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
hyoid bone
The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebr ...
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
The investing layer of deep cervical fascia is the most superficial part of the deep cervical fascia, and encloses the whole neck.
It is considered by some sources to be incomplete or nonexistent.
Attachments
It surrounds the neck like a collar, ...
. 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.
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 overlies the occipital lobe ...
, to the mastoid process of the temporal bone, 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. 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
The stylomandibular ligament is the thickened posterior portion of the investing cervical fascia around the neck. It extends from near the apex of the styloid process of the temporal bone to the angle and posterior border of the angle of the man ...
. 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
Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...
.
Inferior extent of the investing fascia
Below, the fascia is attached to the thoracic outlet ( acromion, clavicle, and
manubrium
The sternum 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, lungs, and major blood vessels from injury. Sha ...
). 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 Carotid artery may refer to:
* Common carotid artery, often "carotids" or "carotid", an artery on each side of the neck which divides into the external carotid artery and internal carotid artery
* External carotid artery, an artery on each side of t ...