» The Forelimb
Skeletal features that may be identified on palpation include the cranial and caudal angles and the tubercle on the spine of the scapula; the caudal part of the greater tubercle of the humerus; the medial and lateral condyles of the humerus and the olecranon at the elbow; and the accessory carpal, revealing the level of the proximal row of carpal bones (see Fig.
32.1). Soft tissue structures that may be identified include the cephalic vein on the cranial aspect of the arm (not always visible but possibly available for puncture) and the skin glands at the caudomedial aspect of the carpus (Fig. 36.4).The Shoulder Joint
The large cranial part of the greater tubercle deflects the intertubercular groove medially and, with it, the biceps tendon. Even so, it is the smaller caudal part of the tubercle that is palpable, together with the infraspinatus tendon approaching it. Intra-articular injection is made at the cranial border of the tendon, immediately proximal to the bone.
The Elbow Joint
The lateral epicondyle of the humerus is accentuated by the sharp crest presented by its caudal border. Insertion of the needle for puncture is made just caudal to this crest, between it and the ulna. In an alternative method that uses the same landmark, the needle is entered at a site 2 or 3 cm proximal to the previous one and is directed mediodistally to pierce the capsule within the olecranon fossa.
The Carpal Joint
This exceptionally movable joint (Fig. 36.1) permits almost 180 degrees of flexion. The accessory carpal bone reveals the locations of the two more proximal compartments of the joint, which are in communication with each other and thus allow a single injection to reach both. Entry is made to either side of the extensor carpi radialis tendon, which is readily identified.
No features of the limb arteries demand notice. Lymph originating from superficial structures of the arm and forearm passes to the ventral superficial cervical nodes. That from deeper structures and from the entire distal part of the limb goes to the axillary lymph nodes of the first rib (cranial to the first rib and ventral to the axillary vessels).