Flexor Tendons - Zones

• Extensor Tendons Zones

Diagnosis of Flexor Injury

• Normal cascade• Independent testing of FDS & FDP• Passive tenodesis test• Forearm compression test

Flexor Tendon Testing

Normal Flexion Cascade

TenosynovitisAnatomy

• Flexor sheaths are closed spaces• Extend from the mid-palmar crease

to the DIPJ (Prox edge of A1 pulley to distal edge of A5 pulley)

• Flexor sheath of small finger is continuous proximally with the Ulnar Bursa, while the sheath of the thumb is continuous with the Radial Bursa

• Radial & Ulnar bursae extend proximal to the TCL and connect with the Parona space(Potential space between FDP & PQ muscle)

TenosynovitisGeneral

• Flexor sheath infections most often as a result of penetrating trauma– More likely at joint flexion creases– Sheaths are separated from skin by only a small amount of

subcutaneous tissue here

• Also, Felons can rupture into the distal flexor sheath• Usual causative agent: S. Aureus• most commonly affected digits:

– Ring, long & index fingers

TenosynovitisGeneral

• Purulence within the sheath destroys the gliding mechanism, rapidly creating adhesions that lead to loss of function

• destroys the blood supply producing tendon necrosis

TenosynovitisClinical

• Kanavel’s 4 cardinal signs:

– Tenderness over & limited to the flexor sheath– Symmetrical enlargement of the digit (“fusiform”)– Severe pain on passive extension of the finger (> proximally)– Flexed posture of the involved digit

• Not all four signs may be present early on• Most reliable sign: pain w. passive extension• Cellulitis of the hand may appear similar, but swelling &

tenderness is not usually isolated to a single digit

TenosynovitisTreatment

• Early infection < 48 hrs (& usually lacking all 4 signs) may initially be treated with IV Abx, splinting & elevation– Failure to respond within 24 hrs. should necessitate drainage

• Established pyogenic tenosynovitis is a surgical emergency– Requires prompt surgical drainage– Delays may result in tendon

&/or skin necrosis