INNERVATION AND FUNCTIONAL RECONSTRUCTION OF THE FOREHEAD

The anatomy of the motor and sensory innervation of the forehead was studied by dissection of 10 cadavers. Some of the temporal branches of the facial nerve supply the frontalis muscle. They run along a line drawn from below the tragus to a point about 1.5 cm above the outer margin of the orbit where the branches enter the muscle from its deep aspect. There is wide variation in the number of branches and the pattern of anastomosis between them. The sensory innervation is from the frontal nerve, a branch of the ophthalmic division of the fifth cranial nerve. Although the pattern of division into four or five branches is very variable and often asymmetrical, there is an important common feature: the most medial branch changes from a submuscular to a subcutaneous plane immediately after leaving the orbit, while each of the successively more lateral branches travels to a higher level before this change takes place. On the basis of these anatomical findings, a functionally satisfactory reconstructive procedure was designed to close skin defects of the forehead of up to 6 cm in diameter, by raising innervated musculocutaneous local flaps.