Triceps Brachii Muscle Location
Triceps brachii muscle is located at the back of the upper arm. It extends from the top of the upper arm to the top of the ulna (the larger of the 2 forearm bones).
- Long head: infraglenoid tubercle of scapula
- Lateral head: posterior surface of humerus, above the radial grove
- Medial head: posterior surface of humerus, below the radial groove
- Reference : 
- Olecranon process of ulna and fascia of forearm 
- The lateral and medial head extend the forearm (backwards) in the elbow .
- The long head of triceps brachii extends the arm (backwards) in the shoulder and the forearm in the elbow .
- Radial nerve, which originates from the spinal roots C6, C7 and C8 
- Deep brachial artery 
Picture 1. Triceps brachii anatomy: origin, insertion, function
(free image use)
Video 1. Triceps brachii anatomy: origin, insertion, actions, related muscles
Related anatomy: shoulder muscles
Triceps tendonitis is an inflammation of the triceps tendon tear at its insertion behind the elbow. It occurs due to repetitive pushing activities, such as weightlifting, throwing and push ups . Risk factors include muscle weakness, inappropriate warm up and insufficient rest between training sessions .
Symptoms include pain and stiffness behind the elbow and muscle weakness during pushing.
Treatment includes ice packs, physiotherapy (massage) and anti-inflammatory drugs, such as ibuprofen .
Recovery may last from few weeks to several months in chronic tendinitis .
Triceps Brachii Tendon Tear
The tendon of the triceps brachii that is attached below and behind the elbow can rupture during weightlifting or injury. Risk factors include heavy training (bodybuilding, weightlifting, football), previous tendon surgery, steroid injections, anabolic steroids abuse, chronic kidney disease and gout (Video 2).
Symptoms and signs of triceps brachii tendon tear :
- Sudden pain behind the elbow, possibly associated with a pop sound
- Swelling or bruising and a palpable gap behind the elbow
- Difficulty or inability to extend the arm in the elbow
A doctor can make the diagnosis of a triceps brachii tear by a physical examination (triceps strength test, video 3), X-ray or magnetic resonance imaging (MRI).
Video 2. Triceps brachii tendon tear
Triceps Brachii Strength Test
To test your triceps brachii muscle strength, you extend the arm in the elbow against resistance of an examiner’s arm (Video 3).
Video 3. Triceps brachii strength test
- Rest from using the affected arm by wearing a splint in extension for 10 days to 6 weeks 
- Surgery for a complete or significant partial tendon tear