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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.
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SUPERFICIAL CERVICAL FASCIA
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The superficial cervical fascia is the subcutaneous layer of the skin in the neck and contains the platysma muscle, cutaneous nerves from the cervical plexus, and superficial vessels and lymph nodes.
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The deep cervical fascia is deep to the superficial fascia and contains muscles and viscera in compartments to enable structures to slide over each other, and to serve as a conduit for neurovascular bundles; forms the following sublayers:
Deep investing fascia. Completely encircles the neck and splits to enclose the sternocleidomastoid and trapezius muscles; forms the roof of the anterior and posterior triangles of the neck.
Pretracheal fascia. Forms a tubular sheath in the anterior part of the neck and extends from the hyoid bone inferiorly into the thorax to blend with the fibrous pericardium.
Contents. Thyroid gland, parathyroid glands, trachea, and esophagus.
Buccopharyngeal fascia. The name of the posterior portion of the pretracheal fascia.
Prevertebral fascia. Forms a tubular sheath around the vertebral column and forms the floor of the posterior triangle of the neck.
Contents. Sympathetic trunk, phrenic nerve, brachial plexus, cervical vertebrae and prevertebral muscles (i.e., longus colli, longus capitis and scalene muscles).
Alar fascia. The anterior lamina of prevertebral fascia has two layers; the anterior layer is referred to as alar fascia.
Axillary sheath. The prevertebral fascia extends laterally as the axillary sheath, which surrounds the axillary vessels and branchial plexus.
Carotid sheath. A tube of fascia that extends from the cranial base to the root of the neck; formed by the investing, pretracheal, and prevertebral layers of fascia.
Contents. Common and internal carotid arteries, internal jugular vein, vagus nerve, deep cervical lymph nodes, and carotid sinus nerve.
Retropharyngeal space. Located between the buccopharyngeal and alar fascia, extends from the skull base to the upper thoracic vertebrae and is the most clinically important interfascial space in the neck.
Contents. Lymph nodes, adipose and loose connective tissue; this is a potential space where normally nothing fills it. However, an abscess can spread easily in this location.
Function. Permits superior and inferior movements of the larynx, pharynx, and esophagus during swallowing relative to the cervical vertebrae.
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Retropharyngeal abscess. Abscesses within the retropharyngeal space may bulge anteriorly and compress the pharynx (swallowing compromised) and trachea (breathing compromised) or spread ...