superior lateral cutaneous nerve of arm superior lateral cutaneous nerve of arm the superior lateral cutaneous nerve of arm (or superior lateral brachial cutaneous nerve) is the continuation of the posterior branch of the axillary nerve, after it pierces the deep fascia. it contains axons from c5-c6 ventral rami. superior lateral cutaneous nerve of armsuprascapular and axillary nerves of right side, seen from behind.cutenaous innervation of the arm. innervation area of axillary, sup. lat. cut. (c5-c6) is seen in blue at top.detailsfromaxillary nerveidentifierslatinnervus cutaneus brachii lateralis superiorta98a14.2.03.061ta26442fma65303anatomical terms of neuroanatomy structure it sweeps around the posterior border of the deltoideus and supplies the skin over the lower two-thirds of the posterior part of this muscle, as well as that covering the long head of the triceps brachii.