Spine Flashcards
Spinal Chord
Spinal chord housed within the vertebral foramen.
Dura Mater
outer most meninges
epidural space and subdural space
Arachnoid Mater
Middle meninges
Subarachnoid Space
csf flows through
Pia Mater
Innermost meninges
Cervical enlargement
The cervical enlargement of the spinal cord is the source of the spinal nerves that contribute to the brachial plexus and supply the upper limbs.
Lumbar enlargement
Nerves supply the lower limbs
Conus medullaris
give rise to the lumbar sympathetic, sacral somatic and sacral parasympathetic nerves which continue downward within the cauda equina.
Spinal nerves
31 pairs of nerves
Cauda equina
these nerves send and receive messages to and from the lower limbs and pelvic organs
Filum terminale
fixate, stabilize, and buffer the distal spinal cord from normal and abnormal cephalic and caudal traction.
Denticulate ligaments
help to anchor the spinal cord in place
Cervical region
c1-8
thoracic region
t1-t12
lumbar region
l1-5
sacral region
s1-5
Coccygeal region
c0
Roots of spinal chord
Axons extend from spinal cord to innervate tissues
Ventral/anterior:motor and Dorsal/posterior:sensory
Anterior median fissure
Groove in front of spinal cord
Posterior median fissure
Groove in back of spinal cord
Anterior horns
Cell bodies of somatic motor neurons
Motor nuclei send out efferent somatic signals
Lateral horns
Cell bodies of autonomic motor neurons (only segments T1-L2)
Motor nuclei send out efferent autonomic signals
Posterior horns
Synaptic knobs of sensory neurons and cell bodies of
interneurons
Sensory nuclei receive afferent somatic and autonomic signals
Gray commissure
Band of gray matter surrounding central canal. Connect left and right gray matter
Posterior funiculus
Ascending sensory tracts
Lateral funiculus
Sensory and motor tracts
Anterior funiculus
Sensory and motor tracts
Somatosensory pathways
sensory info from muscles, joints, skin
Viscerosensory pathways
Sensory information from organs and vessels
Dorsal (posterior) column
Spinal cord to the medulla, transmits sensory info.
Medial lemniscus
Continuation of the dorsal column, from the medulla to the cortex
Anterior root
Axons of motor neurons
Cell bodies located in anterior and lateral horns
Posterior root
Axons of sensory neurons
Cell bodies located in posterior root ganglion
Posterior ramus
Innervates muscles
and skin of back
Anterior ramus
Innervates trunk,
upper and lower limbs
Rami communicantes
Small branches of
autonomic fibers
Nerve plexus
Network of branching spinal
nerves
* Provide a backup system for
sensory and motor function
Cervical plexus
Brachial plexus
Lumbar plexus
Sacral plexus
* Give rise to peripheral
(named) peripheral nerves
Medial lemniscus pathway
a sensory pathway in the central nervous system responsible for carrying information related to fine touch, vibration, proprioception (body position), and two-point discrimination from the body to the somatosensory cortex in the brain
Anterolateral pathway
carries information about noxious stimuli, temperature stimuli, and deep touch and pain.
Spinocerebellar pathways
an ascending tract that travels a path from the spinal cord to the cerebellum ipsilaterally. The function involves carrying unconscious proprioceptive information toward the cerebellum.
Somatic motor pathway
Control skeletal muscle
* Involve 2-3 neurons
Upper motor neurons
“Descending” tracts
Begin in motor cortex,
cerebral nuclei, brainstem
nuclei
Substantia nigra, striatum
Excite or inhibit lower
motor neurons
Lower motor neurons
“Efferent” pathways
Begin in cranial nerve
nucleus or anterior horn of
spinal cord
Synapse with effectors
Direct pathway
Conscious voluntary control
* Involves 2 neurons
Upper motor neuron
Originates at precentral gyrus of cerebral cortex
Axon part of one of two corticospinal tracts
* Lateral corticospinal tract
o Decussates in medulla
o Targets appendicular skeletal muscle
o 85% of direct pathway neurons
* Anterior corticospinal tract
o Does not decussate
o Targets axial skeletal muscle
o 15% of direct pathway neurons
Lower motor neuron
Originates in anterior gray horn of spinal cord
Synapses with skeletal muscle
Indirect Pathway
Unconscious, reflexive
control
* Lateral pathway
Precise, discrete
movement of limbs
Lateral corticospinal
tract and rubrospinal
tract (tegmentum to
spinal cord)
* Medial pathway
Muscle tone and
movement of axial
muscles
Face, head, neck, trunk
Cervical plexus
C1-C5
Innervates head neck and shoulders
Phrenic nerve: innervates diaphragm
Brachial plexus
C6-T1
Innervates upper extremities
Axillary nerve: delt
Median nerve: anterior forearm
Radial nerve: posterior lateral forearm
Ulnar nerve: medial forearm
Lumbar plexus
L1-L5
femoral nerve: hip, anterior thigh
Obturator nerve: medial thigh
Sacral plexus
S1-S5
Sciatic nerve: glute, posterior thigh
longest nerve in the body
Tibial nerve: hamstring, adductors
Common fibular nerve: knee and leg movers
Dermatomes
An area of skin supplied by sensory neurons of a single spinal nerve
Borders overlap
Some overlap of function
Referred pain
