Overview
The following five nerves are involved in an elbow block: radial, median, ulnar, medial antebrachial cutaneous, and lateral antebrachial cutaneous.
- 1.
The radial and lateral antebrachial cutaneous nerves are typically blocked at the same time because of their proximity to one another.
- 2.
The ulnar and medial antebrachial cutaneous nerves are typically blocked at the same time because of their proximity to one another.
Indications for Use
A complete elbow block can be used when soft tissue procedures that cross dermatomal boundaries are performed.
Precautions
Intravascular and intranervous injections are of particular concern when injecting an anesthetic around the elbow.
Pearls
- 1.
The median nerve lies medial to the brachial artery.
- 2.
To remember the order from lateral to medial, use the mnemonic “ B reak R ight T hrough B oth M ilitary P olice” for B rachioradialis, R adial nerve, biceps T endon, B rachial artery, M edian nerve, and P ronator teres.
Equipment
- 1.
Antiseptic: A chlorhexidine prep stick or alcohol-soaked gauze
- 2.
Syringe: 3 × 10 mL syringes
- 3.
Needles:
- a.
Three large-bore, blunt-tipped drawing-up needles
- b.
Three 1½-in. 25-gauge needles
- a.
- 4.
Anesthetics:
- a.
Make sure that the dose of the anesthetic is safe for the patient’s weight and health status.
- b.
Lidocaine: 15 mL of 1%
- c.
Bupivacaine: 15 mL of 0.5%
- (1)
Ulnar and medial antebrachial cutaneous nerves: 10 mL of the anesthetic
- (2)
Median nerve: 5 mL of the anesthetic
- (3)
Radial and lateral antebrachial cutaneous nerves: 10 mL of the anesthetic
- (1)
- a.
- 5.
Sterile gloves
- 6.
4 × 4 in. gauze
Basic Technique
- 1.
Patient positioning: The patient should be seated, and a bedside table should be available to position the extremity.
- a.
Ulnar and medial antebrachial cutaneous nerves:
- (1)
The shoulder at 90 degrees of abduction and external rotation.
- (2)
The elbow at 90 degrees of flexion.
- (1)
- b.
Median nerve:
- (1)
The shoulder at 45 degrees of abduction and maximal external rotation.
- (2)
The elbow extended.
- (1)
- c.
Radial and lateral antebrachial cutaneous nerves:
- (1)
The shoulder at 45 degrees of abduction and maximal external rotation.
- (2)
The elbow extended.
- (1)
- a.
- 2.
Landmarks:
- a.
Ulnar and medial antebrachial cutaneous nerves:
- (1)
Medial epicondyle.
- (2)
Olecranon (a line exists perpendicular to the epicondyle and olecranon).
- (3)
Injection of the ulnar nerve is carried out 1 cm proximal to the line between the medial epicondyle and olecranon.
- (4)
Injection of the medial antebrachial cutaneous nerve is carried out in a subcutaneous block anterior to the ulnar nerve.
- (1)
- b.
Median nerve:
- (1)
Medial and lateral epicondyles: the line between the epicondyles is the “intercondylar line.”
- (2)
Brachial artery.
- (3)
Injection of the median nerve is carried out immediately medial to the brachial artery along the intercondylar line.
- (1)
- c.
Radial and lateral antebrachial cutaneous nerves:
- (1)
Medial and lateral epicondyles: the line between the epicondyles is the “intercondylar line.”
- (2)
Biceps tendon.
- (3)
Injection of the radial and lateral antebrachial cutaneous nerves is carried out 2 cm lateral to the biceps tendon along the intercondylar line.
- (1)
- a.
- 3.
Steps
- a.
Block the ulnar and medial antebrachial cutaneous nerves.
- b.
Block the median nerve.
- c.
Block the radial and lateral antebrachial cutaneous nerves.
- a.
Detailed Technique
Preparation of the Anesthetic
Three syringes should be prepared:
- 1.
Two 10-mL syringes for the radial and lateral antebrachial cutaneous nerves and the ulnar and medial antebrachial cutaneous nerves.
- 2.
One 5-mL syringe for the medial nerve.
The Ulnar and Medial Antebrachial Cutaneous Nerves
- 1.
Position the patient.
- 2.
Palpate the landmarks:
- a.
Mark the medial epicondyle and the olecranon.
- b.
Determine the location of the epicondylar-olecranon line.
- c.
Mark the injection site 1 cm proximal to the line.
- a.
- 3.
Prepare the skin with an antiseptic solution.
- 4.
Numb the skin with ethyl chloride (if desired).
- 5.
Inject the anesthetic ( Fig. 3.1 ):
- a.
Enter at a 30-degree angle to the skin.
- b.
Insert the needle tangentially along the ulnar nerve.
- c.
Maintain contact with the patient to ensure that no paresthesias are noted.
- d.
Aspirate the needle before injection to ensure that intravascular placement has been avoided.
- e.
Inject 5 mL of the anesthetic immediately below the skin. Be vigilant for any warning signs of intravascular injection.
- f.
Redirect the needle anteriorly and advance subcutaneously to the hilt ( Fig. 3.2 ).
- a.
