Color coded map of spinal cord at resource.? Below is a list of cord segments and associated functions. ? Segmental Spinal Cord Level and Function ? ? Level Function ? ? Cl-C6 Neck flexors Cl-T1 Neck extensors C3, C4, C5 Supply diaphragm C5, C6 Shoulder movement, raise arm (deltoid); flexion of elbow (biceps); C6 ?externally rotates the arm (supinates) C6, C7, C8 Extends elbow and wrist (triceps and wrist extensors); pronates wrist C7, C8, Tl Flexes wrist C8, Tl Supply small muscles of the hand Tl -T6 lntercostals and trunk above the waist T7-Ll Abdominal muscles Ll, L2, L3, L4 Thigh flexion L2, L3, L4 Thigh adduction L4, L5, S1 Thigh abduction L5, S1 S2 Extension of leg at the hip (gluteus maximus) L2, L3, L4 Extension of leg at the knee (quadriceps femoris) L4, L5, S1, S2 Flexion of leg at the knee (hamstrings) L4, L5, S1 Dorsiflexion of foot (tibialis anterior) L4, L5, S1 Extension of toes L5, S1, S2 Plantar flexion of foot L5, S1, S2 Nexion of toes ? ? ?
Primary loss and dysfunction of astrocytes may trigger demyelination, as seen in neuromyelitis optica, an inflammatory disease of the central nervous system. In most patients affected by this disease, injury to astrocytes is initiated by the action of autoantibodies targeting aquaporin 4 (AQP-4), a water channel on astrocytes.
Neuromyelitis optica (NMO; Devic’s disease) and the NMO spectrum disorders are idiopathic inflammatory demyelinating disorders that affect the central nervous system and have a predilection for optic nerves and spinal cord. The identification of NMO-IgG as a disease-specific marker and aquaporin 4 as the target antigen has renewed interest in NMO.