Lumbar nerves | |
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Plan of lumbar plexus.
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Details | |
Identifiers | |
Latin | nervi lumbales |
TA | A14.2.05.001 |
FMA | 5861 |
Anatomical terms of neuroanatomy
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The lumbar nerves are the five pairs of spinal nerves emerging from the lumbar vertebrae. They are divided into posterior and anterior divisions.
The lumbar nerves are spinal nerves which arise from either side of the spinal cord. The lumbar spinal nerves arise from the spinal cord between each pair of spinal vertebrae and travel through the intervertebral foramen. The nerves then split into an anterior branch, which travels forward, and a posterior branch, which travels backwards and supplies the area of the back.
The middle divisions of the posterior branches run close to the articular processes of the vertebrae and end in the multifidus muscle. The outer branches supply the erector spinae muscles.
The upper three spinal nerves give off branches to the skin. These pierce the aponeurosis of the latissimus dorsi at the lateral border of the erector spine muscles, and descend across the posterior part of the iliac crest to the skin of the , some of their twigs running as far as the level of the greater trochanter.
The anterior divisions of the lumbar nerves (Latin: rami anteriores) increase in size from above downward.
The anterior divisions communicate with the sympathetic trunk. Near the origin of the divisions, they are joined by gray rami communicantes from the lumbar ganglia of the sympathetic trunk. These rami consist of long, slender branches which accompany the lumbar arteries around the sides of the vertebral bodies, beneath the Psoas major. Their arrangement is somewhat irregular: one ganglion may give rami to two lumbar nerves, or one lumbar nerve may receive (branches) from two ganglia. The first and second, and sometimes the third and fourth lumbar nerves are each connected with the lumbar part of the sympathetic trunk by a white ramus communicans.