Obex

Obex

Hind-brain of a human embryo of three months—viewed from behind and partly from left side.

Rhomboid fossa.
Details
Latin Obex
Identifiers
Gray's p.797
NeuroNames hier-633
NeuroLex ID Obex
Dorlands
/Elsevier
o_01/12585770
TA A14.1.04.021
FMA 78490
Anatomical terms of neuroanatomy

The obex (from the Latin for barrier) is the point in the human brain at which the fourth ventricle narrows to become the central canal of the spinal cord.

The obex occurs in the caudal medulla.

The decussation of sensory fibers happens at this point.

Clinical significance

Lesions at the location can result in obstructive hydrocephalus. The most common lesion at this location is a subependymoma, a benign tumor.[1] Hemangioblastoma has been observed in this location.[2] Neurological surgical intervention in the treatment of syringomyelia or hydromyelia may involve plugging the obex to prevent the transmission of cerebrospinal fluid to the central canal of the spinal cord.

Additional images

References

  1. Hoeffel, C; Boukobza, M; Polivka, M; Lot, G; Guichard, JP; Lafitte, F; Reizine, D; Merland, JJ (Nov–Dec 1995). "MR manifestations of subependymomas.". AJNR. American journal of neuroradiology 16 (10): 2121–9. PMID 8585504.
  2. Pavesi G, Berlucchi S, Feletti A, Opocher G, Scienza R (July 2006). "Hemangioblastoma of the obex mimicking anorexia nervosa". Neurology 67 (1): 178–9. doi:10.1212/01.wnl.0000223354.86636.ed. PMID 16832109.