scalp, the integument covering the top of the head. It consists of three layers of tissue: the skin, an underlying layer of tissue and blood vessels, and the occipitofrontalis muscle stretching from the eyebrows to the back of the head. Except for its abundant growth of hair, the skin of the scalp resembles that of the rest of the body but is especially rich in blood vessels. Hence profuse bleeding may be associated with scalp injuries.