Kolmiknärv

Kolmiknärv, also known as the trigeminal nerve, is the fifth cranial nerve and the largest of the cranial nerves. It is a mixed nerve, meaning it contains both sensory and motor fibers. The trigeminal nerve is responsible for transmitting sensory information from the face, scalp, and anterior parts of the head to the brain, as well as controlling the muscles involved in chewing.

The trigeminal nerve arises from the pons in the brainstem and quickly branches into three main divisions: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3). The ophthalmic nerve supplies sensation to the forehead, scalp, upper eyelid, cornea, and the bridge of the nose. The maxillary nerve provides sensory input from the lower eyelid, cheek, nostril, upper lip, and upper teeth. The mandibular nerve carries both sensory information from the lower lip, chin, jaw, and lower teeth, as well as motor control to the muscles of mastication (chewing), including the temporalis, masseter, and pterygoid muscles.

Sensory signals from the face travel through these divisions to the trigeminal ganglion, a cluster of nerve cell bodies located in the middle cranial fossa. From the ganglion, the sensory fibers ascend to the brainstem and then to the thalamus and the somatosensory cortex for conscious perception.

Dysfunction of the trigeminal nerve can lead to various conditions, the most common being trigeminal neuralgia, a disorder characterized by sudden, severe facial pain. Other issues can include sensory loss, weakness in chewing muscles, and abnormal reflexes.