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5.8 Muscles of the Upper Limb

Deltoid, Biceps Brachii, and Triceps Brachii

Anterior and posterior location of the biceps brachii, triceps brachii and deltoid
Image by OpenStax, CC BY 4.0. Modified text labels.
Location of the deltoid.
Image by OpenStax, CC BY 4.0. Text modified text labels/cropped

Deltoid

Action: Abduction, flexion, and extension of the shoulder

The deltoid is commonly referred to as the ‘delts’ and is the main superficial muscle of the shoulder. It is named after its shape which resembles the Greek letter delta ([latex]\Delta[/latex]).

 
Location of the biceps brachii (short head) and biceps brachii (long head).
Image by OpenStax, CC BY 4.0. Text modified text labels/cropped

Biceps Brachii

Action: Flexion of the elbow

The biceps brachii muscle is named for the number of heads the muscle contains as well as its location. The ‘Bi-‘, meaning two, in biceps refers to the two heads the muscle contains. ‘Brachii’ refers to the muscle’s location within the brachial (upper arm) region.

Location of the triceps brachii (lateral head) and triceps brachii (long head)
Image by OpenStax, CC BY 4.0. Text modified text labels/cropped

Triceps Brachii

Action: Extension of the elbow

The triceps brachii muscle is named for the number of heads the muscle contains as well as its location. The ‘Tri-‘, meaning three, in triceps refers to the three heads the muscle contains. ‘Brachii’ refers to the muscle’s location within the brachial (upper arm) region.

 

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The Foundations of Human Movement and Physical Fitness Copyright © 2025 by A.J. Stephen; Sarah Fraser; and Connor Dalton is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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