Spinal part of deltoid

Looks like

The back head of the deltoid, from the spine of the shoulder blade to the outer upper arm bone.

What it does

Pulls the arm back and turns it outward.

Keeping it well

Often undertrained compared with the front; rows and reverse flyes balance the shoulder.

Related conditions

• Botulism
• Dermatomyositis and polymyositis
• Fibromyalgia
• Frailty & falls in older age
• Frozen shoulder (adhesive capsulitis)
• Heat exhaustion & heatstroke
• Malnutrition & refeeding syndrome
• Muscular dystrophy
• Polymyalgia rheumatica
• Rhabdomyolysis
• Sarcoma
• Sarcopenia
• Shoulder dislocation
• Tetanus