Posts for tag: hand
The wrist is the name usually given to the eight carpal bones (the lunate, scaphoid, triquetrum, pisiform, trapezium, capitate, hamate and trapezoid carpals) that form the part of the hand closest to the forearm, and the joints that they form with each other and the bones of the forearm and hand. The radiocarpal joint connects the hand to the forearm and involves the distal end (furthest from the body) of the radius, the articular disc and eight bones of the wrist itself. The scaphoid, lunate, pisiform and triquetrum carpals articulate (connect) directly with the radius, whereas the other carpal bones are slightly more distal to (further from) the wrist joint. The proximal (closest to the body) parts of the five metacarpals are often included as anatomical components of the wrist.
As we all know from experience, a wide range of movement is possible at the wrist, and the radiocarpal joint allows for flexion (bending) extension (straightening), some hyperextension (bending back) abduction (movement away from the body) adduction (movement towards the body) and circumduction (circular movement of the hand from the wrist).
Although the ulna is larger than the radius, it tapers towards the wrist and becomes narrower. Here, at the end of the forearm, the head of the radius connects with the radial notch of the ulna to form the radioulnar joint. This is separated from the radiocarpal joint by the articular disc and allows for supination and pronation movements of the hand (rotating the palm of the hand to face-up and face-down positions respectively). Both the radiocarpal and radioulnar joints are synovial joints, the radiocarpal being a condyloid (or ellipsoid) joint whereas the radioulnar is a pivot joint.
The midcarpal joint occurs between the carpals most proximal to the wrist and those more distal. Between the carpal bones in each row (proximal or distal) are a series of intercarpal joints. These are a combination of synovial planar (sliding) and saddle joints, which allow a degree of movement in the lower hand, including flexion (bending toward the palm) and extension (straightening toward the back of the hand).
Each bone of the wrist is connected to its neighbors by one or more ligaments. Since there are a total of fifteen bones comprising the various wrist joints (the radius, ulna, eight carpals and five metacarpals), this gives rise to a complex arrangement of wrist ligaments. Two of the largest of these are the medial (ulnar) collateral ligament and lateral (radial) collateral ligament. The lateral collateral ligament connects the radius across the wrist to the scaphoid carpal, and the medial collateral ligament attaches the end of ulna to the triquetrum and pisiform carpals.
Carpal Tunnel Syndrome (CTS) affects about one in a thousand people (mostly women) each year, and is caused by the median nerve being compressed as it runs through the carpal tunnel, a ligament that is located in the wrist. The tendons that control finger movement all run through the carpal tunnel, so when they become inflamed and swollen the amount of space is reduced, putting increased pressure on the median nerve.
In many cases, the cause of carpal tunnel syndrome is not clear. There are some theories as to why women tend to suffer from CTS more than men. One is that they have smaller wrist bones, and thus a smaller space through which the tendons can pass. Another is that, as it is more common during pregnancy and around menopause, hormonal shifts may be a causative factor.
Some people may have a genetic predisposition for CTS. Approximately one out of four people has a close family member who has also has the disorder. Trauma or an injury to the wrist may trigger CTS, such as a sprained or broken wrist. The vibration of power tools or heavy machinery, for instance a rotary sander, can sometimes trigger CTS.
Those who have jobs involving repetitive movements of the arm are more likely to contract carpal tunnel syndrome, such as workers on an assembly line, carpenters, violinists, etc. Interestingly, though long-term computer use was previously thought to contribute to CTS, there is now conflicting information about the relationship between keyboarding and CTS. Some studies, such as one from 2007 published in the journal Arthritis and Rheumatism, have found that those who use a keyboard intensively at work actually have a significantly lower risk of developing CTS.
Some leisure activities can contribute to the risk of CTS as well, including knitting, golfing and anything else that requires you to grip items in your hands for long periods of time.
Among the most commonly recommended treatments for carpal tunnel syndrome are using a wrist splint, resting the wrist, taking pain relievers and physical therapy. If begun within three months of the first signs of CTS, a wrist splint can be a very effective treatment. This can be worn either all day or only overnight, and takes the pressure off your wrist, allowing it to rest and giving your tendons a chance to recover. Chiropractors and physical therapists can physically manipulate the wrist to relieve pain and teach you specific rehab exercises to do at home to help strengthen the wrist and hand.
You may read about surgical options for treating carpal tunnel syndrome, but these should be considered or as a last resort after non-invasive therapies have failed. Treatment of CTS has been evolving rapidly across the last few years so it is important to visit a provider that keeps current on CTS treatment research and treats carpal tunnel patients on a regular basis.