Acromial part of deltoid

Looks like

The middle head of the deltoid, running from the tip of the shoulder (acromion) to the outer side of the upper arm bone.

What it does

Lifts the arm out to the side.

Keeping it well

Powered by the axillary nerve, which can be injured in shoulder dislocation; a numb patch on the upper arm after it needs a doctor.

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