SpinalCord
RelationofSpinalNerveRootstoVertebrae
Plate161
C1 spinal nerve exits
above C1 vertebra
Cervical
enlargement
Occipital
bone
C8 spinal nerve
exits below
C7 vertebra
(there are 8 cervical
nerves but only
7 cervical vertebrae)
Lumbar disc protrusion (
dashed ovals
) does not usually
affect nerve exiting above disc. Lateral protrusion
at disc level L4–5 affects L5 spinal nerve, not
L4 spinal nerve. Protrusion at disc level L5–S1
affects S1 spinal nerve, not L5 spinal nerve.
Lumbar
enlargement
Conus medullaris
(termination of
spinal cord)
Termination of
dural sac
Cauda equina
Coccygeal nerve
Coccyx
Coccygeal nerve
Cervical nerves
Thoracic nerves
Lumbar nerves
Sacral and coccygeal nerves
Medial protrusion at disc level L4–5 (
dashed oval
)
rarely affects L4 spinal nerve but may affect L5
spinal nerve and sometimes S1–4 spinal nerves.
C1
C2
C3
C4
C5
C6
C7
T1
T2
T6
T7
T8
T9
T10
T11
T12
L1
C1
C2
C3
C4
C5
C6
C7
C8
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
L1
L2
L2
L3
L5
L3
L4
L4
L5
Sacrum
S1
S2
S3
S4
S5
S2
L4
L4
L5
L5
S1
L4
L4
L5
L5
S1
S2
S3
S4
S5
