THE METACARPUS — THE LARGE METACARPAL BONE 



87 



THE METACARPUS 

 Three metacarpal bones (Ossa metacarpalia) are present in the horse. Of 

 these, only one, the third or large metacarpal bone, is fully developed and carries a 

 digit; the other two, the second and fourth, are much reduced, and are commonly 

 called the internal and external small metacarpal or "splint" bones. 



.«*r 



Tuberosity 



Groove for 



suspensory 



ligament 



J\ 



C, 



Head of small 

 metacarpal 

 bone 



A'ulrienl 

 foramen 



■ Distal ends of 

 small meta- 

 carpal bones 



.Sesamoid 

 bones 



First phalanx 



Second 

 phalanx 



Fig. 56. — Distal Row of Carpal Boxes, Metacar- 

 pus, First and Second Phalanges, and 

 Proximal Sesamoid Bones of Horse; Pos- 

 terior View, Left Side. 



The fourth (externaD metacarpal bone is wrongly 

 numbered as I. (.A.fter Schmaltz, Atlas, d. .A.nat. d. 

 Pferdes.) 



Metacarpal 



tuberosity 



Head of 

 small 

 metacar- 

 pal bone 



Distal 

 ends of 

 small 

 metacar- 

 pal bones 



Second phidunx 



Lateral 

 cartilage 



^ ^^ ir-/// 



sur- 

 face of 



third 

 phalanx 



Fig. 57. — Left Metacarpal and Digital Bones of 

 Horse, Internal View. (After Schmaltz, 

 Atlas d. .\nat. d. Pferdes.) 



The Large Metacarpal Bone 

 This (Os metacarpale tertium) is a very strong long bone, placed vertically 

 between the carpus above and the first phalanx below\ It consists of a shaft and 

 two extremities. 



