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The lumbar vertebrae are located between the thoracic vertebrae and pelvis. They form the lower part of the back in humans, and the tail end of the back in quadrupeds. In humans, there are five lumbar vertebrae. The term is used to describe the anatomy of humans and quadrupeds, such as horses, pigs, or cattle.
The dorsal rami provide motor innervation to the deep (a.k.a. intrinsic or true) muscles of the back, and sensory innervation to the skin of the posterior portion of the head, neck and back. [1] A spinal nerve splits within the intervertebral foramen to form a dorsal ramus and a ventral ramus. The dorsal ramus then turns to course posterior ...
The lumbosacral trunk is formed by the union of the entire anterior ramus of lumbar nerve L5 and a part of L4 [clarification needed]. [1] [2] [3] L4 first issues its branches to the lumbar plexus, then emerges from the medial border of the psoas muscle [3] to unite with the anterior ramus of L5 just superior to the pelvic brim to form the thick, cord-like trunk which [4] crosses the pelvic ...
For example, in the column, lower limb is medial, upper limb is more lateral. At the medial lemniscus, axons from the leg are more ventral, and axons from the arm are more dorsal. Fibres from the trigeminal nerve (supplying the head) come in dorsal to the arm fibres, and travel up the lemniscus too. The medial lemniscus rotates 90 degrees at ...
In human anatomy, the sacral plexus is a nerve plexus which provides motor and sensory nerves for the posterior thigh, most of the lower leg and foot, and part of the pelvis. It is part of the lumbosacral plexus and emerges from the lumbar vertebrae and sacral vertebrae (L4-S4). [ 1 ]
The medial vestibulospinal tract projects bilaterally from the medial vestibular nucleus within the medial longitudinal fasciculus to the ventral horns in the upper cervical cord (C6 vertebra). [5] It promotes stabilization of head position by innervating the neck muscles, which helps with head coordination and eye movement.
The left crus arises from the corresponding parts of the upper two lumbar vertebrae only. The medial tendinous margins of the crura pass anteriorly and medialward, and meet in the middle line to form an arch across the front of the aorta known as the median arcuate ligament ; this arch is often poorly defined.
The thoracolumbar fascia (lumbodorsal fascia or thoracodorsal fascia) is a complex, [1]: 1137 multilayer arrangement of fascial and aponeurotic layers forming a separation between the paraspinal muscles on one side, and the muscles of the posterior abdominal wall (quadratus lumborum, and psoas major [1]: 1137 ) on the other.