The Anatomy of the Hand
The structure of the hand is highly complex, with numerous bones, muscles, and ligaments that allow for a wide range of movements. If any one of these structures has a problem, it can affect the function of the hand.There are three major bones in the hand (not including the wrist):
- Phalanges: the 14 narrow bones that are found in the fingers of each hand. Each finger has three phalanges (the distal, middle, and proximal), while the thumb has two.
- Metacarpal bones: the five bones that comprise the middle part of the hand.
- Carpal bones: the eight small bones that make up the wrist. The carpal bones are bound in two groups of four bones that are connected to the ulna bone and the radius bone (the two forearm bones).
The muscles are the structures that contract and relax to allow for the movement of the bones in the hand. Each muscle connects to a cord-like tendon. Tendons, such as the flexor tendon, enable you to bend your fingers and thumb so you can grasp an object. Ligaments are straps of fibrous tissue that allow for joint movement. A vast network of arteries and veins supply blood flow and sensation to the hand and fingers.
The fascia is a layer of fibrous tissue under the skin on the palmar side of the hand. It covers the nerves, blood vessels, muscles, and tendons in the hand. Fascia also helps to anchor and stabilize the skin on your palm.
What is Dupuytren’s Contracture?
Dupuytren’s contracture (also called Dupuytren’s disease) is a condition that affects the fascia. This disease causes the fascia to become thicker and form cords. While these cords may look and feel similar to a tendon, they are not connected to a muscle and do not have the same function of allowing movement. The cord tissue formed due to Dupuytren’s contracture is static and does not move.
This condition most often affects the 4th (ring) and 5th (little) fingers of the hand, although sometimes it extends to the 3rd (middle) finger as well. Most people with this condition also have nodules or bumps in the hand.
The cords and nodules gradually become larger and thicker. In later stages, these cords may tighten so severely that your fingers may curl towards your palm and make it difficult to perform certain functions with your hand.
What are the Symptoms of Dupuytren’s Contracture?
The symptoms of Dupuytren’s disease typically progress gradually, over a period of years. The first sign is often a thickening and tightening of the tissue on the palm of your hand.
Signs and symptoms of this condition may include:
- Inability to lay your hand flat on a table, palm down. This is known as Hueston’s tabletop test, where a doctor checks to see if you can fully flatten your fingers in order to diagnose you with Dupuytren’s contracture.
- Tender lumps in the palm (nodules).
- Thick bands of tissue under the skin in the palm of the hand.
- Pits or grooves on the surface of the palm. This occurs when the cords or nodules begin to pull on the overlying skin.
What are the Causes of Dupuytren’s Contracture?
The exact cause of this disease is unknown. There is no evidence to suggest that injuries or occupations that involve vibration to the hand lead to a higher risk of developing Dupuytren’s contracture. There is a mild association with hand trauma, but only in cases where an individual already has several risk factors.
A number of factors are linked to the development or worsening of Dupuytren’s contracture. These include:
- Genetics. The condition is believed to be hereditary. It tends to run in families and ancestry plays an important role.
- Gender. It is more common for men to develop the condition and to have more severe contractures.
- Age. The onset of Dupuytren’s contracture most commonly occurs in middle age.
- Ancestry. It is most common for people of a Scandinavian or Northern European ancestry to develop this condition.
- Certain medical conditions. People with diabetes are more likely to develop the disease, and it is linked with medicines used to treat seizure disorders.
- Tobacco and alcohol use. Smoking is associated with an increased risk of developing the condition, potentially due to microscopic changes within the blood vessels. Drinking alcohol is also associated with Dupuytren’s contracture.