The LSUHSC New Orleans Emergency Medicine Interest Group Presents The Student Procedure Manual

Digital Nerve Block

by Jude Reed

Indications
Contraindications
Materials
Anatomy and Technique

Indications

• Provides excellent anesthesia of both the dorsal and volar aspects of the digits.
  
• Used for repair of lacerations beyond the metacarpal phalangeal or the metatarsal phalangeal junction.
  
• Used for incision and debridement of abscesses and paronychia on the digits.
  
• Used for removal of the nail bed when needed.

Contraindications

• Longer procedures where a short-acting local anesthetic is not indicated.
  
• Multiple injuries to the hand or foot where multiple digits or regions must be anesthetized; a block of one of the nerves to the hand or a complete hand block would be more appropriate.
  
• Patient allergy to the local anesthetic solution or patient intolerance to the site of injection.

Materials

• Lidocaine or other appropriate injectable local anesthetic solution. No more than 4 ml should be necessary for one digit.
  
• 22 gauge or 25 gauge needle and syringe.
  
• Alcohol or other appropriate topical antibacterial preparation pad to cleanse the area to be injected.

Anatomy and Technique

• The digital nerves to the various digits derive from the proper digital nerves just proximal to the metacarpal or metatarsal head.
  They then run down the medial and lateral sides of each digit and branch into dorsal and palmar divisions that supply their respective sides of the digit.
  
• To use the digital nerve block, first clean the proximal part of the effected digit with the antibacterial solution.
  
• Make one injection on the medial or lateral side of the digit on the dorsal surface just proximal to the beginning of the web space.
  
• The needle should be directed downward and just to the side of the proximal phalanx.
  
• There is no need to search for the branches of the nerve by touching the nerve on either side of the bone.
  
• Direct the needle downward until the tip is at a depth where it is just at the level of the palmar side of the phalanx; inject one milliliter of Lidocaine at this point.
  
• Then withdraw the needle until the tip is at a depth where it is just at the level of the dorsal aspect of the phalanx; deposit another I ml of anesthetic at that point.
  
• Repeat the process for the opposite side of the digit to be anesthetized.
  
• For the large thumb and great toe, it may be necessary to inject some anesthetic across the dorsal aspect of the digit from one or both of side injections to numb any dorsal perforator nerves that may be present.