This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
For malignant growths of the axilla, shoulder, or scapula, and, rarely, for injury, the whole upper extremity with the scapula and part or whole of the clavicle have been removed. Anteroposterior flaps are made.
Fig. 264. - Structures exposed by excising the inner portion of the clavicle.
Excision of the clavicle in the living body, like tracheotomy, is much more difficult than when practiced on the dead body; this is due to the condition of the parts for which operation is undertaken. It has been often excised for malignant growths. On the upper anterior surface are attached the clavicular origin of the sternomastoid, the deep cervical fascia, and the trapezius muscle. Crossing the clavicle near its middle is the jugulocephalic vein which sometimes connects the cephalic with the external jugular. It is likewise crossed by the superficial descending branches of the cervical plexus. The external jugular vein, about 2.5 cm. (1 in.) above the middle of the clavicle, pierces the deep fascia and turns inward to empty into the internal jugular just behind the outer edge of the sternomastoid muscle; just below it empties the thoracic duct at the junction of the internal jugular and subclavian veins. The subclavian vein is directly behind the clavicle and the left innominate vein crosses behind the left sternoclavicular joint and passes across the posterior surface of the sternum just below or on a level with its superior border. The omohyoid muscle, if the shoulder is drawn outward and the head turned to the opposite side, is drawn upward above the clavicle.
Behind the upper portion of the clavicle is the suprascapular artery and above it runs the transverse cervical artery, a branch of the thyroid axis. Both these vessels cross over the scalenus anterior muscle on which, toward its inner edge, is lying the phrenic nerve. In front of the scalenus anterior runs the subclavian vein and behind it is the subclavian artery with the cords of the brachial plexus above and to its outer side. Below and in front are attached the pectoralis major and deltoid muscles; the space between them forms the subclavicular triangle and occupies the outer half of the middle third of the bone. The cephalic vein pierces the costocoracoid membrane at this point to enter the subclavian vein.
On the under surface of the bone is the subclavius muscle7 covered with a strong membrane. To the inner side of this muscle is the costoclavicular ligament. Beneath the clavicle, about its middle, passes the subclavian artery, separated from the vein in front by the scalenus anterior muscle. Below and beneath the subclavian artery, which rests directly on it, is the pleura. The internal mammary artery passes behind the inner extremity of the clavicle opposite the cartilage of the first rib.
The clavicle is the first bone in the body to ossify, and it has one epiphysis at its sternal end which appears about the seventeenth year and joins the shaft from the twentieth to the twenty-fifth year. In removing the bone it is first loosened at its outer extremity by dividing the acromioclavicular and coracoclavicular (conoid and trapezoid) ligaments.