The radial artery superficial palmar branch flap: a modified free thenar flap with constant innervation.

The free thenar flap is useful for coverage of volar finger defects but has an inconstant innervation based on the presence of either the lateral antebrachial cutaneous nerve (LABC) or the superficial sensory branch of the radial nerve (SSRN). A detailed anatomic study on 30 adult fresh frozen cadavers preinjected with silicone rubber compound to demarcate arterial anatomy documented locations, numbers, and diameters of arteries and skin perforators with surrounding nerves. The palmar cutaneous branch of the median nerve (PCMN) was present within the flap in all cases. However, the LABC and the SSRN were available in only 43.33% and 46.66%, respectively, with neither of them in 33.33% of the cases. The constantly present PCMN allowed the design of a new flap named the radial artery superficial palmar branch (RASP) flap. The RASP flap is large enough to cover volar finger defects and contain direct skin perforators. Because it is constantly innervated, it is an excellent option for coverage of volar finger defects extending to the fingertips.