Canine Shoulder Anatomy and Common Health Issues

The canine shoulder is a complex joint that's prone to a range of health issues.

The shoulder joint is made up of the scapula, humerus, and clavicle bones, which work together to provide a wide range of motion.

A common issue that affects the canine shoulder is a condition called subluxation, where the humerus bone slips out of the joint.

Subluxation can be caused by a variety of factors, including genetics, injury, or repetitive strain on the joint.

In many cases, subluxation can be treated with rest, physical therapy, and pain management.

The canine shoulder is made up of a simple ball-and-socket joint between the humeral head and the glenoid cavity, surrounded by a fibrous joint capsule.

This joint is stabilized by the adjacent musculature, which extends and/or flexes the thoracic limb. The supraspinatus and infraspinatus muscles extend the joint, while the triceps muscle flexes it, with the biceps and triceps muscles controlling flexion and extension of the elbow.

The proximal biceps tendon originates from the supraglenoid tubercle and traverses the cranial aspect of the proximal humerus in the intertubercular groove.

The canine shoulder is a remarkable joint that deserves some attention. It's a simple ball-and-socket joint between the humeral head and the glenoid cavity.

This joint is surrounded by a fibrous joint capsule and is stabilized by the adjacent musculature. The adjacent musculature plays a crucial role in extending and flexing the thoracic limb.

The joint is extended by the supraspinatus and infraspinatus muscles, while the triceps muscle flexes it. The biceps and triceps muscles also work together to flex and extend the elbow.

The proximal biceps tendon originates from the supraglenoid tubercle and traverses the cranial aspect of the proximal humerus in the intertubercular groove. This tendon forms the biceps muscle at the musculotendinous junction.

Mineralization can occur at any point along the length of the tendon, but it's commonly noted both superimposed with the groove and at the tendon origin. This is where the tendon connects to the bone.

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The supraspinatus tendon is a broad tendon that arises from the supraspinatus muscle and attaches to the lateral aspect of the greater tubercle. Tendinopathy of this tendon is common and can be identified radiographically by mineralization within the tendon.

The infraspinatus tendon is less commonly affected and arises from the infraspinatus muscle, attaching to the lateral greater tubercle slightly distolateral to the supraspinatus tendon. It runs in an oblique plane in a caudoproximal-to-craniodistal direction.

The Canine Shoulder Model is a life-size left canine shoulder anatomy model featuring several key parts. It includes the scapula, humerus, biceps brachii tendon, coracobrachialis tendon, lateral glenohumeral ligament, medial glenohumeral ligament, and transverse humeral ligament.

This model is ideal for demonstrating canine anatomy to veterinary students or dog owners. It comes with a two-sided education card and base included.

The model is based on the shoulder size of an average-sized dog. It's a great tool for learning about canine anatomy.

Here are the dimensions and weight of the model:

The Canine Shoulder Model is manufactured by GPI Anatomical.

Blood vessels play a crucial role in canine shoulder anatomy, supplying the muscles and bones with oxygen and nutrients.

The brachiocephalic artery, which is the largest artery in the dog's body, arises from the aortic arch and supplies blood to the shoulder region.

The radial and ulnar arteries, which are located in the front legs, are responsible for supplying blood to the forelimb, including the shoulder joint.

The shoulder region has a complex network of blood vessels that play a crucial role in supplying oxygen and nutrients to the surrounding muscles and tissues.

The axillary artery is the primary artery that carries blood to the shoulder area, running medial to the scapula and branching into the subscapular artery.

The subscapular artery runs dorsally along the caudal border of the scapula, supplying blood to the thoracodorsal artery, which in turn supplies the latissimus dorsi muscle alongside the thoracodorsal nerve from the brachial plexus.

Recommended read: Canine Scapula Anatomy

Massage of the shoulder and forelimb can assist the circulation of blood and lymph fluid by helping to move blood down to the digits and back up the forelimb.

As blood flows through the capillaries, it exchanges oxygen and other nutrients with the peripheral fascia, and then returns to the heart via the veins.

The subscapular vein collects returning blood flow from the forelimb and moves it back up to the heart through the jugular vein.

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As a responsible dog owner, it's essential to be aware of the common shoulder diseases that can affect your furry friend. Osteochondrosis is a condition that typically occurs in young, large-breed dogs, and it appears radiographically as a flattening of the caudal humeral head.

The most common site of osteochondrosis is the caudal aspect of the humeral head. This condition is often accompanied by a free mineral fragment near the flattened region or more distally in the joint capsule. Free fragments are rarely seen in the intertubercular groove.

Osteochondritis dissecans is another disease that affects young dogs, characterized by failure of endochondral ossification, leading to retention and thickening of cartilaginous tissue. The cartilage may form a flap and/or free fragments in the joint.

Degenerative joint disease affects the entire joint, but the caudal humeral head is a common site of osteophytosis development. This condition appears radiographically as well-defined, irregularly shaped new bone formation on the caudal aspect of the glenoid cavity or the caudal humeral head.

Here are some common shoulder diseases in canines:

It's worth noting that while osteosarcoma is a less common disease, it can appear in the proximal humerus and should be considered if there's a lytic component in the radiograph.