Danger space

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Danger space
Section of the neck at about the level of the sixth cervical vertebra. Showing the arrangement of the fascia coli.
Anatomical terminology

The danger space or alar space, is a region of the neck.[1] The common name originates from the risk that an infection in this space can spread directly to the thorax, and, due to being a space continuous on the left and right, can furthermore allow infection to spread easily to either side.


It is bounded at the top by the skull base, at the front by the alar fascia and behind by the prevertebral fascia. It comes to an end at the level of the diaphragm.

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

Clinical significance[edit]

On CT or MRI it is only visible when distended by fluid or pus, below the level of T1-T6, as the retropharyngeal space ends at this level, allowing distinction between the two entities.[2]


It was first characterized in 1938.[3][4]

See also[edit]


  1. ^ Reynolds SC, Chow AW (2009). "Severe soft tissue infections of the head and neck: a primer for critical care physicians". Lung. 187 (5): 271–9. doi:10.1007/s00408-009-9153-7. PMID 19653038.
  2. ^ Hoang, JK; Branstetter BF, 4th; Eastwood, JD; Glastonbury, CM (April 2011). "Multiplanar CT and MRI of collections in the retropharyngeal space: is it an abscess?". AJR. American Journal of Roentgenology. 196 (4): W426–32. doi:10.2214/AJR.10.5116. PMID 21427307.
  3. ^ Adelson, Robert T. (2005). "Minimally invasive transoral catheter-assisted drainage of a danger-space infection". Ear, Nose & Throat Journal. Retrieved 2008-02-18.
  4. ^ Grodinsky M, Holyoke EA. The fasciae and fascial spaces of the head, neck and adjacent regions. Am J Anat 1938;63:367-408.

External links[edit]