Page 127 - Canine Lameness

7.6 Approaches 99

(A) (B)

Figure 7.1 Carpus: (A) aspirate the radiocarpal joint by palpating the distal end of the radius and inserting
the needle in a craniocaudal direction; (B) aspirate the middle carpal joint by inserting the needle in
between either the second and third or third and fourth carpal bones.

7.6.1 Carpus

The antebrachiocarpal (radiocarpal) joint is one of the most frequently aspirated joints.
Arthrocentesis can be performed by flexing the carpus to increase the joint space and improve
needle access. The joint space can be palpated cranially at the distal end of the radius (a depression
should reveal the landmark for the radiocarpal joint and will identify the site for needle insertion).
The needle should be inserted from the cranial aspect of the joint and aligned perpendicular to the
joint surface (Figure 7.1A and Video 7.1). Arthrocentesis of the middle carpal joint (Figure 7.1B) is
performed between the second and third or third and fourth carpal bones. However, joint fluid
may not always be obtained and therefore aspiration of this joint is less commonly performed.
Clinicians should take care to palpate and avoid the cephalic and accessory cephalic vein when
performing arthrocentesis of this joint.

Video 7.1:

Procedural details for aspiration of the carpal joint.

7.6.2 Elbow
It is the authors’ preference to aspirate the elbow joint from a straight medial direction. If signifi-
cant effusion is present, aspiration in a craniolateral direction at the caudal joint may also be per-
formed. For medial aspiration (Figure 7.2A and Video 7.2), the patient should be placed in lateral
recumbency with the affected limb down on the table. The elbow should be “opened” up by gently
levering it over a towel while extending the joint. The ulnar nerve should be palpated prior to
inserting the needle (which can easily be found just caudal to the epicondyle). The needle should
be inserted at the level below the epicondyle and slightly caudal to this area – NOTE: in a medium‐
sized dog, the location will be a little less than 1 cm distal and caudal to the medial epicondyle.