The human hand is made up of 14 finger bones, or phalanges: three for each finger and two for the thumb. The term "phalanges" comes from the ancient Greek army formation where soldiers stood side-by- side and several rows deep, as do the fingers and toes. The "distal interphalangeal joints," or DIP joints are the hinges between the second and third phalanges of the fingers. A number of different injuries are common with DIP joints.
The hands are an important aspect of human evolution, because they make it possible to produce and hold tools and weapons. Over half of all the bones in the body are found in the hands and feet. Although many of us take our hands for granted, their structure is complex and delicate. Because the hand parts, such as the "distal interphalangeal joints," are so delicate, they can be damaged or develop long-term painful conditions. This can considerably limit a person's ability to complete a number of different tasks, especially if the problem is in the dominant hand.
When someone suffers from osteoarthritis of the hand, it frequently involves the DIP joint. The term "osteoarthritis" describes the degeneration of the articular cartilage or connective tissue that covers the bone surfaces. The osteoarthritis of the DIP joints may occur due to weak cartilage and bone structure, a major injury to the joints such a sprain or fracture, normal aging, or family genetics. The main goal of treatment, which can include anything from change in diet to surgery, is to reduce the pain, enhance or restore lack of joint function, and prevent the damage from recurring.
A common injury that includes the DIP is called mallet finger or dislocation. This occurs when someone jams the joint, has a crushing accident on the job, or severely cuts a finger. The tendon on the back of the finger is ripped from the connecting muscles. At first, the injured finger becomes painful and swollen around the DIP joint, and the end of the finger is bent and can only be straightened with assistance from the other hand. Left untreated, the finger may never straighten completely again. Typically, healthcare professionals diagnosis mallet finger through a physical examination and X-rays.
Dupuytren disease, named after the surgeon Baron Guillaume Dupuytren who described the condition in 1831, consists of a thickening and shrinking of the layer of flesh just under the skin of the palm of the hand. It can result in lumps or dimples in the skin that force the DIP joint into a bent position. It is most found in individuals of northern European descent, so appears to be genetic. Dupuytren most often affects the fourth or "ring" finger, but can affect the others as well. It can appear in one or both hands and can lead to an inability to grasp. Patients with this condition are often helped with stretching exercises and heat application, ultrasound treatments or cortisone injections.
DIP Joints in the Feet
Similar to the hands, the forefoot and toes are made up of many bones. The toe bones connect and form toe joints. The first joint, or the metatarsophalangeal (MTP) joint connects the toe to the foot. The second joint is the proximal interphalangeal (PIP) joint, and the third is the distal interphalangeal (DIP) joint. Each of these joints is held together by a joint capsule consisting of ligaments. You can curl or raise your toes because two tendons run along the bottom of each toe. When someone has a claw toe deformity, both the PIP and DIP are curled downward like a claw. Claw toes commonly occur in individuals who have high arches and a muscle imbalance in which the deeper toe muscles are weaker than the surface ones. This can be caused by more serious nerve problems. The claw toe condition can also happen when a person does not wear the correct shoes. If the shoes are too short, the second or third toe may have to bend in order to fit. This is worse in pointed shoes and high heels, when the foot is continually being pushed downward and the toes squished.