48 



ANATOMY AND PHTSIOLOGY OP 



Q. What are the uses of the porosities 

 and furrows ? — A. They serve as so many 

 attachments for the fibrous tunic of the 

 sensible laminae. 



Q. Wliat name is generally applied to 

 the largest of the perforations found in the 

 coffin bone ? — A. They are termed for- 

 amina?. 



Q. What occupies these foramina^ ? — 

 A. Blood-vessels and nerves. 



Q. Describe the sole of the cofRn bone ? 

 — A. The sole exhibits a broad, uniform, 

 concave surface, resembling in most cases 

 the figure of the inferior part of the hoof; it 

 has porosities similar to those formed on 

 the wall ; it is bounded anteriorly and later- 

 ally by the circumferent edge of the w^all ; 

 posteriorly, by a sharp, uneven, semi-circular 

 edge, which divides it from the tendinous 

 surface. 



Q. What do we find on the tendinous 

 surface? — A. 1st, a rough depression in 

 its fore and middle part, marking the inser- 

 tion of the tendo perforans. 2ndly, two 

 lateral grooves, passing obliquely inwards, 

 and terminating each in a large foramen. 

 3rdly, a porous space intermediate between 

 the two former divisions, into which is fijced 

 the inferior navicular ligament. 



Q. What occupies the lateral grooves? — 

 A. The trunks of the arteries and nerves 

 which occupy the interior of the coffin bone. 



Q. What are the peculiarities of the ar- 

 ticulatory surface of the coffin bone ? — A. 

 It has two lateral depressions, which extend 

 posteriorly to the alae ; a broad eminence 

 runs transversely between them ; this emi- 

 nence is terminated in front by the coronal 

 processes, having an incurvation backwards ; 

 behind it, the surface is bevelled off, to 

 which part is opposed the navicular bone ; 

 the depressions alluded to are deepened by 

 the prominent edge running around the an- 

 terior and lateral parts. 



Q. What portion of the coffin bone does 

 the articulatory surface .occupy? — *A. The 

 superior part. 



Q. What is the form of this surface ? — 

 A. It is half-moon shaped. 



Q. Describe the alae, or wings ? — They 



consist of a protuberance on the posterior 

 part of each side of the coffin bone ; the 

 protuberance, however, is generally bifid; 

 the lower portion which is the largest, is 

 irregular and asperous, and projects in a 

 posterior direction ; the upper portion is tu- 

 bercular, yet smooth ; between the divisions 

 of the alae is a notch, which, at a certain 

 period in the life of- the animal becomes a 

 perfect foramen. 



Q. What is attached to the irregular sur- 

 face of the larger division of the alae ? — A. 

 The cartilage of the foot. 



Q. What is affixed to the tuberculated 

 portion of the alae ? — A. The coffin liga- 

 ments. 



Q. What vessel passes through the 

 notch ? — A. The lateral artery. 



Q. What is there remarkable about the 

 structure of the coffin bone ? — A. It has a 

 spongy, fragile texture, pervaded in every 

 direction by minute canals for the trans- 

 mission of blood-vessels and nerves ; it dif- 

 fers very essentially from many bones of 

 the body, which, in heakhy subjects, are 

 remarkable for compactness and solidity. 



NAVICULAR BONE (oS NAVICULARe). 



Q. What is the general form and division 

 of the navicular bone ? — A. It is semi-lu- 

 nar : its lunated border, however, only forms 

 about one third the circle of its dimensions ; 

 it is divided into two surfaces, two borders, 

 and two extremities. 



Q. Where is this bone situated? — A. 

 At the posterior part of the coffin joint. 



Q. Describe the superior and inferior sur- 

 faces of the navicular bone. — A. The 

 superior surface bears a corresponding 

 aspect to the articulating surface of the 

 coffin bone, having two superficial lateral 

 depressions, with an eminence between 

 them. The inferior surface is also articu- 

 latory ; and exhibits lateral depressions yet 

 more superficial than the superior; it has 

 also an eminence across the middle, nar- 

 rower yet more prominent than the former. 



Q. Name the tendon which articulates 

 over the inferior surface. — A. Tendo per- 

 forans. 



