ae 
584 THE NERVOUS SYSTEM. 
and, after piercing it, supply the sternal part of the pectoralis major. The lower nerve, in 
many cases, sends its branches to the pectoralis major round the lower border of the 
pectoralis minor, and it may supply on its way the axillary arches, if present. These two 
branches are derived—the upper from the seventh, eighth cervical, and first thoracic 
ay 7) 
; kip SUPRASCAPULAR NERVE 
Clavicle (cut) d Ly, ; 4 
Coraco-clavicular ligaments 5 f POSTERIOR CORD OF BRACHIAL 
Pectoralis minor PLEXUS 
Coracoid process fi = y Ssh SHORT SUBSCAPULAR NERVE 
Hi 
Coraco-acromial ligament 
LONG SUBSCAPULAR NERVE 
Circumflex artery 54 
tat} 
i 
CIRCUMFLEX NERVE L! 
LOWER SUBSCAPULAR NERVE 
Serratus magnus 
Dorsal scapular artery 
Long head 
: Subscapularis 
of biceps I 
Teres major 
Pectoralis major 
Coraco-brachialis Latissimus dorsi 
c V-Did c . 
CUTANEOUS BRANCH 
OF MUSCULO-SPIRAL 
Short head~_/¢ \ NERVE ' 
Biceps J re ~ 
\ Long head 
“S SS Triceps (long head) 
NERVE TO INNER HEAD OF 
N PRICEPS (ulnar collateral) 
nerves; the lower from the eighth 
cervical and first thoracic nerves. The 
Triceps pectoral muscles are thus both supplied 
(inner head) . : 
by the two anterior thoracic nerves. 
The clavicular fibres of the pectoralis 
major are innervated by the fifth and 
sixth nerves; the sternal fibres, from 
Muscu.o-cuTANEOUS 
NERVE 
oh Mela A above downwards, by the fifth, sixth, 
Brachialis anticus————_“ | a i r 
Wa yi ae Rate. seventh, and eighth cervical, and first 
) i nterna a i F 
MUSCULO-SPIRAL NERVE a ster. thoracic nerves; and the pectoralis 
} 
Haurtaee minor is supplied by the seventh and 
eighth cervical, and first thoracic nerves. 
Perea | vi MUSCULO-CUTANEOUS NERVE. 
Biceps (cut) 
Extensor carpi radialis 
The musculo-cutaneous nerve 
longior— | Origin of (H. Musculo-cutaneus) takes origin 
flexor, trom the outer cord of the plexus, 
POSTERIOR 7 aaa forearm from the fifth and sixth cervical 
RADIAL NERVE Flexor herves (Fig. 451). The nerve to 
profundus 
digitorum 
the coraco-brachialis muscle, arising 
from the seventh nerve, is usually 
associated with it. Separating from 
the outer head of the median nerve, 
Fia, ae PosTERIOR WaLL OF THE AXILLA AND THEthe yusculo-cutaneous nerve lies at 
RONT OF THE ARM (the biceps being divided). f Ore 
first between the coraco-brachialis 
muscle and the axillary artery. It is then directed downwards between the two 
parts of the coraco-brachialis, and then between the biceps and brachialis anticus 
muscles, to the bend of the elbow. In its course it may send a branch under the 
biceps to join the median nerve. It pierces the deep fascia over the front of the 
Supinator radii brevis 
a 
