The Region of the Shoulder. 25 



though within the abdominal cavity, i.e., the tendon occu- 

 pies the free margin of a reflection of the synovial mem- 

 brane of the joint. It is the main flexor and supinator of 

 the forearm, and harmonizes the action of tihe two joints 

 (shoulder and elbow), and, at the same time, passing as it 

 does over the head of the bone, prevents it from being dis- 

 placed or pushed up against the overhanging arch in ex- 

 tension of the arm. 



Landmarks. The landmark for the shoulder joint 

 is a line drawn from the acromion to the coracoid process, 

 and continued around to the lower margin of tihe head, as 

 felt in the axilla, the arm hanging by the side, palm 'to the 

 front, and the guide to the situation of the head of the 

 bone is the internal condyle which points in the same di- 

 rection as the head. This fact is of assistance in the re- 

 cognition of tine* situation of the head of the bone in dislo- 

 cation at the shoulder joint. Trie landmark for the bicipi- 

 tal groove is the upper part of a line drawn up the middle 

 of the front of the arm, when the latter hangs by the side, 

 palm to the front, and the lower limit of the synovial mem- 

 brane surrounding the biceps tendon will correspond to 

 where the anterior border of the deltoid crosses this line. 

 This groove may be readily felt by pressing on the front 

 surface of the head of the bone and at the same time rota- 

 ting the humerus. When the tendon of the biceps, occu- 

 pying the groove, reaches the head of the humerus (fol- 

 lowing the tendon from below, upwards), it turns inwards 

 to arrive at the glenoid rim, and this latter part of the ten- 

 don corresponds to the middle of the coraco-acromial lig- 

 ament, which lies between the coracoid and the acromion 

 processes. 



Synovitis. In inflammation of the shoulder joint, 

 i.e., synovitis, the arm is somewhat extended, drawn back- 

 wards, and rotated, slightly, inwards. This position may 



