[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › Hypoglossal canal [Skeletal system](https://durgical.com/en/anatomy/system/skeletal-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # Hypoglossal canal The hypoglossal canal is a canal above the occipital condyle at the skull base; it carries the hypoglossal nerve, which moves the tongue. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=hypoglossal_canal&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A canal above the occipital condyle. ## What it does Carries the hypoglossal nerve (XII). ## Key points - A lesion in the canal paralyses one half of the [tongue](https://durgical.com/en/anatomy/tongue/): on protrusion it points toward the damaged side, with wasting and fasciculations on that side - It lies a few millimetres from the jugular foramen: a skull base lesion involving both adds XII to IX, X and XI (Collet-Sicard syndrome); with Horner syndrome as well it is called Villaret syndrome - It runs above the occipital condyle, so condyle fractures and surgery that removes part of the condyle can injure the nerve ## Key facts **Where** Occipital bone, above each occipital condyle **Function** Transmits the hypoglossal nerve (XII) ## Relations **Contents** [Hypoglossal nerve (XII)](https://durgical.com/en/anatomy/hypoglossal-nerve/), a meningeal branch of the ascending pharyngeal artery and a venous plexus joining the veins of the skull base to the [internal jugular vein](https://durgical.com/en/anatomy/internal-jugular-vein/) **Course** Runs forward and laterally through the [occipital bone](https://durgical.com/en/anatomy/occipital-bone/), from an inner opening just above the front edge of the [foramen magnum](https://durgical.com/en/anatomy/foramen-magnum/) to an outer opening above the front of the occipital condyle **Above** Jugular tubercle on the inner surface of the bone; above and lateral, the [jugular foramen](https://durgical.com/en/anatomy/jugular-foramen/) **Below** Occipital condyle, which articulates with the [atlas](https://durgical.com/en/anatomy/atlas/) **Medial** [Medulla oblongata](https://durgical.com/en/anatomy/medulla-oblongata/), from whose groove between pyramid and olive the nerve rootlets emerge; the [vertebral artery](https://durgical.com/en/anatomy/vertebral-artery/) climbs nearby through the foramen magnum ## How to find it It cannot be felt. On the inner skull base it opens just above the anterolateral edge of the foramen magnum; from below, it is found by looking up into the groove above the front of each occipital condyle. Coronal CT shows it with the condyle below and the jugular tubercle above. ## Examination - Tongue protrusion: the tip points toward the damaged side; wasting and fine twitching (fasciculations) of that half mark a lower motor neuron lesion, such as one in the canal - Tongue pushed into the cheek against the examiner's finger: the push is weak into the cheek on the side opposite the lesion ## On imaging Thin-slice CT shows the bony canal and whether a tumour has widened or eroded it; MRI with contrast shows the nerve and lesions such as a hypoglossal schwannoma, a paraganglioma spreading from the jugular foramen, metastases or a dural arteriovenous fistula. ## Clinical notes - Causes of an isolated hypoglossal palsy at the skull base include metastases, chordoma, schwannoma, occipital condyle fractures and, lower in the neck, [internal carotid artery](https://durgical.com/en/anatomy/internal-carotid-artery/) dissection - Occipital condyle fractures after high-energy trauma can injure XII in the canal, sometimes together with the other lower cranial nerves - In far-lateral approaches to the foramen magnum the canal limits how much of the condyle can be drilled away ## Anatomical variants - A bony bridge can divide the canal in two (double hypoglossal canal), on one or both sides; texts differ on how often ## Development All the tongue muscles except palatoglossus arise from one premuscle mass, of occipital somite origin, that carries the hypoglossal nerve forward with it; this is why one nerve, leaving through this canal, supplies them. ## Test yourself Think of the answer, then tap the question to see it. ## Which nerve passes through the hypoglossal canal, and what does a lesion there do to the tongue? The hypoglossal nerve (XII); the tongue points toward the damaged side on protrusion, with wasting and fasciculations on that side. ## What is Collet-Sicard syndrome, involving the hypoglossal canal? A skull base lesion involving the jugular foramen and hypoglossal canal, adding XII palsy to IX, X and XI; with Horner syndrome it is Villaret syndrome. ## Why can occipital condyle fractures injure the hypoglossal nerve? The hypoglossal canal runs just above the occipital condyle. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/hypoglossal-canal/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** canalis hypoglossus TA2 559 **Official Spanish (DeCS)** Conducto del nervio hipogloso **English (TA2)** Hypoglossal canal **Also called** anterior condylar foramen · anterior condylar canal · canalis hypoglossi ## Related - [Hypoglossal nerve (XII)](https://durgical.com/en/anatomy/hypoglossal-nerve/) Sources: Terminologia Anatomica (TA2); [Anatomy, Head and Neck, Skull Foramen](https://www.ncbi.nlm.nih.gov/books/NBK546621/); [Neuroanatomy, Cranial Nerve 12 (Hypoglossal)](https://www.ncbi.nlm.nih.gov/books/NBK532869/); [16.3 The Cranial Nerve Exam](https://openstax.org/books/anatomy-and-physiology-2e/pages/16-3-the-cranial-nerve-exam) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/); Anatomy of the Human Body (20th ed.): Development of the Muscles (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/hypoglossal-canal/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/hypoglossal-canal/