anterior ramus of spinal nerve
Definition: the larger, anterolaterally directed major terminal branch (with the posterior ramus) of all 31 pairs of mixed spinal nerves, formed at the intervertebral foramen. Most anterior rami, especially those involved in the innervation of the limbs, participate in the formation of the major nerve plexuses (cervical, brachial, and lumbosacral) and lose their identities. Most located in the thoracic region, however, remain separate from adjacent rami to become the intercostal and subcostal nerves. Anterior rami provide innervation to the anterolateral body wall and trunk. Terminologia Anatomica lists anterior rami for each group of spinal nerves: 1) cervical (nervorum cervicalium [TA]), 2) thoracic (nervorum thoracicorum [TA]), 3) lumbar (nervorum lumbalium [TA]), 4) sacral (nervorum sacralium [TA]), and 5) coccygeal (nervi coccygei [TA]).