Spinal Cord and Nerves 

Posted bythespinebookadminPosted inAnatomy, Topics

Overview 

  • Terminates as conus medullaris 
  • Adults – L1 inferior border 
  • Neonate – L3 
  • Filum terminale to dorsum of first coccygeal segment 
  • Pia 
  • Arachnoid 
    • Subarachnoid space between pia and arachnoid 
    • CSF 
  • Dura (around the thecal sac) 
  • Pathways (ascending sensory, descending motor) 
    • C spine – central 
    • TLS – progressively peripheral 
    • Long Tracts 
      • A 

Peripheral Nerves 

  • C2-7 – exit above named pedicle 
    • Horizontal exit 
  • C8 – exit between C7 and T1 
  • T1 and below all exit below the named pedicle 
    • Vertical exit (cord shorter than vertebral column) 
  • Dorsal sensory root 
    • Ganglion near exit of foramen 
    • Ganglion synapse of ascending cell bodies 
    • Dysesthesias if manipulated 
    • 3 branches 
      • Ventral ramus 
      • Sinu-vertebral nerve – over PLL 
        • Innervates disk 
      • Dorsal ramus 
        • 3 branches 
  • Ventral motor root 
  • Mixed spinal nerve at combination of roots 
    • triifurcates into ventral branch, dorsal branch, meningeal branch 

Autonomic Nervous System 

  • Sympathetic 
    • 22 ganglia (3C, 11T, 4L, 4S) 
    • Branches from ventral branch of mixed spinal nerve 
    • Middle cervical (Stellate Ganglion) 
      • At risk C6, medial to border of longus colii 
      • Risk of Horner’s syndrome (myosis, pstosis, anhidrosis) 
  • Parasympathetic 
    • Hypogastric plexus S234 (splanchic nerves)