Lumbrical Muscles Hand Origin, Insertion, Action

Table of Contents

Lumbricals of Hand Origin, Insertion, Action
Primary Actions of the Hand Lumbricals
Seconday Actions of the Hand Lumbricals

Origin: From the tendons of flexor digitorum profundus.
First lumbrical: lateral side of the tendon of the index finger.
Second lumbrical: radial side of the tendon of the middle finger.
Third lumbrical: medial side of the tendon of the middle finger. The radial side of the tendon of the ring finger.
Fourth lumbrical: ulnar side of the tendon of the ring finger. The radial side of the tendon of the little finger.

Insertion: Distal tendons of the extensor digitorum (the dorsal digital expansion

Primary Action: Flexion of the fingers at the metacarpophalangeal joints
Secondary Action: Extension of the fingers at the proximal interphalangeal joints.

Innervation:
First and second lumbricals: median nerve (C8, T1).
Third and fourth lumbricals: ulnar nerve (C8, T1).

Blood Supply:

Dorsal digital artery
Superficial palmar arch
Deep palmar arch
Palmar digital artery

If you are looking for pain and symptoms information, please visit the Lumbricals hand pain page

Primary Actions of the Lumbrical Muscles

1. Flexion of the digits at the metacarpophalangeal joints

Agonists:

Dorsal Interossei
Palmar Interossei
Flexor Digiti Minimi
Flexor Digitorum Superficialis
Flexor Digitorum Profundus

Antagonists:

Extensor Digitorum
Extensor Indicis
Extensor Digiti Minimi

Secondary Actions of the Lumbrical Muscles

2. Assists with extension of the digits at the proximal interphalangeal joints

Agonists:

Dorsal Interossei
Palmar Interossei
Extensor Digitorum
Extensor Indicis
Extensor Digiti Minimi

Antagonists:

Flexor Digitorum Superficialis
Flexor Digitorum Profundus

3. Assists with extension of the digits at the distal interphalangeal joints

Agonists:

Dorsal Interossei
Palmar Interossei
Extensor Digitorum
Extensor Indicis
Extensor Digiti Minimi

Antagonists:

Flexor Digitorum Profundus

References:

Clay, J. H., Allen, L., Pounds, D. (2015). Clay & Pounds' Basic Clinical Massage Therapy: Integrating Anatomy and Treatment (3rd ed.). Philadelphia, PA: Lippincott Williams & Wilkins

Netter, F. (2014). Atlas of Human Anatomy (6th ed.). Philadelphia, PA: Saunders.

Muscolino, J., (2016) Kinesiology: The Skeletal System and Muscle Function (3rd ed.). Maryland Heights, Missouri: Mosby.

Image Credits: Dreamstime

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