Chapter 22: Deep Neck Space Infections and Parapharyngeal Space Neoplasms

DEEP NECK SPACE INFECTIONS

ANATOMY OF FASCIAL NECK PLANES AND SPACES

The spatial compartments within the neck are defined by multiple fascial planes. An understanding of this complex anatomy aids the clinician in determining the etiology, spread, and management of infections affecting these compartments (Figure 22–1).

The superficial layer of the deep cervical fascia (SLDCF) extends from the vertebral spinous processes anteriorly and laterally around the neck to its anterior attachments at the sternum, hyoid, and mandible. Along the way it splits to envelop the trapezius, sternocleidomastoid muscle (SCM), submandibular, and parotid glands, as well as the anterior belly of the digastric and mylohyoid muscles, thereby forming the inferior boundary of the submandibular space. The other boundaries of the submandibular space are the mucosa of the floor of mouth superiorly, the mandible anteriorly and laterally, and communication with the parapharyngeal space, posteriorly. The submandibular space may be subdivided further by the mylohyoid muscle into the sublingual and true submandibular portions, which are contiguous around the posterior free margin of the muscle.

Above the mandible, the SLDCF splits to encompass the masseter and pterygoid muscles, forming the lateral boundary of the parapharyngeal space. This space is limited medially by the bucopharyngeal fascia, which is a contribution of the middle layer of deep cervical fascia, and posteriorly by the carotid space, which is bounded by all 3 layers of the deep cervical fascia. Anteriorly, the parapharyngeal space communicates with the submandibular space.

The middle layer of deep cervical fascia (MLDCF) has 2 divisions: the muscular division, which surrounds the infrahyoid muscles, and the more clinically significant visceral division, which splits to form the pretracheal space by enveloping the laryngotrachea, pharynx, thyroid gland, and esophagus and extending to the mediastinum.

The deep layer of the deep cervical fascia (DLDCF) splits into an anterior “alar” division and a posterior “prevertebral” division, forming the so-called danger space, which extends from the skull base to the diaphragm. The alar division of the DLDCF comprises the posterior and lateral boundaries of the retropharyngeal space, which is bounded anteriorly by visceral division of the MLDCF and extends from the skull base to approximately the level of T3. The common path of the descending mediastinitis is inferior spread within the retropharyngeal space.

General Considerations

The usual etiology of deep space neck infections varies between children and adults. Deep space neck infections in children typically arise from pharyngitis, tonsillitis, and suppurative lymphadenitis, ...