A brachial plexus block can be supplemented or "rescued" with a median nerve block for surgeries in the distribution of the median nerve or in the instance when a brachial plexus block may have spared the median nerve distribution. Fibers from C5-T1 spinal roots make up the median nerve. The nerve traverses the anterior-superior part of the axillary artery before exiting the axilla along with the brachial artery. The median nerve lies medial to the brachial artery at the level of the elbow and gives off a number of motor branches to the flexor muscles of the forearm. It lies in between the tendons of the palmaris longus muscle and the flexor carpi radialis in a deeper plane at the level of the wrist. The median nerve provides sensory innervation to part of the palmar surface of the hand, radial portion of ring finger, palmar surface of the thumb, index and middle finger, radial surface of the ring finger, and distal dorsal surfaces of index and middle fingers.
Arrange sterile towels, sterile gloves, gauze pads, marking pen, antiseptic solution, peripheral nerve stimulator, syringes, and needles for local infiltration and nerve block placement.
5-10 ml syringes of local anesthetic.
25 g 1.5 in. needle for skin infiltration.
3% chloroprocaine, 2% lidocaine, 0.5% ropivacaine, 0.5% bupivacaine.
Surface Anatomy and Landmarks Landmarks
Median nerve block at the elbow (A) and median nerve block at the wrist (B):
A. With the patient in a supine position and arm adducted to the patient's side with elbow placed in a slightly flexed position, the brachial artery pulsations at the level of the elbow are palpated. A 25 g 1.5 in. needle is inserted at a point medial to the brachial artery and advanced in a superior-medial direction. Paresthesia is usually elicited at about half to three-quarters inch depth. Then when there is no persistent paresthesia, 5-7 cc of local anesthetic is injected.
B. For this block, the patient is placed in a supine position and the arm is adducted completely to the side of the patient and the elbow is maintained in a slightly flexed position. Palmaris longus tendon is identified while having the patient make a fist and flex the wrist. A 25 g 1.5 in. needle is inserted in a sterile fashion medial to the tendon, and in a slightly superior trajectory (just below the crease of the wrist), elicit a paresthesia. Following the paresthesia which usually occurs at a depth of 0.5 in. and after negative aspiration in the absence of persistent paresthesia, a total of 3-5 cc of local anesthetic solution is injected.
Was this article helpful?
This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.