The lower section of the arms between the elbow and hand is called the forearm. Its bone structure consists of ulna and spoke, which together with the humerus form the elbow joint at their upper end. The wrist is only a connection between the lower end of the spoke and the carpal bones - the ulna is not involved here. The ulna and the spoke are relatively firmly connected by ligaments and the surrounding connective tissue structures, although two spoke-elbow joints allow the spoke to rotate around the ulna. This is essential for the motor skills when gripping and other hand movements.
The forearm bones are surrounded by numerous muscle groups, which on the one hand act as flexors and extensors for the wrist or elbow joint and on the other hand control the rotational movement. The superficial extensor muscles of the forearm include, for example, the brachioradialis and extensor carpi ulnaris muscles. Deeper extensors are the supinator and abductor pollicis longus muscles, with the deeper muscle groups also used to move the fingers. Flexors (flexors) of the forearm in the superficial muscle layer are, for example, the flexor carpi radialis muscle and the flexor carpi ulnaris muscle. For example, the pronator quadratus muscle and the flexor pollicis longus muscle, which are part of the flexor muscles, are located lower. The various forearm muscles are surrounded or divided by the forearm fascia. Tendons and ligaments stabilize the joints and serve to transmit force when the muscles contract, which is necessary for the movements of the joints. Overall, a significant proportion of the muscles that are required to move the fingers and hands can be found in the forearm area.
In addition to the bones, muscles, ligaments and tendons, numerous nerve tracts and blood vessels run through the forearm. For example, the radial artery (radial artery) or the ulnar artery are located in the area of the ulna, as well as the cephalic vein on the spoke side and the basal vein on the elbow side. The most important nerve tracts are the radial nerve, the median nerve and the ulnar nerve. The most common symptoms in the area of the forearm are based on impairments of the nerve pathways, such as, for example, with tendonitis, when the swelling of the tendon sheath leads to compression of the median nerve and thus causes carpal tunnel syndrome. In addition to forearm pain, there may be sensations such as tingling or numbness in the fingers. Movement is also sometimes significantly restricted. Similar complaints appear with a so-called mouse arm, tennis arm or golf arm. What the symptoms have in common is that they are caused by increased stress levels, such as occur in various sports but also when working on the computer. Last but not least, the forearm bones are also relatively susceptible to fractures, with the spoke in particular being increasingly affected by falls and accidents. (fp)