Page 139 - Adams and Stashak's Lameness in Horses, 7th Edition

Examination for Lameness 105

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Figure 2.75. Elevating the limb into extension to flex the elbow joint extends the shoulder and increases the tension on the triceps brachii
tendon at its insertion on the olecranon process.

and supraspinatus muscle atrophy is commonly seen in outpouches that can result in tarsal swelling, and this
horses with suprascapular nerve paralysis or osteochon­ soft, fluctuant swelling is often referred to as “bog
drosis (Figure 2.76). Particular attention should also be spavin.” The synovial effusion can be easily compressed
paid to the bicipital bursa region (cranial aspect of shoul­ from the dorsal pouches to distend the plantar pouches
der), and deep digital palpation is recommended in this of the joint capsule and vice versa (Figure 2.77). Firm,
region. The muscle and tendon should be grasped with the diffuse swelling of the tarsus can occur due to trauma
fingers and thumb and pulled laterally. The shoulder joint and inflammation of the fibrous joint capsule (capsuli­
can be palpated deeply by applying thumb pressure cranial tis) and surrounding ligamentous support structures.
to the infraspinatus tendon at the location for intra‐ This firm swelling may or may not be associated with
articular injection. A consistent painful response is sugges­ synovial effusion of the joint (Figure 2.78). Effusion/
tive of intra‐articular pathology. Fractures of the scapula swelling of the tarsal sheath is often referred to as
and proximal humerus may also elicit a painful response “thoroughpin” and can usually be observed and pal­
with this manipulation. Elevation of the limb as described pated on the medial aspect of the tarsus. Unlike effu­
for the elbow joint may also result in a painful response, sion of the tarsocrural joint, tarsal sheath effusion is
particularly if a fracture or a lesion within the joint is pre­ asymmetrical on the limb (medially) and runs in a distal
sent (Figure 2.75). Horses with midbody scapular fractures to proximal direction (Figure 2.79). Tarsocrural joint
often have an external swelling located above the shoulder effusion is symmetrical and courses circumferentially
joint directly over the scapula. These, often young horses, around the tarsus. Tarsal sheath effusion may be a
will carry their distal limbs toward midline. cosmetic blemish but can be indicative of problems
of the DDFT or the sustentaculum tali of the talus
(Figure 2.79). Effusion of the calcaneal bursa is often
TARSUS (HOCK) characterized by small pockets of fluid on each side of
the SDFT above and below the point of the hock
The tarsus is a common site contributing to hindlimb (Figure 2.80). Swelling associated with a capped hock is
lameness and is complicated anatomically. Understanding subcutaneous, whereas effusion within the calcaneal
the anatomy is critical to be able to accurately diagnose bursa is beneath the SDFT.
problems in this area. Synovial structures located in the The medial aspect of the distal tarsal joint region (dis­
tarsus include the tarsocrural joint, tarsal sheath, tal intertarsal and tarsometatarsal joints) should be closely
and calcaneal bursa. The tarsocrural joint has multiple examined visually and with palpation to detect bone