7Cauda equina Consists of sensory and motor nerve roots below L1 These are unmixed/pure nervesPia mater continues below L1 as a cord named filum terminale
8Length of the spinal cord Black line indicates dura and arachnoid together. Pia is in blue.T12L1L2L3L4L5SacrumCoccyxFoetusat 3 monthsT12L1L2L3L4L5SacrumCoccyxAt birthS2T12L1L2L3L4L5SacrumCoccyxAdult
9Lumbar puncture What are the risks of lumbar puncture ? Performed to get CSF for investigationVertebral column is fully flexedNeedle inserted between L3 and L4 spines (or one space above)Collects CSF from subarachnoid spaceWhat are the risks of lumbar puncture ?
10Cross section of spinal cord Posterior median septumPosterior hornLateral hornAnterior hornAnterior median fissureCentral canalPosterior white columnLateral white columnAnterior white columnAnterior nerve rootPosterior nerve root
14Dorsal and ventral roots Posterior roots contain afferent (sensory) axonAnterior roots contain efferent (motor) axonsThe anterior roots continue out from the spinal cord, and mix with their corresponding posterior nerve root at a point after the ganglionCombination of the two roots is called a mixed spinal nerve.
15Spinal nerve is mixed (motor + sensory + autonomic) Spinal nerve refers to the mixed spinal nerveIt is formed from the dorsal and ventral rootsPasses out through the intervertebral foramenThere are 31 bilaterally-paired spinal nerves8 cervical nerves (C1-C8)12 thoracic nerves (T1-T12)5 lumbar nerves (L1-L5)5 sacral nerves (S1-S5)1 coccygeal nerve (Co)
16DermatomeArea of skin supplied by a single spinal nerve or spinal cord segmentMyotomeThe muscle/s supplied by a single spinal nerve or spinal cord segment
17Nerve plexusIs formed by nerves interlaced with numerous communicating branchesWhat are the advantagesof a nerve plexus?Last’s Anatomy, 10th ed.Page 13
19Two posterior spinal arteries Arise from PICASupply posterior 1/3 of spinal cordOne anterior spinal arteryArise as two from vertebral arteriesSupply anterior 2/3 of spinal cordSegmental spinal arteriesEnter the vertebral canal through intervertebral foraminaDivides into anterior & posterior radicular arteries. Radicular arteries accompany nerve roots