"behind (superficial to) the adductor magnus muscle, and is itself in front of (deep to) one head of the biceps femoris muscle. At the popliteal fossa, the nerve divides into its two branches: The sciatic nerve is the largest nerve in the human body. The sciatic nerve supplies sensation to the skin of the foot, as well as the entire lower leg (except for its inner side). Sensation to skin to the sole of the foot is provided by the tibial nerve, and the lower leg and upper surface of the foot via the common fibular nerve. The sciatic nerve"
"Ulnar nerve In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest unprotected nerve in the human body (meaning unprotected by muscle or bone), so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of these fingers, including both front and back of the tips, perhaps as far back as the fingernail beds. This nerve can cause an electric shock-like sensation"
"was also historically called the ""pneumogastric"" nerve since it innervates both the lungs and the stomach. Vagus nerve The vagus nerve ( ), historically cited as the pneumogastric nerve, is the tenth cranial nerve or CN X, and interfaces with parasympathetic control of the heart, lungs, and digestive tract. The vagus nerves are paired but are normally referred to in the singular. It is the longest nerve of the autonomic nervous system in the human body. Upon leaving the medulla oblongata between the pyramid and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into"
"Vagus nerve The vagus nerve ( ), historically cited as the pneumogastric nerve, is the tenth cranial nerve or CN X, and interfaces with parasympathetic control of the heart, lungs, and digestive tract. The vagus nerves are paired but are normally referred to in the singular. It is the longest nerve of the autonomic nervous system in the human body. Upon leaving the medulla oblongata between the pyramid and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the"
"Saphenous nerve The saphenous nerve (long or internal saphenous nerve) is the largest cutaneous branch of the femoral nerve. It is a strictly sensory nerve, and has no motor function. It approaches the femoral artery where this vessel passes beneath the sartorius, and lies in front of the artery, behind the aponeurotic covering of the adductor canal, as far as the opening in the lower part of the Adductor magnus. Here it diverges from the artery, and emerges from behind the lower edge of the aponeurotic covering of the canal; it descends vertically along the medial side of the knee"
"Femoral nerve The femoral nerve is a nerve in the thigh that supplies skin on the upper thigh and inner leg, and the muscles that extend the knee. Femoral nerve is the major nerve supplying the anterior compartment of the thigh. It is the largest branch of the lumbar plexus, and arises from the dorsal divisions of the ventral rami of the second, third, and fourth lumbar nerves (L2, L3, and L4). The nerve enters the femoral triangle by passing beneath the inguinal ligament, just lateral to the femoral artery. In the thigh, the nerve lies in a groove between"
"Frontal nerve The frontal nerve is the largest branch of the ophthalmic nerve(V), and may be regarded, both from its size and direction, as the continuation of the nerve. It enters the orbit through the superior orbital fissure, not running within the tendinous ring, and runs forward between the levator palpebrae superioris and the periosteum. Midway between the apex and base of the orbit it divides into two branches, supratrochlear nerve and supraorbital nerve. It provides the sensory innervations for the skin of the forehead, mucosa of frontal sinus, and the skin of the upper eyelid via general somatic afferent"
"(GSA) fibers. Frontal nerve The frontal nerve is the largest branch of the ophthalmic nerve(V), and may be regarded, both from its size and direction, as the continuation of the nerve. It enters the orbit through the superior orbital fissure, not running within the tendinous ring, and runs forward between the levator palpebrae superioris and the periosteum. Midway between the apex and base of the orbit it divides into two branches, supratrochlear nerve and supraorbital nerve. It provides the sensory innervations for the skin of the forehead, mucosa of frontal sinus, and the skin of the upper eyelid via general"
"Trigeminal nerve The trigeminal nerve (the fifth cranial nerve, or simply CN V) is a nerve responsible for sensation in the face and motor functions such as biting and chewing; it is the largest of the cranial nerves. Its name (""trigeminal"" = ""tri-"", or three, and ""- geminus"", or twin: thrice-twinned) derives from the fact that each of the two nerves (one on each side of the pons) has three major branches: the ophthalmic nerve (V), the maxillary nerve (V), and the mandibular nerve (V). The ophthalmic and maxillary nerves are purely sensory, whereas the mandibular nerve supplies motor as"
"Great auricular nerve The great auricular nerve (or greater auricular nerve) originates from the cervical plexus, composed of branches of spinal nerves C2 and C3. It provides sensory innervation for the skin over parotid gland and mastoid process, and both surfaces of the outer ear. It is the largest of the ascending branches of the cervical plexus. It arises from the second and third cervical nerves, winds around the posterior border of the sternocleidomastoideus, and, after perforating the deep fascia, ascends upon that muscle beneath the platysma to the parotid gland, where it divides into an anterior and a posterior"
"These include the greater occipital nerve, which provides sensation to the back of the head, the lesser occipital nerve, which provides sensation to the area behind the ears, the greater auricular nerve and the lesser auricular nerve. The phrenic nerve is a nerve essential for our survival which arises from nerve roots C3, C4 and C5. It supplies the thoracic diaphragm, enabling breathing. If the spinal cord is transected above C3, then spontaneous breathing is not possible. The last four cervical spinal nerves, C5 through C8, and the first thoracic spinal nerve, T1, combine to form the brachial plexus, or"
"Middle cardiac nerve The middle cardiac nerve (""great cardiac nerve""), the largest of the three cardiac nerves, arises from the middle cervical ganglion, or from the trunk between the middle and inferior ganglia. On the right side it descends behind the common carotid artery, and at the root of the neck runs either in front of or behind the subclavian artery; it then descends on the trachea, receives a few filaments from the recurrent nerve, and joins the right half of the deep part of the cardiac plexus. In the neck, it communicates with the superior cardiac and recurrent nerves."
"branch. Great auricular nerve The great auricular nerve (or greater auricular nerve) originates from the cervical plexus, composed of branches of spinal nerves C2 and C3. It provides sensory innervation for the skin over parotid gland and mastoid process, and both surfaces of the outer ear. It is the largest of the ascending branches of the cervical plexus. It arises from the second and third cervical nerves, winds around the posterior border of the sternocleidomastoideus, and, after perforating the deep fascia, ascends upon that muscle beneath the platysma to the parotid gland, where it divides into an anterior and a"
"not responsible for the innervation of the obturator internus, despite the similarity in name. Obturator nerve The obturator nerve in human anatomy arises from the ventral divisions of the second, third, and fourth lumbar nerves in the lumbar plexus; the branch from the third is the largest, while that from the second is often very small. It descends through the fibers of the psoas major, and emerges from its medial border near the brim of the pelvis; it then passes behind the common iliac arteries, and on the lateral side of the internal iliac artery and ureter, and runs along"
"and may be aggravated by climbing stairs. Usually, in this case, motor function of the lower leg will not be impaired. This is a key distinction between saphenous nerve neuropathy and lower back radiculopathy. Saphenous nerve neuropathy only demonstrates ""sensory alterations"", while lumbar radiculopathy will affect the motor, sensory, and deep tendon reflexes of the lower leg. Saphenous nerve The saphenous nerve (long or internal saphenous nerve) is the largest cutaneous branch of the femoral nerve. It is a strictly sensory nerve, and has no motor function. It approaches the femoral artery where this vessel passes beneath the sartorius, and"
"On the left side, the middle cardiac nerve enters the chest between the left carotid and subclavian arteries, and joins the left half of the deep part of the cardiac plexus. Middle cardiac nerve The middle cardiac nerve (""great cardiac nerve""), the largest of the three cardiac nerves, arises from the middle cervical ganglion, or from the trunk between the middle and inferior ganglia. On the right side it descends behind the common carotid artery, and at the root of the neck runs either in front of or behind the subclavian artery; it then descends on the trachea, receives a"
"this nerve is one of the causes of cervicogenic headaches, referred to as occipital neuralgias. A common site, and usually misdiagnosed area of entrapment for the greater occipital nerve is at the obliquus capitis inferior muscle. Most people with tension headaches experience increasing intensity with time, and report pain originating in the back of the head (occipital) moving to the front of the head (supraorbital). Neurostimulation is sometimes used to treat tension headaches that originate from the occipital nerve. Greater occipital nerve The greater occipital nerve is a spinal nerve, specifically the medial branch of the dorsal primary ramus of"
"Obturator nerve The obturator nerve in human anatomy arises from the ventral divisions of the second, third, and fourth lumbar nerves in the lumbar plexus; the branch from the third is the largest, while that from the second is often very small. It descends through the fibers of the psoas major, and emerges from its medial border near the brim of the pelvis; it then passes behind the common iliac arteries, and on the lateral side of the internal iliac artery and ureter, and runs along the lateral wall of the lesser pelvis, above and in front of the obturator"
"nerve, which run from the base of the spinal cord to the big toe of each foot. The diameter of axons is also variable. Most individual axons are microscopic in diameter (typically about one micrometer (µm) across). The largest mammalian axons can reach a diameter of up to 20 µm. The squid giant axon, which is specialized to conduct signals very rapidly, is close to 1 millimetre in diameter, the size of a small pencil lead. The numbers of axonal telodendria (the branching structures at the end of the axon) can also differ from one nerve fiber to the next."
"nervous system (PNS), although on a structural level the olfactory (I), optic (II), and trigeminal (V) nerves are more accurately considered part of the central nervous system (CNS). Most typically, humans are considered to have twelve pairs of cranial nerves (I–XII), with the terminal nerve (0) more recently canonized. They are: the olfactory nerve (I), the optic nerve (II), oculomotor nerve (III), trochlear nerve (IV), trigeminal nerve (V), abducens nerve (VI), facial nerve (VII), vestibulocochlear nerve (VIII), glossopharyngeal nerve (IX), vagus nerve (X), accessory nerve (XI), and hypoglossal nerve (XII). Cranial nerves are generally named according to their structure or"
"to the pharynx. In most other nematodes, these specialised cells have been replaced by an organ consisting of two parallel ducts connected by a single transverse duct. This transverse duct opens into a common canal that runs to the excretory pore. Four peripheral nerves run the length of the body on the dorsal, ventral, and lateral surfaces. Each nerve lies within a cord of connective tissue lying beneath the cuticle and between the muscle cells. The ventral nerve is the largest, and has a double structure forward of the excretory pore. The dorsal nerve is responsible for motor control, while"
"Inferior gluteal nerve The inferior gluteal nerve is the main motor neuron that innervates the gluteus maximus muscle. It is responsible for the movement of the gluteus maximus in activities requiring the hip to extend the thigh, such as climbing stairs. Injury to this nerve is rare but often occurs as a complication of posterior approach to the hip during hip replacement. When damaged, one would develop gluteus maximus lurch, which is a gait abnormality which causes the individual to 'lurch' backwards to compensate lack in hip extension. The largest muscle of the posterior hip, gluteus maximus, is innervated by"
"to the pleura and peritoneum afferent sensory innervation are the only ones that do not originate from a plexus. The ventral rami of L1-L5 spinal nerves with a contribution of T12 form Lumbar plexus. This plexus lies within the psoas major muscle. Nervi of the plexus serve the skin and the muscles of the lower abdominal wall, the thigh and external genitals. The largest nerve of the plexus is the femoral nerve. It supplies anterior muscles of the thigh and a part of skin distal to the inguinal ligament. Ventral rami of L4-S3 with parts of L4 and S4 spinal"
"Spinal nerve A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system. Each spinal nerve is"
"Mandibular nerve The mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). The large sensory root emerges from the lateral part of the trigeminal ganglion and exits the cranial cavity through the foramen ovale. Portio minor, the small motor root of the trigeminal nerve, passes under the trigeminal ganglion and through the foramen ovale to unite with the sensory root just outside the skull. The mandibular nerve immediately passes between tensor veli palatini, which is medial, and lateral pterygoid, which is lateral, and gives off a meningeal branch (nervus"
"nerve plexus around the superior pancreaticoduodenal artery. Cystic plexus The cystic plexus is the derivation of the hepatic plexus, which is the largest offshoot from the celiac plexus. Formed by branches from the celiac plexus, the right and left vagi and the right phrenic nerve, parasympathetic nerves are motor to the musculature of the gall bladder and bile ducts, but inhibitory to the sphincters. Sympathetic nerves derived from thoracic seven to nine segments are vasomotor and motor to sphincters. It supplies the gall bladder, common hepatic duct, cystic duct and upper part of the bile duct. The lower part of"
"Axillary nerve The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus (upper trunk, posterior division, posterior cord) at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. The axillary nerve travels through the quadrangular space with the posterior circumflex humeral artery and vein. The nerve lies at first behind the axillary artery, and in front of the subscapularis, and passes downward to the lower border of that muscle. It then winds backward, in company with the posterior humeral circumflex artery, through a quadrangular space"
"""efferent"" correspond to the prefixes ""ad-"" (to, toward) and ""ex-"" (out of). There are 43 segments of nerves in the human body. With each segment, there is a pair of sensory and motor nerves. In the body, 31 segments of nerves are in the spinal cord and 12 are in the brain stem. Besides these, thousands of association nerves are also present in the body. Thus the somatic nervous system consists of two parts: The somatic nervous system controls all voluntary muscular systems within the body, and the process of voluntary reflex arcs. The basic route of nerve signals within"
"caused by damage to cranial nerve IV (trochlear nerve). Trochlear nerve The trochlear nerve, also called the fourth cranial nerve or CN IV, is a motor nerve (a somatic efferent nerve) that innervates only a single muscle: the superior oblique muscle of the eye, which operates through the pulley-like trochlea. The trochlear nerve is unique among the cranial nerves in several respects: Homologous trochlear nerves are found in all jawed vertebrates. The unique features of the trochlear nerve, including its dorsal exit from the brainstem and its contralateral innervation, are seen in the primitive brains of sharks. The human trochlear"
"nerves. Pallial nerves are the subject of the majority of scientific research. Visceral nerves are split into two subcategories: the main visceral nerve and the rectal visceral nerve. The main visceral nerve is on the snail's back and connects to a large group of nerve cells to transmit information in the body. The rectal visceral nerve starts further down under the main visceral and extends a short length before branching off near the rectum. Heat can stimulate reactions in the West African snail as a result of the snail's nervous system. The nerves produce warm responsive fibers when the temperature"
"the largest cells (by size of cell body) in the nervous system. The adult human brain is estimated to contain 86±8 billion neurons, with a roughly equal number (85±10 billion) of non-neuronal cells. Out of these neurons, 16 billion (19%) are located in the cerebral cortex, and 69 billion (80%) are in the cerebellum. Types of glial cell are astrocytes (including Bergmann glia), oligodendrocytes, ependymal cells (including tanycytes), radial glial cells and microglia. Astrocytes are the largest of the glial cells. They are stellate cells with many processes radiating from their cell bodies. Some of these processes end as perivascular"
"the pelvic area near the iliac spine, and supplies the skin of the anterior thigh. The obturator nerve (L2-L4) passes medially behind psoas major to exit the pelvis through the obturator canal, after which it gives off branches to obturator externus and divides into two branches passing behind and in front of adductor brevis to supply motor innervation to all the other adductor muscles. The anterior branch also supplies sensory nerves to the skin on a small area on the distal medial aspect of the thigh. The femoral nerve (L2-L4) is the largest and longest of the nerves of the"
"cranial nerves found in amniotes including reptiles, mammals and birds. As with humans, damage to the nerve or nerve pathway will result in difficulties moving the tongue or lapping water, decreased tongue strength, and generally cause deviation away from the affected side initially, and then to the affected side as contractures develop. The evolutionary origins of the nerve have been explored through studies of the nerve in rodents and reptiles. The nerve is regarded as arising evolutionarily from nerves of the cervical spine, which has been incorporated into a separate nerve over the course of evolution. The size of the"