SPINAL CORD Flashcards
Relationship of spinal nerves to intervertebral foramina:
C1-C7 spinal nerves pass above corresponding pedicle
C8 & below pass below corresponding pedicle
Relationship of spinal cord levels to vertebral levels:
Spinous process/Vertebral body/ Spinal cord segment C6*, C6/7, C8 T4, T5, T6 T11, T11, Lumbar L1*, L1, SACRAL SEGMENTS L2-5*, L2-5, CAUDA EQUINA
SPINAL CORD FUNCTION:
- Conduit for ascending (sensory) & descending (motor) pathways
- Intrinsic Functions – processing: reflexes & central pattern generators
WHITE MATTER
3 columnsS (funiculus) - DORSAL, LATERAL, VENTRAL funiculus contain ascending or descending axons area of white matter made up of unmylinated/ thinnly mylinated fibres called dorsolateral tract
Organisation of the spinal grey matter:
REXED LAMINAE: I - X SUBNUCLEI: SUBSTANTIA GELATINOSA NUCLEUS PROPRIUS DORSAL NUCLEUS/CLARKE'S N INTERMEDIOLATERAL NUCLEUS MOTOR NEURONS OF ANTERIOR
SUBSTANTIA GELATINOSA
PAIN MODULATION
DORSAL NUCLEUS/CLARKE’S N
*Clarke’s N C8-L3 Non-conscious proprioception
MOTOR NEURONS OF ANTERIOR
LOWER MOTOR NEURONS
Transverse sections of the spinal cord at different levels: varying amounts of white & grey matter
The amount of grey matter present in the ventral horn is proportional to the amount of muscle innervated at that level.
The amount of white matter present at any level is proportional to the number of ascending / descending fibres.
LATERAL HORNS
Contain cell bodies of pre-ganglionic autonomic neurons. Present T1-L2, S2-4.
The dorsal funiculus:
below T6 has only 1 column = Fasciculus gracilis above T6 has 2 columns separated by a dorsal intermediate sulcus = Fasciculus gracilis (MEDIAL ) & Fasciculus cuneatus
column
Funiculus
TRACT
Fasciculus
Neurons in the white & grey matter
maintain a somatotopic organisation
1 large anterior spinal artery
A branch from each vertebral artery joins and descends in the anterior median fissure as 1 large anterior spinal artery