The sternomastoid, is a large, thick muscle, which passes obliquely across the side of the neck, being inclosed between two layers of deep fascia. It has its origin at the sternum and clavicle and attaches to the mastoid process of the temporal bone. By making the perpendicular incision in the lower third, in as much as the muscle slightly covers the artery, it can either be cut or pushed to the outside of the incision. It is best to push the muscle to the outside with the thumb, and with the handle of the scalpel, work down deep through the areolar tissue. The operator will now arrive at the common sheath, or that part of the deep fascia surrounding the artery, vein and nerve. The common sheath will be very tough and a slit must first be cut, then it can be torn the length of the incision. The artery will now be seen lying next to the wind pipe and the internal jugular vein to the outside. In the lower third the artery will be about one-half inch deep, while in the upper third it will be about one to two inches deep, owing to the amount of fat in this region. In the upper third, the omohyoid muscle crosses over the artery, which must be either pushed aside or cut in two. It is always advisable, to raise this artery in the lower third, as it is less apt to show in that third. Loosen the artery well from the surrounding tissues with the aneurism hook, raise to the surface and place a bone separator beneath the artery. Now remove the individual sheath, incise the artery and insert the arterial tube. If it is desired to raise the internal jugular vein for the withdrawal of blood, it is best not to open up the common sheath, but to raise the artery and the vein both at the same time. Having raised them to the surface they can then be separated by the removal of the common sheath and dropping it back into the incision. If it is desired only to raise the carotid, the hook should always be inserted between the artery and the vein, and directed toward the trachea. If it is directed around the artery in the other direction there is danger of rupturing the vein, and thus getting a bloody incision.