MUSCLES OF THE PECTORAL REGION. 311 
border of the pectoralis major or latissimus dorsi, is attached to the coracoid process, alone or 
along with one of the muscles attached to that bone. These variable slips of muscle are supplied 
by the internal anterior thoracic nerve, the lesser internal cutaneous nerve, or the intercosto- 
humeral. 
The pectoralis minor is a narrow, flat, triangular muscle. It arises from (1) 
the third, fourth, and fifth ribs near their anterior ends, and (2) from the fascia 
NUN 
SrERNO-MASTOID 
TRAPEZIUS 
SUBCLAVIUS 
Coracoid 
process 
PECTORALIS 
MAJOR (divided) 
PECTORALIS 
MINOR 
PECTORALIS 
sternal part MAJOR (divided) 
yy 
. SERRATUS 
Y 
MAGNUS 
Abdominal 
PECTORALIS MAJOR 
i part 
} SERRATUS 
3 MAGNUS 
yw 
Sheath of rectus 
muscle 
___OBLIQUUS EXTERNUS 
ABDOMINIS 
Linea seinilunaris 
RECTUS ABDOMINIS — Linea alba 
PYRAMIDALIS ABDOMINIS 
Poupart’s ligament 
External abdominal ring 
Triangular fascia 
ca EET 
= 
Fia. 232,—ANTERIOR MUSCLES OF THE TRUNK. 
covering the third and fourth intercostal spaces between these ribs. Directed 
obliquely outwards and upwards, it is inserted into the front of the extremity of the 
coracoid process, and usually also into the conjoint origin of the biceps and coraco- 
brachialis. It is wholly concealed by the pectoralis major, except when the arm is 
raised, when the outer border of the muscle becomes superficial. It enters into 
the formation of the front wall of the axilla, and gives attachment along its upper 
