Spinal Cord Flashcards
The Central Nervous System consist of?
Brain, Spinal Cord
How long is the spinal cord?
43 cm long
Narrowest and roundest at what region?
Thoracic region
Fibrous connective tissue contains?
Fibrocytes, Collagen and elastic fibers, intercellular fluid, Various other cells (e.g. Schwann cell)
Glial connective tissue consists of?
Astrocytes, Oligodendrocytes, Microglia, Ependyma
At the end of the 8th week, coccygeal cord atrophies becomes?
Filum terminale
At birth, cord ends at L2 or L3 vertebrae. In adults, the cord ends at?
L1 or L2 vertebrae.
T or F: the more CAUDAL the nerve root, the further it must travel to exit the vertebral column.
True
Pierces dural sac thru sacral hiatus to attach to the dorsal coccyx
Filum terminale
bet. periosteum and dura
fat, venous plexus
Epidural space
thick, tough outer meningeal layer
encloses dural sac
continuous with cranial dura
Dura mater
Long tubular sheath within vertebral canal, from foramen magnum and ends at about S2
Caudally, anchored to the coccyx by the filum terminale
Dural sac
–Fibrous and elastic tissue, avascular –Thick and sturdy enough to be handled –Lines duralsac –Encloses CSF –Pushed against the duraby CSF pressure
Arachnoidmater
–Potential space
–Only gets filled after bleeding (hematoma formation)
Subdural space
–arachnoidgranulations extend to the pia
–filled with CSF
Subarachnoid space
Has lateral extensions bet dorsal and ventral roots, the denticulate ligament to the dura seen from foramen magnum up to about L2
Pia mater
–Terminal portion of dural sac (L2 to S2)
–Contains CSF and the cauda equina
–Access point for lumbar puncture procedures
Lumbar cistern
In Lumber punctures, indwelling catheter inserted into epidural space, enesthetic bathes spinal nerves after they exit the dural sac.
Epidural block
T or F:
a thin WHITE commissure posteriorly containing the central canal lined with ependymaextending into the 4thventricle cephaladand the terminal ventricle in the filumcaudad
F
Dorsal root carries ____ fibers to the _____ horn of the cord.
Sensory; dorsal
Ventral root carries motor fibers frmo the cell bodies in the?
ventral horn of the spinal cord
Spinal nerve contains?
Sensory input from periphery (e.g. skin, subcutaneous tissues, viscera) to dorsal root ganglion then axon to dorsal horn
Motor impulses from spinal motor neuron cell bodies in ventral horn to skeletal muscle
31 pairs of spinal nerves: _ cervical _ thoracic _ lumbar _ sacral _ coccygeal
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal (may be absent)
3 longitudinal arteries?
Single ventral median artery (anterior spinal a)
Paired dorso-lateral arteries (posterior spinal aa)
Paired dorso-lateral arteries (posterior spinal aa) receives?
segmental arteries(radicular aa) at regular intervals from the aorta
T or F:
Each SEGMENTAL ARTERY enters the intervertebral foramina with each spinal nerve with each dorsal and ventral root
T
in Blood supply, paramedian branches via?
Ventral Median
Union of branches of the posterior inferior cerebellarand vertebral arteries?
Anterior median a
each a branch of the ipsilateralposterior inferior cerebellarartery and vertebral artery?
Paired posterior aa
3 longitudinal venous systems?
- Spinal cord plexus in the subarachnoid space
- Epidural (internal vertebral) plexus in the epidural space along the length of the vertebral column up to the foramen magnum.
- External venous plexus along the outside of the vertebral column communicating freely with the epidural plexus.
T or F:
Valveless, bloodflow is bidirectional from spinal cord and regional network of veins of each spinal segment which eventually drain to the inferior vena cava
T
Loss of Spinal Cord Function may be due to?
Interruption, Compression, Ischemia
Loss of spinal Cord function manifests as?
Loss of sensation, Loss of motor power, Loss of autonomic function (e.g. Bowel/bladder control)
in ascending tracts:
Discriminative modalities/ deep modalities; vibration, position sense, 2-point discrimination, touch;
Dorsal columns (F gracilis, F Cuneatus)
Dorsal columns decussates at the?
cervico-medullary junction
Dorsal columns ascends as the?
medial leminiscus to the thalamus
in Dorsal columns, lesions or interruption cause?
1.Loss of position sense
2.Loss of vibration sense
3.Graphanesthesia
4.Steroanesthesiaa
5.Sensory ataxia
6.Kinanesthesia
Spare touch, pain and temperature modalities
In Ascending tracts:
•Superficial somatosensory modalities
•Mediate touch, pain and temperature
•Enter the cord via dorsal root at the dorsolateral tract of lissauer
•Synapse in the same, up and down a level
Ventro-lateral spinothalamic tract
Ventro-lateral spinothalamic tract decussates at the?
ventral white commissure into other side and ascend as the ventro-lateral spinothalamic tract or spinal leminiscus
Pain and temperature pathway?
Ventro-lateral spinothalamic tract
In Ascending tracts:
•Convey proprioceptive impulses to the cerebellum, which coordinates the contraction of skeletal muscles
•Serve mainly the lower extremities
Dorsal and Ventral Spinocerebellar Tracts
Peripheral course of the Dorsal and Ventral Spino-cerebellar Tracts?
nerves coming from pressure receptors in the skin and the Golgi tendon organ and muscle spindles
Central course of the Dorsal and Ventral Spino-cerebellar Tracts?
- Dorsal, uncrossed
* Ventral, crossed
T or F:
in Dorsal and Ventral Spinocerebellar Tracts, the dorsal tract enters the inferior cerebellar peduncle and the ventral tract enters through the superior peduncle.
T
Arises from the cerebral motor cortex, mainly the precentral gyrus?
Pyramidal Tract
Components of the Pyramidal Tract?
- Corticospinal Tract to the spinal cord
* Corticobulbar Tract to the brain stem
T or F:
The pyramidal tract mediates voluntary contractions of the skeletal muscles
T
T or F:
In the pyramidal tract, interruption of this tract results in weakness or paralysis of voluntary movements?
T
T or F:
Interruption of one pyramidal tract will paralyze voluntary movement on one side of the body (hemiplegia)
T
A lesion rostral to the decussation causes?
Contralateral weakness
A lesion caudal to the decussation causes?
ipsilateral weakness
Clinical features of UMN lesions?
Paralyze movements in hemoplegic, quadriplegic, or paraplegic distribution, not individual muscles
Atrophy of disuse only (late and slight)
Hyperactive MSRs and spasticity
Clonus
Absent abdominal and cremasteric reflexes
Extensor toe sign (babinski sign)
Clinical features of LMN Lesions?
Paralyze individual muscles or sets of muscles in root or peripheral nerve distribution
Atrophy of denervation (early and severe)
Fasciculations and dibrillations
Hypoactive or absent MSRs
Hypotonia
