A ring block is a type of digital nerve block that is used to numb the fingers. It is also known as a traditional ring block.
To perform a bilateral dorsal injection (traditional ring block), place the hand and wrist prone (palm down). On one side of the finger, insert the needle perpendicularly into the dorsal web space, adjacent to the medial aspect of the metacarpal head. Slowly inject about 1 mL of anesthetic to block the dorsal digital nerve.
The most common local anesthetic used in a ring block is lidocaine. It is effective, acts rapidly and is relatively free from toxicity and sensitivity. It generally lasts two hours.
Lidocaine works by blocking the influx of sodium ions into the membrane surrounding nerves. This prevents the initiation and conduction of impulses along the nerve, which results in an anesthetic effect.
The benefits of a ring block include reducing pain during procedures and reducing the need for general anesthesia. Apart from the sting from the needle prick, there might be some slight pain and tingling. The side effects are uncommon but can include infection, bleeding, and nerve damage.
The signs of nerve damage from local anesthetic in ring blocks include numbness, tingling, and weakness. Patients should be told that if they experience any of these symptoms after a ring block, they should contact their health care provider immediately.
You can learn more about different local anaesthesia used in minor injuries in our main article: A Guide to Local Anesthesia for Minor Injuries and our recommended minor injuries and acute wound care training courses for healthcare providers in a primary care setting.