What is the anatomy of the fascial planes relevant to deep neck infections?

Updated: Apr 30, 2020
  • Author: Alan D Murray, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Two main fascial divisions exist, the superficial cervical fascia and the deep cervical fascia.

  • Superficial cervical fascia: The superficial fascia, which lies just deep to the dermis, surrounds the muscles of facial expression. It includes the superficial musculoaponeurotic system (SMAS) and extends from the epicranium to the axillae and chest. The space deep to this layer contains fat, neurovascular bundles, and lymphatics. It does not constitute part of the deep neck space system.

  • Deep cervical fascia: The deep cervical fascia encloses the deep neck spaces and is further divided into 3 layers, the superficial, middle, and deep layers of the deep cervical fascia.

    • The superficial layer of the deep cervical fascia is an investing fascia that surrounds the neck. It encompasses the sternocleidomastoid muscle, trapezius, muscles of mastication, and submandibular and parotid glands. It is limited superiorly by the nuchal ridge, mandible, zygoma, mastoid, and hyoid bones. Inferiorly, it is bounded by the clavicles, sternum, scapula, hyoid, and acromion. It contributes to the fascia covering the digastric muscle and to the lateral aspect of the carotid sheath. In its course from the hyoid bone to the medial table of the ramus of the mandible, it envelops the anterior belly of the digastric muscle and forms the floor of the submandibular space. Laterally, this fascia helps to define the parotid and masticator spaces.

    • The middle layer of the deep cervical fascia has 2 divisions, muscular and visceral. The muscular division surrounds the strap muscles (ie, sternohyoid, sternothyroid, thyrohyoid, omohyoid) and the adventitia of the great vessels. The visceral division surrounds the constrictor muscles of the pharynx and esophagus to create the buccopharyngeal fascia and the anterior wall of the retropharyngeal space. Both the muscular and visceral divisions contribute to the formation of the carotid sheath. The middle layer also envelops the larynx, trachea, and thyroid gland. It attaches to the base of the skull superiorly and extends inferiorly as low as the pericardium via the carotid sheath.

    • The deep layer of the deep cervical fascia is also subdivided into 2 divisions, prevertebral and alar. The prevertebral division adheres to the anterior aspect of the vertebral body and extends laterally to the transverse processes of the vertebrae. The alar division lies between the prevertebral division and the visceral division of the middle layer and defines the posterior border of the retropharyngeal space. It surrounds the deep neck muscles and contributes to the carotid sheath. Posteriorly, the muscular division of the middle layer of the deep cervical fascia fuses with the alar division of the deep layer of the deep cervical fascia at the level of thoracic vertebrae 1-2 (T1-T2).


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