The deep cervical fascia (or fascia colli in older texts) lies under cover of the
platysma, and invests the muscles of the neck; it also forms sheaths for the
carotid vessels, and for the structures situated in front of the
vertebral column
The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmente ...
. Its attachment to the
hyoid bone prevents the formation of a
dewlap.
The
investing portion of the fascia is attached behind to the
ligamentum nuchæ and to the spinous process of the seventh
cervical vertebra.
The ''alar fascia'' is a portion of the ''deep cervical fascia''.
Divisions
The deep cervical fascia is often divided into a superficial, middle, and deep layer.
The superficial layer is also known as the
investing layer of deep cervical fascia. It envelops the trapezius, sternocleidomastoid, and muscles of facial expression. It also contains the submandibular and parotid salivary gland as well as the muscles of mastication (the masseter, pterygoid, and temporalis muscles).
The middle layer is also known as the
pretracheal fascia. It envelopes the strap muscles (sternohyoid, sternothyroid, thyrohyoid, and omohyoid muscles). It also surrounds the pharynx, larynx, trachea, esophagus, thyroid, parathyroids, buccinators, and constrictor muscles of the pharynx.
The deep layer is also known as the
prevertebral fascia. It surrounds the paraspinous muscles and cervical vertebrae.
The
carotid sheath is also considered a component of the deep cervical fascia.
Superior extent of the investing fascia
Above, the fascia is attached to the
superior nuchal line of the
occipital bone
The occipital bone () is a neurocranium, cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone lies over the occipital lob ...
, to the
mastoid process of the
temporal bone
The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...
, and to the whole length of the inferior border of the body of the
mandible
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla).
The jawbone i ...
.
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. It also contributes to the sheath of the digastric.
At the level of the jaw, it splits to enclose the submandibular gland, with the upper leaflet inserting on the mylohyoid line just inferior to mylohyoid and the inferior leaflet inserting onto the lower margin of the jaw. The posterior portion of the upper leaflet helps separate the parotid gland from the submandibular gland where the mylohyoid is deficient while the posterior border is thickened into a strong band extending between the angle of the jaw and the
temporal styloid process, forming the
stylomandibular ligament. It is complemented by the
pterygospinous ligament, which 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.
Inferior extent of the investing fascia
Below, the fascia is attached to the thoracic outlet (
acromion,
clavicle, and
manubrium
The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, human lung, lungs, and ma ...
). In doing so, it bifurcates 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 sternocleidomastoid, and sometimes a
lymph gland.
Deeper fascial layers
The fascia which lines the deep surface of the sternocleidomastoideus gives off the following processes:
* A process envelops the tendon at the
omohyoideus, and binds it down to the sternum and first
costal cartilage.
* A strong sheath, the
carotid sheath, encloses the
carotid artery,
internal jugular vein, and
vagus nerve
The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibe ...
.
* The
prevertebral fascia extends medialward behind the carotid vessels, where it assists in forming their sheath, and passes in front of the prevertebral muscles.
* The
pretracheal fascia extends medially in front of the
carotid vessels, and assists in forming the
carotid sheath.
References
External links
Sagittal Section Showing Deep Cervical Fascial Layers*
ttps://web.archive.org/web/20060515201222/http://iris3.med.tufts.edu/headneck/supr.htm Suprahyoid Cross-Section Showing Layers of Deep Cervical Fascia
{{Portal bar, Anatomy
Fascial spaces of the head and neck