The artery lies along the inner and under border of the large muscle on top of the arm known as the biceps. The biceps is the muscle used when lifting a weight. To those whose occupation is to exercise the muscular tissue of the body liberally, this muscle becomes quite large, and generally the artery is proportionally large. _Linear Guide._—The course of the brachial artery may be marked out by drawing a line from the middle of the axillary space (arm pit) to the center of the elbow, provided the palm of the hand be turned upward. This line will be immediately over the artery, which will be found by cutting through the skin at any point on the line, and dissecting through the subcutaneous tissue toward the center of the arm. _The Anatomical Guide._—In the upper third the artery lies between the biceps and coracobrachialis muscles which lie above the artery, and the triceps muscle which lies below the artery. In the upper third the nerve lies close to the muscle, the artery below and to the inner side toward the body, and the vein a little farther to the inside. In the middle third the artery lies between the biceps which lies above the artery, and the triceps muscle which lies below the artery. In the middle third the artery will lie beneath the nerve. In the lower third the artery lies between the biceps which lies above the artery, and the triceps which lies below the artery. In the lower third the artery lies next to the muscle and the nerve to the inner side next to the body, and the vein still farther to the inner side.