Peroneal nerve block:

• The peroneal nerve is found where it runs obliquely below the lateral condyle of the tibia, from caudodorsally to cranioventrally, about 2.5 cm below the lateral condyle of the tibia; it may be palpated by using thumbnail pressure to move the skin and underlying tissues. (B205.13.w13)
• 5 mL of 2% lidocaine is injected at this site. (B205.13.w13)

Tibial nerve block:

• On the medial side of the leg at the hock, between the flexor tendons and the tendon of gastrocnemius, inject 4 mL of 2% lidocaine. (B205.13.w13)
• Inject an additional 1 mL of lidocaine on the lateral side of the limb at the same site; this blocks a small cutaneous nerve which is a branch of the common peroneal nerve originating at the middle of the thigh. (B205.13.w13)

Onset of analgesia should occur within 15 minutes. As the block takes effect the hock straightens (tibial nerve block) and the animal will stand on the dorsal surface of the fetlock (peroneal nerve block). (B205.13.w13) 

• To provide analgesia below the hock. (B205.13.w13)

• The analgesic technique chosen should be decided based on the procedure to be undertaken, the facilities available and the skills of the practitioner. (J215.7.w1)
• Standard aseptic techniques should be practiced when performing local analgesia, including surgical preparation of the skin, and sterile injection techniques. (J215.7.w1)
• Aspiration to check for blood should be carried out prior to injection, to avoid inadvertent intravenous injection. (J215.7.w1)
• Epinephrine (adrenalin) at 1 part per 200,000 or norepinephrine (noradrenaline) at 1 part per 100,000 may be added to local anaesthetic solution to decrease the absorption of the agents and prolong their action. These vasopressors should not be used for analgesia of appendages such as the tail, teats or toes as they may produce sufficient circulatory compromise of the appendage to result in tissue necrosis and sloughing. (J215.7.w1)
• Hyaluronidase may be added to local anaesthetic solutions to increase tissue permeability and thus decrease the time to onset of analgesia and reduce the volume of local anaesthetic solution required; it will also reduce the duration of analgesia. However it is questionable whether it is needed other than with procaine hydrochloride solution, since other local anaesthetic agents, such as lidocaine, penetrate tissues adequately. If used, then 150 turbidity reducing units (TRUs) of hyaluronidase may be added per 25 mL of 2% lidocaine. Combining both adrenaline and hyaluronidase with local anaesthetic solution may both increase initial spread and onset while also reducing uptake and therefore prolonging anaesthesia. Note: Use of hyaluronidase is NOT a substitute for accurate placement of local anaesthetic solution, since the tissue fascial planes will still act as barriers. (B342.16.w16)

• 2% lidocaine solution. (B205.13.w13)
• Needle. (B205.13.w13)
• Syringe. (B205.13.w13)

• Procedure should only be undertaken by an individual with appropriate clinical training and practical experience; this would usually be a veterinarian or someone with advanced veterinary technician training.

• Inexpensive.