Trapezoid ligament

Looks like

A flat four-sided band from the top of the coracoid process to a ridge on the underside of the collarbone, beside the conoid.

What it does

Part of the coracoclavicular ligament; resists the collarbone sliding over the shoulder blade.

Keeping it well

Torn in high-grade AC joint injuries, giving a visible bump; reconstruction is sometimes needed.

Related conditions

• Frozen shoulder (adhesive capsulitis)
• Gout
• Haemophilia & bleeding disorders
• Lyme disease
• Marfan syndrome & connective tissue disorders
• Osteoarthritis
• Polymyalgia rheumatica
• Psoriatic arthritis
• Rheumatic fever & rheumatic heart disease
• Rheumatoid arthritis
• Shoulder dislocation
• Systemic lupus erythematosus
• Temporomandibular joint disorder