EPISTERNUM OF MAN 



35 



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

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



d. 



Fig. 24.— EiiisteiiKil 

 vestiges in Man. 

 <i, Clavicle, sawn 

 through ; «, " (t\n- 

 sterimiu " (stenio- 

 clavicnlar cartilage) ; 

 /', inter el avicular 

 ligament ; /", costo- 

 clavicular ligament ; 

 ■j)t.s, nianuljrium 

 stenii ; '/..s, ossa 

 suprasternalia ; r.c, 

 first rib ; st, ster- 

 num. (From Wie- 

 dersheiin's Structure 

 of Mail.) 



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 (Jirdle. 

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

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

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

 l)ackboue ; 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 tirm way 

 of the hiud-linil)S ; 1)ut, again, in the climbing creatures Ijoth 

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

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

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

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

 column l)y means of the ribs. 



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

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

 1 Fcr'jl. Aiuit. dcr Wirbelth. Leipzig, 1898, p. 497. 



