Page 202 - Canine Lameness

174 13 Carpal Region

(A) (C) (E)

CARPAL REGION

(B) (D) (F)

Figure 13.2 Normal anatomy of the carpal joint depicted by radiographs of (A, B) an adult dog and of
(C–F) an immature dog: (a) radius; (b) ulna; (c) intermedioradial carpal bone; (d) ulnar carpal bone; (e) first
carpal bone; (f) second carpal bone; (g) third carpal bone; (h) fourth carpal bone; (i) accessory carpal bone;
(j) first metacarpal bone; (k) second metacarpal bone; (l) third metacarpal bone; (m) fourth metacarpal
bone; (n) fifth metacarpal bone; (o) sesamoid bone of abductor pollicis longus muscle; (p) antebrachiocarpal
joint; (q) middle carpal joint; (r) carpometacarpal joint; (s) distal radial physis; and (t) distal ulnar physis.

The carpus has a slight lateral (valgus) orientation of 5° (Goodrich et al. 2014) and allows approx-
imately 20° of motion in the frontal plane (Jaegger et al. 2002). A small amount of pronation and
supination occurs within the carpus but has not been differentiated from the pronation and
supination that occurs within the antebrachium.
Osteoarthritis of the carpus can result from a variety of causes such as the subluxation present
in dogs with chondrodystrophy (Theyse et al. 2005), joint instability (e.g. hyperextension injury
and collateral ligament injury), intra-articular fracture, IMPA, or the presence of deep wounds
including shearing injuries. Treatment of carpal osteoarthritis ranges from nonsurgical manage-
ment to carpal arthrodesis.