Knowing the function of each spine segment can aid in determining where spinal injury may have occurred.
Different segments of the spine are basically responsible for flexion or extension of joints, or adduction or abduction of the thigh. Appropriately, the higher regions of the spine are associated with movement in the neck and upper body while lower regions of the spine correlate to movement in the lower body. The upper region of the spine correlate to movement in the joints of the upper body including the elbows, wrists and shoulders. The middle segments of the spine are responsible for abdominal (torso and core) movement. The next lowest segment deals with thigh movement- adduction, abduction and flexion. The lowest part of the spine relates to foot and ankle movement.
Knowing how each part of the body relates back to the spine is key in knowing what portion of the spine is affected by injury. Lack of movement, numbness or sharp pain in, for example, the wrist, can indicate a specific issue with the C6 or C7 spinal segment. See the image below for specific locations on the spine and their relative area of function.
Divisions of Spinal Segments
Segmental Spinal Cord Level and Function
Level Function
Cl-C6 Neck flexors
Cl-C7,
Tl Neck extensors
C3-C5 Supply diaphragm (mostly C4)
C5-C6 Shoulder movement, raise arm (deltoid); flexion of elbow (biceps); C6 externally rotates the arm (supinates)
C6-C7 Extends elbow and wrist (triceps and wrist extensors); pronates wrist
C7, T1 Flexes wrist
C7, T1 Supply small muscles of the hand
T1-T6 Intercostals and trunk above the waist
T7-T12,
L1 Abdominal muscles
L1-L4 Thigh flexion
L2-L4 Thigh adduction
L4-L5, S1 Thigh abduction
L5,
S1-S2 Extension of leg at the hip (gluteus maximus)
L2-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 Flexion of toes
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