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Extensor Digitorum Anatomy: Origin, Insertion, Actions

Muscle Anatomy of the Extensor Digitorum

Extensor Digitorum Muscle Origin, Insertion, Action, Innervation

Muscle Anatomy of the Extensor Digitorum

Origin: Lateral epicondyle of the humerus via the common extensor tendon.
Insertion: Main attachment: dorsal aspect of the base of the proximal phalanx of each of the four digits.
Central slip: dorsal aspect of the base of the middle phalanx of each of the four digits.
Lateral bands: via two slips to the dorsal aspect of the base of the distal phalanx of each of the four digits.
Actions: Extension of the fingers
Innervation: Radial nerve (C6, C7, C8).
Blood Supply: Posterior interosseous artery from the ulnar artery.

Muscle Anatomy: Extensor Digitorum Actions

Primary Actions of the Extensor Digitorum

1. Extension of the digits at the metacarpophalangeal joints

  Agonists:

  • Extensor Indicis (second digit)
  • Extensor Digiti Minimi (fifth digit)

  Antagonists:

  • Dorsal Interossei
  • Flexor Digiti Minimi (fifth digit)
  • Lumbricals (hand)
  • Palmar Interossei
  • Flexor Digitorum Profundus
  • Flexor Digitorum Superficialis

2. Extension of the digits at the proximal interphalangeal joints when metacarpophalangeal joints are flexed

  Agonists:

  • Dorsal Interossei
  • Palmar Interossei
  • Extensor Indicis (second digit)
  • Lumbricals
  • Extensor Digiti Minimi (fifth digit)

  Antagonists:

  • Flexor Digitorum Profundus
  • Flexor Digitorum Superficialis

3. Extension of the digits at the distal interphalangeal joints when metacarpophalangeal joints are flexed

  Agonists: 

  • Dorsal Interossei
  • Palmar Interossei
  • Extensor Indicis (second digit)
  • Lumbricals
  • Extensor Digiti Minimi (fifth digit)

  Antagonists:

  • Flexor Digitorum Profundus

Secondary Actions of the Extensor Digitorum:

1. Assists with extension of the wrist with digits flexed at the metacarpophalangeal joints

  Agonists:

  • Extensor Carpi Radialis Longus
  • Extensor Carpi Radialis Brevis
  • Extensor Carpi Ulnaris

  Antagonists:

  • Flexor Carpi Radialis
  • Palmaris Longus
  • Flexor Carpi Ulnaris

2. Assists with abduction of the digits during extension of the carpometacarpal joints

  Agonists:

  • Dorsal Interossei
  • Extensor Digiti Minimi (fifth digit)

  Antagonists: Palmar Interossei

Note: Extensor digiti minimi and extensor pollicis longus assist with extension of the wrist.

 

Information about cause and effect of Extensor Digitorum pain:

Extensor Digitorum Muscle: Arm, Hand, Finger Pain

Recommended Anatomy Books:

Anatomy Coloring Book

The Anatomy Coloring Book is one of the best study and reference books for beginning anatomy students. The diagrams are clearly labeled and allow you to see the relationship and placement of the various structures of the body. You will also be surprised how the act of coloring will help with recall. But this is not just a beginners book, it is also great for practitioners and therapists to have on hand to use with clients and patients to use as a visual reference.

Human Muscle Anatomy

The Trail Guide To The Body is another excellent book to help you learn the musculature of the human body. Though the book is geared toward massage therapists and physical therapist assistants, the book with its illustrations and text helps anyone gain a thorough understanding of the human musculoskeletal system and movement. I highly recommend this book for anyone studying anatomy and believe that MTs, PTAs, and teachers of body movements should have this book in their possession. I also highly recommend this book for the lay person who wants to gain understanding of the muscle, skeletal system and how our bodies move. This book will not disappoint!

Basic Clinical Massage Therapy

Out of the scores of books in my office Basic Clinical Massage Therapy is by far the most referenced book in my library. The musculoskeletal system is overlaid on human models allowing you to learn the precise location, origin and insertions of each muscle. The models are pictured in various poses throughout the book which also helps you visualize muscles in motion and their actions relationship with the skeletal structure and other muscles. Though it is written for massage therapists, it is an excellent book for anyone who wants to learn about the muscular system. MT's will benefit from recommended treatments for each muscle.

Muscle Anatomy Flashcards

Musculoskeletal Anatomy Flashcards Are you a student or professional therapist who needs to brush up on the musculoskeletal system? Dr. Joseph E. Muscolino DC has developed a comprehensive set of flashcards that will help develop a mind's picture of exactly where the muscles lie under the skin. A highly recommended study aid for students. Great for non students who want an easy comprehensive anatomy guide.

Massage Therapist

Owner: thewellnessdigest.com

Twelve years of experience working with clients with chronic pain, post injury pain, and post surgery pain. Muscle dysfunction is often overlooked but can hold the key to many pain conditions.

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