Lymph Vessels of the Skin of the Forelimb
The lymph vessels of the skin of the forelimb mainly drain to the superficial cervical lymph nodes (Figure 13: 3, 3’), to a lesser extent the axillary lymph node and possibly the accessory axillary lymph node (Figure 13: 4). The efferent vessels from the paw and antebrachium merge to form 3 to 6 larger vessels, of which some travel proximally with the accessory cephalic vein on the cranial aspect of the antebrachium, and some with the antebrachial cephalic vein on the medial side of the antebrachium, up to the caudal side of the antebrachium and the medial side of the elbow joint. From here, the lymph vessels travel proximally, some together with the superficial connecting branch of the cephalic vein, to the external jugular vein, and some on the superficial pectoral muscles, on the pars clavicularis of the M. brachiocephalicus (Figure 13: g) and over the M. deltoideus (Figure 13: h), to all drain into the superficial cervical lymph nodes, most likely to the ventral-most lymph node in the group (Figure 13: g’).
The lymph vessels of the skin of the lateral side of the elbow joint, including the olecranon, and from the lateral side of the upper limb area, all drain, as shown in Figure 13, to the superficial cervical lymph nodes.
The lymph vessels of the skin on the caudal aspect of the shoulder, brachium, and elbow joint (Figure 13: 13’, 81) run around the posterior border of the shoulder and brachium muscles to the medial aspect, and accompany the lymph vessels of the lateral thoracic wall to drain to the axillary lymph node. Some of these vessels will drain first to the accessory axillary lymph node if present.
Most of the lymph vessels of the skin on the medial side of the brachium, including the elbow joint, drain to the superficial cervical lymph nodes. Only the lymph vessels (or some of the lymph vessels) from a small area of the skin on the medial side of the olecranon and on the medial side of the brachium near its caudal border turn directly upwards, joining the lymph vessels draining the lateral thoracic wall, and drain into the axillary lymph nodes, with some draining to the accessory axillary lymph node if present.