13/02/2026
đ§ đĻ´ Anatomy of the Spinal Cord â The Main Communication Highway of the Body
The spinal cord is a long, cylindrical part of the central nervous system that extends from the foramen magnum of the skull to approximately the L1âL2 vertebral level in adults. It transmits nerve impulses between the brain and the body and controls reflex activity.
đ Location & Protection
The spinal cord lies within the vertebral canal and is protected by:
âĸ Vertebrae
âĸ Meninges (dura mater, arachnoid mater, pia mater)
âĸ Cerebrospinal fluid
đ Length & Enlargements
The cord shows two important enlargements:
âĸ Cervical enlargement â supplies upper limbs
âĸ Lumbosacral enlargement â supplies lower limbs
đ§Ŧ External Features
âĸ Anterior median fissure (deep groove in front)
âĸ Posterior median sulcus (shallow groove behind)
âĸ Spinal nerve roots emerge laterally
âĸ Ends as conus medullaris
âĸ Continues as filum terminale
âĸ Nerve roots form cauda equina
đ Internal Structure (Cross-section)
Gray Matter (central H-shaped)
âĸ Anterior horns â motor neurons
âĸ Posterior horns â sensory neurons
âĸ Lateral horns â autonomic neurons (T1âL2)
White Matter (surrounding)
Contains ascending and descending tracts:
âĸ Sensory tracts â brain
âĸ Motor tracts â body
đ§ Spinal Nerves
Each spinal segment gives rise to:
âĸ Posterior (sensory) root with dorsal root ganglion
âĸ Anterior (motor) root
â Join to form a mixed spinal nerve
Total: 31 pairs
𩸠Blood Supply
âĸ Anterior spinal artery (supplies front 2/3)
âĸ Two posterior spinal arteries
âĸ Reinforced by segmental arteries
âī¸ Clinical Importance
âĸ Cord compression â paralysis or sensory loss
âĸ Herniated disc may press nerve roots
âĸ Spinal anesthesia done in lumbar region
âĸ Injury level determines deficit pattern
đ The spinal cord acts as the bodyâs information superhighway â linking the brain to every organ and muscle.