The supraorbital nerve is a branch of the frontal nerve, which, itself, branches away from a major cranial nerve that originates from the brainstem. Passing through the eye socket, also known as the orbit, and up to the forehead allows the supraorbital nerve to innervate some of the regions of the forehead, frontal sinuses, scalp, and eyes. Nerves are cord-like bundles of fibrous tissue that permit the transmission of sensory information such as that of touch, taste, pain, and temperature to travel to the brain for processing.
The frontal nerve is the biggest branch of the ophthalmic nerve, which itself is one of three branches of the trigeminal or fifth cranial nerve. The frontal nerve passes through the superior orbital fissure, which is a foramen, or hole, in the human skull located between the greater and lesser wings of the sphenoid bone, which is the area behind the eye in the back of the eye socket. Halfway between the base, which is the part of the eye socket that opens to the face, and the apex, or the back of the eye socket, the frontal nerve divides into two branches, the supratrachlear nerve and the supraorbital nerve.
The supraorbital nerve is an endmost, or terminal, branch of the frontal nerve that goes through the supraorbital foramen, which is also called the supraorbital notch and is a bony cleft located above the eye socket just underneath the eyebrow. The supraorbital artery joins the supraorbital nerve as it passes through the supraorbital notch, and then divides into a superficial and a deep branch. A branch of the supraorbital vein also passes through the supraorbital notch as it descends from the forehead.
Traveling from beneath the eyebrow up to the forehead, the supraorbital nerve terminates in two branches called the lateral and medial branches. Both branches of the supraorbital nerve begin at the frontalis muscle, which is also known as the occipitofrontalis and epicranium and is located on the forehead. The lateral and medial branches then extend across the scalp, ending just before the lamboidal suture, which is the joint that connects the parietal and temporal bones of the skull with the occipital bone, located at the very back of the head. Both branches diverge into small twigs that supply the pericranium, which is the membraneous covering of the skull bones, and is consistent with the periosteum that covers the other bones of the body.