hypoglossal nerve
Pronunciation: hy-po-GLOS-al
Cranial nerve XII responsible for motor innervation of intrinsic and most extrinsic tongue muscles.
Full Definition
The hypoglossal nerve is the twelfth cranial nerve that provides motor innervation to the intrinsic muscles of the tongue and most extrinsic tongue muscles, with the exception of the palatoglossus muscle. The nerve exits the skull through the hypoglossal canal and courses superficial to the hyoid bone before entering the tongue. In maxillofacial surgery, the hypoglossal nerve is at risk during procedures involving the floor of mouth, submandibular space, and major oral and oropharyngeal reconstructions. Injury to this nerve results in ipsilateral tongue paralysis, leading to speech difficulties, swallowing problems, and tongue deviation toward the affected side. The nerve may be used as a donor for facial nerve reconstruction in cases of permanent facial paralysis.
Usage
Usage note: May be abbreviated as CN XII in clinical documentation.
In Context
- "Careful dissection was required to preserve the hypoglossal nerve during submandibular gland excision." — operative report
- "Hypoglossal nerve injury resulted in ipsilateral tongue paralysis and speech impairment." — complication documentation