Glossary: The Peripheral Nervous System

abducens nerve: sixth cranial nerve; responsible for contraction of one of the extraocular muscles

brachial plexus: nerve plexus associated with the lower cervical spinal nerves and first thoracic spinal nerve

cervical plexus: nerve plexus associated with the upper cervical spinal nerves

cranial nerve: one of twelve nerves connected to the brain that are responsible for sensory or motor functions of the head and neck

endoneurium: innermost layer of connective tissue that surrounds individual axons within a nerve

epineurium: outermost layer of connective tissue that surrounds an entire nerve

esophageal plexus: neuronal plexus in the wall of the esophagus that is part of the enteric nervous system

extraocular muscles: six skeletal muscles that control eye movement within the orbit

facial nerve: seventh cranial nerve; responsible for contraction of the facial muscles and for part of the sense of taste, as well as causing saliva production

fascicle: small bundles of nerve or muscle fibers enclosed by connective tissue

femoral nerve: systemic nerve of the anterior leg that arises from the lumbar plexus

fibular nerve: systemic nerve of the posterior leg that begins as part of the sciatic nerve

glossopharyngeal nerve: ninth cranial nerve; responsible for contraction of muscles in the tongue and throat and for part of the sense of taste, as well as causing saliva production

intercostal nerve: systemic nerve in the thoracic cavity that is found between two ribs

lumbar plexus: nerve plexus associated with the lumbar spinal nerves

median nerve: systemic nerve of the arm, located between the ulnar and radial nerves

nerve plexus: network of nerves without neuronal cell bodies included

oculomotor nerve: third cranial nerve; responsible for contraction of four of the extraocular muscles, the muscle in the upper eyelid, and pupillary constriction

olfaction: special sense responsible for smell, which has a unique, direct connection to the cerebrum

olfactory nerve: first cranial nerve; responsible for the sense of smell

optic nerve: second cranial nerve; responsible for visual sensation

perineurium: layer of connective tissue surrounding fascicles within a nerve

phrenic nerve: systemic nerve from the cervical plexus that enervates the diaphragm

plexus: network of nerves or nervous tissue

radial nerve: systemic nerve of the arm, the distal component of which is located near the radial bone

sacral plexus: nerve plexus associated with the lower lumbar and sacral spinal nerves

saphenous nerve: systemic nerve of the lower anterior leg that is a branch from the femoral nerve

sciatic nerve: systemic nerve from the sacral plexus that is a combination of the tibial and fibular nerves and extends across the hip joint and gluteal region into the upper posterior leg

sciatica: painful condition resulting from inflammation or compression of the sciatic nerve or any of the spinal nerves that contribute to it

spinal accessory nerve: eleventh cranial nerve; responsible for contraction of neck muscles

spinal nerve: one of 31 nerves connected to the spinal cord

systemic nerve: nerve in the periphery distal to a nerve plexus or spinal nerve

tibial nerve: systemic nerve of the posterior leg that begins as part of the sciatic nerve

trigeminal ganglion: sensory ganglion that contributes sensory fibers to the trigeminal nerve

trigeminal nerve: fifth cranial nerve; responsible for cutaneous sensation of the face and contraction of the muscles of mastication

trochlear nerve: fourth cranial nerve; responsible for contraction of one of the extraocular muscles

ulnar nerve: systemic nerve of the arm located close to the ulna, a bone of the forearm

vagus nerve: tenth cranial nerve; responsible for the autonomic control of organs in the thoracic and upper abdominal cavities

vestibulocochlear nerve: eighth cranial nerve; responsible for the sensations of hearing and balance