Among all different types of photography showcased on the Smashing Magazine, **underwater photography** is probably one of the most difficult ones. It requires a very specialized equipment and the knowledge of some advanced techniques to get a perfect picture.
Anatomical terms of neuroanatomy. A nerve plexus is a plexus (branching network) of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels. There are five spinal nerve plexuses, except in the thoracic region, as well as other forms of autonomic plexuses, many of which are a part of the enteric nervous system.
The sacral plexus is a network of nerve fibres that supplies the skin and muscles of the pelvis and lower limb. It is located on the surface of the posterior pelvic wall, anterior to the piriformis muscle. The plexus is formed by the anterior rami (divisions) of the sacral spinal nerves S1, S2, S3 and S4.