The third phalanx of the horse shows a sponge-like appearance as a whole on account of the bone trabeculae assuming a sponge-like structure. It is known that changes have been found in these trabeculae in the case of various diseases of the third phalanx. These changes are the basis of radiological diagnosis. Although changes in the trabeculae of various bones have been clarified in man, no corresponding changes have been clearly demonstrated in horses. Especially, stereoscopic radiographical findings are lacking in these animals.
The following results were obtained from radiographical examination on the substantia spongiosa of the third phalanx of 142 specimens collected from horses, including a fetus 10 months old and an adult 16 years of age.
1. Compact parts were found on the dorsal and volar surface. In horses less than 24 months old the border parts were thick, while in adults the thickest part was found directly beneath the protuberance for the extensor tendon and the part of the flexor surface.
2. Seven systems were distinguished fundamentally among the lines of bone trabeculae in radiographs.
3. The first and the second system appeared in fetuses 10 to 11 months old, completing at the age of 2 years. On the other hand, the 3rd and 4th system began to appear in the 9th to 12th month and the 5th to 7th system by 2 years of age, both completing by 5 to 6 years of age.
4. In a radiograph taken at the dorsovolar position, the bone tradeculae were shown as a radiating picture and arranged in lamellar form.
5. From the radiograph, the dynamic adaptation of the bone trabeculae was considered as follows. When pressure was exerted on the third system arranged horizontally below the joint as a pressurereceiving plate, it was transmitted to the compact part on the same side through the first, second, and 6th system. The 4th, 5th, and 7th system responded to the power of traction by the flexor tendon.
抄録全体を表示