Hypoglossal Nerve, Lateral View

Description

Arising from the medulla and exiting the skull via the hypoglossal canal, the hypoglossal nerve (CN XII) is traced in lateral profile as it descends in the upper neck and then turns anteriorly toward the tongue. Along its cervical course it lies deep to the angle of the mandible, inferior to the external acoustic meatus, and anterior to the upper cervical vertebrae, with the hyoid region and floor of mouth forming its anterior target territory. Neighboring cranial and cervical nerves are also rendered in yellow, allowing orientation to the parotid, submandibular, and suprahyoid region without obscuring the bony landmarks of the cranium, mandible, and cervical spine. Spatial relationships read cleanly. Teeth, nasal cavity, and auricular structures anchor the lateral anatomy. Clinically, CN XII matters because its long extracranial course makes it vulnerable at predictable choke points, including carotid endarterectomy exposure near the carotid bifurcation, submandibular gland surgery, and trauma around the mandibular angle. Iatrogenic hypoglossal palsy produces ipsilateral tongue weakness with deviation toward the injured side on protrusion, a bedside sign that maps directly onto the motor supply of intrinsic and extrinsic tongue muscles. This view also helps teach the distinction between isolated CN XII lesions and more proximal skull base syndromes where multiple lower cranial nerves travel together. Use this illustration for head and neck anatomy teaching in medical and dental curricula, for operative anatomy figures in vascular and otolaryngology texts, or as a patient-facing graphic when counseling about post-operative tongue weakness after neck dissection or carotid surgery. It also suits neuroradiology correlation when explaining lesion localization from the hypoglossal canal to the sublingual space. Anatomical accuracy verified by SciePro's Medical Advisory Board.