432 I^R- C. F. SOXXTAG ox THE 



the precetliiig part. It woi'ks over a strong cord running from 

 the first rib to the head of the humerus (text-fig. IOC, C.C.L). 

 And this ligament may replace the costo-coracoid ligament in 

 Man. The iir.st and third p irts receive separate nerves from the 

 median nerve, but tlie latter probably only serves as a track from 

 the brachial plexus (text-fig. 23). 



The pectoralis minor may be replaced by the third part of 

 pectoralis major. 



A lonof, narrow muscle, composed of two bellies, takes origin 

 fi'om the free edge of the latissimus dorsi, crosses the axillary 

 vessels and brachial nerves, and spreads out into a thin fan- 

 sliaped aponeurosis. The latter covers the coraco-brachialis and 

 bicep-, and is inserted into the deep surface of the insertion of 

 pectoralis major. It has a double nerve supply from the second 

 intercostal nerve and brachial plexus (text-fig. 11, G). 



The subclavins (taxt-^g. IOC) is very strong. It arises from 

 the inner end of the first rib by a strong pointed tendon, and is 

 inserted into the inner five-sixths of the posterior surface of the 

 clavicle. 



The clelto-jjectoral triangle (text-fig. 10 A, D.P.T) is long and 

 narrow. It contains the cephalic vein and thoracic axis artery-, 

 but no lymphatic glands. 



The skin over the pectoral region is supplied, as in Man, by 

 the supraclavicular nerves from the cervical plexus. 



The trapezius arises from the inner part of the occipital crest, 

 the inion, ligamentum nuchte, seventh cervical and upper six 

 dorsal spines, and supraspinal ligaments. And the thick, strong 

 fibres converge, a.s in Man. They are inserted as in Man, but the 

 fibres which are attached to the root of the spine of the scapula 

 end in a very strong triangular tendon, under which the spinal 

 accessory nerve passes to the posterior part of the muscle. The 

 sub-trapezial nerve plexus formed by the spinal accessory and 

 cervical nerves is well-de%'eloped. 



Latissimus dorsi: — Xo fibres are derived from ribs and the 

 posterior angle of the scapula, and the upper fibres of origin are 

 under cover of the trapezius. They extend from the fourth Lo 

 the last dorsal vertebra, behind which they arise from the lumbar 

 aponeurosis, but no fibres extend back to the ilium. The fibres 

 converge, wind roun<l the lower border of the teres major, and end 

 in a very strong, flat tendon which is inserted into the humerus 

 at the base of the pectoral crest (text-figs. 10, L.D and 11, H). 

 The tendon is intimately connected to the teres major and dorso- 

 epitrochlearis. 



The levator angidi scapuke ai-ises from the dorsal surfaces of 

 the transverse processes of the first four cervical vertebi-je, and 

 the slip from the first one is the largest. The fibres unite to 

 form a thick muscle, which is inserted into the vertebral border 

 and deep surface of the scapula in its anterior part. 



The rhomboids form a strong muscular sheet arising from the 

 vertebral spines from the seventh cervical to the fifth dorsal ; 



