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In human anatomy, the five vertebrae are between the rib cage and the pelvis.They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process (since it is only found in the cervical region) and by the absence of facets on the sides of the body (as found only in the thoracic region).
The fifth lumbar spinal nerve 5 (L5) [5] originates from the spinal column from below the lumbar vertebra 5 (L5). L5 supplies many muscles, either directly or through nerves originating from L5. They are not innervated with L5 as single origin, but partly by L5 and partly by other spinal nerves. The muscles are: gluteus maximus muscle mainly S1
The thoracic, lumbar, and sacral nerves are then numbered by the vertebra above. In the case of a lumbarized S1 vertebra (also known as L6) or a sacralized L5 vertebra, the nerves are typically still counted to L5 and the next nerve is S1. Scheme showing structure of a typical spinal nerve 1. Somatic efferent. 2. Somatic afferent. 3,4,5.
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.
Retrolisthesis of L5-S1. Complete Retrolisthesis - The body of one vertebra is posterior to both the vertebral body of the segment of the spine above as well as below. [citation needed] Stairstepped Retrolisthesis - The body of one vertebra is posterior to the body of the spinal segment above, but is anterior to the one below. [citation needed]
The discs between these vertebrae create a natural lumbar lordosis (a spinal curvature that is concave posteriorly). [citation needed] This is due to the difference in thickness between the front and back parts of the intervertebral discs. The lumbar vertebrae are located between the ribcage and the pelvis and are the largest of the vertebrae.
Bertolotti's syndrome is characterized by sacralization of the lowest lumbar vertebral body and lumbarization of the uppermost sacral segment. It involves a total or partial unilateral or bilateral fusion of the transverse process of the lowest lumbar vertebra to the sacrum, leading to the formation of a transitional 5th lumbar vertebra.
For example, the facet joint between T1 and T2 is innervated by C8 and T1 medial branch nerves. Facet joint between L1 and L2; the T12 and L1 medial branch nerves. However, the L5 and S1 facet joint is innervated by the L4 medial branch nerve and the L5 dorsal ramus. In this case, there is no L5 medial branch to innervate the facet joint.