Successful treatment of the skin cancer patient revolves around three goals: (1) tumor-free surgical margins; (2) preservation of function; and (3) restoration and optimization of cosmesis. Before conceptualizing any repair, the surgeon must keep in mind that the primary goal of the oncologic surgeon is achievement of a tumor-free plane. Residual tumor will lead to recurrence, which can be devastating functionally and cosmetically, and potentially life threatening with aggressive tumors. One must understand tumor biology and relevant anatomy in order to be successful in this endeavor. From an aesthetic perspective, reconstructions planned according to the cosmetic unit principle provide optimal cosmesis.

The forehead, which includes the temple region, is defined superiorly and laterally by the natural anterior hairline and inferiorly by the zygomatic arch, eyebrows, and nasal root. It may be subdivided into five subunits: the central forehead, which is contiguous with the scalp; the bilateral temples; and the hair-bearing eyebrows ( Fig. 11.1 ). Relaxed-skin tension lines (RSTLs) run horizontally in the central forehead, perpendicular to the underlying frontalis musculature, and curve laterally as the temple is approached ( Fig. 11.2 ). Convex centrally, the lateral subunit of the temple is relatively concave. Composed of moderately sebaceous skin, the central forehead is relatively immobile, with adherence to the underlying frontalis muscles. The temple subunit is more mobile, as it is loosely adherent to the underlying temporal fascia. The paired frontalis muscles insert into the inferior musculature and the brow without muscle directly midline. Inferiorly, the procerus muscle acts centrally, with bilateral corrugator supercilii muscles, and more laterally the superior aspects of orbicular oculi ( Fig. 11.3 ). The superficial musculoaponeurotic system (SMAS), which underlies the dermis and subcutaneous tissue superiorly, is composed of the galea aponeurotica of the scalp, which invests the frontalis muscle and orbicularis oculi. Laterally, the galea is contiguous with temporoparietal fascia. In the temporal region, the superficial temporal fascia lies just beneath the subcutaneous tissue and is contiguous with the galea superiorly, the frontalis muscle, and the SMAS. Deep to this layer is the innominate fascia. Concern in this region must be taken for preservation of the temporal branch of the facial nerve, which generally runs just beneath the superficial temporal fascia within the SMAS creating a relative “danger zone,” though some consider this branch to course deeper in the innominate fascia. This region is generally defined inferiorly by a line drawn from the earlobe to the lateral brow and superiorly by a line drawn from the tragus to the lateral aspect of the highest RSTL on the forehead, with the nerve being most superficial and at risk as it crosses the midzygomatic arch ( Fig. 11.4 ).

Cosmetic units. The cosmetic units of the forehead and temple area can be divided into five subunits: the central forehead, the paired lateral foreheads or temples, and the paired eyebrows.

Relaxed-skin tension lines (RSTL). The RSTL run horizontally in the central forehead and curve inferiorly as the temple is reached perpendicular to the underlying musculature.

Musculature anatomy. The frontalis muscle is shown as it interdigitates with the procerus, orbicularis oculi, corrugator supercilii, and depressor supercilii. The frontalis muscle also interdigitates with the skin of the eyebrow inferiorly. Portions of the frontalis, orbicularis oculi, and depressor supercilii have been dissected to reveal the corrugator muscle.

Temporal nerve danger zone. The temporal branches lie between two lines drawn from the earlobe to the lateral brow and to the lateral end of the highest forehead crease. From the time the nerve exits the parotid and enters the frontalis, it lies in the superficial musculoaponeurotic system (SMAS), just below the subcutaneous fat.

Vascular supply to the majority of the forehead is supplied by the dorsal nasal artery, supratrochlear artery, and supraorbital artery, all branches of the internal carotid artery. The supratrochlear artery, which is most medial, is the axial artery for the paramedian forehead flap. Laterally, the temple region is supplied by the superficial temporal artery, which arises from the external carotid artery ( Fig. 11.5 ). This artery runs within and then above the SMAS layers of the lateral forehead. Generally, two undermining planes may be defined on the forehead—above the frontalis muscle and below the muscle and deep fascia. This latter plane provides a relatively bloodless plane but can result in transection of the major vessels and requires repair of the frontalis muscle. Sensory innervation mirrors the vasculature medially and arises from the supratrochlear and supraorbital branches of the ophthalmic division of the trigeminal nerve ( Fig. 11.6 ). These nerves divide into four to six terminal branches collectively and may have variable anatomy, but notably these nerves quickly penetrate the muscle and enter the superficial subcutaneous plane after leaving their foramens. As a result, horizontal closure in this area may result in a fan-shaped area of numbness superior to the closure that is usually temporary. Laterally the temple receives sensory innervation from the zygomaticotemporal nerve, a branch of the maxillary division of the trigeminal nerve. Motor innervation is provided predominantly by the temporal branch of the facial nerve. Contraction of the frontalis muscle causes brow elevation, and denervation results in brow ptosis. The paired corrugator supercilii muscles are also innervated by the temporal branch of the facial nerve and act to pull the brow medially and downward while the central procerus muscle is innervated by the zygomatic branch of the facial nerve and acts to depress the brow. Laterally the paired orbicular oculi muscles are innervated by the temporal branch of the facial nerve and act to close the eyes.

Temporal artery. The temporal artery runs within and above the superficial musculoaponeurotic system (SMAS) layer of the lateral forehead. The branches of this artery can be localized by palpation. When possible these vessels should be dissected and ligated before severing, thereby decreasing the risk of postoperative hematoma.

(A) Medially positioned supratrochlear and laterally positioned supraorbital nerve; (B) sagittal view of supraorbital and supratrochlear nerves; (C) schematic demonstrating how sacrifice of supraorbital and supratrochlear nerves can result in a fan-shaped sensory deficit.

As in the case of surgical defects in any location, various repairs may be considered on the forehead. Generally a poor match for skin grafts, secondary intention, primary linear closure, M-plasty, advancement flaps including rotation flaps, and transposition flaps may all be considered in this subunit. Which type of repair is optimal depends on the size and location of the defect, as well as the patient’s individual anatomy. Maintenance of brow position is of utmost importance with respect to cosmesis, and consideration of tension placed on the eyelid must be observed more laterally in the temple region.