Page 247 - Adams and Stashak's Lameness in Horses, 7th Edition

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Figure 3.41. (Continued ) Lateromedial (LM) projection of the 10. Superimposed distal parts of the medial and lateral palmar
distal phalanges and navicular bone. (a) Proximal phalanx, (b) processes on the distal phalanx.
middle phalanx (c) distal phalanx, and (d) navicular bone. 11. Medial and lateral distal (solar) borders of the distal phalanx.
1. Palmar aspect of the medial and lateral condyles on the distal On oblique projections, these borders may be separated farther.
extremity of the proximal phalanx. 12. Flexor surface of the distal phalanx, where the deep digital
2. Transverse bony prominence on the proximopalmar aspect of flexor attaches.
the middle phalanx. 13. Semilunar line on the solar surface of the distal phalanx.
3. Superimposed medial and lateral condyles on the distopalmar 14. Opaque line representing the bone cortex on the concave solar
aspect of the middle phalanx. surface of the distal phalanx.
4. Articular surface of the navicular bone. 15. Solar canal of the distal phalanx on end. This canal makes a
5. Proximal border of the navicular bone. semicircular loop in the distal phalanx, and its visibility depends
6. Flexor cortex and surface of the navicular bone; the medullary on its size and the X‐ray beam angle.
cavity (spongiosa) is the less opaque area in the center of the 16. Dorsal surface of the distal phalanx.
navicular bone. 17. Extensor process of the distal phalanx, which may have a
7. Superimposed medial and lateral proximal parts of the palmar single‐humped, double‐humped, or pointed appearance. The
process on the distal phalanx. The size of this palmar process surface should always be smooth.
varies depending on the mineralization and ossification of the 18. Dorsal extent of the distal articular surface on the middle
collateral cartilages. The palmar process also superimposes phalanx. The slight projection on the articular margin should not
over the navicular bone, sometimes creating confusing be mistaken for an osteophyte.
opacities. 19. Eminences for collateral ligament attachments from the distal
8. Distal border of the navicular bone, the border of which may interphalangeal joint. They may be prominent or small, but their
appear as a distinct ridge or may blend with the contour of the surface should be smooth; they should not be mistaken for
navicular bone. Slight obliquity on the lateromedial projection periosteal bone production.
alters the navicular bone’s apparent shape. 20. Extensor process of the middle phalanx.
9. Palmar process incisure. 21. Distal dorsal articular surface of the proximal phalanx.

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