Triceps Brachii

The triceps brachii, or triceps, is a large, thick muscle in the upper arm that’s responsible for extending the elbow joint. It’s located on the back of the upper arm, between the shoulder and the elbow, and often appears horseshoe-shaped. The triceps is made up of three parts, or heads: the long head, the lateral head, and the medial head.

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Triceps Brachii
Triceps Brachii

Triceps Brachii

Anatomy

[Origin]

  • Long head: infraglenoid tubercle of scapula
  • Lateral head: posterior surface of humerus, superior to radial groove
  • Medial head: posterior surface of humerus, inferior to radial groove

[Insertion]

  • Proximal end of olecranon of ulna and fascia of forearm

[Action]

  • Chief extensor of forearm; long head resists dislocation of humerus; especially important during adduction

Clinical Relevance

Functions of The 3 Heads

    • Long Head: Because it attaches to the scapula, the long head not only extends the elbow but will also have a small action on the glenohumeral With the arm adducted, the triceps muscle acts to hold the head of the humerus in the glenoid cavity. This action helps prevent any displacement of the humerus.
    • Lateral Head: Strongest head of the three. It is active during extension of the forearm at the elbow joint when the forearm is supinated or pronated.
    • Medial Head: As the medial head does not attach to the scapula and therefore has no action on the glenohumeral joint, whether with stabilization or movement. However, the medial head is active during extension of the forearm at the elbow joint when the forearm is supinated or pronated.

~ Evidence-Based Exercises ~

According to an EMG study, the exercises that demonstrated significant muscle contractions of Triceps Brachii are;

  • Vertical Dip
  • Triceps Pulldown
  • Overhead Triceps Extension

Vertical Dip

Vertical Dip

Triceps Pulldown

Triceps Pulldown

Overhead Triceps Extension

Overhead Triceps Extension

< Reference >

  • Keith L. Moore, Anne M. R. Agur, Arthur F. Dalley. Moore Clinically Oriented Anatomy 7th Edition, Lippincott Williams & Wilkins, 2013
  • Tiwana MS, Sinkler MA, Bordoni B. Anatomy, Shoulder and Upper Limb, Triceps Muscle. In: StatPearls. StatPearls Publishing; 2024. Accessed May 21, 2024. http://www.ncbi.nlm.nih.gov/books/NBK536996/
  • Bagchi, A. (June, 2015). A comparative electromyographical investigation of triceps brachii and pectoralis major during four different freehand exercises. Journal of Physical Education Research, Volume 2, Issue 11, 20-27.

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