Exam 2: Spinal Cord & Spinal Nerves Flashcards
Posterior median sulcus
Posterior groove that divided the spinal cord into a left & right side
Anterior median fissure
Deeper grove on anterior side that divides the spinal cord into a L&R side
Cervical enlargement
Nerves of shoulders & upper limbs
Lumbar enlargement
Nerves of pelvis & lower limbs
Conus medullaris
Thin, conical spinal cord below lumbar enlargement
Cause equina
“Horse tail”
Nerve roots extending below conus medullaris
Film terminale
Thin thread of fibrous tissue at end of conus medullaris
Attaches to coccygeal ligament
Ventral root
Branch of spinal nerves that contain axons of motor neurons
Dorsal root
Branch of spinal nerves that contains axons of sensory neurons
Dorsal root ganglion
Contains cell bodies of sensory neurons
Spinal nerve
Dorsal & ventral roots join to form spinal nerve
Pass at the intervertebral foramen btwn 2 vertebrae
Mixed nerves
Spinal nerves are mixed nerves
Carry both afferent (sensory) & efferent (motor) fibers
Meninges
Specialized membranes isolate spinal cord from surroundings
Spinal meninges:
Protect spinal cord
Carry blood supply
continuous with cranial meninges
Meningitis
Inflammation of meninges; viral or bacterial infection
Stiff neck Confusion Severe headache Sensitivity to bright light Fever Sleepiness Nausea Vomiting
Spinal dura mater
Tough & fibrous
Cranially: end oatmeal layer fused w/ periosteum
Caudally: tapers to a dense cord, joins film terminale in coccygeal ligament
Epidural space
Btwn walls of vertebral canal & dura mater
Contains loose connective & adipose tissue
Spinal anesthesia “epidural block”
Injection of a mixture of local anesthetic & anti inflammatory to control inflammation & pain
Arachnoid mater
Covered by simple squamous epithelia
Subdural space
Btwn dura & arachnoid mater
Used for spinal anesthesia
Subarachnoid space
Btwn arachnoid & pia mater
Contains collagen/ elastin fiber network arachnoid trabeculae
Filled with CSF
CSF
Found in subarachnoid space
Spinal tap: withdraw CSF
Pia mater
Innermost meningeal layer
Mesh of collagen & elastic fibers
Bound to underlying neural tissue
White matter
Superficial
Contains myelinated & unmyelinated axons
3 columns:
Posterior white column
Lateral white column
Anterior white column
Gray matter
Surrounds central canal
Contains neuron cell bodies & neuroglia
Has projections: gray horns
Posterior gray horn
Contain somatic and visceral sensory nuclei
Lateral gray horns
In thoracic and lumbar segments
Contain visceral motor nuclei
Anterior gray horns
Contain somatic motor nuclei
4 major nerve plexuses
Complex, interwoven networks of nerve fibers
Control skeletal muscles
Cervical plexus
Included ventral rami of spinal nerves C1-C5
Inner area neck, thoracic cavity & diaphragmatic muscles
Major nerve: phrenic nerve (controls diaphragm)
Brachial plexus
Includes spinal nerves C5-T1
Inner area pectoral girdle & upper limbs
Lumbar & sacral plexuses
Innervate pelvis girdle & lower limbs
Herniated disc
Discs consist of 2 layers:
Outer, fibrous ring, annulus fibrosus
Inner, soft portion, nucleus pulposus, which can bulge out causing inflammation & nerve root compression
Spinal cord
~ 18 in. long & 1/2 in. wide
ENDS BTWN L1 & L2
