which branch of a spinal nerve is the widest in diameter
The sciatic nerve is the longest and largest nerve in the body; it measures three-quarters of an inch in diameter. It originates in the sacral plexus; a network of nerves in the low back (lumbosacral spine). The lumbosacral spine refers to the lumbar spine and the sacrum combined.he sciatic nerve starts in your low back, which is called your lumbar spine. The nerve roots are at the L4 and L5 vertebrae (the 'L' means lumbar, and the numbers indicate the level of the vertebraâwhere it is in your back). The sciatic nerve also travels through your pelvic region (sacrum).