The =superficial fascia= is in part two-layered, and contains the
cervical portion of the panniculus. The fasciæ of the right and left
sides are attached along the dorsal line of the neck to the ligamentum
nuchæ, while along the ventral line they meet in a fibrous raphé. A deep
layer is detached which passes underneath the panniculus, bridges over
the jugular furrow, and crosses over the deep face of the
mastoido-humeralis and omo-hyoideus to join the superficial layer. It
again separates to pass under the cervical trapezius, and become
attached to the ligamentum nuchæ. Along the ventral line a septum is
detached which separates the sterno-cephalici. Two other layers in front
of the shoulder inclose the prescapular lymph glands.
The =deep fascia= also forms two layers. The =superficial layer= is
attached to the wing of the atlas and the lower edge of the
trachelo-mastoideus and scalenus. Passing downward, it incloses the
trachea, and, together with the deep layer, furnishes sheaths for the
vagus and sympathetic nerves and the carotid artery. Passing upward it
detaches septa between the extensor muscles of the spine. Anteriorly it
covers the thyroid gland, the guttural pouch, the adjacent vessels and
nerves and the larynx, and is attached to the mastoid process of the
temporal bone and the thyroid cornu of the hyoid bone. Posteriorly, it
is attached to the first rib and the cariniform cartilage of the
sternum. The =deep layer= (prevertebral fascia) covers the ventral
surface of the longus colli, and incloses the trachea and œsophagus.
Anteriorly, it forms, with the corresponding layer of the opposite side,
a septum between the guttural pouches; posteriorly, it becomes
continuous with the endothoracic fascia. A =fascia propria= forms a
tubular sheath around the trachea, inclosing also the recurrent nerves.