Description

The axillary nerve

Axillary nerve

The axillary nerve or the circumflex nerve is a nerve of the human body, that comes off the of the brachial plexus at the level of the axilla and carries nerve fibers from C5 and C6...

 block is a type of brachial plexus

Brachial plexus

The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...

 nerve block

Nerve block

Regional nerve blockade, or more commonly nerve block, is a general term used to refer to the injection of local anesthetic onto or near nerves for temporary control of pain. It can also be used as a diagnostic tool to identify specific nerves as pain generators...

 commonly employed to provide upper limb

Upper limb

The upper limb or upper extremity is the region in an animal extending from the deltoid region to the hand, including the arm, axilla and shoulder.-Definition:...

 anesthesia

Anesthesia

Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...

 and analgesia. It is particularly useful in providing anesthesia for surgery to the hand, wrist or forearm. The Axillary block is a very common block due to its ease of performance and reliable success rate.

Contraindications

General relative contraindications to this block include Local Anesthetic Allergies, pre-existing upper limb neuropathies, and patient use of anticoagulants.

Complications and Side Effects

General complications of the Axillary block include Infection

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

, Hematoma

Hematoma

A hematoma, or haematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise...

 Formation, Vascular Puncture, Local Anesthetic Toxicity

Local anesthetic toxicity

While generally safe, local anesthetic agents can be toxic if used in excessive doses or administered improperly. Even when administered properly, patients may still experience unintended reactions to local anesthetics....

, and Nerve Damage

Nerve Damage

Nerve Damage is a compilation album by Groove Metal band Skinlab, released in 2004. It is a 2CD collection of rare and unreleased material, including a live set, demos, remixes, alternate mixes, and two new tracks.-Disc 1:# "Losing All" – 4:04...

.

Technique

Resuscitative equipment, monitoring and personnel must be immediately available prior to performance of this block.

The Axillary Block is performed with the patient supine, looking contralaterally and with the ipsilateral arm abducted and with the elbow at 90 degrees.
The axillary artery

Axillary artery

In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla and the upper limb...

 is palpated as proximal as possible and marked. The skin is prepared in a sterile fashion. Prepare the nerve stimulator and apple the electrode. The index and middle fingers of the palpating hand should be firmly pressed against the arm, straddling the pulse of the axillary artery. This maneuver helps to stabilize the artery and shorten the distance to the nerves. This hand should be kept immobile throughout the procedure.

The nerve stimulator should be first set to 1-2mA when seeking twitches. The needle (22-27 Gauge, 4–5 cm long) is inserted through a local anesthetic

Local anesthetic

A local anesthetic is a drug that causes reversible local anesthesia, generally for the aim of having local analgesic effect, that is, inducing absence of pain sensation, although other local senses are often affected as well...

 (LA) wheal in a cephalad manner (45deg), either superior or inferior, to the axillary pulse with the other hand. Advance slowly until stimulation of the brachial plexus

Brachial plexus

The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...

, arterial blood, or paresthesia

Paresthesia

Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...

 is obtained.

If arterial blood is obtained, continue to insert the needle through the posterior arterial wall and once through, confirm a negative blood aspiration and inject 50% of your solution. Pull the needle back out with continuous aspiration until blood is no longer aspirated, indicating you are now anterior to the artery and inject the rest of the LA. If twitches or paresthesia

Paresthesia

Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...

, in the distribution of the brachial plexus

Brachial plexus

The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...

 are obtained, then fine tune the position of the needle tip whilst decreasing the stimulating current to maintain twitches at 0.5-0.6mA. Inject the LA solution at this time and confirm loss of twitches. The total volume of LA should be approximately 30-40cc and not exceed toxic limits for the patient.

Supplemental infiltration of LA may be required as the musculocutaneous nerve

Musculocutaneous nerve

The musculocutaneous nerve arises from the lateral cord of the brachial plexus, opposite the lower border of the Pectoralis major, its fibers being derived from C5, C6 and C7.-Path:...

 (MSC) can sometimes be missed with the Axillary Block. A secondary peripheral block of the MSC nerve can be performed by using a nerve stimulator to identify the nerve as it runs through the coracobrachialis muscle

Coracobrachialis muscle

The Coracobrachialis is the smallest of the three muscles that attach to the coracoid process of the scapula. It is situated at the upper and medial part of the arm....

. Identify this nerve with a nerve stimulator and inject 5-10cc of LA solution. A high upper arm

Arm

In human anatomy, the arm is the part of the upper limb between the shoulder and the elbow joints. In other animals, the term arm can also be used for analogous structures, such as one of the paired forelimbs of a four-legged animal or the arms of cephalopods...

 tourniquet

Tourniquet

An emergency tourniquet is a tightly tied band applied around a body part sometimes used in an attempt to stop severe traumatic bleeding. Tourniquets are also used during venipuncture and other medical procedures. Severe bleeding means the loss of more than 1,000 ml of blood. This flow of blood...

 may be poorly tolerated because the medial upper arm is supplied by the intercostobrachial nerve

Intercostobrachial nerve

-Second intercostal nerve:The lateral cutaneous branch of the second intercostal nerve does not divide, like the others, into an anterior and a posterior branch; it is named the intercostobrachial nerve. It pierces the Intercostalis externus and the Serratus anterior, crosses the axilla to the...

s which are the cutaneous branches of the intercostal

Intercostal

Intercostal means "between the ribs". It can refer to:* Intercostal muscle* Highest intercostal vein* Intercostal arteries* Intercostal space...

(T2, T3) nerves. LA infiltration over the medial aspect of the arm in the axilla helps patients tolerate an arm tourniquet by blocking these nerves.