Macroscopic and microangiographic anatomy of the teres major muscle: a new free functional muscle flap?

The teres major can be seen as an additional head of the latissimus dorsi muscle for three-dimensional movement of the arm. It gained importance in pedicled muscle transfers for the treatment of plexus palsies and shoulder instability. Its supplying vessels belong to the subscapular system. According to the literature, the muscle was transferred only once as a free microvascular but nonfunctional graft.Eleven flaps from fresh cadavers were dissected and perfused with radiopaque media. The detailed macroscopic and microangiographic anatomy was investigated to determine its potential use as a free functional muscle flap.Three different access routes are possible. The mean length of the flap was 158 mm, and the distal and proximal tendinous widths were 24 mm and 52 mm, respectively. A Taylor type 1 nerve and Mathes type 2 vessel distribution was found in all specimens. The main pedicle is situated in the middle third of the superomedial border of the flap and derives almost exclusively from the circumflex scapular artery. Radioangiograms indicate possible splitting of the muscle in the transverse and longitudinal directions. The nerve could always be isolated to a considerable length (66 mm) before reaching the posterior cord.This anatomical study indicates that the teres major can be seen as a separate entity in the subscapular system and can be transferred as a free flap either alone or in combination. According to what is known from pedicled transfers, the donor-site morbidity should be low if the latissimus dorsi is left intact.