Spinal Cord Flashcards
Number of spinal nerves
31
Number of vertebra
33
C1 vertebra
Atlas
C2 vertebra
Axis
Number of cervical vertebrae
7
Number of thoracic vertebrae
12
Number of lumbar vertebrae
5
Number of sacral vertebrae
5 - fused to form sacrum
Number of coccyx vertebrae
4 — fused
Dens
Prominent spike on C2 vertebra
What does the transverse Foramen of the cervical vertebra contain
Vertebral artery and sympathetic chain
What cervical vertebrae does not have a bifid spinous process
C7
Thoracic vertebra spinous processes
Thinner and more descending
Thoracic vertebral Foramen
Circular
Lumbar spinous processes
Thick and broad
Lumbar vertebral Foramen
Triangular
2 enlargements of spinal cord
Cervical (C3-T1) to upper limbs
Lumbar (L1-S3) to lower limbs
Central canal
CSF surrounding spinal cord
What is the spinal cord covered by
Meninges
Dura—>arachnoid—>pia
Conus medullaris
Spinal cord tapers to a cone
Filum terminale
Spinal cord ends in a strand of tissue
Where does spinal cord end in adults
Between L1 and L2
Where does the spinal cord end at birth
L3
Where does the spinal cord end at 3 months of fetal life
Extends the whole length of spinal cord
Axons in dorsal cord
Afferent neurones- sensory
Axons in ventral cord
Efferent neurones- motor
Spinal nerves leave the spine- cervical segments
Around 1 vertebra higher than their corresponding vertebra
Except C8 which is below
Spinal nerves leave the spine- thoracic segments
1-2 vertebra below corresponding vertebra
Spinal nerves leave the spine- lumbar segments
3-4 vertebra below corresponding vertebra
Spinal nerves leave the spine- sacral segments
5 vertebra below corresponding vertebra
Number of pairs of cervical spinal nerves
8
Number of pairs of thoracic spinal nerves
12
Number of pairs of lumbar spinal nerves
5
Number of pairs of sacral spinal nerves
5
Number of pairs of coccygeal spinal nerves
1
3 layers of tissue covering nerves
Epineurium
Perineurium
Endoneurium
Funiculi
Fascicles can be collected into larger bundles
Epineurium
Outermost layer
Surrounds several fascicles
Perineurium
Covers each fascicle
Composed of several layers of epithelium bound by tight junctions
Endoneurium
Delicate connective tissue around the myelin sheath of each individual axon
What stains white matter black
Osmium
What stains grey matter black
Silver stain
What is silver stain used for
Cell bodies
What is osmium stain used for
Myelin
Which part of the spinal cord has more white matter
Higher levels
Grey matter in spinal cord
H shaped with 4 protrusions
2 dorsal horns
2 ventral horns
Rexed laminae
10 layers of grey matter
Defined by their cellular structure
Laminae I-III
Substantia gelatinosa
Laminae VII
Clarke’s column (C8-L3)
Laminae IX
Motor supply
Number of layers of grey matter in rexed laminae
10
Which spinal nerves control spinal reflexes of the front of the arm
C5/C6
Which spinal nerves control spinal reflexes of the back of the arm
C7/C8
Which spinal nerves control spinal reflexes of the diaphragm
C3/4/5
Which spinal nerves control spinal reflexes of the erection of penis
S2/S3/S4 - pudendal nerve
Which spinal nerves control spinal reflexes of the ankle jerk
S1/S2
Which spinal nerves control spinal reflexes of the knee jerk
L3/L4
Which spinal nerves control spinal reflexes of the wrist and bicep
C5/C6
Which spinal nerves control spinal reflexes of the triceps
C7/C8
Which nerve innervates the penis
Pudendal nerve
Conscious ascending tracts
DCML pathway and Spinothalamic pathways
Unconscious ascending tracts
Spinocerebellar tracts
Dorsal column-medial lemniscal information
Fine touch
Vibration
Proprioception
Dorsal column-medial lemniscal pathway
Travels via dorsal columns in spinal cord then transmitted through medial lemniscus in brainstem
Dorsal column-medial lemniscal first order neurones
Carry sensory information from peripheral nerves to medulla
Dorsal column-medial lemniscal first order neurones- upper limb pathways
Signals from upper limbs (T6 and above)
Travel in fasciculus cuneatus
Synapse in nucleus cuneatus
Dorsal column-medial lemniscal first order neurones- lower limbs pathway
Signals from lower limbs
Travel in fasciculus gracilis
Synapse in nucleus gracilis
Dorsal column-medial lemniscal second order neurones
From cuneate of gracilis nuclei fibres carry information to 3rd order neurones
Decussate in medulla —> travel to contralateral thalamus
Where do Dorsal column-medial lemniscal second order neurones decussate
Medulla
Dorsal column-medial lemniscal third order neurones
Transmit sensory information to thalamus and ipsilateral primary sensory cortex
3 types of ascending tracts
Dorsal column-medial lemniscal
Spinothalamic
Spinocerebellar
2 types of Spinothalamic tracts
Anterior Spinothalamic tract
Lateral Spinothalamic tracts
Function of anterior Spinothalamic tracts
Crude touch and pressure
Function of lateral Spinothalamic tracts
Pain and temperature
Spinothalamic tracts first order neurons arise from
Sensory receptors in the periphery
Spinothalamic tracts first order neurons pathway
Sensory receptors
Enter spinal cord and synapse at tip of dorsal horn
Spinothalamic tracts second order neurons
Carry information from dorsal horn to thalamus
Fibres decussate in spinal cord
Where do Spinothalamic tracts second order neurons decussate
Spinal cord
Spinothalamic tracts third order neurons
From thalamus to ipsilateral primary sensory cortex
Spinocerebellar tracts
Group of tracts carrying unconscious proprioceptive information from muscles to cerebellum
4 types of Spinocerebellar tracts
Posterior
Cuneocerebellar
Anterior
Rostral
Posterior Spinocerebellar tracts
Lower limbs to ipsilateral cerebellum
Cuenocerebellar tracts
Upper limbs to ipsilateral cerebellum
Anterior Spinocerebellar tracts
Lower limbs to ipsilateral cerebellum
Fibres in tract decussate twice
Rostral Spinocerebellar tracts
Upper limbs to ipsilateral cerebellum
2 Spinocerebellar tracts from upper limb
Cuneocerebellar tracts
Rostral Spinocerebellar tracts
2 Spinocerebellar tracts from lower limbs
Posterior Spinocerebellar tracts
Anterior Spinocerebellar tracts
Which Spinocerebellar tract decussates twice
Anterior Spinocerebellar tracts
Topographically
Fibres in the dorsal columns are arranged topographically
such that the fibers that convey information from lower limbs are in the medial subdivision of the dorsal columns, called the gracile tract, a fact of some significance in the clinical localization of neural injury. The lateral subdivision, called the cuneate tract, contains axons conveying information from the upper limbs, trunk, and neck. At the level of the upper thorax, the dorsal columns account for more than a third of the cross-sectional area of the human spinal cord.
Characteristic of dorsal column-medial lemniscal system conduction velocities
Fast
dorsal column-medial lemniscal system function
Carries touch and proprioception
Topographical organisation of dorsal columns
Gracile
Cuneate
Where does the dorsal column-medial lemniscal system decussate
Medulla then thalamus to somatosensory cortex
Spinothalamic tract and Nociceptive information
Conveys nociceptive information contralaterally up the spinal cord.
Brown-Sequard Syndrome. Following traumatic hemisection of the spinal cord on the right at the level of C7, the patient presents with which ONE of the following signs and symptoms?:-
Lower motor neuron paralysis at the level of C7 on the ipsilateral side.