THE HOOF 



767 



referred to as forming the white line on the ground surface of the hoof. The angle 

 of junction is rounded internally and presents a number of low ridges and specially 

 large openings for the papillae of the matrix. There is frequently a ridge of larger 

 size at the toe. 



The concave border has the form of a deep angle which is occupied by the bars 

 and frog. By its junction with these it forms two pronounced ridges in the interior 

 of the foot. The parts of the sole between the wall and bars may be termed its 

 angles. 



3. The frog (Furca unguhe) is a wedge-shaped mass which occupies the angle 

 between the bars and sole, and extends considerably below these on the ground 

 surface of the foot. It may be described as having four surfaces, a base, and an 

 apex. 



Fcrioplc at coronary margin 



Coronary groove 



Lamince 



Median furrow 



Lateral ridge 

 Spine or frog-stay 



Fig. 576. — Internal Surface of Part of Hoof of Horse. (After Schmaltz, Atlas d. Anat. d. Pferdes.) 



The superior or internal surface is deeply concave from side to side. It bears 

 a central ridge, the spine or "frog-stay" (Spina furcse ungulse), which is high pos- 

 teriorly and subsides abruptly in front. On either side of this is a deep depression, 

 bounded outwardly by the rounded ridge formed by the junction of the frog with 

 the bar and sole. This surface presents fine stria^ and openings for the papilla? 

 of the frog matrix. 



The inferior or ground surface presents a central furrow (Sulcus nitercrurahs), 

 which is bounded by two ridges or crura (Crura furcse unguLTe); these converge 

 and form the apex. 



The sides (Facies medialis et lateralis) are united at the upper part with the 

 bars and sole, but are free below and form the central wall of the deep lateral 

 furrows (Sulci cruroparietales) , which are bounded outwardly by the bars. 



The base is wide and high. It is depressed centrally and prom.inent at the 



