Elbow
Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.
More about the experts All content is checked by medical journalists.The elbow is the joint that connects the upper arm bone (humerus) with the two forearm bones ulna and radius (ulna and radius). In this joint we can bend and straighten, twist and turn the forearm. Read everything important about the structure and function of the elbow as well as common health problems in the area of this joint!
What is the elbow?
The elbow is a compound joint that involves three bones - the upper arm bone (humerus) and the two forearm bones, the spoke (radius) and ulna (ulna). More precisely, there are three partial joints with a common joint cavity and a single joint capsule that form a functional unit:
- Articulatio humeroulnaris (joint connection between humerus and ulna)
- Articulatio humeroradialis (joint connection between the humerus and the radius)
- Articulatio radioulnaris proximalis (joint connection between ulna and radius)
The elbow joint is held inside and outside by side ligaments.
The most important nerves and blood vessels run along the flexor side of the joint - when the blood is taken, the doctor pricks a vein in the crook of the elbow.
What is the function of the elbow?
The elbow allows the forearm to flex and extend against the upper arm. Furthermore, by rotating the joint, the hand can be turned outwards (palm up) or inwards (palm down). During the first movement (supination) the two bones of the radius and ulna are parallel to each other, during the second movement (pronation) they are crossed. The hinge joint between the upper arm and ulna enables, in interaction with the other two joints, a wheel movement - the rotation of the forearm against the upper arm.
Several muscles act on the joint and thus make the various movements possible. The two-headed arm muscle (biceps brachii) bends the forearm against the upper arm with its long end tendon, which attaches to the radius in the elbow pit. The tendon is wrapped around the radius when the hand is pronated and turns the hand into the supination position when the muscle is tensed and the tendon unwinds from the radius.
The arm flexor (brachialis) that lies under the biceps also flexes in the elbow joint.
The upper arm radial muscle (brachioradialis) is an important arm flexor that is used particularly when lifting and carrying heavy loads.
The arm extensor (Triceps brachii) is the only extensor muscle on the elbow. Since the three flexor muscles have a stronger tone than the extensor muscle at rest, the forearm is always in a slightly flexed position when we let it hang loosely.
Where is the elbow located?
The elbow is the articulated connection between the humerus and the two forearm bones.
What problems can the elbow cause?
A break in the elbow usually happens when you fall on your outstretched hand. The fracture line can run at different points in the area of the joint, that is: The term elbow fracture includes all fractures of the upper arm, ulna or radius in the vicinity of the elbow joint. This includes, for example, the olecranon fracture (break of the elbow-side end of the ulna).
The elbow joint can also dislocate. This dislocation usually takes place in the humeroulnar joint, i.e. in the partial joint between the humerus and ulna. The cause is usually a fall on an outstretched or slightly bent arm.
Like other joints, the elbow can also be affected by signs of wear and tear (osteoarthritis) and, as a result, painful when moving.
A bursa near the joint can become painfully inflamed (bursitis olecrani). Sometimes bacteria are the cause. In other cases it is an abacterial inflammation, as it can occur, for example, in the context of rheumatoid arthritis or gout. Chronic pressure from frequent leaning on the elbow (“student elbow”) can also be the trigger for abacterial bursitis.
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