Page 208 - Adams and Stashak's Lameness in Horses, 7th Edition

174 Chapter 2

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Common or
long digital
extensor tendon

First
phalanx

Extensor
process Dorsal branch of
Coronary band suspensory ligament
Second Collateral ligament
phalanx
of pastern joint

Third phalanx

Figure 2.168. Location for injecting the proximal palmar/plantar pouch of the fetlock joint in the standing horse.

synovial fluid because the synovial villi plug the plantar eminence of P1. The landmarks are the distal
needle. 34,46 aspect of the proximal sesamoid bone and collateral ses­
Performing the palmar/plantar approach with the fet­ amoidean ligament proximally, the proximal palmar/
lock flexed can potentially minimize these complications plantar eminence of P1 distally, and the digital vein,
(Figure 2.169; Video 2.23). With the fetlock flexed, there artery, and nerve palmar/plantarly. A 1.5‐inch (3.8‐cm),
72
is a very palpable depression at the very distal aspect of 20‐gauge needle is inserted in the depression and directed
the pouch just above the branch of the suspensory liga­ slightly dorsally (10°–20°) and proximally (10°) until the
ment. A 1‐inch (2.5‐cm), 20‐gauge needle is inserted at joint is entered (Figure 2.171; Video 2.25). To avoid
this location and directed distally at a 45° angle. The penetration of the digital sheath, it is important that the
more distal location in the palmar/plantar pouch reduces needle be inserted dorsal to the PD artery, vein, and
the risk of iatrogenic hemorrhage. nerve. The advantages to this approach are that the land­
marks are easily palpable, synovial fluid is often obtained,
it can be performed in the standing horse, and horses
Collateral Sesamoidean Approach
tolerate the procedure well. 72
Arthrocentesis of the fetlock through the lateral collateral
sesamoidean ligament is probably the best approach to
obtain a hemorrhage‐free synovial fluid sample. The Dorsal Approach
fetlock is flexed to increase the space between the articular The dorsal approach is usually performed with the
surfaces of the proximal sesamoid bones and the limb weight‐bearing. The needle is inserted proximal to
metacarpus/ metatarsus. The depression between the bones the proximodorsal limits of P1 in the palpable joint space
is palpated, and a 1‐inch, 20‐gauge needle inserted through in a slightly oblique manner, either lateral or medial to
the collateral sesamoidean ligament perpendicular to the extensor tendon (Figure 2.172; Video 2.26). The fet­
the limb (Figure 2.170; Video 2.24). If the needle fails lock joint capsule is thicker in this location than in the
46
to advance, it is most likely contacting bone and will need palmar/plantar pouch and appears to cause greater dis­
to be redirected to enter the joint space. comfort to the horse than the other techniques.

Distal Palmar/Plantar Approach Digital Flexor Tendon Sheath (DFTS)
The distal palmar/plantar approach is performed in There are several outpouchings of the DFTS that may
the palpable depression formed by the distal aspect of be used for synoviocentesis. In general, the proximal
the proximal sesamoid bone and the proximopalmar/ pouch palmar/plantar to the suspensory and the distal