Issue 021
January 2007
By Rosi Sexton
The straight armlock has always been one of the most common submissions in mixed martial arts (MMA). There are many variations in the technique used to lock the joint, the most common of which is the classic armbar (juji gatame in Japanese terminology).
Straight armlocks are the only techniques to affect the elbow joint exclusively. As we will see in a future column, the bent armlocks – keylocks and kimuras – exert most of their effect on the shoulder. In order to understand what a straight armlock does, let us start with the anatomy of the elbow joint.
The elbow joint actually consists of three articulations. It is where the two bones of the forearm – the radius on the thumb side and the ulna on the little finger side - come together with the humerus of the upper arm. The hinge joint that most people think of as the elbow is the one that joins the ulna and the humerus. A part of the end of the humerus, called the trochlea, sits in a notch of the ulna (imaginatively enough called the trochlear notch) and allows the elbow to bend and straighten. It is a pure hinge joint, and this is the only movement it allows.
Hang on a minute though: in that case, how is it that I can turn my hand round? Something else certainly seems to be going on at the elbow. This is where the other two joints of the elbow come into play. The movement that allows you to turn your hand palm up is called supination and the opposite (turning palm down) is called pronation. For pronation to occur, the radius crosses over the ulna. We don’t need to go into much detail on this to understand the straight armlock, but it is useful to have a picture of how the whole thing works.
When the elbow is fully straightened (extended), the bones are locked together. The very end of the ulna – the olecranon process – fits into a notch on the humerus called the olecranon fossa preventing further movement.
A straight armlock works by hyperextending (or over–extending) the elbow joint. This can be done by either fixing the elbow and the shoulder and forcing down on the wrist (as in the face up armbar) or alternatively fixing the shoulder and the wrist and forcing in on the elbow. From now on, I will refer specifically to the face up armbar (juji gatame) in order to simplify the explanation. The same basic mechanics work for all straight armlocks, however.
If the arm is held so that the palm is up and the force is applied to the wrist in the direction from front of hand to back of hand, then this will force together the bony olecranon and olecranon fossa. This can quickly cause a lot of pain as the joint surfaces are compressed, but it can often take a good deal more force to break the joint. If enough leverage is applied, or the person’s bones are sufficiently weak, it can cause a fracture of the olecranon. The elbow is generally pretty strong in this direction, however. There are other, weaker, links that are more likely to be damaged by an armbar.
Thumbs up
A good submission fighter knows that the best way to apply an armbar is to turn the thumb upwards. What difference does this make? Aside from changing the position of the shoulder in a way that makes the lock harder to escape, it also changes the orientation of the elbow joint so that more stress is put on some of the ligaments. These are weaker and more easily damaged than the bone.
The collateral ligaments of the elbow stabilise the joint on either side. The medial (or ulnar) collateral ligament is difficult to attack with a straight armlock, as it is hard to stop the arm bending when force is applied in that direction, but may be affected by a keylock. The ligament we are chiefly interested in here is the lateral (or radial) collateral ligament. This runs from the humerus to the radius, and joins with another ligament called the annular ligament which runs round the head of the radius and keeps it in place so that it moves smoothly against both the humerus and the ulna.
A straight armbar, when strongly applied with thumb pointing upwards, is likely to damage the radial collateral ligament and may also disrupt the joint between the radius and the humerus. In extreme cases, the head of the radius may dislocate although this is a relatively uncommon injury in adults.
Everyone’s body is slightly different, and there are always many different possible effects of any particular technique depending on exactly how it is applied, and who it is being applied to. So far this article has considered the main mechanism of the lock and the damage most likely caused by it. There are other structures that may also be damaged – for example, if someone has particularly tight biceps, over-stretching it may tear the muscle.
A sensitive bit of kit
The elbow, like most joints, is a complicated and sensitive bit of kit that relies on three bones, three main ligaments, a joint capsule, several nerves, numerous muscles and the right balance of nutrients and fluids. Disrupting any piece of the system can cause problems with elbow function.
As always, if you suspect a potential fracture, dislocation or other serious injury from an armbar (and certainly if there is obvious deformity of the joint, or any loss of sensation in the arm or hand) then you should seek immediate medical attention. For a less serious injury, apply RICE (Rest, Ice, Compression, Elevation) as soon as possible to reduce the inflammation. Ice can be used for up to ten minutes every two hours for as much as three days from the time of injury. Many people underestimate how much difference this can make; for some injuries it can halve your recovery time. Continuing to gently move the joint can also aid recovery and avoid stiffness, but care should be taken not to cause any further damage.
Chronic problems can occur following either single or repeated application of an armlock. These are best addressed by consulting a qualified professional, for example a physiotherapist or osteopath.
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