The extensor indicis is a muscle located in the deep compartment of the posterior forearm. It functions to allow independent extension of the index finger, distinct from the extension of the other digits. Its origins are on the posterior surface of the ulna, and the interosseous membrane, with its tendon passing through the 4th extensor compartment at the wrist to attach at the extensor hood of the index finger.
Actions of the extensor indicis muscle include extension of the index finger at both the interphalangeal and metacarpophalangeal joints.
The extensor indicis muscle is innervated by the radial nerve, specifically the posterior interosseous branch. The muscle is supplied with blood from the ulnar artery.
For visual reference, figure 1 illustrates the muscles within the deep layer of the posterior forearm.
These muscles play a significant role in the movement of the posterior forearm, allowing for independent movement and extension of the digits.
The extensor indicis muscle is of particular importance, as it provides independent movement of the index finger. This allows the patient to engage in activities that require fine motor manipulation without the simultaneous activation of other muscles, such as in picking up and moving small objects, typing on a keyboard or pressing a particular key on a musical instrument. When this muscle is damaged, it can lead to significant difficulties in performing these daily activities.
Therefore, the extensor indicis muscle plays an important role in the functionality of the forearm and hand, and should be treated with great care. Injuries to the muscle should be addressed by a medical professional, and any existing conditions should be closely monitored to ensure proper healing.
Proper strength and range of motion for the extensor indicis muscle can be bolstered through targeted exercises. These can include isotonic exercises such as finger flexion and extension, wrist extension and flexion, and pronation and supination of the forearm. Additionally, dynamic stretching of the forearm and wrist muscles can be conducted to further promote strength and range of motion.
The extensor indicis muscle is an important component of the deep compartment of the posterior forearm. It allows for independent extension of the index finger, distinct from the other digits. Important in both everyday activities and therapeutic exercises, the muscle is innervated by the radial nerve and is supplied with blood from the ulnar artery. Figure 1 demonstrates the muscles in the deep layer of the posterior forearm, alongside the extensor indicis muscle.
Injuries to the muscle should be addressed by a medical professional, and any existing conditions should be closely monitored to ensure proper healing. Exercises such as isotonic exercises and dynamic stretching of the forearm and wrist can further promote proper muscle function.
