Trigemimusnerven

Trigemimusnerven, also known as the trigeminal nerve (nervus trigeminus in Latin), is the fifth cranial nerve. It is the largest cranial nerve and serves a dual role as the main conduit for somatic sensation from the face and, in its mandibular division, as a motor nerve to muscles of mastication. The nerve emerges from the brainstem, with a larger sensory root and a smaller motor root that join to form the nerve trunk. It exits the skull through three different foramina for its divisions: V1 (ophthalmic) via the superior orbital fissure, V2 (maxillary) via the foramen rotundum, and V3 (mandibular) via the foramen ovale.

The trigeminal nerve splits into three main divisions. V1 is purely sensory and supplies the forehead, scalp, upper eyelid, and cornea; V2 is also sensory, innervating the midface, upper cheek, upper lip, nasal cavity, palate, and maxillary teeth; V3 carries both sensory and motor fibers, providing general sensation to the lower face and mandible and motor innervation to the muscles of mastication (masseter, temporalis, medial and lateral pterygoids) as well as to the tensor tympani, tensor veli palatini, and the anterior belly of the digastric and mylohyoid.

The sensory cell bodies reside in the trigeminal (Gasserian) ganglion. Central processes project to the principal (chief) sensory nucleus and the spinal trigeminal nucleus in the brainstem, while motor fibers originate from the motor nucleus of V and travel with V3 to the masticatory muscles.

Clinical relevance includes trigeminal neuralgia, facial numbness, or weakness of mastication. Diagnostic assessments often involve testing facial sensation, corneal reflexes, and, when indicated, imaging to assess vascular compression or lesions along the nerve’s pathway.