FDS and FDP are abbreviations for tendons located in the forearm and hand that are essential for finger flexion.
Detailed Explanation
Here's a breakdown of what FDS and FDP represent:
-
FDS: Stands for Flexor Digitorum Superficialis. This is a muscle in the forearm that flexes the fingers at the proximal interphalangeal (PIP) joints (the middle joint of each finger). Each finger (except the thumb) has a tendon from the FDS muscle attached to it.
-
FDP: Stands for Flexor Digitorum Profundus. This is another muscle in the forearm, located deeper than the FDS. The FDP also flexes the fingers, but it flexes them at the distal interphalangeal (DIP) joints (the joint closest to the fingertip) in addition to the PIP and metacarpophalangeal (MCP) joints (where the fingers meet the hand). Like the FDS, each finger (except the thumb) has a tendon from the FDP attached to it.
Key Differences and Relationship
The FDS and FDP work together to provide a wide range of finger movements. A key characteristic is the path they take in the fingers. The FDS tendon splits to allow the FDP tendon to pass through it and reach the distal phalanx (the bone at the tip of the finger). This unique anatomical arrangement allows for independent and coordinated finger flexion.
Clinical Significance
Both the FDS and FDP tendons are susceptible to injury. Common injuries include:
- Tendon Lacerations: Cuts to the forearm or hand can sever these tendons, impairing finger flexion.
- Tendon Ruptures: Forceful extension of a flexed finger can rupture one or both of these tendons (e.g., jersey finger, which involves the FDP).
- Tenosynovitis: Inflammation of the tendon sheaths surrounding these tendons can cause pain and limited movement. The tendons of FDS and FDP are enclosed in a common synovial sheath, the ulnar bursa, which extends from the wrist proximally to the hand distally and continues to the synovial bursa of the fifth finger.
Summary
In essence, FDS (Flexor Digitorum Superficialis) and FDP (Flexor Digitorum Profundus) are vital tendons in the forearm and hand that allow for finger flexion at different joints. They work in concert to enable a full range of hand movements.
