The ulnar and radial bursae and the synovial tendon sheaths of the fingers Fig 146

The flexor tendons traverse a fibro-osseous tunnel in each digit. This tunnel is made up posteriorly by the metacarpal head, the phalanges and the fronts of the intervening joints. The anterior fibrous part consists of condensed deep fascia attached to the sharp anterolateral margin of each phalanx and termed the fibrous flexor sheath. This is particularly tough over the phalanges but loose over the front of each joint; it therefore holds the flexor tendons in place without 'bow-stringing' during flexion of the fingers, but does not impede movement of the joints.

Distally, the fibrous sheath ends at the insertion of the profundus tendon (or flexor pollicis longus tendon in the case of the thumb) at the base of the distal phalanx.

These fibrous sheaths are lined by synovial membrane which is reflected around each tendon. The tendons of the 2nd, 3rd and 4th fingers have synovial sheaths which are closed off proximally at the metacarpal head, but the synovial sheaths of the thumb and little finger extend proxi-mally into the palm.

That of the long flexor tendon of the thumb extends through the palm, deep to the flexor retinaculum, to about 1 in (2.5 cm) proximal to the wrist and is termed the radial bursa. The synovial sheath of the 5th finger continues as the ulnar bursa, an expanded synovial sheath which encloses all the

Radial Bursa
Fig. 146 The synovial sheaths of the flexor tendons of the hand— the radial and ulnar bursae track proximally deep to the flexor retinaculum and provide a potential pathway of infection into the forearm. In many cases these bursae communicate.

finger tendons in the palm and which also extends proximally below the flexor retinaculum for 1 in (2.5 cm) above the wrist. In about 50% of cases the radial and ulnar bursae communicate. These synovial sheaths may become infected either directly—for example, following the entry of a splinter—or may be secondarily involved from a neglected pulp-space infection. Infection of the 2nd, 3rd and 4th sheaths are confined to the finger concerned, but sepsis in the 1st and 5 th sheaths may spread proximally into the palm through the radial and ulnar bursa respectively, and may pass from one bursa to the other via the frequent cross-communication between the two.

Since these bursae both extend proximally beyond the wrist, infection may, on occasion, spread into the forearm.

Two spaces deep in the palm of the hand may rarely become distended with pus; these are the midpalmar and thenar spaces (Fig. 147).

The midpalmar space lies behind the flexor tendons and ulnar bursa in the palm and in front of the 3rd, 4th and 5th metacarpals with their attached interossei. The 1st and 2nd metacarpals are curtained off from this space by the adductor pollicis, which arises from the shaft of the 3rd metacarpal and passes as a triangular sheet to the base of the proximal phalanx of the thumb.

The thenar space is the space superficial to the 2nd and 3rd metacarpals and the adductor pollicis. It is separated from the midpalmar space by a fibrous partition.

Fig. 147 The midpalmar and thenar spaces:

(a) projected on to the surface of the hand and

(b) in transverse section.

Fig. 147 The midpalmar and thenar spaces:

(a) projected on to the surface of the hand and

(b) in transverse section.

Mid Palmar Space Infection

Infection of these two spaces sometimes results from penetrating wounds or may be due to secondary involvement from a long-neglected tendon sheath infection. Nowadays they are fortunately extremely rare, thanks to antibiotic treatment and the early surgical drainage of pus collections.

Part 4

The Lower Limb

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Responses

  • Leslie Rivera
    What is ulnar bursa and radial bursa?
    3 years ago
  • sofia
    What tendon enclose radial bursa?
    3 years ago
  • robel
    What are the contents of the ulna bursa?
    2 years ago
  • stephen
    Which tendon is found in the radial bursa?
    2 years ago
  • kaelyn
    What Is ulnar and radial bursa Concept plzz?
    2 years ago

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