first serration of the great serratus muscle, and has behind it the posterior thoracic nerve; the brachial plexus is external and posterior to the vessel; on its inner side is the axillary vein; in front of it are the clavicle, the great pectoral muscle, the subclavius muscle, the costocoracoid membrane, the cephalic and acromiothoracic veins, and the external anterior thoracic nerve. The branches of the first part of the axillary artery are the superior thoracic and the acromiothoracic. The second part of the artery is not ligated. The brachial plexus surrounds the second portion. The third part is covered in front, above, by the great pectoral, but is covered below by skin and fascia; behind, it has the tendon of the subscapularis, the latissimus dorsi, and the teres major; the coracobrachialis is on the outer side; the axillary vein is on the inner side. It is important to remember that there may be three veins, one external and two internal. The axillary vein is formed by the venæ comites of the brachial artery joining, and this new vein effecting a junction with the basilic vein. The median nerve lies upon the axillary artery in the upper part of the third portion of the vessel's course, and passes to the outer side. The musculocutaneous nerve is external, but it is only seen high up; the ulnar nerve is internal; the lesser internal and the internal cutaneous nerves are internal; the musculospiral and the circumflex nerves are behind. The branches of the third portion of the axillary artery are the subscapular and the anterior and posterior circumflex.

Operations.-Ligation of the Third Portion (Pl. 2, Fig. 4). -The position in this operation is supine with the shoulders raised and the arm abducted to a right angle. The surgeon stands between the patient's arm and side, with his back toward the subject's feet. An incision is made three inches in length. It begins half-way up the axilla opposite to the head of the humerus, and comes downward parallel to the lower edge of the great pectoral muscle and crosses the junction of the anterior and middle thirds of the outlet of the axilla. Incise the integuments and fascia. The vein or veins will be prominent to the inner side and may overlie the vessel. To the inner side with the veins are the ulnar and internal cutaneous nerves. The median is upon and the external cutaneous nerve to the outer side of the artery. Feel for the pulsations of the artery, find the median nerve and draw it outward, draw the internal nerve and veins inward, clear the artery from the venæ comites, and pass the ligature from within outward. Apply the ligature well below the circumflex branches.

Ligation of the First Part.-This operation (Pl. 3, Fig. 2) was first performed in 1815 by Chamberlaine of Jamaica. The position is supine, the upper part of the body being raised, a sand-pillow being placed between the scapula to insure carrying back of the point of the shoulder, and the arm being brought down along the side. In operating on the left side the surgeon stands on the outer side of the left arm; in operating on the right side he stands to the right of the subject's head and leans over his shoulder. The incision, which is slightly curved downward, begins external to the sternoclavicular joint and ends internal to the margin of the deltoid, thus avoiding the cephalic vein. The incision is half an inch below the clavicle. Incise skin, platysma myoides muscle, superficial nerves, and deep fascia. In the outer angle of the wound watch out for the acromiothoracic artery and the cephalic vein. Incise the pectoralis major; draw the pectoralis minor down; retract the lower margin of the wound, cut through the costocoracoid membrane close to the coracoid process and upper border of the lesser pectoral. Bring the arm to the side so as to relax the structures. Find the brachial plexus, feel for the artery internal to it, clear the vessel, draw the vein internally, and pass the needle from within outward. This avoids the dangerous neighbor, which is the axillary vein. This operation is difficult, dangerous, and unusual, and in its performance the axillary vein, which has a close attachment to the costocoracoid membrane, is apt to be torn.

Subclavian Artery.-There is no line for this vessel.

Anatomy (Pl. 3, Fig. 1).-The subclavian artery of the right side arises from the innominate; of the left side, from the arch of the aorta. The subclavian is divided into three parts. The first part runs from the origin of the vessel to the inner border of the scalenus anticus muscle; the second part lies behind the scalenus anticus muscle; and the third part runs from the outer edge of the muscle to the lower border of the first rib.

At the present day the first and second portions are not ligated. The third portion is contained in the subclavian triangle (Fig. 61), and is superficial. It rises, as a rule, to half an inch above the clavicle. The subclavian vein is below the artery, being separated from it by the scalenus anticus muscle. The brachial plexus is above and external to the artery. The vessel rests upon the first rib, and behind it is the scalenus medius muscle. The suprascapular and transversalis colli arteries and veins and branches of the cervical

1, Anatomy, 2, Ligation, of the Subclavian Artery and First Part of the Axillary Artery. 3, Anatomy of the Neck. and Facial Arteries. 5, Anatomy, 6, Ligation, of the Anterior Tibial and Peroneal Arteries. (From Bernard.)

4, Ligation of the Carotid, Lingual,

plexus lie in front of the artery, and the external jugular vein crosses it at its inner side. The third portion gives off no branches.

Ligation of the Third Part.-This operation (Pl. 3, Fig. 2) was first successfully performed in 1817 by Post of New York. The position is as follows: place the patient upon his back, raise the shoulders, extend and turn the head toward the opposite side, pull down the arm, and hold it by pushing the forearm under the patient's back (Treves). This pulls down the clavicle, thus increasing the size of the subclavian triangle. The operator stands facing the shoulder, with his back toward the patient's feet. Draw the skin over the subclavian triangle, half an inch above the clavicle, down upon this bone, and incise. This maneuver avoids the external jugular vein and gives an incision half an inch above the collar-bone. The incision reaches from the anterior edge of the trapezius to the posterior border of the sternocleidomastoid (Pl. 3, Fig. 2), and is about three inches long. By this incision are divided the skin, the superficial fascia, the platysma myoides, the vein running from the cephalic to the external jugular, and some superficial nerves. Open the deep fascia. Draw the external jugular vein into the inner angle of the wound, and do not divide it unnecessarily; if forced to do so, tie the vein with two ligatures and cut between them. Find the outer edge of the anterior scalene muscle, and run the finger down along it to the tubercule on the first rib. Draw up the posterior belly of the omohyoid muscle. With the finger on the tubercle recall the fact that the vein is in front of the finger and the artery is behind it, and that the subclavian vein is on a lower plane than the artery. The artery is felt beating as it lies upon the rib. Clear the artery and expose the lower cord of the brachial plexus. Guard the vein with the finger and pass the needle from above downward, as the plexus, which is in more danger than the vein, is to be avoided. In this operation never cut the transversalis colli or suprascapular arteries, as they are necessary to the future anastomotic circulation. If the field of operation is too small, incise the trapezius or sternocleidomastoid or both.

The vertebral artery was first successfully ligated by Smyth of New Orleans.

Anatomy. This vessel is the largest branch of the subclavian, and is the first branch from the first portion of the subclavian. The vertebral artery ascends and enters the foramen in the transverse process of the sixth cervical ver