Spinal Cord Flashcards
Spinal Cord
Review - Image
Spinal cord termination (adult)
at the level of the lower border of L1
In childrem, spinal cord termination is at the upper border of the third lumbar vertebra (L3)
The upper 2/3 of the vertebral colum is occupied by (1) while the remaining is occupied by (2)
(1) spinal cord
(2) caud equina
Enumerate Spinal Cord Divisions
- Cervical spinal cord (8 nerves)
- Thoracic spinal cord (12 nerves)
- Lumbar spinal cord (5 nerves)
- sacral spinal cord(5 nerves)
- coccygeal spinal cord (1 nerve)
Which areas of the spinal cord are enlarged?
Cervical & lumbosacral spinal cords
enlarged to form the origin of the brachial and lumbosacral plexuses respectively
What is the end of the spinal cord called?
conus medullaris
Enumerate the structures (4) found grossly at the spinal cord transverse section
- anterior median fissure
- posterior median sulcus
- posterolateral sulcus - entry of post./dorsal sensory root
- anterolateral sulcus - exit of ant./ventral motor root
Enumerate the spinal cord coverings (superficial to deep)
- Dura mater
- Arachnoid mater
- Pia mater
The prolongation of the pia mater from the apex of the conus medullaris to the posterior surface of the coccyx
Filum Terminale
The subarachnoid space at the level of the cauda equina enlarges to form what structure?
Lumbar cistern
the site for lumbar puncture and spinal anesthesia
The pia mater attaches to the vertebral column laterally by what structure
Denticulate ligament
Arrangement of Spinal cord mater
- inner gray matter
- outer white matter
The spinal gray matter is divided into 4 major areas forming an H-shape
- Dorsal Horn - receives sensory
- Ventral horn - sends motor signals
- Gray commissure - connection of horns; contains the central canal
- Small lateral gray horn - in thoracic and upper lumbar regions
Enumerate the 4 nerve groups of the posterior gray horn
- substantia gelatinosa group (lamina II)
- nucleus proprius group (lamina III & IV)
- Nucleus dorsalis group (Clarke’s column - lamina VII)
- Visceral afferent nucleus
What are the functions of the 4 nerve group of the posterior horn?
- substantia gelatinosa - receives afferents for pain, touch and temperature
- Nucleus proprius - receives sensory for proprioception, two-point discrimination, and vibration from the posterior column
- Clarke’s column - receives proprioception mainly from muscle and tendon spindles
- Visceral afferent nucleus - receives visceral information
Enumerate white matter columns
- Anterior column (btwn. midline & emergence of the anterior nerve roots)
- Lateral column (btwn. emergence of ant. nerve roots & entry of post. nerve roots)
- Posterior column (btwn. entry or post. nerve roots & dorsal midline)
Each column is divided into tracts (Fasciculi) - can be ascending, descending, intersegmental
Spinothalamic tracts aka anterolateral system is composed of
- Anterior Spinothalamic Tract (light touch and pressure)
- Lateral Spinothalamic Tract (pain and temperature sensations)
Spinothalamic tract pathway
1) enter the spinal cord travel in the posterolateral tract of Lissauer
2) synapse in lamina I, II, and IV
3) fibers from 2nd order neurons cross to the opposite side - synapse in the ventral posterolateral and intralaminar thalamic nuclei
4) 3rd order neurons send axons that pass through the internal capsule to the somatosensory cortex
**sensation from lower parts travel laterally, sensations from upper parts travel medially”
Dorsal Column Tract for what sensation?
Carry fine and discriminative touch, vibration, and proprioception
Divided into:
1. Fasciculus gracilis (lower body)
2. Fasciculus cuneatus (upper part of the body)
Dorsal Column Tract Pathway
1) to ipsilateral posterior white column - ascend without synapse till the brainstem
2) synapse at medulla oblongata on nuclei gracilis and cuneatus
3) 2nd order neurons decussate and ascend forming the medial lemniscus to synapse in the ventral posterolateral nucleus of the thalamus
4) 3rd order neurons to the somatosensory cortex
Main Somatosensory Pathways to Consciousness
Dorsal Spinocerebellar Tract function
Convey proprioception and deep pressure from muscles to the cerebellum
Dorsal Spinocerebellar Pathway
1) 1st order neurons synapse on Clarke’s column
2) 2nd order neurons to the ipsilateral lateral white funiculus
3) ascend to inferior cerebellar peduncle - terminate at cerebellar cortex
Anterior Spinocerebellar Tract Function and Pathway
similar to spinocerebellar tract with addition of sensation from the skin
1) axons synapse on Clarke’s column
2) 2nd order neurons decussate and ascend to enter the cerebellum in the superior cerebellar peduncle
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Enumerate Ascending Tracts of the Spinal Cord
MAIN:
- lateral spinothalamic tract
- anterior spinothalamic tract
- dorsal column tract
- dorsal spinocerebellar tract
- anterior spinocerebellar tract
OTHERS
- spinotectal tract (visual reflexes)
- spinorecticular tract
- spinoolivary tract
- visceral sensory tract
Blood Supply of the Spinal Cord
Venous Drainage of Spinal Cord
