Typical Spinal Nerve Flashcards
Spinal Cord
Tubular bundle of nervous tissue and support cells. Component of CNS. Runs from cervical vertebra to level of L2, ends in conus medullarus. Spinal nerves continue to descend.
Conus Medullaris
Sugar cone shaped lower end of the spinal cord (L2). Present in this area: filum terminale (composed of pia mater), cauda equina,
Cauda equina
Latin for horse’s tail. As spinal cord tapers out at the conus medullaris, the spinal nerves branch out of the conus medullaris forming the cauda equina. Located in the lumbar cistern (subarachnoid space). Dorsal and ventral rootlets are directed towards the intervertebral foramina in order to exit the spinal column.
Filum terminale
Composed of pia mater, delicate strand of fibrous tissue proceeding downward from conus medullaris. Provides longitudinal support to the spinal cord.
Spinal Cord Gray Matter
Collection of Cell Bodies (neurons) and unmyelinated axons and dendrites (processes of neurons) within the CNS in order to send/receive messages to/from other neurons.
Spinal Cord White Matter
Contain myelinated dendrites and axon. No cell bodies. These are the tracts used to transmit messages over long distances.
Cervical Enlargement
Receive information from brain to transmit to upper limbs. Extends from C3 to T2, largest at C6.
Lumbar Enlargement
Receive information from brain to transmit to lower limbs. Extends L1-S3.
Vasculature of the Spinal Cord
Three arteries supply the spinal cord: anterior spinal artery, right posterior spinal and left posterior spinal artery. All are branches of the vertebral arteries, and travel in subarachnoid space, send branches into spinal cord. All are rather small, posteriors even smaller than anterior. Anterior spinal artery travels anteriomedially down the entire length of the spinal cord. Posterior spinal arteries descend the cord and are resupplied by various other arteries along the way, including posterior intercostal arteries, lumbar arteries, and lateral sacral arteries.
Layers of the spinal meninges
Dura mater, arachnoid mater, pia mater
Dura Mater
Tough mother, outside layer, thick, durable
Arachnoid Mater
Intermediate layer, thin, glossy (like spider web)
Pia Mater
Inner layer, very delicate, unlike brain comes off laterally in a saw tooth manner. Serves as an anchor. (Filum terminales is pia mater)
Denticulate Ligaments
Attachments of the pia mater to the other layers of the meninges and to the spinal cord. One on each side of the spinal cord. Named for their tooth-like apperance. Provide stability for the spinal cord against motion within the vertebral column.
Epidural Space
Space outside/above the dura mater. Epi=on/upon. Space is used for administration of anesthetic (blocking transmission of signals through nerve fibers in spinal cord). Epidural hematoma is a type of TBI where a buildup of blood occurs in the space between dura mater and skull (epidural space). Can be deadly because of build up of pressure.
Subarachnoid Space
Only normally fluid filled space in the brain. Typically has CSF present in it.
Lumbar cistern
Enlargement of the subarachnoid space between the conus medullaris (L2) and the inferior end of the inferior end of subarachnoid space (S2). Houses the cauda equina and filum terminale, and is filled with CSF (as is all subarachnoid space). Site for lumbar puncture/spinal tap.
Spinal Nerves
Collection of neuronal (cell) processes, dendrites (sensory) and axons (motor), surrounded by connective tissue coverings. 31 pairs: 8 cervical, 12 thoracic,5 lumbar, 5 sacral, 1 coccygeal. Distributed peripherally into zones
Deratome
Area of skin supplied by a single spinal nerve
Myotome
Group of muscles supplied by a single nerve root
Neuron
Basic functional unit of the Nervous System
Synapse
Functional communication between a series of neurons
Afferent
Neuron which sends impulses towards the CNS. Sensory. Goes to the posterior part of CNS.