BETWEEN THE TRUNK AND THE UPPER LIMB ANTERIORLY. 211 



tendinous lines of which are seen through the abdominal aponeurosis ; 18, gluteus medius ; 19, tensor 

 vaginae femoris ; 20, rectus femoris; 21, sartorius ; 22, femoral part of the ilio-psoas ; 23, pectineus ; 

 24, adductor longus ; 25, gracilis. On each side of 16, the external abdominal ring is indicated. 



fifth by tendinous slips which are blended with the anterior intercostal aponeuroses. 

 Its fibres converge to a narrow tendon, which is inserted into the anterior half of the 

 inner border and upper surf ace of thecoracoid process, in contact with the conjoined 

 origin of the coraco-brachialis and biceps muscles. 



Relations. This muscle is covered by the pectoralis major, and forms a part of the 

 anterior wall of the axilla. It crosses the axillary vessels and brachial plexus of nerves. 

 When the arm is much raised, a portion of the muscle may be seen projecting beyond the lower 

 margin of the pectoralis major. 



Varieties. The pectoralis minor is sometimes found split up or subdivided into as many 

 pieces as it has costal attachments. The place and number of the costal slips are subject to 



Fig. 229. VIEW OP SOME OF THE DEEPER MUS- 

 CLES OP THE SHOULDER AND TRUNK. FROM 



BEFORE. (Allen Thomson.) i 



On the right side the pectoralis major and 

 external oblique muscles have been removed. 

 (t, coracoid process ; b, manubrium ; c, c, carti- 

 lages of the fifth ribs ; d, ensiform process ; 1, 

 levator ariguli scapulae muscle ; 2, on the middle 

 of the clavicle, points to the subclavius muscle ; 

 3, pectoralis minor ; 4, subscapularis ; 4', its in- 

 sertion into the small tuberosity of the humerus ; 

 5, coraco-brachialis cut short ; 6, coracoid, and 

 6', glenoid head of the biceps brachii, both cut 

 short ; 7, on the tendon of the latissimus dorsi, 

 points by a line to the tendon of the teres major, 

 both cut short and passing to their insertion 

 inside the bicipital groove ; 8, folded tendon of 

 the pectoralis major ; 9, insertion of the deltoid : 

 10, brachialis anticus, embracing the insertion 

 of the deltoid ; 11, part of the inner head of the 

 triceps, the middle head of which is seen pass- 

 ing behind the tendons of the latissimus and 

 teres ; 12, 12, on the fifth and eighth ribs, point 

 to the origin of the serratus magnus ; 13, 13', 

 recti abdominis. 



slight variation. The tendon of insertion 

 is not unfrequently continued in part or 

 wholly over the coracoid process, from 



which it is separated by a bursa, and through the coraco-acromial ligament to the 

 capsule of the shoulder and the great tuberosity of the humerus : this condition is usual 

 in apes. The humeral insertion of the tendon is represented normally by the coraco- 

 humeral ligament (p. 167). The insertion of the pectoralis minor is often connected by 

 aponeurosis with the upper part of the coraco-brachialis ; and the two may be more 

 elosely united, so that there is only a tendinous intersection between their fibres. Absence of 

 the muscle has been observed, generally in association with defect of the pectoralis major. 



Tb&pectoralig mlnimiisisa, rare supernumerary muscle. extending from the first rib-cartilage 

 to the coracoid process. 



The subclavius muscle arises by a short thick tendon from the first costal arch 

 at the junction of the rib and cartilage, close in front of the costo-clavicular ligament. 

 From this tendon its fibres pass outwards and upwards, forming a prismatic belly, 

 which is inserted into the groove on the under surface of the clavicle, extending as 

 far as the recess between the conoid and trapezoid parts of the coraco-clavicular 

 ligament. 



Eelations. The subclavius is encased by the costo-coracoid membrane, and is placed 

 immediately over the great vessels and nerves entering the limb. 



Varieties. The subclavius is sometimes found to be without any attachment to the 



VOL. II. 



