Page 134 - Adams and Stashak's Lameness in Horses, 7th Edition

100 Chapter 2

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Figure 2.62. Palpation of the medial (axial) surfaces of the small metacarpal bones. The fetlock can be flexed to relax the suspensory
ligament to permit easier palpation.

with the thumb with the limb held in a flexed position separate them. Most horses respond slightly to “pinch­
(Figure 2.63). Alternatively, pressure can be applied to ing” the SDFT between the thumb and index finger. Pain
this region by placing the palm of the hand on the dorsal will be elicited easily with palpation in most horses with
MC and wrapping the fingers around the medial side tendonitis. The inferior check ligament (accessory liga­
of the MC. The fingertips are used to “squeeze” the ment of the DDFT) lies directly palmar to the suspensory
limb and apply pressure to the proximal palmar MC ligament and can be palpated by holding the ligament
region (Figure 2.64). Many horses may react initially between the index finger and the thumb or by applying
by withdrawing (flexing) the limb. However, with con­ pressure from the palmar aspect with the thumb.
stant pressure, this response often fatigues. A painful
withdrawal that persists (does not fatigue) often sug­ CARPUS
gests a problem in the proximal suspensory region. 10,15
Palpation of the proximal suspensory region is more dif­ The carpus should be visually examined for swelling/
ficult in the hindlimbs than the forelimbs because it is effusion on the dorsal and palmar surfaces. Point swell­
closely surrounded by the small metatarsal bones and ing associated with the radiocarpal and middle carpal
the SDFT is less easily pushed to the side (Figure 2.65). joints that occurs medial to the extensor carpi radialis
tendon is often present in horses with osteochondral
chip fractures and/or OA (Figure 2.67). More diffuse
FLEXOR TENDONS swelling of these joints may indicate more severe articu­
lar pathology. Distention of the tendon sheaths of the
The SDFT and DDFT are located palmar to the sus­ extensor tendons overlying the carpus (common digital
pensory ligament and are intimately associated with and extensor carpi radialis) is uncommon but may indi­
each other. The proximal one‐third of the flexors (associ­ cate tenosynovitis and/or rupture, particularly of the
ated with the carpus) and distal one‐third (associated common digital extensor tendon in foals (Figure 2.68).
with the fetlock) are encased in tendon sheaths, whereas A diffuse fluctuant, subcutaneous swelling over the dor­
the central one‐third is covered by a paratendon only. sal surface of the carpus is consistent with acute hema­
Each region should be palpated carefully for heat, pain, toma/seroma or chronic hygroma (Figure 2.69). Swelling/
and swelling with the tendons weighted and then again effusion of the palmar carpal canal may be found with
with the limb unweighted and the tendons relaxed. With accessory carpal bone fractures, tenosynovitis (carpal
the limb held in one hand, an attempt should be made to tunnel syndrome), or osteochondroma formation of the
roll or separate the SDFT from the DDFT with the caudal distal aspect of the radius (Figure 2.70). 15
thumb and forefinger (Figure 2.66). If normal, they can Palpation of the carpal joints and bones including the
be easily separated and differentiated. With pathology accessory carpal bone is best done with the carpus flexed.
such as tendonitis, varying degrees of adhesions between The degree of carpal flexion or range of motion should
the two as well as thickening will result in an inability to also be evaluated. In the normal horse the flexor surface of