Wk6 Spinal Cords Flashcards
The simplest of all neural circuits is the stretch reflex. What is the significance of a withdrawal reflex being a spinal reflex not mediated by the brain?
Allows rapid movement away from a damaging stimulus (protection)
what are the contents of the vertebral column?
Spinal cord Meninges of spinal cord Spinal nerve roots Blood vessels supplying the cord, meninges, vertebrae’s, joints, muscles and ligaments Spine is composed of 22 bones (vertebrae) divided into 5 sections - Cervical (C1-C7) Thoracic (T1-T12) Lumbar (L1-L54) Sacrum (S2-S5) Coccyx base
Meningeal ramus
Purely sensory Innervate spinal cord itself C6 - sensory to meninges T4 - sensory to meninges L3 - sensory to meninges
Ventral ramus
Mixed + much longer
Innervates limbs + muscles + skin of front
C6 - mixed + autonomic - brachial plexus + upper limb
T4 - mixed + autonomic - 4th intercostal space, thoracic wall strip
L3 - mixed + autonomic - lower limb plexus
Dorsal ramus
Mixed Innervates muscles + skin of back C6 - skin and muscles of back of neck T4 - skin and muscles and thoracic back L3 - skin and muscles of lower back
Where are the C1, T1, L1 and S1 cord segments in relation to the vertebrae?
C1 - located in the neck
T1 - located in upper back and attached to rib cage
L1 - located in the lower back
S1 - located in the pelvis
Where are the cauda equina and filum terminale?
Cauda equina - stretched out bundle of nerves and rootlets that come from spinal divisions L2-S5 and travel down the spinal column unprotected to leave through the correct intervertebral foramina
Filum terminal- connective tissue filament continuous with the pain mater that extends 20cm from the conus medullaris (end of the spinal cord) to connect with the coccyx
What content of the subarachnoid space produces the bright white region surrounding the spinal cord?
CSF appears bright white in T2 imaging
What type of information is conveyed by sensory neurones innervating the skin?
Responsable for sensing touch, temperature, posture, limb position etc. C2 - back of scalp and upper neck C3+4 - shoulders C5+C6 - top of arm C7 - middle fingers and medial arm T4 - nipple T10 - umbilicus L2, L3 + L4 - front of leg S1, S2 + S3 - back of leg S4 + S5 - converge of coccyx The remaining dermatoses fall into logical order
How would you assess the strength or weakness of a muscle? Describe such a test for testing the strength of biceps brachialis?
Oxford scale
- Flicker of movement
- Through full range actively with gravity counter balanced
- Through full range actively against gravity
- Through full range actively against some resistance
- Through full range actively against strong resist
How to test biceps brachialis?
Patient flexes elbow against your applied force, if brachialis are weak, the patient will pronate forearm before flexing the elbow
What is muscle atrophy and why does it occur?
Wasting or loss of muscle tissue
2 types - disease atrophy + neurogenic atrophy
Causes: lack of physical activity due to injury/illness, poor nutrition, genetics
If a muscle doesn’t get any use, the body will eventually break ut down to conserve energy
