What are the features of the spinal cord?
- continuation of medulla through foramen magnum
- 31 pairs of nerves (dorsal-sensory) (ventral-motor) pass through intervertebral foramena
- spinal cord ends at L2
Where is lumbar puncture/spinal tap taken from?
L3/L4 (below where spinal cord ends)
What are the key features at the end of the spinal cord?
- conus medullaris: tapering terminal end at L2
- cauda equina: horse tail of spinal nerves
- filum terminale: extension that anchors within dural sheath
What is radiculopathy?
- compression of nerve in spine (herniation, bone spur, otseoarthritis, scoliosis, diabetes)
- numbness, tingling, weakness
- problem areas: C3, L4, L5 (lateral disk prolapse or compression)
What are the spinal cord regions?
- 31 segments of vertebral level exits
- Cervical (8): brachial plexus, cervical enlargement (C3 max motor), C5 max forelimb
- thoracic (12): trunk, intermediolateral horn enlargement (sympathetic) T5 small spinal, gross movement
- lumbar (5): lumbar plexus, lumbar enlargement (L5-mostly gray, lower extremeity motoneurons)
- sacral (5): sacral plexus (with L5), pelvic muscles, posterior lower limbs
- coccygeal (1): with S4,5 innervate skin over coccyx and anus
What is a morphogen?
- molecule that diffuesed to form a concentration gradient and affects developing embryo
- sonic hedgehog
What is BMP?
- growth factor or cytokines and metabologens induces bone & cartilage formation
- orchestrate tissue architecture
Where is the spinal cord derived?
- neural plate (neuroectoderm)
- forms nerual tube & excludes nerual crest cells which form DRGs
- DRG: primary afferent sensory
- orchestrated by morphogenic proteins, SHH, creat alar and basal plates
- alar: dorsal sensory
- basal: ventral motor
What are Rexed's Laminae?
- organization of gray matter of spinal cord
- dorsal layers
- ventral circles
- I: pain, temp, proprioception & touch
- II & III: substantia gelatinosa (same stimuli)
- IX: motor neurons in columns
- X: visceral nocicption
What is the somatotopic organization of spinal white matter?
- representation of the body within the CNS
- sacral & lumbar enter first then thoracic & cervical
- ascending sensory
- descending motor
- dorsal colums:carry proprioceptive info
- gracile faciculous: medial 2 dorsal column, carry info from sacral & lumbar
- cuneate fasciculus: throracic & cervical
- lateral corticospinal: ascend on same side (cervical medial, lumbar lateral)
- spinothalmic tract: somatotopically (sacral lateral, cervical medial)