DEOPPED ELBOW. 313 



rib, than cart horses which have to toil at a walk. It is evident 

 that la forward plunge, with one shoulder more in advance than 

 the other shoulder, would be more likely to cause this accident 

 than if both shoulders met the collar simultaneously. A horse 

 which has fractured the first rib on one side will, occasionally, 

 after recovery, repeat the operation on the other side. Here, the 

 memory of the pain does not cure the vice, but only reminds the 

 animal that he must not practise it on the side which was 

 injured. Figs. 123, 124, 125, and 126, which are reproductions 

 of photographs I took from specimens very kindly lent to me by 

 Mr. Willis, show these fractures. Increased thickness of bone due 

 to fracture, is well marked in these illustrations. 



Occasionally, saddle horses meet with this accident from falls 

 and other injuries. 



SYMPTOMS. — Sudden lameness with more or less paralysis of the 

 limb ; and " dropped elbow," in which case tiie elbow of the affected 

 leg is held about six inches lower than its fellow, with the knee 

 and fetlock bent, and the heel raised. The toe generally rests 

 on the ground a little behind the toe of the sound leg. The 

 lameness is characterised by inability to raise the foot, although 

 the limb can be drawn forward to a greater or less extent; and 

 by circumduction (outward rotation of the foot, during forward 

 movement). This peculiarity of gait is caused by the fact that 

 any contraction of the muscles whose office is to keep the limb 

 close to the side of the animal (the adductor muscles), would 

 give rise to pain by setting up movement in the broken surfaces 

 of bone; and that the muscle (the levator humeri) which draws 

 the limb forward, has very little disturbing influence on the seat 

 of injury. This muscle is attached at one end to the humerus 

 (the bone which lies between the elbow and the point of the 

 shoulder), and at the other, to the top of the head. Mr. Willis 

 ("Vet. Record," 11th May, 1901) tells us that as a rule the con- 

 dition of dropped elbow lasts five or six weeks, and that the 

 lameness gradually passes off in a few weeks longer. Owing to 

 disuse, there is some w^asting of the flexor hrachii muscle (pp. 58 

 to 60), v^hich recovers its normal state after a time. 



Mr. James McKenny, M.E.C.Y.S. {Vet. Record, 21st June, 1902), 

 appears to be the first to point out a reliable method for dis- 

 tinguishing fracture of the first rib from other injuries (for in- 

 stance, sprain of the flexor brachii, fracture of the scapula, fracture 

 of the trapezium bone, and fracture of the navicular bone) which 

 present the symptoms of '' dropped elbow." He tells us that 

 " crepitus of a fractured first rib can be obtained only by cross- 

 ing the fore leg near the affected rib as far as possible across the 



