Anatomy

It is bounded superiorly by the skull base, anteriorly by the alar fascia

Alar fascia

The alar fascia is a layer of fascia, sometimes described as part of the prevertebral fascia, and sometimes as in front of it.Anteriorly, it reaches the skull, and caudally, it reaches the second thoracic vertebra....

 and posteriorly by the prevertebral fascia

Prevertebral fascia

The prevertebral fascia is a fascia in the neck.-Variations:In some literature, the prevertebral fascia also includes the rest of the fascia extending around the vertebral column and enclosing all muscles laterally and posteriorly to it...

. It comes to an end at the level of the diaphragm.

The retropharyngeal space

Retropharyngeal space

The retropharyngeal space is a space bounded by the buccopharyngeal fascia anteriorly and the alar fascia posteriorly.It includes the retropharyngeal lymph nodes....

is found anterior to the danger space between the buccopharnygeal fascia and alar fascia. There exists a midline raphe in this space so some infections of this space appear unilateral.

Clinical significance

It gets its common name from the risk that an infection in this space can spread directly to the thorax, it is sometimes also referred to as the Alar space. It is a median space without a midline raphe and hence infection can spread easily to either side.

External links

• http://iris3.med.tufts.edu/headneck/spaces.htm
• http://www.bcm.edu/oto/grand/10694.html