The area of the limb between the elbow and wrist is known as the forearm. Sometimes pain occurs in the region without affecting the upper arm or hand. The reasons may be specific to the structures in the forearm. Pain alone can be difficult to identify when other symptoms are not present. Isolating factors like whether the pain arises or exacerbates during movement, while at rest with certain orientations of the arm may help to identify the problem.
Parts of the Forearm
The forearm is primarily occupied by bones and muscles. The two long bones in the forearm are the radius and ulna. It communicates with the upper arm bone (humerus) at the elbow and the carpal bones at the wrist. The muscles in the forearm are organized into two compartments, one at the front of the forearm and the other at the back. These muscles mainly control the hand movements by long tendons which run through to the bones of the hand.
Ligaments provide support to the joints and muscles. There are also blood vessels running through the forearm that supplies this area and carries blood to and from the hand and fingers. Similarly nerves running through the forearm supply this area as well as the hands and fingers. Two important nerves of the forearm are the ulnar nerve, median nerve and radial nerve. It is also important to note that tendons from some muscles of the upper arm attach to the forearm.
Causes of Forearm Pain
Some of the more common causes of forearm pain is discussed below along with conditions that are specific to the forearm. There are many other causes that also need to be considered.
Trauma can occur through any number of ways. Blunt force trauma may arise with blows, falls, car accidents and twisting of the arm. Penetrating injuries are often associated with industrial accidents or assaults. Usually there is sign of trauma on the skin surface, like redness of the skin or bleeding.
Bone fractures may also occur with trauma. If the fractured bone does not damage the surrounding soft tissue then it is referred to as a simple fracture. At times it may not be obvious if the forearm is not deformed. When the bone penetrates the skin it is known as a compound fracture.
Strain and Sprain
For most of us the hands are constantly working throughout the waking day. The muscles of the forearm control the hand and is therefore easily strained by overactivity. This can also affect the tendons and result in tendonitis. Muscle and tendon tears are not common but can occur. When the ligaments are exerted severely like with twisting or suddenly snapping then it can lead to sprains. Pain may be felt in the forearm while hand movement is affected.
Apart from muscle and tendon strain there are other muscle problems that can arise in the forearm and lead to pain. Cramps or spasm are common with overexertion. Another problem known as writer’s cramp is where the opposing compartment of muscles do not contract and relax in a co-ordinated manner and this can lead to pain as the muscles pull against each other. It is more likely to occur in people who use their hands for long periods of time, like with writing.
A range of conditions can affect the nerves which may then lead to pain. The more common nerve conditions leading to forearm pain are associated with trauma or compression. The nerves of the arms originate from the cervical vertebra (neck vertebrae). If there is compression at this level then it can cause arm pain.
However, compression can occur anywhere along the course of the nerve. Once such condition causes stretching and compression of the ulnar nerve at the elbow and this is known as cubital tunnel syndrome. When there is entrapment at the level of the wrist then it is known as carpal tunnel syndrome but this is more likely to cause hand symptoms.
Arthritis and Bursitis
Arthritis is inflammation of the joints and can occur for various reasons. It can affect the elbow or wrist joints as well at the smaller joints between the two forearm bones. The joint cartilage may erode (osteoarthritis), become inflamed due to autoimmune factors (rheumatoid arthritis), injured (post-traumatic arthritis) or infected (septic arthritis).
Bursae are tiny fluid-filled pouches that are located throughout the body to reduce friction between moving structures like the muscles, tendons and bones. The bursae (singular ~ bursa) can become inflamed especially with overuse and this is known as bursitis. Pain is usually present and is worsened with movement.
The main circulatory problem that can lead to forearm of the pain is a blood clot in a blood vessel of the forearm. This can arise for various reasons but one of the common causes is after the insertion of an IV drip or following blood removal for diagnostic tests. It is also more likely to occur in IV drug users. There is also the risk infection of the blood vessel which can quickly spread to other parts of the body through the bloodstream.
Skin and Subcutaneous Tissue
The superficial tissue (skin and underlying fat and connective tissue) can be affected in various ways to result in forearm pain. Trauma may cause bruising which results in pain. The skin and subcutaneous issue can also become infected leading to conditions like cellulitis and impetigo which can become very serious in a short period of time. Various skin diseases can also present with pain especially when there are open wounds on the skin.
Arm pain may times be unrelated to any problem in the arm. One of the concerns with arm pain is that it may be related to cardiac (heart) problems. This is seen in conditions like a heart attack where left arm pain is common. It may also occur for short periods during angina attacks. Sometimes arm pain may be the only symptom of coronary artery disease, the main cause of a heart attack.