We return to an anterior view of the shoulder and chest. We orient ourselves by showing the jawline and the midline, the clavicle, and the shoulder. Superiorly we see fibers of the platysma. We show the outline of the pectoralis major. We identify this serratus anterior and latissimus dorsi. We see the deltoid and the biceps. We note the presence of the cephalic vein in the deltopectoral groove. We detach the remainder of the deltoid from the clavicle and we reflect it laterally. The humeral head comes into view. We see the greater and lesser tubercles. With the deltoid reflected laterally, we can identify the coracoid process, the lesser and greater tubercles of the humerus, and the surgical neck of the humerus. We also note the tendon of the long head of the biceps, passing in the intertubercular groove between the greater and lesser tubercles. We now reflect the pectoralis major laterally by incising it's clavicular, sternal, and costal attachments. We reflect the pectoralis major laterally and deep to it we see the pectoralis minor muscle. Along the medial border of the pectoralis minor, we see the lateral pectoral nerve and accompanying vessels running on the deep surface of the pectoralis major. Along the lateral border of the pectoralis minor, we see the medial pectoral nerves, which supply the pectoralis minor and the pectoralis major. We recall that these nerves are named for their origins from the medial and lateral cords of the brachial plexus. The pectoralis major, with its intact neurovascular bundle, can be used for reconstructive surgery. We follow the cephalic vein proximately and we reflect the pectoralis major. Medial to the pectoralis minor, we see the cephalic vein entering the axillary vein, which passes underneath the clavicle to become the subclavian vein. Adjacent to the axillary vein, we see the axillary artery, and adjacent to it, we see portions of the brachial plexus. In order to complete our reflection of the pectoralis major, we divide the neurovascular bundle. This procedure allows us to visualize the shoulder joint and expose the brachial plexus. We're now exposing the tendon of the long head of the biceps. We follow it to the intertubercular groove between the greater and lesser tubercle. The tendon of the long head of the biceps passes over the head of the humerus. As it does, it merges with the capsule and finally inserts on the supraglenoid tubercle on the superior border of the glenoid fossa. We divide the cephalic vein and reflect it in order to continue our dissection. This is a higher power and slightly more superior view. We show the clavicle and the acromion and we've widened the acromioclavicular joint to reveal its location. We show the coracoid process, the lesser tubercle of the humerus, the greater tubercle of the humerus, and the surgical neck. We identify the coracoid process, which is a common origin of several muscles. We show the pectoralis minor muscle and the common origin of the coracobrachialis and short head of the biceps. We see the tendon of the long head of the biceps running into bicipital groove, passing over the head of the humerus to attach on the supraglenoid tubercle on the upper rim of the glenoid fossa. We identify the tendon of the pectoralis major, which attaches to the lateral margin of the bicipital groove. At this point, we can identify one of the major branches of the brachial plexus, the musculocutaneous nerve. The musculocutaneous nerve provides motor innervation to muscles of the anterior arm and cutaneous sensation to the lateral forearm. We divide the conjoint tendon and the tendon of the pectoralis minor in order to expose the shoulder joint and the brachial plexus. The axillary vein and the axillary sheath are now coming into view. The brachial plexus is within the axillary sheath. In order to continue our reflection of the pectoralis minor, we divide the medial pectoral nerve and associated vessels. We reflect the deltoid, the pectoralis minor, the coracobrachialis, and the short head of the biceps and we follow the subscapularis muscle to its insertion on the lesser tubercle. We incise the tendon of the subscapularis muscle in order to expose the shoulder joint. With the subscapularis tendon divided and the capstone sized, we laterally rotate the humerus to show its articular surface. This is a higher power view. We show the cut ends of the subscapularis muscle, the articular cartilage of the humeral head, and the portion of the glenoid labrum. The glenoid labrum is a rim of fibrocartilage that encircles the glenoid cavity.
