Spinal nerves in the context of "Coccygeal vertebrae"

The cauda equina (from Latin tail of horse) is a bundle of spinal nerves and spinal nerve rootlets, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enlargement and the conus medullaris of the spinal cord. The cauda equina occupies the lumbar cistern, a subarachnoid space inferior to the conus medullaris. The nerves that compose the cauda equina innervate the pelvic organs and lower limbs to include motor innervation of the hips, knees, ankles, feet, internal anal sphincter and external anal sphincter. In addition, the cauda equina extends to sensory innervation of the perineum and, partially, parasympathetic innervation of the bladder.

The general somatic afferent fibers (GSA or somatic sensory fibers) are afferent fibers that arise from neurons in sensory ganglia and are found in all the spinal nerves, except occasionally the first cervical. General somatic afferents conduct impulses of pain, touch and temperature from the surface of the body through the dorsal roots to the spinal cord, and impulses of muscle sense, tendon sense and joint sense from the deeper structures.

The lumbar nerves are the five pairs of spinal nerves emerging from the lumbar vertebrae. They are divided into posterior and anterior divisions.