The forehead is the continuation of the scalp from the hairline to the eyebrows.

The glabella, frontal sinuses, and frontal bone give the forehead its underlying contour.

Overlying the bone, the soft tissue layers of the forehead, from deep to superficial, include the pericranium, loose areolar tissue, muscular layer (ie, frontalis muscle and galea aponeurosis), subcutaneous connective tissue and fat, dermis, and epidermis.

Sensory nerves are supplied from supratrochlear and supraorbital nerves, emerging from the supraorbital rim at 1.7 and 2.5 cm from the midline, respectively, via a foramen or notch along with associated arteries.

The paired frontalis muscles are brow elevators with vertically oriented fibers, and their attachments with the dermis give rise to horizontal rhytides of the forehead.

Medial, intermediate, and lateral fibers of the frontalis are continuous with the procerus muscle, corrugator supercilii, and orbicularis oculi muscles, respectively.

The procerus muscle is a brow depressor vertically oriented, originates from the periosteum over the nasal bones, and inserts into the frontalis muscle and the glabellar dermis which is responsible for rhytides at the root of the nose.

The corrugator supercilii muscles are brow depressors obliquely oriented originating from the medial superciliary arch and passing through the orbicularis oculi muscle superolaterally inserting into the dermis of the brow and are responsible for vertical frown lines in the glabella.

The paired depressor supercilii muscles are brow depressors originating from the medial orbital rim and inserting into the glabellar dermis and are responsible for oblique rhytides in the medial eyebrow area.

The orbital portion of the orbicularis oculi muscle is a brow depressor (FIG 1).

Recession of the upper hairline and temporal hairline increases the length and width of the forehead, respectively.

Eyebrow ptosis occurs with age secondary to involutional changes of the facial soft tissues from thinning fat and dermis, collagen laxity, and aging. It is usually first seen in the lateral forehead and eyebrows because the frontalis muscle may compensate by elevating the medial twothirds of the eyebrows. Brow ptosis may also occur due to blepharospasm from hyperactivity of the orbicularis oculi muscle or weakness of the facial nerve and frontalis muscle.

Frontal bossing is typically due to hyperaeration of the frontal sinuses and less commonly due to soft tissue excess.

A comprehensive analysis is recommended of the face, hairline, brow position and arch, forehead length, width, contour, soft tissue quality, and rhytides. A significantly elongated forehead is best rejuvenated with an open approach via a pretrichial incision to remove excess skin (discussed in another chapter). A useful method to analyze the brow position is to eliminate the compensation from the frontalis muscle by asking the patient to smile or close their eyes tightly and then open them just enough to see the examiner. The uncompensated position of the eyebrows is at the supraorbital rim in males or slightly above in females, with its apex at the lateral limbus of the eye.

Then, rhytide evaluation is recommended in repose, smiling, and frowning. Deep static forehead rhytides are best treated with a subcutaneous approach rather than the endoscopic approach, whereas the fine rhytides are treated with laser resurfacing after endoscopic brow lift.

Imaging is only warranted if there are contour abnormalities due to a soft tissue mass or underlying bony defect that must be evaluated and addressed prior to forehead rejuvenation.

A combination of botulinum toxin injection, fillers, and fat grafting may be used to perform forehead rejuvenation nonoperatively.

Endoscopic brow lift is indicated in patients with eyebrow ptosis and hyperactive forehead muscles without static deep horizontal forehead wrinkles or excess forehead length. This is done on an outpatient basis under intravenous sedation or general anesthesia. Compared to open technique, there is a smaller chance of hair loss or forehead elongation (commonly observed after a coronal incision), as well as improved visualization with magnification.

Disadvantages of endoscopic rejuvenation include the need for specialized instruments and a learning curve due to operating while looking at a monitor with a two-dimensional view.