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.
When the line of fracture is oblique and in an adult, healing with a certain, often considerable, amount of deformity is almost constant, the only efficient way of combating its occurrence is to place the patient in bed on his back. This is the best way of removing the weight of the arm, of quieting the muscles, and by pressure of the scapula close to the thorax of levering the shoulder out (see Fig. 258).
Fig. 258. - Showing how the shoulder falls inward and the posterior edge of the scapula tilts outward when the prop-like action of the clavicle is destroyed by fracture.
Attached to the outer third of the clavicle on its under surface, extending not quite to its end, are the coraco-clavicular (conoid and trapezoid) ligaments. The conoid inserts into the conoid tubercle near the posterior edge of the clavicle, while the trapezoid is broader and passes from the conoid tubercle outward and anteriorly not quite to the extremity of the bone (see Fig. 267). The bone may be fractured either through the part to which the conoid and trapezoid ligaments are attached, or between them and the end of the bone, a distance of about 2 cm. (A in.). The line of the fracture is either transverse or inclines backward and outward (see Fig. 259).
The displacement of the outer fragment is downward and inward. If the fracture is through the ligaments the displacement is not marked. If beyond the ligaments, the shoulder drops, carrying down the outer fragment, and the inner Fragment may be elevated slightly above the outer one, but the up-and-down displacement is not conspicuous. In many cases the anteroposterior displacement is very marked and peculiar. The outer fragment is bent sharply inward at the site of fracture, producing a deformity which is pathognomonic. It is caused by the curved shape of the bone at this point, by the weight of the arm, and by the action of the muscles passing from the shoulder to the trunk, especially the pectoralis major (see Fig. 259).
Fig. 259. - Fracture of the outer end of the clavicle. The outer fragment is drawn inward by the pectoralis major latissimus dorsi, and teres major muscles.
As the deformity is not very marked any of the usual bandages, such as those of Velpeau, Desault, or posterior figure eight are fairly satisfactory.