Hypoglossal canal
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At the time the article was created Frank Gaillard had no recorded disclosures.
View Frank Gaillard's current disclosuresAt the time the article was last revised Alex Zheng had no financial relationships to ineligible companies to disclose.
View Alex Zheng's current disclosuresThe hypoglossal canal is located between the occipital condyle and jugular tubercle and runs obliquely forwards (posteromedial to anterolateral) allowing the hypoglossal nerve to exit the posterior cranial fossa.
Its proximal portion is often divided by a fibrous (sometimes ossified) septum, which separates the two roots of the hypoglossal nerve (these have formed by the convergence of numerous rootlets). These roots merge within the canal and a single nerve emerges.
In addition to the hypoglossal nerve, the canal also allows a meningeal branch of the ascending pharyngeal artery to enter the skull, as well as multiple veins to exit the skull, forming the hypoglossal venous plexus 5.
Radiographic features
The hypoglossal canal is most easily identified on axial or coronal images through the occipital condyles, where it can be seen passing anterolaterally from the posterior fossa into the upper neck.
On coronal imaging, the jugular tubercle appears beak-like extending over the hypoglossal canal. Combined with occipital condyle the coronal appearance is reminiscent of an eagle seen in profile, making this a convenient landmark 3,4.
Variant anatomy
may be enlarged and contain a persistent hypoglossal artery
osseous spurs protruding into the canal 6
complete osseous bridging along part or all of the length of the canal 6
Quiz questions
References
- 1. McMinn. Lasts Anatomy Regional and Applied. Churchill Livingstone. (2003) ISBN:B0084AQDG8. Read it at Google Books - Find it at Amazon
- 2. Carmine D. Clemente. Anatomy. (2011) ISBN: 9781582558899 - Google Books
- 3. Osborn A, Brinton W, Smith W. Radiology of the Jugular Tubercles. AJR Am J Roentgenol. 1978;131(6):1037-40. doi:10.2214/ajr.131.6.1037 - Pubmed
- 4. M. Thu, N. Waters, M. Gandhi, J. Sommerville. A Pictorial Review - Hypoglossal Canal. European Congress of Radiology - 2015 ASM. 2015. https://epos.myesr.org/poster/ranzcr/ranzcr2015/R-0091
- 5. Hacein-Bey L, Daniels D, Ulmer J et al. The Ascending Pharyngeal Artery: Branches, Anastomoses, and Clinical Significance. AJNR Am J Neuroradiol. 2002;23(7):1246-56. PMC8185735 - Pubmed
- 6. Paraskevas G, Tsitsopoulos P, Papaziogas B, Kitsoulis P, Spanidou S, Tsitsopoulos P. Osseous Variations of the Hypoglossal Canal Area. Med Sci Monit. 2009;15(3):BR75-83. - Pubmed
Incoming Links
- Inferior petrosal sinus
- Persistent hypoglossal artery
- Hypoglossal nerve
- Cranial foramina
- Marginal sinus (foramen magnum)
- Tectorial membrane of the spine
- Persistent proatlantal intersegmental artery
- Occipital condyle syndrome
- Proatlantal artery
- Posterior cranial fossa
- Occipital bone
- Anterior condylar confluence
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