1150 



SURGICAL AND TOPOGRAPHICAL ANATOMY 



great tuberosity looks outwards, the head inwards, and the lesser tuberosity some- 

 what forwards. Between the two tuberosities runs the bicipital groove, which, 

 with the arm in the above position, looks directly forwards. In thin subjects its 

 lower part can be defined. Besides the tendon and its synovial sheath, the inser- 

 tion of the latissimus dorsi, the humeral branch of the acromio-thoracic artery, and 

 the anterior circumflex artery run in the groove. When the fingers are placed on 

 the acromion, and the thumb in the axilla, the lower edge of the glenoid cavity 

 can be felt; and if the humerus be rotated (the elbow-joint being flexed), the head 

 of the humerus can be felt also. 



The characteristic roundness of the shoulder is due to the deltoid, supported 

 by the head of the humerus and the tuberosities (fig. 715). Close to the clavicle, 

 between the contiguous origins of the pectoralis major and deltoid, is^ the infra- 

 clavicular fossa, in which lie the cephalic vein and the humeral branch, of the 

 acromio-thoracic artery. On pressing deeply here, the coracoid process can be 

 made out if the muscles are relaxed and the axillary artery compressed against the 

 second rib. 



On raising the arm and abducting it, the different parts of the deltoid can often 

 be made out — viz. fibres from the lower border of the spine of the scapula, the 

 outer edge of the acromion, and the outer third or more of the front of the clavicle; 



Fig. 712.— Transverse Section throx^gh the Right Shoulder-joint, showing 

 THE Structures in contact with it. (Braune.) 



ACROMION 

 Supra -spinatus 



Trapezius 

 Infra-apinatus - 



Teres minor 



Teres major 

 Latissimus dorsi 



Deltoid 

 Pectoralis major 



Axillary vessels and NER VES 



Tendon of subaoapularis blended with 

 the scapular ligament 

 Coraeo-braehialis and short head of biceps 



the characteristic knitting of the surface owing to the presence of muscular bundles, 

 separated by depressions caused by the tendinous septa, will also be seen. The 

 muscle will be marked out by a base-line reaching along the above bony points, 

 and two sides converging from its extremities to the apex, a point on the outer 

 surface of the humerus, about its centre. To map out the pectoralis major, a 

 line should be drawn down the lateral aspect of the sternum as far as the sixth 

 costal cartilage, and then two others marking the borders of the muscle — the upper 

 corresponding to the deltoid, the lower starting from the sixth cartilage, and the 

 two converging to the folded tendon, which is inserted as a double layer into the 

 outer Incipital ridge. The pectoralis minor will Ije marked out by two lines, from 

 the upper border of the third and the lower border of the fifth rib, just external to 

 their cartilages, and meeting at the coracoid process. The lower line gives the level 

 of the long thoracic artery; the upper, where it meets the line of the axillary 

 artery, that of the acromio-thoracic. 



When the arm is abducted and the humerus rotated a little outwards, the promi- 

 nence of a well-developed coraco-brachialis comes into view; a line drawn from 

 the centre of the clavicle along the inner border of this muscle to its insertion into 

 the humerus gives the line of the axillary artery. 



The depression of the axilla is best marked when the arm is raised from the 



