What structures are found in the elbow joint and forearm?
The elbow joints often don’t get as much attention as the more popular hip joints and shoulder joints, but we’d find it hard to do many daily tasks without them. In this article we’ll take a closer look at the elbow joint, the main muscles that cross it, and the movements that happen there.
Bones of the elbow joint
The elbow joint is a general name that is technically comprised of two joints: the humeroulnar joint and the humeroradial joint. There is a third joint that is sometimes referred to as a part of the elbow, but it is more often considered independent of the elbow joint itself because it does different movements. This is the proximal radioulnar joint. Let’s look at each of these individual joints a little closer.
The humeroulnar joint is where the upper arm bone, the humerus, meets the ulna, the smaller of the two forearm bones. The second part of the elbow joint, the humeroradial joint, is where the humerus meets the radius, the larger of the two forearm bones. The third joint that we’ll discuss in relation to the elbow is the proximal radioulnar joint. This is where the proximal (closer to the head) end of the ulna and radius meet and articulate with one another, separately from the articulations with the humerus. There is also a distal (farther from the head) radioulnar joint which you’ll remember we already covered as part of the wrist joints.
Movements of the elbow joint
The humeroulnar joint and humeroradial joint, which make up what we more generally know as the elbow joint, make a hinge joint that does the movements of flexion and extension of the elbow. At the proximal radioulnar joint, the articulation between the radius and ulna is a pivot joint which allows us to supinate and pronate (types of rotation) the forearm.
Muscles of the elbow joint and forearm
Let’s take a look at the muscles at the elbow joint that contribute to its actions.
Flexors of the forearm:
- Biceps brachii
Extensors of the elbow:
- Triceps brachii
Pronators of the forearm at the proximal radioulnar joint:
- Pronator teres
- Pronator quadratus
- Brachioradialis (assists pronation)
Supinators of the forearm:
- Supinator muscle
- Biceps brachii (assists supination)
The elbow joint makes so many important actions possible. It’s the link in the kinetic chain between our shoulder joint and our wrist and hand. So many movements that we take for granted each day rely on the movements of the elbow joint to make them possible, from turning a doorknob to drinking a glass of water. Hopefully you now have a better understanding of the structures that are found there. If you’d like to learn more about the surrounding joints in the kinetic chain of the arm, check out the articles Hand And Wrist Anatomy and What Is The Shoulder Girdle Or Shoulder Complex?