Lumbricals Muscles: Origin, Insertion, Action & Nerve Supply

The lumbricals are intrinsic muscles of the hand that flexes the metacarpophalangeal joints and extends the interphalangeal joints.

Attachment of the Lumbricals Muscles

Origin: tendons of flexor digitorum profundus in the palm
Insertion: Extensor expansion on the dorsum of proximal phalanx after passing along the lateral side of metacarpophalangeal joints.

Nerve Supply of the Lumbricals Muscles

Ulnar two lumbricals by ulnar nerve, radial two lumbricals by median nerve

Function of the Lumbricals Muscles

The lumbricals muscles contraction leads to flexion in the metacarpophalangeal joints (MCP) and extension in both the proximal (PIP) and distal interphalangeal joints (DIP).

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