Deep spaces of the head and neck

Head and neck anatomy is described in slightly different terms in the radiology literature reflecting the importance of fascia lined spaces in confining various pathologies. As such the neck has been divided into a number of 'deep spaces' which overlap with traditional anatomical description.

A knowledge of these spaces not only allows for better communication between radiologists and specialists familiar with imaging of this region but also aid in diagnosis as each space has a distinct group of pathologies. 

Gross anatomy

The anatomy of the neck can be divided into suprahyoid and infrahyoid portions:

• suprahyoid neck: encompasses the deep spaces between the base of the skull and hyoid bone
• infrahyoid neck: lies inferiorly between the hyoid bone and clavicles

Three layers of deep cervical fascia form the boundaries of the deep spaces in the neck:

1. investing fascia completely surrounds the neck and splits to enclose the sternocleidomastoid and trapezius muscles
2. pretracheal fascia encloses the contents of the visceral space
3. prevertebral fascia encloses the paraspinous and prevertebral muscles to form the prevertebral space

All three layers meet at the carotid sheath which is a dense feltwork of areolar tissue that surrounds the carotid arteries, internal jugular vein and vagus nerve.

Contents

The deep anatomy is separated by fascial planes into deep compartments, and by the hyoid bone into supra- and infrahyoid neck ¹. Please note that the divisions are arbitrary in there is some continuation of suprahyoid neck spaces into the infrahyoid neck spaces, and continuation of some infrahyoid neck spaces into the superior mediastinum. 

• supra- and infrahyoid neck
  • carotid space (post-styloid parapharyngeal space)
  • retropharyngeal space and danger space
  • perivertebral space (including prevertebral space)
  • posterior cervical space
• suprahyoid neck
  • parapharyngeal space (pre-styloid parapharyngeal space)
  • masticator space
  • buccal space
  • parotid space
  • sublingual space
  • submandibular space
  • pharyngeal mucosal space
• infrahyoid neck
  • anterior cervical space
  • visceral space

Relations

• parapharyngeal space lies in a central location in the deep face
• pharyngeal mucosal space is medial to the parapharyngeal space
• masticator space is anterior to the parapharyngeal space
• parotid space is lateral of the parapharyngeal space
• carotid space is posterior to the parapharyngeal space
• retropharyngeal space is posterior to parapharyngeal space
• perivertebral space is posterior to the retropharyngeal space

Related pathology

Many of the disease states that affect the deep structures of the head and neck are confined to one compartment. However, there are some diseases that are considered trans-spacial diseases. A list of differentials for related pathology can be found in the article for each individual space.