Crutch

alt=|thumb|Underarm (axillary) crutches used to keep weight off the injured leg.

alt=Man using forearm crutches|thumb|A man using forearm crutches

A crutch is a mobility aid that transfers weight from the legs to the upper body. It is often used by people who cannot use their legs to support their weight, for reasons ranging from short-term injuries to lifelong disabilities.

History

Crutches were used in ancient Egypt. In 1917, Emile Schlick patented the first commercially produced crutch; the design consisted of a walking stick with an upper arm support. Later, A.R. Lofstrand Jr. developed the first crutches with a height-adjustable feature. Over time, the design of crutches has not changed much, and the classic design continues to be the most commonly used.

With underarm crutches, sometimes a towel or some kind of soft cover is needed to prevent or reduce armpit injury. A condition known as crutch paralysis, or crutch palsy can arise from pressure on nerves in the armpit, or axilla. Specifically, "the brachial plexus in the axilla is often damaged from the pressure of a crutch...In these cases the radial is the nerve most frequently implicated; the ulnar nerve suffers next in frequency." These crutches also contain a spring mechanism at the bottom. The idea behind this design is to allow the user to propel themselves further, resulting in quicker movement from place to place, though research has shown that the difference in speed is very small when comparing standard axillary crutches to spring-loaded crutches.

Forearm

thumb|right|A typical forearm crutch

A forearm crutch (also commonly known as an elbow crutch, Canadian crutch or "Lofstrand" crutch due to a brand by this name) has a cuff at the top that goes around the forearm.

Forearm crutches are the dominant type used in Europe, whether for short or long term use. Outside of Europe forearm crutches are more likely to be used by users with long-term disabilities, with axillary crutches more common for short-term use.

Walking sticks or canes serve an identical purpose to crutches, but are held only in the hand and have a limited load bearing capability because of this.

Types of gaits

thumb|Small boy learns to use his crutches (1942).

One crutch

When using one crutch, the crutch may be placed on the side of the unaffected leg or used to bear the load of the affected leg.

Four-point gait

Those who can tolerate partial weight bearing on both legs usually use the four point gait. The sequence is right crutch, left leg, left crutch, right leg. This is the slowest of all gaits but also the safest in that three of the four points are in contact with the ground at any given time.

Two-point gait

Those who can tolerate partial weight bearing on both legs but require less support than a four-point gait usually use the two-point gait. The sequence is right crutch with left leg and then left crutch with right leg.

Three-point gait

The three point gait is usually used by those who cannot bear weight on one leg. Both crutches are advanced while bearing weight on the unaffected leg. Then the unaffected leg is advanced while bearing weight on the crutches.

Swing-to gait

A person with a non-weight bearing injury generally performs a "swing-to" gait: lifting the affected leg, the user places both crutches in front of themself, and then swings his uninjured leg to meet the crutches. A similar "swing-through" gait is when both legs are advanced in front of the crutches rather than beside them.

Stairs

When climbing up stairs, the unaffected leg is advanced first, then the affected leg and the crutches are advanced. When descending stairs, the crutches are advanced first and then the affected leg and the unaffected leg.