El'ISTERNUM OF MAN 



35 



pair of similar bones in the Hamster.^ It is possible that these 

 are to be referred to the same category. It has also been 

 d. 



Fig. 24. — Eijisternal 

 ^^ vestiges in ]\Ian. 



■' • d, Clavicle, sawn 



tLrough ; cs, " epi- 



..r.c, sternum " (sterno- 



clavicular cartilage) ; 

 /', interclavicular 

 ligament ; /", costo- 

 clavicular ligament ; 

 VI. s, manubrium 

 sterni ; o.s, ossa 

 suprasterualia ; r.c, 

 iirst rib ; sf, ster- 

 num. (From Wie- 

 dersheim's Structure 

 of Man.) 



suggested that these supposed episternal rudiments are the 

 vestiges of a pair of cervical ribs. 



The Pectoral Girdle. — The skeleton by which the fore-limb 

 is connected with the trunk is known as the Pectoral Girdle. 

 The main part of this girdle is formed by the large scapula, or 

 blade-bone as it is often termed. The coracoidal elements will be 

 dealt with later. The scapula is not firmly connected with the 

 backbone ; it is attached merely by muscles, thus presenting a 

 great difference from the corresponding pelvic girdle. The reason 

 for this difference is not easy to understand. On the one hand 

 it may be pointed out that in all running animals at any rate 

 there is a greater need for the fixation in a particularly firm way 

 of the hind-limbs ; but, again, in the climbing creatures both 

 limbs would, one might suppose, be bettered by a firm fixation. It 

 must be remembered, however, that in the latter case the same 

 result is at least partly brought about by a well-developed clavicle, 

 which fixes the girdle to the sternum and so to the vertebral 

 column by means of the ribs. 



Broadly speaking, too, the fore-limbs require a greater freedom 

 and variety of movement than the hind-limbs, which are supports 

 ' Ferrjl. Anat. dm Wirbclth. Leipzig, 1898, p. 497. 



