2 3 o APPLIED ANATOMY. 



If firm pressure is made along the inner or lower edge of the outer extremity 

 of the anterior axillary fold the upper end of the biceps muscle can be felt, and lying 

 along with it, to its inner side, is the swell formed by the coracobrachialis muscle. 



Along the inner edge of the coracobrachialis muscle lies the axillary artery with 

 its vein to the inner side. This is a little anterior to the middle of the axilla. The 

 artery can be felt pulsating along the inner edge of the coracobrachialis and can be com- 

 pressed by pressure made in an outward and backward direction against the humerus. 

 The line of the axillary artery is from the middle of the clavicle down along the inner 

 edge of the coracobrachialis muscle, which will be anterior to the middle of the axilla. 



The posterior fold of the axilla is formed by the latissimus dorsi and teres major 

 muscles. By deep pressure in the axilla, posterior to the vessels, the arm being 

 abducted, the rounded head of the humerus can be felt. 



When the arm is brought more to the side the tissues of the axilla relax and any 

 enlarged lymph-nodes present may be recognized. When normal they cannot be felt. 



Winding around the surgical neck of the humerus from behind forward under 

 the deltoid muscle about at the junction of its upper and middle thirds is the pos- 



Biceps 

 Deltoid 



Pectoralis major 



Coracobrachialis 



. Groove for axillary 

 vessels and nerves 



Long head of triceps muscle 



Teres major and l^tissimus dorsi muscles 





FIG. 242. Surface anatomy of the axilla. 



terior circumflex artery and circumflex nerve. Hence a blow at this point may injure 

 the nerve and cause paralysis of the deltoid muscle. The line of fracture of the 

 surgical neck of the humerus would also lie at this point. 



DISLOCATIONS OF THE CLAVICLE. 



Dislocation of the Sternal End of the Clavicle. The sternal end of the 

 clavicle is most commonly dislocated forward. Other dislocations, which may be 

 upward or backward, are very rare. The range of movement of the clavicle approxi- 

 mates 60 degrees. 



The bone is lowest when the elbow is brought forward across the front of the body 

 and highest when the arm is raised and placed behind the neck. The luxation is pro- 

 duced by the shoulder being violently depressed and pushed backward, as in falling 

 on it; in some cases an inward thrust may be added. As the clavicle descends its under 

 surface comes into contact with the first rib, which acts as a fulcrum, and the inner 

 extremity is lifted upward and forward, rupturing the sternoclavicular ligaments. The 

 rhomboid ligament remaining intact prevents a wider displacement of the bone. 



