EEGIONAL ANATOMY 



39 



marked by a series of rings which run horizontally from 

 heel to heel. These are due to varying influences of food, 

 climate, and slight or severe disease. This will be noted 

 again in a later page. In a young and healthy horse the 

 whole of the external face of the wall is smooth and 

 shining. This appearance is due to a thin layer of horn, 

 secreted independently of the wall proper, termed the periople. 

 The Internal Face of the wall, that adapted to the sensi- 

 tive laminae, is closely covered over its entire surface with 



i 





Fig. 20. 



-Internal Fkatures of the Wall, Frog, and Sole 

 (Mesian Section of Hoof). 



1, Horny laminae covering internal face of wall ; 2, superior border of wall ; 

 3, junction of wall with horny sole ; 4, the cutigeral groove ; 5, the 

 horny sole ; 6, the horny frog (that portion of it known as the ' frog- 

 stay') ; 7, X-shaped ridge on Mall and sole (known as the 'toe-stay') ; 

 8, anterior face of wall ; 9, inferior border of wall. 



white parallel leaves {Keraphyllce, or horn leaves, to distin- 

 guish them from the PodophylUe, or sensitive leaves). These 

 keraphyllffi dovetail intimately with the sensitive laminae, 

 covering the os pedis. Eunning along the superior portion 

 of the inner face is the Cutigeral Groove. This cavity has 

 been mentioned before as accommodating the coronary 

 cushion, whose shape and general contour it closely follows, 

 being widest and deepest in front, and gradually decreasing 

 as it proceeds backwards. It is hollowed out at the 

 expense of the wall, and shows on its surface numberless 



