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Deltoid Anatomy: Origin, Insertion, Action, Innervation

Deltoid Anatomy Study

deltoid_muscle_med Origin: Anterior Part: Anterior border of the lateral third of the clavicle
Medial Part:
Lateral border of the acromion process of the scapula
Posterior Part:
Inferior edge of the scapular spine

Insertion: Anterior Part: The deltoid tuberosity on the lateral surface of the proximal humeral shaft
Medial Part:
The deltoid tuberosity on the lateral surface of the proximal humeral shaft.
Posterior Part:
The deltoid tuberosity on the lateral surface of the proximal humeral shaft.

Action: Shoulder abduction, flexion and extension
Innervation: Axillary nerve (C5, C6)
Blood Supply: Posterior circumflex humeral artery from the axillary artery and the deltoid artery from the thoraco-acromial artery

Synergist: Supraspinatus, Infraspinatus, Teres major and minor, Subscapularis.

Antagonist: Pectoralis major and minor, Subclavius, Serratus anterior, Trapezius, Latissimus dorsi, Rhomboid major and minor, and Levator scapulae

 

 

Primary Actions: Deltoid Anterior Fibers

1. Flexion of the arm at the shoulder

  • Agonists: Biceps Brachii, Coracobrachialis, Pectoralis Major (clavicular head)
  • Antagonists: Deltoid (posterior fibers) Triceps Brachii (long head), Latissimus Dorsi, Pectoralis Major (sternal head), Teres Major

2. Internal Rotation of the arm at the shoulder

  • Agonists: Subscapularis, Pectoralis Major, Latissimus Dorsi, Teres Major
  • Antagonists: Infraspinatus, Teres Minor, Deltoid (posterior fibers)

Primary Actions: Deltoid Middle Fibers

1. Abduction of the arm at the shoulder

  • Agonists: Deltoid (anterior and posterior fibers), Supraspinatus
  • Antagonists: Latissimus Dorsi , Pectoralis Major, Triceps Brachii (long head)

Primary Actions: Deltoid Posterior Fibers

1. Extension of arm at shoulder

  • Agonists: Triceps Brachii (long head), Latissimus Dorsi, Pectoralis Major (sternal head), Teres Major
  • Antagonists: Deltoid (anterior fibers), Biceps Brachii, Coracobrachialis and Pectoralis Major (clavicular head)

Secondary Actions:

1. Assists with external rotation of the arm at the shoulder

  • Agonists: Infraspinatus, Teres Minor
  • Antagonists: Deltoid (anterior fibers), Teres Major, Latissimus Dorsi, Pectoralis Major, Subscapularis

For pain and symptom information see:  Deltoid muscles shoulder pain and weakness


Recommended Anatomy Books

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   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

Massage Therapy Principles and Practice – Susan Salvo

Theory & Practice of Therapeutic Massage – Mark Beck

 

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