Anatomy & Organs

Musculus triceps brachii – structure, function & diseases

Musculus triceps brachii

The triceps is what is known as the triceps brachii muscle , a muscle on the back of the upper arm. This muscle allows the forearm to be stretched at the elbow joint. Both overuse and inactivity can lead to triceps problems.

What is the triceps?

The German translation of the triceps brachii muscle , colloquially known as the triceps , is three-headed arm muscle. It belongs to the skeletal muscles and here to the group of upper arm muscles. The triceps are located the entire length of the back of the upper arm . Parts of the triceps run over two joints , the shoulder and the elbow .

Since it is an arm extensor muscle, it is also called the three-headed arm extensor. The antagonists or opponents of the arm extensors are the arm flexors. The term “three-headed” is based on the fact that the triceps consists of three muscle heads. Skeletal muscles are always attached to the skeleton or fascia via tendons in at least two places, the origin and the insertion .

In the case of multiple origins, the muscle heads (Latin caput ) are the different parts of origin of a muscle. The triceps has three root parts or three muscle heads that have a common approach. The triceps are responsible for extending and rotating the forearm at the elbow joint.

Anatomy & Structure

The three muscle heads of the triceps are the long head ( caput longum ), the inner head ( caput mediale ), and the lateral head ( caput laterale ). The Caput longum originates below the joint socket on the shoulder blade (scapula). It forms the lateral and medial axillary space. The armpits are vascular and nerve tracts in the shoulder area. The Caput mediale and the Caput laterale have their origin on the rear side of the upper arm bone ( humerus ). The three muscle heads converge to form a common, sinewy insertion at the olecranon. The olecranon is the bony end of the ulna), one of the forearm bones. From here fibers radiate to the joint capsule of the elbow and to the forearm fascia.

The tendon of the triceps, which forms the insertion, begins in the middle of the muscle and is composed of two aponeuroses. Aponeuroses are connective tissue structures that serve as a sinewy attachment of muscles. Of the two aponeuroses of the triceps, one covers the lower part of the muscle outwards while the other extends deep into the muscle. Underneath the triceps tendon is a bursa that provides protection from excessive friction between the muscle and the bony olecranon.

Function & Tasks

The triceps, together with the anconeus muscle , which is also known as the elbow or elbow hump muscle, enables stretching (extension) of the forearm in the elbow joint. The triceps also allow the arm to be pulled towards the body (adduction) via the shoulder joint and guided backwards (retroversion). The caput mediale and the caput laterale are responsible for the extension.Adduction and retroversion can occur through the caput longum. Another function of the triceps is to fix the elbow joint. This prevents your arms from buckling when you support yourself and allows you to make fine hand movements, such as when writing. The triceps is the antagonist of the biceps, which is called the biceps brachii muscle in medical jargon and also belongs to the upper arm muscles, but is an arm flexor muscle.

Also, the triceps is an antagonist of the brachialis muscle , the upper arm muscle that lies behind the biceps on the outside of the upper arm. When you flex your forearm, your biceps contract and your triceps stretch. When you stretch your forearm, the opposite happens: the triceps contract and the biceps relax.

In contrast to the heart muscles and the smooth muscles of the internal organs, the skeletal muscles, and thus also the triceps, can be moved voluntarily and consciously. In addition to movement, skeletal muscles also stabilize joints such as the shoulder. The muscles also generate part of the body heat.

Diseases & Ailments

Various complaints of different causes can occur in the triceps area. Pulling or burning pain along the entire back of the arm or stabbing, localized pain can occur, as well as tension or restricted movement. Pain can radiate to the upper back and fingers. Slight swelling can also occur.This can be caused by external forces such as an accident or tendinitis . Inflammation of the triceps tendon occurs when the tendon rubs against the bone when it is overloaded (e.g. due to heavy weights during strength training). If left untreated, tendinitis can develop into chronic inflammation. Underloading due to inactivity can lead to complaints, just like severe overloading.

Activities in which the arms are constantly held in front of the body, such as working at a desk or on long car journeys, can lead to constant stretching of the caput longum. Over time, this can lead to passive overload of the triceps. In various sports, such as swimming, tennis or volleyball, the triceps can be actively overloaded.

The so-called epicondylitis is the colloquial tennis elbow. Epicondylitis is not unique to tennis players, but irritation of the triceps tendon insertions is particularly common. When weight training or bodybuilding, various exercises such as bench presses or push-ups can put a lot of strain on the triceps. In rare cases where the triceps are subjected to extreme stress, hamstring tears can also occur, where the muscle tissue tears.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.