The nerve exits the skull through the hypoglossal canal and goes ventrorostrally to run parallel to the lingual artery. Injury to the frontal and marginal mandibular branches of the facial nerve in particular can lead to obvious clinical deficits, and areas where these nerves are. The hypoglossal nerve is of a general somatic efferent gse type. The hypoglossal nerve is the twelfth and last cranial nerve and supplies the tongue with motor control. The muscle tone of the oropharynx is evaluated, these muscles are innervated by glossopharyngeal cn ix and vagus cn x nerves. Another important nerve structure that has to be recognized and preserved during surgery is hypoglossal nerve which brings supply to tongues muscles. The hypoglossal nerve is used for daily functions most people take for granted, like eating and speech.
The hypoglossal nerve, the xiith cranial nerve, is the motor nerve to the muscles of the tongue. Other articles where hypoglossal nerve is discussed. The nerve exits the cranium via the hypoglossal canal. The hypoglossal nerve is the motor supply to the tongue muscles and may be damaged in its intracranial or extracranial course.
The hypoglossal nerve is the 12th cranial nerve and knowledge of the detailed anatomy and relationship with critical structures is of paramount importance in neurosurgery, in head and neck and. Anatomical study of the iliohypogastric, ilioinguinal and. The hypoglossal nerve is divided into five segments. Hypoglossal nerve palsy is a rare occurrence usually associated with other cranial nerve palsies and long tract signs. Following further dissection, we found the main trunk of the true hypoglossal nerve. The hypoglossal nerve innervates certain muscles that control movement of the tongue. It leaves the medulla oblongata laterally to the pyramids by means of several rootlets. Clinical anatomy of the cranial nerves 1st edition pdf. Indeed, hn partly derives its blood supply from vertebral branches. Robertson is senior staff neurologist at henry ford hospital in detroit, michigan. The hypoglossal nerve is the twelfth cranial nerve and controls movements of the tongue. The clinical examination is the principal method by which hypoglossal nerve palsy can be detected, but imaging studies, either computed tomography or magnetic. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Hypoglossal nerve definition, either one of the twelfth pair of cranial nerves, consisting of motor fibers that innervate the muscles of the tongue. Lmns in the hypoglossal nucleus of the caudal medulla exit from the ventral surface of the medulla in the preolivary sulcus between the medullary pyramid and the inferior olive to innervate the extrinsic muscles of the tongue the hyoglossus, styloglossus, chondroglossus. Cisternal hypoglossal schwannoma with tongue atrophy 42. Anatomy of the sn is of clinical importance due to its. Ten adult human cadaver heads from a us source fixed by formalin 20 sides and 20 dry human skulls from indian. Any information contained in this pdf file is automatically generated from digital material. Anatomy physiological nystagmus is assessed by moving the patients head from left to right in a horizontal plane, and then back again. Applied anatomy of the superficial peroneal nerve in real clinical situations requires a good knowledge of the anatomical relationships and. Brachial plexus, anatomic variation, musculocutaneous nerve, median nerve.
The hypoglossal nerve is motor to muscles of the tongue intrinsic and extrinsic and to the genihyoideus and thyrohyoideus muscles. Surgical anatomy of the cervical part of the hypoglossal nerve. The face a neurosensory perspective swiss dental journal sso. To revise the anatomy of the v cranial nerve and its different segments, with a special interest in those of fundamental importance for the correct interpretation of. Surgical anatomy and procedures used to accomplish the nerve connection are described.
The clinical anatomy of the cranial nerves wiley online. Hypoglossal nerve palsy hypoglossal nerve disorder. The slight bulge into the fourth ventricle is termed the hypoglossal eminence. Vertebrobasilar dolichoectasia with hypoglossal nerve palsy 40. Medial antebrachial cutaneous nerve macn courses in the medial arm to provide sensory innervation to the medial forearm.
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. Hypoglossal rootlets project ventrally through the medulla to emerge in the preolivary sulcus. A new classification system for selective upper airway stimulation. When these features are recognized, the radiologist, armed with knowledge of the normal anatomy of the area, can focus on each segment of the nerve in search of a cause. Its dozen roots pass across the posterior cranial fossa laterally before merging into the unique trunk of the nerve in the hypoglossal canal. The hypoglossal vertebral entrapment syndrome 1 occurs as the hypoglossal rootlets converge directly over the distorted vessel with resultant mechanical compression and direct nerve ischemia. Hypoglossal nerve definition of hypoglossal nerve at. The hypoglossal nerve twelfth cranial nerve, cn xii, latin. The use and interpretation of medical examinations to determine the integrity and adequate function of the hypoglossal nerve twelfth cranial nerve. Isolated bilateral paralysis of the hypoglossal nerve. The hypoglossal canal is located between the occipital condyle and jugular tubercle and runs obliquely forwards posteromedial to anterolateral allowing the hypoglossal nerve to exit the posterior cranial fossa its proximal portion is often divided by a fibrous sometimes ossified septum, which separates the two roots of the hypoglossal nerve these have formed by the convergence of. Hypoglossal nerve 12th cranial nerve originconnection. All the nerves are distributed in the head and neck except the tenth, which also supplies structures in the thorax and abdomen.
The path of the nerve starts in the hypoglossal nucleus of the brainstem, which is located near the midline of the medulla oblongata, and then travels between the carotid artery and jugular vein to end up on the underside of the tongue. Others segments of surgical anatomy of this region we will talk about during surgery discussion. Commonly tested with the glossopharyngeal and vagus nerves, lesions to the hypoglossal nerve are appreciated by having the patient open their mouth and examining the tongue. The hypoglossal nerve arises from the hypoglossal nucleus in the medulla oblongata of the brainstem. It then passes laterally across the posterior cranial fossa, within the subarachnoid space. Now extracranial, the nerve receives a branch of the cervical plexus that conducts fibres from c1c2 spinal nerve roots. Hypoglossal nerve cranial nerve xii palsy is uncommon. The size of a halfcut end of the hypoglossal nerve matches a cut end of the injured facial nerve very well. The microsurgical anatomy of the hypoglossal canal. Isolated hypoglossal palsy caused by synovial cyst 43. We describe the case of a 68yearold man who presented with an anterior floor of mouth squamous cell carcinoma and underwent bilateral neck dissection. The muscles, attached to the underside of the top and back parts of the tongue. Only a few anatomic studies of the entire course of the hypoglossal nerve cranial nerve xii have been reported. Nerve modality nucleus location distribution hypoglossal nerve gse hypoglossal nucleus medulla motor innervation to all tongue muscles except palatoglossus function 3.
By using the technique described, a length of facial nerve sufficient to achieve a tensionless communication can consistently be obtained. The hypoglossal nerve leaves the brainstem through the anterolateral sulcus of the medulla oblongata. Bilateral hypoglossal nerve damage due to the use of the. So thats all on clinical anatomy of the cranial nerves. The face is a unique part of the body with its indi vidual anatomical. These fibres do not combine with the hypoglossal nerve they merely travel within its sheath.
Vilensky is professor of anatomy and cell biology at indiana university school of medicine, fort wayne, indiana. Hypoglossal nerve an overview sciencedirect topics. Sural nerve sn courses from the posterior aspect of leg to the lateral side of ankle and foot. It allows control of the tongue for such things as mixing food you have eaten into a ball. This video is about the hypoglossal nerve 12th cranial nerve, its nucleus, connections, course, relations, branches communicating and distributing branches with applied anatomy in detail. The superior root of the ansa cervicalis is classically described as a long slender branch that emerges from the superior por tion of the arc of the hypoglossal nerve as that nerve makes the turn around the. Anatomy of the sural nerve related to calcaneal tendon. Aberrant anatomy of the hypoglossal nerve the journal of.
Clinical pharmacology and therapeutics 8th edition free pdf download. Anatomy the mouth is opened and a finger is inserted through the oral cavity into the oropharynx. Hypoglossal nerve damage from surgical causes is uncommon, occurring in only 0. Adequate knowledge of the anatomy of the hc and its related bony, neural, and vascular structures is essential for surgery of lesions involving this area. The left and right genioglossus muscles in particular are responsible for protruding the tongue. Anatomic variations of brachial plexus anatomical sciences journal. During surgery, we identified an aberrant branch of the hypoglossal nerve, which took a more ventral and superior course in the carotid triangle, prior to entering the base of the tongue.
Clinical anatomy of the superficial peroneal nerve in the distal leg. Scullys medical problems in dentistry seventh edition, 2014. Hypoglossalvertebral entrapment syndrome neurology. Schema anatomy intrinsic muscles of tongue, superior longitudinal, transverse and vertical, inferior longitudinal, styloglossus muscle, meningeal branch, nucleus of hypoglossal nerve, occipital condyle, inferior ganglion of vagus nerve, hypoglossal nerve cn xii in hypoglossal. The hypoglossal canal hc is a region of the skull base whose involvement in many pathological entities is often ignored.
These muscles are involved in moving and manipulating the tongue. The hypoglossal nerve is a motor nerve that innervates almost all the muscles of the tongue, as well as the one suprahyoid muscle, the geniohyoid muscle. A branch of the cervical plexus runs inside the sheath of the hypoglossal nerve, but the fibers of these two nerves dont join together in any way. Hypoglossal nerve palsy is an uncommon neurological deficit characterized by unilateral weakness andor atrophy of the tongue that may arise due to trauma, iatrogenic causes eg. Farid abolhassani is associate professor at anatomy department of. Jeanpierre barral, alain croibier, in manual therapy for the cranial nerves, 2009. 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. Subsequently, the patient developed permanent bilateral hypoglossal palsies, causing significant dysphagia, dysarthria and breathing difficulties.
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