Hypoglossal nerve -segmental approach

The hypoglossal nerve, responsible for motor innervation to the tongue, can be affected along its five anatomical segments: medullary, cisternal, skull base, carotid space, and sublingual. Segmental localization of hypoglossal nerve palsy enables targeted diagnosis and appropriate investigation. We present four cases of hypoglossal nerve palsy evaluated using this approach. Case 1 involved a glomus jugulare tumor affecting the skull base segment. Case 2 presented with Horner’s syndrome and tongue deviation, revealing a malignant salivary neoplasm in the carotid space. Case 3 was diagnosed as squamous cell carcinoma of the tongue with sublingual segment involvement. Case 4 had acute hemiparesis and tongue deviation, consistent with medial medullary syndrome due to infarction of the medullary segment. Segmental analysis based on clinical presentation and imaging led to accurate localization in each case. This method is essential for identifying diverse pathologies along the nerve's course and improving diagnostic precision in hypoglossal nerve palsy.