Surgical anatomy of hypoglossal nerve as a guide for important head and neck surgeries

Abstract

IntroductionThe hypoglossal nerve (HN) may be damaged during neck surgeries. A detailed understanding of the anatomy of the hypoglossal nerve in relation to various anatomical landmarks and surrounding structures is important to reduce procedural complications and the risk of nerve damage. MethodsThe study was carried out using 21 sagittal sections of head and neck of male cadavers (16 right and 5 left). To measure the required parameters the anatomical landmarks taken were the posterior belly of digastric muscle (PBD), descendens hypoglossi of ansa cervicalis (AC), bifurcation of common carotid artery (CCA), tip of the mastoid process (TMP), lingual artery (LA) at the posterior border of hyoglossus muscle, tip of greater cornu of hyoid bone (GH), bifurcation of CCA to the attachment of descendens hypoglossi (CCA-AC). ResultsThe length of PBD was 3.77±1.08cm on right side and 3.15±0.05cm on left side. The extended length was measured from the TMP to GH which was 6.7±1.23cm on right side and 6.75±0.75 on left side. The distance between HN to the GH did not vary much between right and left sides which were 1.21±0.35 and 1.2±0.69cm respectively. The distance between HN and LA at the posterior border of hyoglossus was 1.12±0.3cm on right side and 0.5±0.3cm on left side. DiscussionHN dissection is more complicated, as the location of the HN is much deeper. Moreover, there are no bony landmarks around the HN. Therefore PBD, CCA, ICA, ECA, LA were used as landmarks for HN in head and neck surgeries.