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Extensor Digitorum Anatomy: Origin, Insertion, Actions

Extensor Digitorum Anatomy Study

Extensor Digitorum Anatomy

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.
Action: Extension of the fingers
Blood Suppy: Posterior interosseous artery from the ulnar artery.
Innervation:  Radial nerve (C6, 7, 8).

 

For pain and symptom information see: Extensor Digitorum Pain

 




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, Lumbricals, Extensor Digiti Minimi
  • 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, Lumbricals, Palmar Interossei, Lumbricals, Extensor Indicis, Extensor Digiti Minimi
  • Antagonists: Flexor Digitorum Profundus

Secondary Actions of the Extensor Digitorum:

4. 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

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

  • Agonists:  Dorsal Interossei, Extensor Digiti Minimi (fifth digit)
  • Antagonists: Palmar Interossei

 


Anatomy Coloring Book

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.

TRAIL GUIDE TO THE BODY

Trail Guide To The Body

 

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!

 

References:

The Trigger Point Therapy Workbook – Claire Davies, Amber Davies, and David G. Simons

Basic Clinical Massage Therapy: Integrating Anatomy and Treatment – James H. Clay and David M. Pounds

Trigger Point Therapy for Myofascial Pain – Donna Finando and Steven Finando