The dorsal interossei are four muscles in the back of the hand that performs to abduct the index, middle, and ring fingers and assists in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints of the middle, index and ring fingers.
Attachment of the Dorsal Interossei Muscles
Origin: Dorsal 1 – 4: Adjacent sides of two metacarpals (bipennate muscles)
Insertion: Dorsal 1 – 4: Extensor expansions and bases of proximal phalanges of digits 2 – 4
Nerve Supply of the Dorsal Interossei Muscles
Deep branch of ulnar nerve (C8 and T1)
Blood Supply of the Dorsal Interossei Muscles
Dorsal 1 – 4: Dorsal and palmar metacarpal arteries
Function of the Dorsal Interossei Muscles
Dorsal 1 – 4: Abduct digits from axial line and act with lumbricals to flex metacarpophalangeal joints and extend interphalangeal joints.
Upper Extremity 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