Infraspinatus Muscle: Origin, Insertion, Nerve Supply & Action

Infraspinatus Muscle: The infraspinatus muscle is a thick triangular muscle, which occupies the most part of the infraspinatus fossa. It is one of the four muscles of the rotator cuff, the main function of the infraspinatus is to externally rotate the humerus and stabilize the shoulder joint.

Attachments of the infraspinatus Muscle

Origin:
Infraspinous fossa of the scapula
Insertion:
The middle part of the greater tubercle of the humerus.

Actions of the infraspinatus Muscle

Laterally rotates the arm at the shoulder joint

Helps stabilize the shoulder by drawing the humerus toward the glenoid fossa of the scapula

Nerve supply of the infraspinatus Muscle

Suprascapular nerve
Nerve roots: C5 and C6.

Upper Extrimity Muscle Atlas

• Abductor Pollicis Longus
• Abductor Digiti Minimi
• Abductor Pollicis Brevis
• Adductor Pollicis
• Anconeus
• Biceps Brachii
• Brachioradialis
• Brachialis
• Coracobrachialis
• Deltoid
• Extensor Carpi Radialis Longus
• Extensor Carpi Radialis Brevis
• Extensor Carpi Ulnaris
• Extensor Digitorum
• Extensor Digiti Minimi
• Extensor Indicis
• Extensor Pollicis Longus
• Extensor Pollicis Brevis
• Flexor Carpi Radialis
• Flexor Carpi Ulnaris
• Flexor Digitorum Profundus
• Flexor Digitorum Superficialis
• Flexor Digiti Minimi Brevis
• Flexor Pollicis Brevis
• Flexor Pollicis Longus
• Infraspinatus
• Interosseous Muscles, Dorsal
• Interosseous Muscles, Palmar
• Levator Scapulae
• Latissimus Dorsi
• Opponens Digiti Minimi
• Opponens Pollicis
• Pectoralis Major
• Pectoralis Minor
• Palmaris Longus
• Pronator Quadratus
• Pronator Teres
• Rhomboid Major and Minor
• Subscapularis
• Supinator
• Serratus Anterior
• Supraspinatus
• Trapezius
• Triceps Brachii
• Teres Major
• Teres Minor