See the general section on hand injections and also the Handout on Trigger fingers
Beware - Common digital nerves
- Flexor tendons
Anatomy
• Note relative safe zone over flexor sheath
Tips
• Palpate the flexor sheath and mark the line with your thumb nail -
You do not have to inject into the sheath - superficial is perfectly adequate
− Get the patient to flex their fingers in & out if you are having trouble
• Clean with alcohol swab then no touch technique
• If the needle goes too deep it will hit the flexor tendon
− not the N/V bundle
Injections
• Never inject against resistance
• Aim to inject superficial to flexor sheath
− The local anaesthetic and cortisone will leak around the inflammed synovium just proximal to the A1 pulley
Ask patient to gently move their fingers while injecting
If the needle moves with finger ROM it is in the tendon!!!
The finger will be numb for an hour. Sometimes the triggering increases due to the volume of fluid but this rapidly resolves.