The cervical fascia consists of concentric layers of fascia that compartmentalize structures in the neck (Figure 25-1). These fascial layers are defined as the superficial fascia and the deep fascia, with sublayers within the deep fascia. The fascia of the neck can determine the direction in which infection in the neck may spread.
Cross-section of the neck through the thyroid gland, showing the layers of the cervical fascia.
Superficial Cervical Fascia
The superficial cervical fascia is the subcutaneous layer of the skin in the neck. This thin layer contains the muscles of facial expression, including the platysma muscle in the neck. The cutaneous nerves, superficial vessels, and superficial lymph nodes course within the superior cervical fascia.
The deep cervical fascia is deep to the superficial fascia. The deep cervical fascia is condensed in various regions to form the following sublayers: the investing layer of the deep cervical fascia, the pretracheal fascia, the prevertebral fascia, and the carotid sheath. The function of the deep fascia is to provide containment of muscles and viscera in compartments, to enable structures to slide over each other, and to serve as a conduit for neurovascular bundles.
The investing fascia attaches as follows:
- Posteriorly to the nuchal ligament, completely encircling the neck and splitting to enclose the sternocleidomastoid and trapezius muscles.
- Superiorly to the hyoid bone and then splitting to enclose the submandibular gland.
- Along the mandible and splitting to enclose the parotid gland.
- Superiorly to the mastoid process, occipital bone, and zygomatic arch.
- Inferiorly along the acromion, scapular spine, clavicle, and manubrium.
The pretracheal fascia forms a tubular sheath in the anterior part of the neck. The pretracheal fascia extends superiorly from the hyoid bone and inferiorly to the thorax, where it blends with the fibrous pericardium. The pretracheal fascia:
- Encloses the infrahyoid muscles.
- Encloses separately the thyroid gland, trachea, and esophagus.
- Blends laterally with the carotid sheath.
- Is contiguous inferiorly with the buccopharyngeal fascia of the pharynx.
The prevertebral fascia forms a tubular sheath around the vertebral column and the prevertebral muscles, which are attached to the vertebral column. The prevertebral muscles are:
- Anteriorly, the longus colli and capitis muscles.
- Laterally, the anterior, middle, and posterior scalene muscles.
- Posteriorly, the deep cervical muscles.
- Attaches superiorly from the base of the skull and inferiorly to the endothoracic fascia in the thorax.
- Extends laterally as the axillary sheath, which surrounds the axillary vessels and brachial plexus of nerves to the upper limb.
- Contains, within its ...