2. Flexor Tendons - Zones

3. • Extensor Tendons Zones

12. Diagnosis of Flexor Injury
• Normal cascade
• Independent testing of FDS & FDP
• Passive tenodesis test
• Forearm compression test

13. Flexor Tendon Testing

14. Normal Flexion Cascade

15. Tenosynovitis
Anatomy
• 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)

16. Tenosynovitis
General
• 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

17. Tenosynovitis
General
• Purulence within the sheath destroys the gliding mechanism,
rapidly creating adhesions that lead to loss of function
• destroys the blood supply producing tendon necrosis

18. Tenosynovitis
Clinical
• 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

19. Tenosynovitis
Treatment
• 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