Download MBBS (Bachelor of Medicine and Bachelor of Surgery) Latest Deep Fascia of the Neck Lecture PPT
? Pretracheal fascia
? This layer of deep cervical fascia covers the front
and sides of trachea, hence its name--pretracheal
fascia.
? It splits to enclose the thyroid gland forming its
capsule and is attached to the oblique line of
thyroid cartilage and to the arch of cricoid cartilage
anteriorly.
? Ligament of Berry is derived from this fascia and
connects the capsule of the lateral lobe of the
thyroid gland to the cricoid cartilage
? Tracing of the pretracheal fascia
? Horizontal tracing:
? It merges with the investing layer of deep cervical
fascia enclosing the sternocleidomastoid and the
anterior wall of the carotid sheath.
? Vertical tracing:
? It is attached to the hyoid bone and when traced
below, it enters the thorax in front of the trachea
and blends with the apex of the fibrous
pericardium.
? Prevertebral fascia
? It is extremely strong and lies in front of the
prevertebral muscles
? Tracing of the prevertebral fascia
? Horizontal tracing:
? It forms the fascial carpet of the posterior triangle.
? It also forms axillary sheath, which may extend up
to the elbow.
? Subclavian and axillary veins lie outside the sheath
? Vertical tracing:
? Traced aboveextends up to the base of the skull
to which it is attached.
? Traced below continues downwards and blends
with the anterior longitudinal ligament of the upper
thoracic vertebrae (T1 to T3).
Retropharyngeal space
? Anteriorly, the prevertebral layer of deep cervical
fascia is separated from posterior aspect of the
pharynx and its covering, buccopharyngeal fascia,
by a potential space called retropharyngeal space.
? The retropharyngeal space is continuous with the
parapharyngeal spaces at the sides of the pharynx.
? The retropharyngeal space is divided into two
lateral compartments (spaces of Gillette) by a
midline fibrous raphe.
? The space behind the prevertebral fascia and in
front of the vertebral bodies is called prevertebral
space.
SIDE OF THE NECK
Side of the Neck
? Quadrangular in shape.
? It is bounded
? Anteriorly anterior midline
of the neck
? Posteriorly anterior border
of the trapezius
? Superiorly lower border of
the body of the mandible and
a line extending from the
angle of the mandible to the
mastoid process
? Inferiorly clavicle.
Triangles on the side of the neck
? This quadrilateral area
is divided into large
anterior and posterior
triangles by the
sternocleidomastoid
muscle
? Which runs across this
area diagonally from
mastoid process to
the upper end of the
sternum.
Sternocleidomastoid Muscle
Origin
Sternal headarises by a rounded
tendon from the superolateral part
Of the front of the manubrium
sterni, below the suprasternal notch.
Clavicular head flat and
musculoaponeurotic. It arises from
the medial third of the superior
surface of the clavicle.
Insertion
by a thick tendon on the lateral
surface of the mastoid process and by
a thin aponeurosis into the lateral
half
of the superior nuchal line of the
occipital bone
? Arterial Supply
? The sternocleidomastoid is supplied by branches of
following arteries:
Upper part occipital and posterior auricular art.
Middle part superior thyroid artery.
Lower part suprascapular artery.
? Nerve Supply
? Supplied by the spinal accessory nerve.
? It is also supplied by the ventral rami of C2 and C3,
which are mostly sensory and carry proprioceptive
sensations from the muscle.
? Actions
? When muscle acting alone , it tilts the head towards
the shoulder on the same side and rotates the head
so that chin turns to the opposite side. This
movement occurs during an upward sideways glance.
? When muscles of both sides contract together they
draw the head forwards as in lifting the head from
the pillow or bending the head during eating food.
? If the head is fixed by prevertebral muscles, the two
sternocleidomastoid muscles act as accessory
muscles of respiration during forced inspiration.
Torticollis or wry neck
? Head is bent to one side and chin points to the opposite side.
? This occurs due to spasm of sternocleidomastoid and
trapezius muscles supplied by spinal accessory nerve.
? Spasmodic torticollis is characterized by repeated painful
contractions of the trapezius and sternocleidomastoid
muscles on one side. Caused by exposure to cold and
maladjustment of pillow during sleep.
? Reflex torticollis occurs due to irritation of spinal accessory
nerve caused by inflamed or suppurating lymph nodes.
? Congenital torticollis occurs due to birth injury to muscle.
Permanent torticollis may occur due to subsequent ischemic
contracture
POSTERIOR TRIANGLE
? It is the triangular space on the side of neck behind the
sternocleidomastoid muscle. Its apex is directed
upwards and backwards towards the mastoid process
and base downwards towards the clavicle.
? Boundaries
? Anterior: Posterior border of sternocleidomastoid
muscle.
? Posterior: Anterior border of trapezius muscle.
? Inferior (base): Superior aspect of middle third of the
clavicle.
? Superior (apex): Meeting point of sternocleidomastoid
and trapezius muscles at the superior nuchal line of the
occipital bone
? Roof
? Formed by investing layer of the deep cervical fascia
? superficial fascia overlying the roof contains platysma,
external jugular and posterior jugular veins, and
cutaneous nerves and vessels.
? Structures piercing the roof of the posterior triangle
are
1. Four cutaneous branches of cervical plexus
(a) Lesser occipital nerve (C2)
(b) Great auricular nerve (C2, C3)
(c) Transverse cervical nerve (C2, C3)
(d) Supraclavicular nerves (C3, C4).
2. External jugular vein
? Floor
? The floor of posterior triangle is muscular.
? Formed from above downwards by
1. Semispinalis capitis.
2. Splenius capitis.
3. Levator scapulae.
4. Scalenus medius.
5. First digitation of serratus anterior (sometimes).
? Fascial carpet of the posterior triangle
? The muscular floor of posterior triangle is covered
by prevertebral layer of deep cervical fascia, which
forms the fascial carpet of the floor of the
posterior triangle.
? It forms axillary sheath around subclavian artery
and brachial plexus travelling from the root of the
neck to the upper limb.
? The lower part of the posterior triangle is crossed
by inferior belly of omohyoid superficial to the
fascial carpet.
? Subdivisions
? The posterior triangle is subdivided into two
parts by the inferior belly of the omohyoid.
? (a) occipital triangle a upper larger part.
? (b) subclavian (supraclavicular) triangle small
lower part.
? These parts are so named because they contain
occipital and subclavian arteries, respectively.
? Contents
1. In the occipital triangle
(a) Spinal accessory nerve
(b) 3rd and 4th cervical nerves providing branches to
levator scapulae and trapezius muscles
(c) Dorsal scapular nerve (C5)
(d) Four cutaneous branches of cervical plexus (initial
parts)
(e) Superficial transverse cervical artery
(f) Occipital artery
2. In the subclavian(supraclavicular triangle)
(a) 3rd part of the subclavian artery
(b) Subclavian vein
(c) Terminal part of external jugular vein
(d) Trunks of brachial plexus
(e) Superficial (transverse) cervical, suprascapular,
and dorsal scapular arteries
(f) Lymph nodes
? All the important contents of the posterior triangle
lie deep to the fascial carpet of the floor
? except spinal accessory nerve, which lies just
underneath the roof.
? In operations on the posterior triangle all the
structures except spinal accessory nerve are safe,
provided fascial carpet of posterior triangle is left
intact.
Spinal accessory nerve
? This nerve emerges in the
posterior triangle by piercing
the posterior border of the
sternocleidomastoid (a little
above the middle of this
border).
? It is related to lymph nodes of
the upper deep cervical chain .
? The nerve running downwards
parallel to the fibres of levator
scapulae muscle to
? Disappear underneath to the
anterior border of trapezius and
supplies trapezius muscle.
? In the posterior triangle it is
adherent to the deep aspect of
the fascial roof of this triangle.
Four cutaneous branches of cervical plexus
? It emerge at the midpoint (just above)
of the posterior border of the
sternocleidomastoid by piercing the
deep cervical fascia.
(a)lesser occipital nerve
auricle and head behind the auricle.
(b) great auricular nerve
anterior and posterior branches.
skin on angle of the mandible
mastoid
region and auricle (lower part).
(c) transverse cervical nerve
ascending and descending br.
skin of the front of the neck.
(d) supraclavicular nerve
medial, intermediate, lateral
supraclavicular
skin on chest up to the 2nd rib, front of
the chest, deltoid muscle(upper half)
? Transverse cervical artery: branch of thyrocervical
trunk of the first part of subclavian artery.
? Suprascapular artery: branch of thyrocervical trunk
? Dorsal scapular artery: It arises from the third part
of the subclavian artery.
? Occipital artery: branch of external carotid artery
? Subclavian artery
Lymph nodes
? These are deep cervical lymph
nodes found at the following
sites in the posterior triangle:
(a) A chain of nodes along the
posterior border of
sternocleidomastoid.
(b) A chain of nodes along the
spinal accessory nerve.
(c) A few nodes in the apical
region of the triangle called
occipital lymph nodes.
(d) A group of supraclavicular
lymph nodes.
? These nodes lie superficial to
brachial plexus and subclavian
vessels.
Swelling in the posterior triangle
? Most common cause of swelling in the posterior
triangle is due to enlargement of lymph nodes.
? Supraclavicular lymph nodes are commonly
involved and enlarged in tuberculosis, Hodgkin's
disease, and malignant growth of breast, arm, and
chest.
? Left supraclavicular lymph nodes (Virchow's lymph
nodes) are commonly involved in metastasis from
cancer stomach, cancer testis, and cancer of other
abdominal organs.
? The biopsy of these lymph nodes is helpful in early
diagnosis of distant malignancies.
This post was last modified on 30 November 2021