eRadiograph Volume 7: Imaging of Oral Cavity | Page 290

Introduction: The retropharyngeal space is a fat filled midline space which lies
posterior to the pharynx and oesophagus.
Extent and Anatomy: It extends superiorly from the base of the skull inferiorly to the
upper mediastinum. It is bounded by the bucopharyngeal fascia anteriorly and the
prevertebral fascia posteriorly. The retropharyngeal space is bounded by the carotid
spaces laterally, Anteriorly by the pharyngeal mucosal space in the suprahyoid neck
and the visceral space in the infrahyoid neck. Anterolaterally by the parapharyngeal
space and posteriorly by the perivertebral space. A mass lesion in the retropharyngeal
space displaces the parapharyngeal space anterio-laterally, pharyngeal mucosal space
anteriorly, carotid space laterally and remains anterior to the prevertebral muscles.
Medially from the carotid sheaths extends the alar fascia which divides the
retropharyngeal space into two parts, an anterior component known as true
retropharyngeal space and a posterior component known as the danger space. This
alar fascia extends from the clivus superiorly to fuse with the visceral fascia between C1
and C6 level inferiorly. This fusion of the alar fascia with the visceral fascia obliterates
the true retropharyngeal space marking the inferior end of the true retropharyngeal
space. The posterior danger space extends from the clivus to the diaphragm. The
danger space acts as a conduit for spread of infection from the pharynx to the posterior
mediastinum. The retropharyngeal space can also be divided into supra hyoid and infra
hyoid components as their contents differ.

Pathology:
Infection and Abscess
These nodes are present in children and atrophy by puberty. In children these lymph
nodes may get infected to from a retropharyngeal abscesses. In adults retropharyngeal
abscesses occur due to penetrating injuries or spread of infectious process from other
neck spaces. Infectious processes which gain access to the retropharyngeal space have
a potential to extend into the posterior retropharyngeal space so called danger space
extending to the posterior mediastinum.
Tortous Internal Carotid Artery:
Atherosclerotic ectasia of the carotid arteries may result in the carotid arteries taking a
more medial course and extending into the lateral aspect of the retropharyngeal space.
When both carotids are involved they may come very close referred to as kissing
carotids. These present as a pulsatile mass in the lateral pharynx and referred to as a
pseudomass.

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Retropharyngeal Space

Content: The suprahyoid component contains fat and lymph nodes, the infrahyoid
component only contains fat. There are two groups of nodes in the supra hyoid
component- medial and lateral. The medial group are inconsistently present, the lateral
group is known as nodes of rouvier.