|Origin||Long head: infraglenoid tubercle of scapula
Lateral head: above the radial groove
Medial head: below the radial groove
|Insertion||Olecranon process of ulna|
|Action||All heads: extension of elbow.
Long head: adduction and extension of the arm at the shoulder joint
|Nerve||Radial nerve (C6, C7, C8)|
|Artery||Deep brachial artery
Long head: posterior circumflex humeral artery
Location & Overview
The triceps brachii is a three headed muscle of the arm. It is a relatively large muscle which is located posterior to the humerus and is primarily responsible for flexion of the elbow. It often has a horseshoe like appearance. The Latin word ‘brachii’ is a reference to the muscle being located in the arm. The ‘tri’ in the word triceps is a reference to its three muscle heads (or points of origin). The word ‘ceps’ means head. The three heads of the triceps are: a long head, a lateral head, and a medial head  .
Origin & Insertion
The long head originates from the infraglenoid tubercle of the scapula. The medial head originates just inferior to the radial groove, whereas the lateral head originates superior to the radial groove. The medial head of the triceps is mostly covered by the lateral and long heads. The fibres of the three heads then converge to a single tendon which then inserts onto the olecranon process of the ulna (a bony prominence of the elbow which is located on the upper portion of the ulna)   .
All the heads of the triceps brachii can assist in extension of elbow. However, because the long head crosses the shoulder joint; the long head can also assist in adduction and extension of the arm at the shoulder joint  .
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Triceps Brachii Flashcards
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|↑2, ↑5||Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017.|
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|↑9||Glover NM, Murphy PB. Anatomy, Shoulder and Upper Limb, Radial Nerve. 2021 Jul 27. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 30521261.|
|↑10||Tang A, Varacallo M. Anatomy, Head and Neck, Posterior Humeral Circumflex Artery. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538283/|
|↑11||Dankel SJ, Jessee MB, Abe T, Loenneke JP. The Effects of Blood Flow Restriction on Upper-Body Musculature Located Distal and Proximal to Applied Pressure. Sports Med. 2016 Jan;46(1):23-33. doi: 10.1007/s40279-015-0407-7. PMID: 26446893.|