THE ANTERIOR LIMBS. 



8. Digital Region. In the domesticated animals the number of complete digits is as 

 follows : 



Carnivora 5 



Pig 4 



Ruminants 2 



The five digits of the Dog and Cat are exactly analogous to those of Man. Thus, the 

 external corresponds to the auricularis, the second to the annularis, the third to the 

 medius, the fourth to the index, and the internal to the thumb. The latter, very small, 

 has only two phalanges and does not come into contact with the ground. Each of the 

 first four is composed: 1, Of a first phalanx, to which are annexed two sesamoids; 

 2, A second phalanx, which yet represents a veritable long bone ; 3, A conical phalan- 

 gette, pointed, bent downwards, and hollowed at its base by a circular groove, in which 

 is lodged the matrix of the claw. The small sesamoid (or navicular bone) is absent, but 

 is replaced by a prominence of the ungual phalanx. The auricularis and index are 

 alike, and not so long as the annularis and medius, which are the same in length. 



The Pig has four complete digits articulating from the metaciirpals ; the thumb is 

 absent. The index and auricularis, or fourth and fifth digits, are short, and do not 

 usually rest on the ground. 



Ruminants certainly possess four digits, but only two are perfect the medius and 

 annularis and these articulate with the inferior extremity of the principal metacarpal. 

 The two others the index and auricularis - are in a rudimentary condition, and are 

 represented by two small bones situated above and behind the metacarpo-phalangeal 

 articulation. 



In the Ox, Sheep, and Goat, each of the perfect digits comprises three phalanges and 

 three sesamoids. 



The first phalanx fairly represents the moiety 

 of the phalanx in the Horse. It has no posterior 

 imprints, but shows them on its inner surface 

 for the attachment of several ligaments. This 

 internal face is plane, and the external convex ; 

 these characters are repeated in the other two 

 phalanges. It is also remarked in all the plia- 

 langeal bones, that the external articular facet 

 of the extremities is always larger than the 

 internal. Of the two sesamoids, the external is 

 larger and less elongated than the internal, 

 first particulate with each other, and with the 

 They halanx by small diarthrodial facets. 



The second phalanx is hollowed internally 

 by a small medullary cavity. 



The ungual phalanx, as a whole, resembles 

 one of the lateral moieties of the os pedis of 

 solipeds. This phalanx has no complementary 

 fibre-cartilage, basilar process, or retrossal emi- 

 nence, nor yet a cavity of insertion on the sides 

 of the pyramidal eminence. The semilunar 

 crest is replaced by an obtuse, thick, and rugged 

 relief, which occupies quite the posterior limit 

 of the inferior face of the bone. Three large 

 canals penetrate the third phalanx, two to the 

 base of the pyramidal eminence, and one towards 

 the origin of the preplantar fissure. They form, 

 in the interior of the bone, a vast sinus, giving 

 rise to several vascular canals which open on the 

 surface. There is only one foramen at the base of 

 the pyramidal eminence in the smaller Ruminants. 



COMPARISON OF THE THORACIC LIMB OP MAN WITH 

 THAT OF THE DOMESTICATED ANIMALS. 



Fig. 54. 



A. SHOVLDER. The shoulder of man (fig. 54) 

 has for its base two well-developed bones, the 

 scapula and clavicle. The scapula is more dis- 

 tinctly triangular than that of all the domesti- 

 cated animals ; its vertebral border is also more extensive. The scapular spine, very 



HUMAN SCAPULA; EXTERNAL ASPECT. 



1, Supraspinous fossa; 2, Infraspinous 

 fossa; 3, Superior border; 4, Supra- 

 scapular notch ; 5, Anterior or axillary 

 border ; 6, Head of the scapular and 

 glenoid cavity; 7, Inferior angle; 8, 

 Neck of the scapula ; 9, Posterior 

 border; 10, Spine; 11, Triangular 

 smooth surface, over which the tendon 

 of the trapezius glides, with the tuber- 

 culum spinae scapula? between it and 

 10; 12, Acromion process; 13, Nutrient 

 foramen , 14, Coracoid process. 



