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Deep Fascia of the Neck
By
Prof. Dr. Muhammad Imran Qureshi
Deep Cervical Fascia
1. Investing Fascia
2. Prevertebral Fascia
3. Middle Cervical Fascia
4. Pretracheal Fascia
5. Carotid Sheath
6. Buccopharyngeal Fascia
It forms the boundaries of compartments. The fascial spaces in it can communicate
infection or fluid to other regions of the body. It can be used as a guide to surgical
dissection. It allows the neck structures to glide past one another. It supports the
thyroid, lymph nodes and blood vessels
Investing Layer
Attachments Above:
On the skull, it is attached to the external
occipital protuberance and the whole
extent of the superior nuchal line right up
to the mastoid process. The same is the
origin of the Trapezius and the
Sternocleidomastoid muscles. Therefore,
here the fascia invests these two muscles. Posteriorly, it blends with the ligamentum
nuchae, which is attached to the spines of the cervical vertebrae. Anteriorly, it is
attached to the hyoid bone; and above to the lower border of the mandible (from the
angle to the chin).
Between the tip of the mastoid process and the angle of the mandible, it splits into
two layers that diverge from each other. The parotid gland lies between these two
layers (Parotid fascia).
The superficial layer extends from the tip of the
mastoid process across the cartilaginous part of the
external auditory meatus to the lower border of the
zygomatic process of the temporal bone. From just in
front of the lower border of the temporozygomatic
suture, it passes to the angle of the mandible. This
anterior border is not free but it blends with the
epimysium on the surface of masseter (Masseteric
fascia)
The Deep layer of the Parotid fascia is attached along
the base of the skull from the tip of the mastoid
process to the lower border of tympanic part of the
temporal bone as far medially as the carotid canal.
Here it blends with the carotid sheath. Its part that extends between the styloid
process and the angle of the mandible is thicker than the rest and forms the
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stylomandibular ligament. The deep layer also has a
free anterior border which thins out and becomes
adherent to the deep surface of the capsule of the
parotid gland.
Attachments Below:
It is attached to the Pectoral girdle. Where it follows
the insertions of the Trapezius and the
Sternocleidomastoid. Thus across the attachment of
the Trapezius, it passes from the spine of the
scapula to the acromion and the lateral part of the
clavicle. Across the attachment of the
Sternocleidomastoid it is attached to the medial end
of the clavicle and the sternum.
In the intervals between these muscles, it splits into
two layers and is attached to the middle thirds of
both clavicles. The deeper of these splits around the
inferior belly of omohyoid, forming a fascial sling that binds the muscle down to the
clavicle.
In the interval between the insertions of the two sternocleidomastoids, it splits again
and is attached to the anterior and posterior borders jugular notch (Suprasternal
space of Burn’s… contains anterior jugular
veins)
Prevertebral fascia
The deep fascia on the anterior surface of the
prevertebral muscles is called the prevertebral
fascia. It is a tough membrane that lies in front of
the prevertebral muscles.
It extends from the base of the skull in front of the
longus capitis, rectus capitis lateralis and longus
coli muscles down to blend with the anterior
longitudinal ligament (body of T4vertebra)
On the sides it passes over the scalene muscles
and as it passes laterally, it gradually becomes
thinner and thinner until it fades away under
cover of the anterior border of trapezius.
All the nerves (Cervical plexus & Brachial plexus)
lie deep to it The third part of the subclavian
artery also runs deep to it. The Accessory nerve
and Lymph nodes lie superficial to it.
As the neurovascular bundle passes laterally to the arm, it draws an extension of
this fascia in front of it for some distance in the form of axillary sheath.
The Subclavian vein lies outside the sheath as it needs dead space around it in case
of increased venous return. It is also pierced by the four cutaneous branches of the
cervical plexus. It provides a fixed basis for the mobile viscera of the neck.
It is supposed to blend with the back of the esophagus at the level of the
manubrium.
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Middle Cervical Fascia
The narrow gap between sternohyoids is bridged
by a continuation of the deep fascia surrounding
one sternohyoid across the midline to join that
around the other.
Additionally, the deep fascia around each
sternohyoid is prolonged laterally to merge with
the deep fascia around each omohyoid. Thus, the
sternohyoids, omohyoids, and their intervening
fascia form a musculofascial apron at the front
and, inferiorly, also at the side of the neck. The
fascial component of the apron is called the
middle cervical fascia. It has one important
specialization.
Where the middle cervical fascia envelopes the
intermediate tendon of the omohyoid it is
thickened and gains attachment to the back of the clavicle. In fact, it acts as a pulley
to redirect the path of the intermediate tendon, which is held near the back of the
clavicle at the level of C7.
Pretracheal fascia
It lies deep to the Infrahyoid (Strap) muscles.
The upper attachment of these muscles
describes its upper attachment i.e. the hyoid
bone in the midline and oblique line of the
thyroid cartilage more laterally.
It splits to enclose the Thyroid gland to which it
is loosely attached.
It is pierced by the thyroid vessels. Laterally, on
the deep surface of the sternocleidomastoid it
fuses with the front of the carotid sheath.
Inferiorly it passes behind the brachiocephalic
veins to blend with the adventitia of the arch
aorta and the fibrous pericardium. As no
structure lies between the pretracheal fascia and
the trachea, it provides a slippery surface for up
and down gliding of the trachea during
swallowing and neck movements.
Carotid Sheath
It is a membrane comprising of dense felt work of areolar tissue that surrounds the
carotid arteries (Common and Internal), internal jugular vein and the Vagus nerve.
Over the vein it is thin and loose (to allow space for the vein during increased
venous return). Above at the base of the skull it is attached at the margins of the
carotid canal. Below it reaches the aortic arch. It is firmly attached to deep surface of
the sternocleidomastoid. It is here where the pretracheal fascia blends with it.
Behind between the sheath and the prevertebral fascia is a little amount of loose
areolar tissue. Here lies the cervical sympathetic.
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Buccopharyngeal Fascia
It exists in the form of a delicate, distensible
layer that covers the buccinator and extends
below it to cover the pharyngeal constrictor
muscles.
It extends from the base of the skull to the
oesophagus.
Together with a similar layer on the internal
surface of these muscles (Pharyngobasilar
fascia), it closes the gaps in the muscular wall of
the pharynx.
Deep Cervical Fascial Spaces
Retropharyngeal - between prevertebral
and buccopharyngeal
Pretracheal - between infrahyoids and
trachea
Lateral pharyngeal - lateral to pharynx and communicate with RP and SM
spaces
Submandibular - below tongue
deep portion above mylohyoid
superficial portion below mylohyoid
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