The authors studied 50 fresh cadaver serratus anterior muscles to describe the neurovascular anatomy of the muscle slip and subslip. All 260 slips could be separated into a deep and a superficial subslip, yielding a total of 520 subslips. A branch of the serratus artery and a branch of the long thoracic nerve were identified for each of these. Deep subslips were thinner than superficial subslips, both at the origin of the slip on the rib periosteum (2.4mm versus 3.0mm) and centrally at the serratus artery (3.3mm versus 4.0mm). Also, the most inferior subslips were thinner than those of more superior slips, both at the slip origin (2.3mm vs 2.8mm) and at the serratus artery (3.0mm vs 3.8mm). Fine anastomosing vessels were present between the slips (mean 1.7) and the subslips (mean 2.1). After division of these vessels, a mean length of 9.6cm is available to allow independent orientation of each subslip. Using its component subslips, the serratus flap could possibly generate 10 force vectors transferable on a single vascular pedicle. Subslips are significantly thinner than donor muscles commonly used today. Mimetic muscles such as the orbicularis oculi and orbicularis oris could possibly be reconstructed in their proper anatomical positions.