medial cluneal nerves medial cluneal nerves the medial clunial nerves innervate the skin of the buttocks closest to the midline of the body. those nerves arise from the posterior rami of sacral spinal nerves (s1, s2, and s3). medial cluneal nervesareas of distribution of the cutaneous branches of the posterior divisions of the spinal nerves. the areas of the medial branches are in black, those of the lateral in red.cutaneous nerves of the right lower extremity. front and posterior views. (posterior div of sacral visible in pink at upper left.)detailsfromposterior branches of sacral nervesinnervatesbuttocksidentifierslatinnervi clunium mediita98a14.2.06.006ta26509fma75489anatomical terms of neuroanatomy additional images diagram of the distribution of the cutaneous branches of the posterior divisions of the spinal nerves. the posterior divisions of the sacral nerves.