21/09/2026
MUSCLE MONDAY: THE SUBSCAPULARIS 🐾💪
Today we are diving under the shoulder blade to highlight a critical deep stabilizer: the Subscapularis!
Unlike muscles you can easily feel on the surface, the subscapularis lies tucked away on the medial (inner) side of the scapula, filling the entire subscapular fossa and inserting directly into the humerus.
📍 What does it do?
The subscapularis is a primary dynamic stabilizer of the shoulder joint:
Medial Shoulder Stabilization: Because the canine shoulder joint lacks true collateral ligaments, the subscapularis acts as a living ligament on the inside of the shoulder, keeping the head of the humerus securely in its socket.
Shoulder Extension & Adduction: It helps pull the forelimb inward toward the body’s midline (adduction) and assists in extending the shoulder joint during movement.
📍 Why we see it in the clinic:
Medial Shoulder Instability (MSI): Slipping, abduction injuries, or chronic repetitive strain can stretch or tear the subscapularis tendon, leading to significant shoulder joint looseness, weakness, and lameness.
Compensatory Strain from Elbow or Paw Injuries: When a dog offloads a lower forelimb, the subscapularis works in overdrive to keep the top of the limb stabilized, leading to deep, tender muscle spasms along the ribcage side of the shoulder blade.
Restricted Forelimb Extension: Chronic tightness in this muscle limits how far forward the dog can reach with their front leg, resulting in a shortened, stiff front-limb stride.
