Actions & innervation of Brachialis.
Knowledge of origins & insertions is NOT required but an appreciation of the surface topography is required.
Curriculum
Origin | Anteriorly from distal half of Humerus |
Insertion | Tuberosity of Ulna and coronoid process of Ulna |
Nerve supply | Musculocutaneous nerve |
Actions | Flexion of forearm |
Though the curriculum says origin and insertion not required, we’ve included them as that knowledge will help you understand the movements better based on muscle orientation.
![](https://cdn.frcemprep.com/wp-content/uploads/2021/04/Brachialis.jpg)
Brachialis muscle Origin and Insertions – Image modified from BodyParts3D, © The Database Center for Life Science licensed under CC Attribution-Share Alike 2.1 Japan
The orange colored muscle is coracobrachialis and the wider brownish muscle is the Brachialis in the image.
When it inserts on the Ulna, it goes between 2 heads of flexor digitorum profundus.
The position of muscle should help you understand the actions when it contracts. It’ll pull the forearm anteriorly (flexion).
All the anterior arm muscles – Coracobrachialis, Brachialis and Biceps brachii are supplied by the same nerve – The Musculocutaneous nerve, the terminal branch of the lateral cord of the brachial plexus (C5-C7). The nerve becomes lateral cutaneous nerve of forearm to supply lateral part of forearm. Muscles of Upper Arm and Skin of Forearm are supplied.
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