A forehead or brow lift is done to raise a brow which is heavy or low. This is called brow ptosis.
It is common to remove or divide some of the muscle that causes movement and wrinkles of the forehead.
The forehead muscles are divided into those that cause up and down (vertical movement) and those that cause a horizontal or crossways pull.
up and down muscle
• frontalis muscle, is a large muscle that extends across the width of the forehead and lifts the whole brow up. It causes transverse lines.
• procerus muscles (one on each side) are almost an extension of the frontalis on to the nose and only lift up the inner brow . They cause transverse wrinkles of the lower forehead and root of the nose
transverse or crosswise muscle
• corrugator muscles (one on each side) are slightly angled but pull mainly in a transverse direction. so that the inner brow moves to the center. They cause the vertical wrinkles of the forehead and a frowning appearance.
Numbness of the scalp after forehead surgery is more likely if a large part of corrugator muscle is removed because the supratrochlear nerve lies in the middle part of the muscle.