490 INJURIES TO THE SADDLE-BED. 



fcributed as evenly, and over as large a surfaee, as possible. (2) Pressure 

 must be confined to parts fitted to bear it. (3) Those portions of the 

 saddle which bear on the body must be properly stuffed, or the 

 back covered with a folded rug, &c. Weight can only be borne 

 where muscles or fat underlie the skin, as is the case along both sides 

 of the vertebral column in the dorsal region. 



In the middle line of the back and on the withers, where the 

 bones are not cushioned, any considerable pressure causes bruising. 

 Saddles are, therefore, made to bear on the protected parts only. 



The anatomy of that portion of the horse's back carrying the 

 saddle may be briefly described as follows (Fig. 386) : — 



(A) In the middle line of the withers and back, under and closely 



Fig. 386.— Transverse section through horse's thorax (semi-diagrammatic, after 

 Franck). a, Skin ; b, fascia of panniculus ; o, dorsal fascia ; d, muscular layers ; 

 e, external fascia of withers ; /, muscular layers ; rj, subscapular fascia. 



adherent to the skin (a), lies the fascia of the dorsal panniculus (b). 

 Below it extends the dorsal fascia (c), which is applied closely to 

 the termination of the ligamentum nucha?, covering the superior 

 spinous processes of the 5th — 10th dorsal vertebrae (d). This is not 

 covered with muscular padding. 



(B) On either side of the vertebral column, in the " saddle-bed," 

 or surface on which the saddle rests, the skin is provided with a 

 strongly developed subcutis, and covers the fascia of the dorsal 

 panniculus (b), which is attached by loose connective tissue to the 

 dorsal fascia (c). Below this lies a pad of muscle, comprising the 

 latissimus and longissimus dorsi, the spinalis and semispinalis dorsi, 

 the trapezius, rhomboideus posterior and the ilio-costalis (retractor 

 costae) muscles. 



Injuries to the saddle-bed occur most frecpaently from irregularly 

 distributed pressure continued for a considerable time. Limited 



