Distal variations of the neurovascular pedicle of the serratus anterior muscle as a flap

The serratus anterior muscle has recently been suggested as a versatile and reliable flap for reconstruction of complex craniofacial and neck lesions, extremity and sacroiliac region injuries, as well as intrathoracic and extrathoracic reconstruction procedures. The muscle has been used as a microvascular flap or a pedicled transfer and has been transferred in combination with other muscles, bones, and skin. We performed 15 dissections of adult axilla regions that were examined under ×3.5 loupe magnification to collect anatomic data regarding the neurovascular pedicle of the serratus anterior muscle. The serratus muscle and fascia were found to have a dual blood supply, with the upper part supplied by the lateral thoracic artery and the lower part by terminal branches of the thoracodorsal artery. The lateral thoracic artery was noted to supply the upper four slips but it extended into the lower serratus anterior muscle in two cases. Seven branching patterns were found in the lower serratus anterior muscle. In type I, the only branch of serrati proceeded over the long thoracic nerve. Type II had the only branch of serrati proceeding under the long thoracic nerve. In type III, double branches of serrati proceeded over the long thoracic nerve; while in type IV branches of serrati ran with a double branch under the long thoracic nerve. In type V, three serrati branches proceeded over the long thoracic nerve. Type VI serrati branches were branches of thoracodorsalis, which was hypoplastic, and the supply was maintained from the lateral thoracic artery. In type VII, one serrati branch ran over the long thoracic nerve. There was no connection between the branches of serrati and the branches of the lateral thoracic artery. The length of the long thoracic nerve, the number of motor axons and the vascular network in anatomic proximity to this nerve make it an expendable but powerful source of reconstructions of head, neck, chest wall and extremity defects. Results of this study provide an anatomic framework to improve current reconstructive or aesthetic procedures on the serratus anterior neurovascular structures.