Vertebrobasilar dolichoectasia with hypoglossal nerve palsy 40. This is found the full length of the medulla, close to the midline. This article covers the anatomy, muscles, neurovasculature, and histology of the tongue. The hypoglossal nucleus is a thin and long nucleus lies in the ventral portion of the medulla, near the midline. The nerve has a purely somatic motor function, innervating all the extrinsic and intrinsic muscles of the tongue except the palatoglossus, innervated by vagus nerve in this article, we shall look at the anatomy of the hypoglossal. Cervical nerve fibers could be observed within the hypoglossal nerve even after. The hypoglossal nerve is the twelfth cranial nerve, and innervates all the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus which is innervated by the vagus nerve.
The nerve arises from the hypoglossal nucleus in the medulla as a number of small rootlets, passes through the hypoglossal canal and down through the. The findings indicated that the branching pattern of the hypoglossal nerve is characterized by the positional relationships to the components of the extrinsic muscles. This is one of many videos provided by clutch prep to prepare you to succeed in your college classes. Isolated unilateral hypoglossal nerve palsy due to. Hypoglossal nerve an overview sciencedirect topics. The sihler stained hypoglossal nerves demonstrate branches to the styloglossus.
The hypoglossal nerve hn may be damaged during neck surgeries. We report an unusual intraoperative finding of an aberrant branch of the hypoglossal nerve, encountered during a. The hypoglossal nerve cn xii is the motor nerve of the tongue. From the hypoglossal nucleus in the medulla oblongata, general somatic efferent fibres exit the cranial cavity through the hypoglossal canal and enter the neck in close proximity. The path of the nerve starts in the hypoglossal nucleus of. Iatrogenic hypoglossal nerve palsy practical neurology. Tracking the glossopharyngeal nerve pathway through anatomical. Further, cervical nerve fibers were continuously issued to the peripheral layers of the hypoglossal nerve where the fibers of the two nerves intermingled, forming a. This definition incorporates text from a public domain edition of gray s anatomy 20th u.
Department of anatomy, kasturba medical college, manipal, karnataka, india. This video is part of a playlist of short videos which are intended to combine multiple choice questions answering experience with an improved understanding of anatomy. The region is discussed under two subsections, the hard tissue framework and the soft tissue envelope to describe the skeletal anatomy and the connective tissues, nerves, and vascular anatomy of the region. Hypoglossal nerve applied anatomy unilateral injurytip tilts towards paralysed side atrophy.
Surgical anatomy of the cervical part of the hypoglossal nerve. The nerve emerges from the medulla laterally, between the pyramid and the olive as a number of rootlets. The hypoglossal nerve arises from the hypoglossal nucleus. The nerve can be transected during trauma or surgery but there are also several reports in the otolaryngology, anesthesia, and neurology literature concerning iatrogenic hypoglossal nerve palsy without direct nerve injury following tonsillectomy, 1,2 laryngoscopy, 3 transoral intubation, 4 use of the laryngeal mask airway lma 5 tooth. The hypoglossal nerve is the twelfth cranial nerve and controls movements of the tongue. Pdf with 8 figures this study aimed at revealing the origin, course and distribution of the hypoglossal nerve in 20. The hypoglossal nerve is the twelfth cranial nerve, and innervates all the extrinsic and intrinsic. It gives motor innervation to muscles of the tongue. Clinical pharmacology and therapeutics 8th edition free pdf download. In this study, the bifurcation of the superior root of the. The hypoglossal canal is formed during the embryological stage of development in mammals, sometimes leading to the presence of more than two canals as the occipital bone is formed. Microsurgical anatomy of the hypoglossal nerve request pdf. Cervical nerve fibers could be observed within the hypoglossal nerve even after the ramification of those branches.
The hypoglossal nerve supplies all the muscles of the tongue including the. Pdf origin, course and distribution of the hypoglossal nerve in. The roots of the hypoglossal nerve itself arise between the olive and the pyramid. Cisternal hypoglossal schwannoma with tongue atrophy 42. Correlation of in vitro mr images with histologic sections. All the intrinsic and extrinsic tongue muscles are supplied by the hypoglossal nerve cranial nerve xii except the palatoglossus, which is supplied by the pharyngeal branch of the vagus nerve.
Hypoglossal nerve xii the area of attachment of a cranial nerve to the surface of the brain is termed its superficial or apparent origin. Grays anatomy 38 1999 sensory afferent nerve motor efferent nerve. The hypoglossal nerve, providing motor innervation for the tongue, can be affected in many diseases of the neck and skull base, leading to dysarthria, dysphagia, and ultimately atrophy of the tongue. The nerve originates from its motor nucleus, simply called the nucleus of the hypoglossal nerve, or hypoglossal nucleus. The sensory neurons in the olfactory epithelium are outside the meninges and below the cribriform plate. Morphological features of the branching pattern of the hypoglossal nerve. Extracranial course of the hypoglossal nerve, left view. Isolated hypoglossal palsy caused by synovial cyst 43. It is comprised of both superior and inferior roots. Subject anatomy yousef omar correction doctor mohammad. Other articles where hypoglossal nerve is discussed. The axons of the hypoglossal nucleus run in a ventral and slightly lateral direction and emerge as 1015 fiber bundles on the ventral surface of the lower medulla. This nerve also carries secretomotor fibres to the submandibular and sublingual glands.
Variant anatomy of the hypoglossal nerve is very rare. So thats all on clinical anatomy of the cranial nerves. The hypoglossal nerve is the twelfth and last cranial nerve and supplies the tongue with motor control. Hypoglossal nerve 12th cranial nerve detailed anatomy. The superior root of the ansa cervicalis, the ramus descendens hypoglossi, travels with the hypoglossal nerve and descends along the anterior wall of the carotid sheath. Robertson is senior staff neurologist at henry ford hospital in detroit, michigan. Nerve modality nucleus location distribution hypoglossal nerve gse hypoglossal nucleus medulla motor innervation to all tongue muscles except palatoglossus function 3.
Accessory and hypoglossal nerves cranial nerves xi, xii. Vascular, inflammatory, traumatic, or spaceoccupying lesions can affect the cn xii anywhere in its course, from the nucleus in the caudal medulla, through the intracranial extramedullary portion of the nerve, across the hypoglossal canal, or into its extracranial. We describe the anatomical course, function, pathology and major clinical syndromes. We hypothesize that the human tongue is supplied more richly with motor nerves than are those of living apes and propose that canal size in fossil hominids. The hypoglossal canal and the origin of human vocal. This canal is absolutely and relatively larger in modern humans than it is in the african apes pan and gorilla. Improved gray white differentiation may be due to much greater t1 shortening. Nasopalatine nerve 3 all of the following supplied by vagus nerve except.
Clinical anatomy of the cranial nerves 1st edition pdf. The hypoglossal nerve, the xiith cranial nerve, is the motor nerve to the muscles of the tongue. Motor to muscles of the tongue opening of the skull. Olfactory optic oculomotor trochlear abducent ophthalmic. The mammalian hypoglossal canal transmits the nerve that supplies the muscles of the tongue. It contains only fibers from the first and second cervical spinal nerve c12, not including the hypoglossal nerve. Its fibers arise from the cells of the hypoglossal nucleus, which is an upward prolongation of the base of the anterior column of gray substance of the medulla spinalis. The hypoglossal nerve gives off this descending branch, then turns and runs forward. Surgical anatomy of hypoglossal nerve as a guide for. Vilensky is professor of anatomy and cell biology at indiana university school of medicine, fort wayne, indiana.
Anatomy texts just dont get any better than gray s anatomy for students. Cranial nerves anatomy, medical imaging and elearning. The study was carried out using 21 sagittal sections of head. The twelfth cranial nerve, the hypoglossal nerve cn xii, is a pure motor nerve that exits at the level of the postolivary sulcus in the medulla and courses anterolaterally to reach the homonymous canal. Between pyramid and olive 2 which nerve passes through incisive canal. The hypoglossal nerve innervates certain muscles that control movement of the tongue.
The hypoglossal nerve, cranial nerve xll, is the motor supply of the tongue. They synapse in the bulb itself, and those secondary neurons project. Study of this area aids in the diagnosis of a variety of tumors found at the base of the skull, including. Functional anatomy of the hypoglossal innervated muscles of the rat. We determined the feasibility of direct visualization of the hypoglossal nerve in the neck with ultrasound, testing this technique on.
Contains the submandibular gland and portions of the hypoglossal nerve, facial artery, facial vein c carotid triangle. Cranial nerve anatomy by greg mclauchlin i olfactory nerve the olfactory nerve is unique, but not in ways that make it particularly interesting. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The hypoglossal nerve is the twelfth paired cranial nerve its name is derived from ancient greek, hypo meaning under, and glossal meaning tongue. Request pdf surgical anatomy of the cervical part of the hypoglossal nerve iatrogenic injuries to cranial nerves, half of which affect the hypoglossal nerve, occur in up to 20% of surgical. Paul rea, in clinical anatomy of the cranial nerves, 2014. The hypoglossal nerve is the motor nerve of the tongue. In addition, the hypoglossal nerve were rarely hooked by the small vessel to the thyrohyoid or sternocleidomastoid imparato et al. It runs just below the styloglossus muscle, and passes forward into the gap between hyoglossus medially, and the mylohyoid muscle laterally. 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. Somatic motor innervates all the intrinsic and most of the extrinsic muscles of the tongue for shape and movement. Head and neck anat 6010 gross anatomy department of neurobiology and anatomy. The glossopharyngeal nerve gpn or ix cranial nerve is one of the most unattended cranial nerves in imaging examinations.
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