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The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated by the vagus nerve. [a] CN XII is a nerve with a sole motor function.
Sometimes: cranial accessory, spinal accessory. Mainly motor Cranial and Spinal Roots Located in the jugular foramen. Controls the sternocleidomastoid and trapezius muscles, and overlaps with functions of the vagus nerve (CN X). Symptoms of damage: inability to shrug, weak head movement. XII Hypoglossal: Mainly motor Medulla
Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs.Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck, including the special senses of vision, taste, smell, and hearing.
The lingual nerve supplies general somatic afferent (i.e. general sensory) innervation to the mucous membrane of the anterior two-thirds of the tongue (i.e. body of tongue) (whereas the posterior one-third (i.e. root of tongue) is innervated via the glossopharyngeal nerve (CN IX) [citation needed]), the floor of the oral cavity, and the mandibular/inferior lingual gingiva.
Unilateral loss indicates a possible nerve lesion or deviated septum. This test is usually skipped on a cranial nerve exam. [1] The short axons of the first cranial nerve regenerate on a regular basis. The neurons in the olfactory epithelium have a limited life span, and new cells grow to replace the ones that die off.
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue.
Injury to the chorda tympani nerve leads to loss or distortion of taste from anterior 2/3 of tongue. [13] However, taste from the posterior 1/3 of tongue (supplied by the glossopharyngeal nerve) remains intact. The chorda tympani appears to exert a particularly strong inhibitory influence on other taste nerves, as well as on pain fibers in the ...
Many voluntary movements rely on spinal lower motor neurons, which innervate skeletal muscle fibers and act as a link between upper motor neurons and muscles. [2] [3] Cranial nerve lower motor neurons also control some voluntary movements of the eyes, face and tongue, and contribute to chewing, swallowing and vocalization. [4]