154 THE SURGICAL ANATOMY OF THE HORSE 



" By the exercise of moderate care in operating, pus formation can 

 be avoided ; and even should it occur, it seldom entails grave con- 

 sequences, for, on account of the flat position of the knife while making 

 the incision, there is little danger of opening the joint, and thus pro- 

 ducing dangerous arthritis. 



" The horse must be rested for at least four to six vi^eeks after operation, 

 and during this time movement, as far as possible, avoided. Some 

 operators even recommend fastening the animal up short to prevent it 

 lying down." 



THE TENDON OF THE PERONEUS MUSCLE AND ITS 

 SHEATH— PERONEAL TENOTOMY 



The peroneus muscle lies to the outer side of and behind the extensor 

 pedis, and between this muscle and the flexor perforans. It is succeeded 

 by a tendon which plays through a groove on the outer side of the 

 external malleolus of the tibia, and subsequently through a synovial canal 

 in the external lateral ligament of the hock. It then inclines slightly 

 forwards and passes beneath the most inferior of the three annular bands, 

 and ultimately terminates near the junction of the upper and middle 

 thirds of the metatarsal region by joining the tendon of the extensor 

 pedis. In close relationship to the peroneal tendon, and running parallel 

 to it along its inner edge, is the extensor brevis muscle, whilst beneath 

 this muscle and the tendon the large metatarsal artery runs. From the 

 point where the anterior tibial artery divides at the front of the inferior 

 portion of the hock the large metatarsal division takes a course which 

 is obliquely downwards and outwards, and emerges from beneath the 

 peroneal tendon just below the inferior edge of the annular band referred 

 to above. 



The peroneal tendon is supplied with an extensive synovial sheath, 

 the superior limit of which is placed above the upper extremity of the 



