The deep cervical fascia is the sheet of fibrous connective tissue which envelops most of the muscles, blood vessels, and nerves of the neck. It is located right beneath the platysma muscle. It is composed of three layers: 1) the superficial layer (lamina superficialis), which tightly envelops all the cervical muscles and submandibular gland; 2) the middle layer (lamina pretrachealis), which forms a sheath for the infrahyoid group of muscles, investing the neurovascular bundles; and 3) the deep layer, or prevertebral fascia (lamina prevertebralis), which constitutes the sheath for the prevertebral group of muscles.
Superficial layer- The anterior part of the deep cervical fascia superficial layer is the continuation of the fascia of the chest and neck. The lower part of the fascia is attached to the anterior border of the clavicle and the manubrium of the sternum (upper segment of the sternum). As it extends upwards, it forms a sheath for the sternocleidomastoid muscles. Also being attached to the hyoid bone, it invests the suprahyoid group of cervical muscles. On the face, it is continuous with the masseteric and parotid fasciae (fascia masseterica & fascia parotidea).
Middle layer- Also known as the pretracheal layer, it arises from the posterior surfaces of the clavicles and the manubrium of sternum, ascending to form a sheath for the thyroid gland and the group of infrahyoid muscles. As it extends upwards, it forms a sheath for the neurovascular bundle of the neck (carotid sheath), which invests the internal jugular vein, the common carotid artery, and the vagus nerve. The petracheal layer blends with the superficial layer at the posterior border of the sternocleidomastoid muscle.
Deep layer- Also called prevertebral fascia, it originates from the base of the skull, descending to invest the group of prevertebral muscles. Its lateral parts blend with the costal processes of the cervical vertebrae, forming an osteofibrous sheath for the prevertebral muscles. At the level of the third thoracic vertebra, its lower parts are continuous with the endothoracic fascia. On the periphery, this layer of the fascia passes over the scalenus muscles.
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