triceps brachii muscle
Also known as triceps, tri, triceps brachii
The triceps, or triceps brachii (Latin for "three-headed muscle of the arm"), is a large muscle on the back of the upper limb of many vertebrates. It consists of three parts: the medial, lateral, and long head. All three heads cross the elbow joint. However, the long head also crosses the shoulder joint. The triceps muscle contracts when the elbow is straightened and expands when the elbow is bent. The long head gets a further contraction when the arm is behind the torso due to how it crosses the shoulder joint. It is the muscle principally responsible for extension of the elbow joint (straigh
Key facts
- Muscle.Name
- Triceps
- Muscle.Latin
- musculus triceps brachii
- Muscle.Image
- Triceps brachii.png
- Muscle.Caption
- Triceps brachii seen from behind.
- Muscle.Image2
- Triceps brachii muscle06.png
- Muscle.Caption2
- Triceps brachii seen from behind. Three different colors represent three different bundles which compose triceps.
- Muscle.Origin
- Long head: infraglenoid tubercle of scapula Lateral head: above the radial grooveMedial head: below the radial groove
- Muscle.Insertion
- Olecranon process of ulna
- Muscle.Blood
- Deep brachial artery, posterior circumflex humeral artery (long head only)
- Muscle.Nerve
- Radial nerve
- Muscle.Action
- Extends forearm, long head extends, adducts arm, extends shoulder
Article
13 sectionsContents
- Structure
- Innervation
- Variation
- Function
- Training
- Clinical significance
- History
- Etymology
- Other animals
- Additional images
- See also
- References
- External links
The triceps, or triceps brachii (Latin for "three-headed muscle of the arm"), is a large muscle on the back of the upper limb of many vertebrates. It consists of three parts: the medial, lateral, and long head. All three heads cross the elbow joint. However, the long head also crosses the shoulder joint. The triceps muscle contracts when the elbow is straightened and expands when the elbow is bent. The long head gets a further contraction when the arm is behind the torso due to how it crosses the shoulder joint. It is the muscle principally responsible for extension of the elbow joint (straightening of the arm).
== Structure == The long head arises from the infraglenoid tubercle of the scapula. It extends distally anterior to the teres minor and posterior to the teres major. The medial head arises proximally in the humerus, just inferior to the groove of the radial nerve; from the dorsal (back) surface of the humerus; from the medial intermuscular septum; and its distal part also arises from the lateral intermuscular septum. The medial head is mostly covered by the lateral and long heads and is only visible distally on the humerus. The lateral head arises from the dorsal surface of the humerus, lateral and proximal to the groove of the radial nerve, from the greater tubercle down to the region of the lateral intermuscular septum.