process fixed: 1.elevates the ribs for respiration
if
ribs fixed: 2.rotates to side opposite of contraction 3.laterally flexes to the
contracted side 4.bilaterally flexes the neck
•
Blood: inferior thyroid artery (branch of the thyrocervical
trunk) • Nerve: ventral rami C3-C6
Middle scalene
•
Attachment A: transverse processes of all cervical vertebrae • Attachment B:
1st rib (behind anterior scalene) • Action:
if
transverse process fixed: 1.elevates the ribs for respiration
if
ribs fixed: 2.rotates to side opposite of contraction 3.laterally flexes to the
contracted side 4.bilaterally flexes the neck
•
Blood: ascending cervical artery • Nerve: ventral rami C3-C8
Posterior scalene
•
Attachment A: posterior tubercles of transverse processes of C5 & C6 •
Attachment B: 2nd and/or 3rd rib • Action:
if
transverse process fixed: 1.elevates the ribs for respiration
if
ribs fixed: 2.rotates to side opposite of contraction 3.laterally flexes to the
contracted side 4.bilaterally flexes the neck
•
Blood: ascending cervical artery • Nerve: ventral rami C5-C7
Longus colli
• Origin: lower anterior vertebral bodies and
transverse processes • Insertion: anterior vertebral bodies and transverse
processes several segments above • Action: flexes the head and neck • Blood:
muscular branches of the aorta • Nerve: ventral rami C2-C6
Longus capitis
•
Origin: upper anterior vertebral bodies and transverse processes • Insertion:
anterior vertebral bodies and transverse processes several segments above •
Action: flexes the head and neck • Blood: muscular branches of the aorta •
Nerve: ventral rami C1-C3
Rectus capitis
anterior
•
Origin: anterior base of the transverse process of the atlas • Insertion:
occipital bone anterior to foramen magnum • Action: flexes the head • Blood:
muscular branches of the aorta • Nerve: ventral rami C2,3
Rectus
capitis lateralis
•
Origin: transverse process of the atlas • Insertion: jugular process of the
occipital bone • Action: bends the head laterally • Blood: muscular branches of
the aorta • Nerve: ventral rami C2,3
Neck prevertebral
deep Musculature
Theme 3. THE TOPOGRAPHY AND FASCIAE OF THE HEAD AND NECK
Topography of
the neck
Neck
has follow regions:
Anterior region is bordered overhead by lower margin
of mandible, from below by sternum, from one side – by the sternocleidomastoid
muscle. Median line of the neck divides anterior region into right and left anterior triangles. There are some areas in each triangle:
1.
Submandibular trigone
bordered by lower margin of mandible and both bellies of digastric muscle
2.
There is lingual trigone
of Pyrohov in Submandibular triangle that
bordered by back margin of mylohyoid muscle, tendon
of posterior belly of digastric muscle and hypoglossal nerve. There is lingual
artery in this triangle.
3.
Carotid trigone
bordered by posterior belly of digastric muscle,
superior belly of omohyoid, anterior margin of the
sternocleidomastoid and linea alba of the neck.
4.
Muscular (omotracheal)
trigone bordered by superior belly of omohyoid, anterior margin of the sternocleidomastoid and linea alba of the neck.
5.
Mental trigone
bordered by anterior bellies of both digastric muscles, hyoid bone and
mandible.
The Fascia Colli (deep
cervical fascia) lies under cover of the
Platysma, and invests the neck; it also forms sheaths
for the carotid vessels, and for the structures situated in front of the vertebral
column.
The investing portion of the fascia is
attached behind to the ligamentum nuchæ
and to the spinous process of the seventh cervical
vertebra. It forms a thin investment to the Trapezius, and at the anterior
border of this muscle is continued forward as a rather loose areolar layer,
covering the posterior triangle of the neck, to the posterior border of the Sternocleidomastoideus, where it begins to assume the
appearance of a fascial membrane. Along the hinder
edge of the Sternocleidomastoideus it divides to
enclose the muscle, and at the anterior margin again forms a single lamella,
which covers the anterior triangle of the neck, and reaches forward to the
middle line, where it is continuous with the corresponding part from the
opposite side of the neck. In the middle line of the neck it is attached to the
symphysis menti and the
body of the hyoid bone.
Above, the fascia is attached to
the superior nuchal line of the occipital, to the mastoid process of the
temporal, and to the whole length of the inferior border of the body of the
mandible. Opposite the angle of the mandible the fascia is very strong, and
binds the anterior edge of the Sternocleidomastoideus
firmly to that bone. Between the mandible and the mastoid process it ensheathes the parotid gland—the layer which covers the
gland extends upward under the name of the parotideomasseteric
fascia and is fixed to the zygomatic arch. From
the part which passes under the parotid gland a strong band extends upward to
the styloid process, forming the stylomandibular
ligament. Two other bands may be defined: the sphenomandibular
(page 297) and the pterygospinous
ligaments. The pterygospinous ligament
stretches from the upper part of the posterior border of the lateral pterygoid plate to the spinous
process of the sphenoid. It occasionally ossifies, and in such cases, between
its upper border and the base of the skull, a foramen is formed which transmits
the branches of the mandibular nerve to the muscles of mastication.
Below, the fascia is attached to
the acromion, the clavicle, and the manubrium sterni.
Some little distance above the last it splits into two layers, superficial and
deep. The former is attached to the anterior border of the manubrium, the
latter to its posterior border and to the interclavicular
ligament. Between these two layers is a slit-like interval, the suprasternal
space (space of Burns); it contains a small quantity of areolar
tissue, the lower portions of the anterior jugular veins and their transverse
connecting branch, the sternal heads of the Sternocleidomastoidei,
and sometimes a lymph gland.
The fascia which lines the deep surface of
the Sternocleidomastoideus gives off the following
processes: (1) A process envelops the tendon at the Omohyoideus,
and binds it down to the sternum and first costal cartilage. (2) A strong
sheath, the carotid sheath, encloses the carotid artery, internal
jugular vein, and vagus nerve. (3) The prevertebral fascia extends medialward behind the carotid vessels, where it assists in
forming their sheath, and passes in front of the prevertebral
muscles. It forms the posterior limit of a fibrous compartment, which contains
the larynx and trachea, the thyroid gland, and the pharynx and esophagus. The prevertebral
fascia is fixed above to the base of the skull, and below is continued into the
thorax in front of the Longus colli
muscles. Parallel to the carotid sheath and along its medial aspect the prevertebral fascia gives off a thin lamina, the buccopharyngeal fascia, which closely invests
the Constrictor muscles of the pharynx, and is continued forward from the
Constrictor pharyngis superior on to the Buccinator. It is attached to the prevertebral
layer by loose connective tissue only, and thus an easily distended space, the retropharyngeal
space, is found between them. This space is limited above by the base of
the skull, while below it extends behind the esophagus
into the posterior mediastinal cavity of the thorax.
The prevertebral fascia is prolonged downward and lateralward behind the carotid vessels and in front of the Scaleni, and forms a sheath for the brachial nerves and subclavian vessels in the posterior triangle of the neck;
it is continued under the clavicle as the axillary sheath and is attached to
the deep surface of the coracoclavicular fascia.
Immediately above and behind the clavicle an areolar space exists between the
investing layer and the sheath of the subclavian
vessels, and in this space are found the lower part of the external jugular
vein, the descending clavicular nerves, the
transverse scapular and transverse cervical vessels, and the inferior belly of
the Omohyoideus muscle. This space is limited below
by the fusion of the coracoclavicular fascia with the
anterior wall of the axillary sheath. (4) The pretrachial
fascia extends medially in front of the carotid vessels, and assists in
forming the carotid sheath. It is continued behind the depressor muscles of the
hyoid bone, and, after enveloping the thyroid gland, is prolonged in front of
the trachea to meet the corresponding layer of the opposite side.
Section of the neck at about the level of the sixth
cervical vertebra.
Showing the arrangement of the fascia
coli.
Above, it is fixed to the hyoid bone, while below it is
carried downward in front of the trachea and large vessels at the root of the
neck, and ultimately blends with the fibrous pericardium. This layer is fused
on either side with the prevertebral fascia, and with
it completes the compartment containing the larynx and trachea, the thyroid
gland, and the pharynx and esophagus.
Variations.—The
Sternocleidomastoideus varies much in the extent of
its origin from the clavicle: in some cases the clavicular
head may be as narrow as the sternal; in others it may be as much as
Triangles of the Neck.—This
muscle divides the quadrilateral area of the side of the neck into two
triangles, an anterior and a posterior. The boundaries of the anterior
triangle are, in front, the median line of the neck; above,
the lower border of the body of the mandible, and an imaginary line drawn from
the angle of the mandible to the Sternocleidomastoideus;
behind, the anterior border of the Sternocleidomastoideus.
The apex of the triangle is at the upper border of the sternum. The boundaries
of the posterior triangle are, in front, the posterior border of
the Sternocleidomastoideus; below, the middle
third of the clavicle; behind, the anterior margin of the Trapezius. The
apex corresponds with the meeting of the Sternocleidomastoideus
and Trapezius on the occipital bone. The anatomy of these triangles will be
more fully described with that of the vessels of the neck (p. 562).
Nerves.—The Sternocleidomastoideus is supplied by the accessory nerve
and branches from the anterior divisions of the second and third cervical
nerves.
Actions.—When only one Sternocleidomastoideus acts, it draws the head toward the
shoulder of the same side, assisted by the Splenius and the Obliquus
capitis inferior of the opposite side. At the same
time it rotates the head so as to carry the face toward the opposite side.
Acting together from their sternoclavicular
attachments the muscles will flex the cervical part of the vertebral column. If
the head be fixed, the two muscles assist in elevating the thorax in forced
inspiration.
Sternocleidomastoid
region answers the projection of the same name muscle.
Lateral region of the neck is bordered by back
margin of the sternocleido-mastoid, anterior margin
of the trapezius muscle and upper margin of clavicle. There are follow areas in
this region:
1.
Omo-trapezial trigone is bordered by back margin of the
sternocleidomastoid, lower belly of omohyoid and
anterior margin of the trapezius muscles.
2.
Omo-clavicular
(greater supraclavicular) trigone of neck is bordered
by back margin of the sternocleidomastoid, lower belly of omohyoid
and upper margin of the clavicle.
Posterior
region answers the projection of the trapezius muscle.
Cervical
fascia
According V.M.Shevkunenko there are 5 cervical
fasciae:
I - superficial cervical fascia envelops the platizma
Proper cervical fascia has two sheets:
II - superficial lamina of the proper cervical fasciae starts from
front surface of the sternum and clavicle, lower margin of mandible and
attaches the spinous processes of the cervical
vertebrae. It forms the sheath for sternocleidomastoid and trapezius muscles.
III - deep lamina of the proper cervical fasciae starts from back
surface of the sternum and clavicle and attaches to the hyoid bone from sides
bordered by omohyoid muscles. This fascia forms linea alba of neck and the sheath for infrahyoid
muscles.
Suprasternal interaponeurotic space
made up between superficial and deep lamina of the proper cervical fasciae. It
contains jugular venous arch and fat tissue. Suprasternal space connects with
lateral recesses located behind the lower part of sternocleidomastoid muscle.
s.
According international nomenclature (PNA)
there are 3 laminae of
cervical fasciae:
IV - internal cervical fascia subdivides into parietal and visceral
sheets. Parietal lamina envelopes all organs of neck together and visceral –
each organ separately. Previsceral
space positioned between parietal and visceral laminae
and contains adipose tissue, lymphatic nodes, and nerves and communicates with
anterior mediastinum. Pretracheal
space located before trachea between parietal and visceral sheet
V - prevertebral
fascia envelops all deep cervical muscles forming their sheathes.
Retropharyngeal space made up between V fascia and parietal lamina of IV
fasciae. Retrovisceral space positioned
between internal cervical and prevertebral fasciae
and contains adipose tissue and continues into posterior mediastinum.
1.
Superficial lamina
meets the superficial lamina of the proper cervical fasciae according V.M.Shevkunenko and contains the suprasternal space.
2.
Pretracheal
lamina meets the deep lamina of the proper cervical
fasciae according V.M.Shevkunenko and forms carotid sheath.
3.
Prevertebral
lamina meets the same fasciae according V.M.Shevkunenko.
Interscalenum space positioned between anterior and middle scalene muscles where subclavian artery passes. Anterscalenum space located in front of scalene
muscles where subclavian vein passes.
Deep lamina of the proper cervical fasciae (V.M.Shevkunenko)
associating infrahyoid muscles forms omoclavicular aponeurosis or cervical sail (Rishe).
Cervical sail assists to drain superficial veins of neck that spliced with it.
Prepared by
Reminetskyy
B.Y.