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Brachialis muscle

Flexor muscle in the upper arm

Field	Value
Name	Brachialis
Latin	musculus brachialis
Image	Brachialis.png
Caption	Deep muscles of the chest and front of the arm, with the boundaries of the axilla. (Brachialis visible at bottom right.)
Image2	Brachialis muscle11.png
Caption2	Position of brachialis (shown in red).
Origin	Anterior surface of the humerus, particularly the distal half of this bone
Insertion	Coronoid process and the tuberosity of the ulna
Blood	Radial recurrent artery, brachial artery
Nerve	Musculocutaneous nerve (C5-C7) and radial nerve (C5, C6)
Action	Flexion at elbow joint

The brachialis (also brachialis anticus or Casserio muscle) is a muscle in the upper arm that flexes the elbow. It lies beneath the biceps brachii, and makes up part of the floor of the region known as the cubital fossa (elbow pit). It originates from the anterior aspect of the distal humerus; it inserts onto the tuberosity of the ulna. It is innervated by the musculocutaneous nerve, and commonly also receives additional innervation from the radial nerve. The brachialis is the prime mover of elbow flexion generating about 50% more power than the biceps.

Structure

Origin

The brachialis originates from the anterior surface of the distal half of the humerus, near the insertion of the deltoid muscle, which it embraces by two angular processes. Its origin extends below to within 2.5 cm of the margin of the articular surface of the humerus at the elbow joint.

Insertion

Its fibers converge to a thick tendon which is inserted into the tuberosity of the ulna, and the rough depression on the anterior surface of the coronoid process of the ulna.

Innervation

The brachialis muscle is innervated by the musculocutaneous nerve (also Casserio nerve), which runs on its superficial surface, between it and the biceps brachii. However, in 70-80% of people, the muscle has double innervation with the radial nerve (C5-T1). The divide between the two innervations is at the insertion of the deltoid.

Blood supply

The brachialis is supplied by muscular branches of the brachial artery and by the recurrent radial artery.

Variation

The muscle is occasionally doubled; additional muscle slips to the supinator, pronator teres, biceps brachii, lacertus fibrosus, or radius are more rarely found.

Function

The brachialis flexes the arm at the elbow joint. Unlike the biceps, the brachialis does not insert on the radius, and does not participate in pronation and supination of the forearm.

History

Etymology

The brachialis muscle and brachial muscle can be considered as the anglicized variant of the Latin expression musculus bracchialis. In classical Latin bracchialis means of or belonging to the arm, and is derived from classical Latin bracchium,"arm". The expression musculus brachialis is used in the current official anatomic nomenclature Terminologia Anatomica.

Additional images

File:Brachialis muscle - animation03.gif|Position of brachialis (shown in red). Animation. File:Brachialis muscle01.png|Still image. File:Gray413 color.png|Horizontal section through the middle of upper arm. (Brachialis labeled at center left.) File:Muscles of upper limb.(cross section - human cadaver).jpg|Muscles of forearm, including insertion of brachialis tendon. Cross section. (Brachialis labeled at bottom left.) File:Gray207.png|Left humerus. Anterior view. File:Gray213.png|Bones of left forearm. Anterior aspect. File:Nerves_of_the_left_upper_extremity.gif|Nerves of the left upper extremity. File:Slide10zzz.JPG|Brachialis muscle (labeled in green text)

References

Drake, Richard L.. (2005). "Gray's anatomy for students". Elsevier/Churchill Livingstone.
"Brachialis Muscle." Kenhub. Kenhub, Aug. 2001
Saladin, Kenneth S, Stephen J. Sullivan, and Christina A. Gan. Anatomy & Physiology: The Unity of Form and Function. 2015. Print.{{pn. (June 2025)
(2012). "Human Osteology".
"Brachialis." UW Department of Radiology. University of Washington, Nov. 2005
Dirckx, J.H. (Ed.) (1997).''Stedman’s concise medical dictionary for the health professions.'' (3rd edition). Baltimore: Williams & Wilkins.
Anderson, D.M. (2000). ''Dorland’s illustrated medical dictionary'' (29th edition). Philadelphia/London/Toronto/Montreal/Sydney/Tokyo: W.B. Saunders Company.{{pn. (June 2025)
Triepel, H. (1910). ''Die anatomischen Namen. Ihre Ableitung und Aussprache. Mit einem Anhang: Biographische Notizen.''(Dritte Auflage). Wiesbaden: Verlag J.F. Bergmann.{{pn. (June 2025)
Lewis, C.T. & Short, C. (1879). ''A Latin dictionary founded on Andrews' edition of Freund's Latin dictionary.'' Oxford: Clarendon Press.{{pn. (June 2025)
Federative Committee on Anatomical Terminology (FCAT) (1998). ''Terminologia Anatomica''. Stuttgart: Thieme.{{pn. (June 2025)

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

elbow-flexors muscles-of-the-upper-limb

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