[TA] terminal branch (with the medial branch) of the posterior ramus of spinal nerves. In the thoracic region, the lateral branches of the upper thoracic spinal nerves are only muscular and do not reach the skin; the lateral branches of the lower thoracic spinal nerves are musculocutaneous, supplying and continuing past the muscles of the back to reach the overlying skin. SYN: rami laterales ramorum posteriorum nervorum cervicalium/thoracalium/lumbalium [TA].