PECTORALIS MAJOR MUSCLE. 



195 



hyoid ; 3, iipper, S', lower belly of the omo-hyoid ; 4, levator aiiguli scapulas ; 4', 4", scalene 

 muscles ; 5, anterior part of the trapezius ; 6, deltoid ; 7, upper part of the triceps brachii 

 in the left arm ; 8, teres minor ; 9, teres major ; 10, latissimus dorsi ; 11 jiectoralis 

 major ; 11', on the right side its clavicular jiortion ; 12, part of the pectoralis minor ; 13, 

 serratus m;ignus ; 14, extei'nal oblique muscle of the abdomen ; 15, placed on the 

 xiphoid cartilage at the upper end of the linea alba ; 15', is placed on the umbilicus ; 16, 

 is x^laced over the symphj-sis pubis, and at the lower end of the linea alba, above Ifi, 

 tlie jiyramidal muscles are seen through the abdominal aponeurosis ; 15 to 17, the 

 linea semilunaris at the outside of the I'cctus muscle, the transverse tendinous lines of 

 which are seen through the abdominal aponeurosis ; 18, part of the gluteus medius ; 19, 

 tensor vaginse femoris ; 20, rectus femoris ; 21, sartorius ; 22, femoral part of the iliaciis 

 and psoas ; 23, pectineus ; 24, adductor longus ; 25, gracilis. On each side of 16, the 

 external abdominal ring is indicated. 



It is further prolonged upwards by a slip which runs over the bicipital 

 groove to the great tuberosity, and gives an offset to the head of the 

 humerus. The lower or doubled end of the tendon is closely united 

 with the insertion of the deltoid, and a slip is prolonged from its inferior 

 margin to the fascia of the arm. 



Fig. 1G7. — View op some of Fig. 167. 



THE DEEPER MuSCLES OF 



THE Shoulder and Trunk, 



FROJI BEFORE. (A.T) i 



On the right side the pec- 

 toralis major and external 

 oblique muscles have been re- 

 moved, a, coracoid process of 

 scapula ; b, manubrium of 

 sternum ; c, c, cartilages o^ 

 the lifth ribs ; d, ensiform 

 portion of the sternum ; 1, 

 upper part of the levator anguli 

 scapulje muscle ; 2, on the 

 middle of the clavicle, points 

 to the subclavius muscle ; S, 

 pectoralis minor ; 4, subscapu- 

 laris ; 4', its insertion into the 

 lesser tuberosity of the hume- 

 rus ; 5, coraco-brachialis cut 

 short ; 6, coracoid, and 6' glenoid 

 head of the biceps brachii, both 

 cut short near the place where 

 they unite into one muscle ; 7, 

 ■on the tendon of the latissimus 

 <lorsi, points by a line to the ten- 

 don of the teres major, both 

 ■cut short and passing to their 

 insertion inside the bicipital 

 groove ; S, 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 passing behind the tendons of the latissimus and teres ; 12, 12, on the fifth and 

 eighth ribs, point to the insertion of the serratus magnus ; 13, 13', recti abdominis. 



_ Relations. — Tlie folded inferior border of the pectoralis major forms the ante- 

 rior margin of the axilla ; the superior runs parallel with that of the deltoid 

 muscle, from which it is separated only by a slight interval which becomes wider 

 towards the clavicle, and in v/hich run the cephalic vein and the humeral branch 

 of the acromio-thoracic artery. The anterior sui-face is subcutaneous in the 

 greater pait of its extent being covered only by some of the fibres of the 



o 2 



