Ulnar Bursa, Radial Bursa and Digital Synovial Sheaths
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Radial and ulnar bursa
- Extent of ulnar and radial bursa .
- Continuity of ulnar and radial bursawith digital synovial sheaths.
- Digital synovial sheaths.
- Applied Aspect.[/expand]
Ulnar bursa
- It is a common synovial sheath that encloses the tendons of flexor digitorum superficialis(FDS) and flexor digitorum profundus(FDP) as they pass deep to the flexor retinaculum..
- It extends proximally into the forearm upto 5cm, proximal to flexor retinaculum.
- Distally it extends into the palm upto the middle of the shaft of the metacarpals.
- The distal end of ulnar bursa is continuous with the digital synovial sheath of the little finger.
Radial bursa
- It is the synovial sheath that encloses the tendon of flexor pollicis longus as it passes deep to the flexor retinaculum..
- It extends proximally into the forearm upto 5cm, proximal to flexor retinaculum.
- Distally it is continuous with the digital synovial sheath of the thumb.
Digital synovial sheaths
- These are the synovial sheaths that enclose the flexor tendons of digits as they pass deep to fibrous flexor sheaths.
- They extend from the heads of the metacarpals to the distal phalanges of the digits.
- Digital synovial sheath of little finger is continuous with the ulnar bursa.
- Digital synovial sheath of thumb is continuous with the radial bursa.
Function of ulnar bursa, radial bursa and digital synovial sheaths is to reduce friction and allow smooth movement of the flexor tendons as they pass deep to the flexor retnacum or fibrous flexor sheaths.
Applied Aspect
Infections of the little finger and thumb are more dangerous than the infections of index, middle and ring fingers because in case of infection of little and thumb the infection can spread to forearm space of Parona ( between flexor digitorum profundus and interosseous membrane.) as they are continuous with the ulnar and radial bursa respectively.
As the digital synovial sheaths of index, middle and ring finger do not communicate with ulnar bursa, therefore infection from these digits do not pass to palm and forearm. this is the reason for pricking the ring finger of non-dominant hand for withdrawing blood.
anatomyqa you really help alot . hope everyone have same experience like me
Helped me a lot. Just what I was looking for.
Thanks