Position the patient supine or comfortably sitting (our preference).

Prepare the skin with an antimicrobial agent such as alcohol, Betadine, or chlorhexidine gluconate (our preference).

The minimum length of needle is 1.5 inches. Since a large amount of soft tissue surrounds the shoulder, when in doubt use a spinal needle. The gauge of needle depends on the procedure: larger bore (18G to 20G) for aspirations and smaller for injections (22G to 25G).

Optional: The overlying skin is anesthetized with 2 to 3 cc of 1% lidocaine using a 25G to 30G needle. The use of local anesthetic is debatable. Some physicians feel it is not helpful because only the skin will be anesthetized, and a second injection is required. We do not routinely use local anesthetic prior to skin penetration. However, the needle should penetrate the skin quickly to minimize pain.

The entry site is found 1 cm lateral to the coracoid process and medial to the lesser tuberosity. Typically, the clinician feels a “pop” as the needle traverses the anterior capsule (Fig. 2-1).

Completely bury a 1.5-inch needle and aspirate to obtain synovial fluid confirming that you are in the joint. Depending on the procedure, continue to aspirate the necessary amount of fluid or inject medication.

Traditionally, 1 cm lateral to the coracoid has been used as the entry site, but we have had improved accuracy entering immediately lateral to the coracoid (Fig. 2-2).

Position the patient in a seated posture to allow access to the posterior portion of the shoulder. If the patient is unable to sit, then position lateral decubitus with the affected shoulder up.

Again a 1.5-inch needle is the minimum length needed, and a longer needle is used for larger patients. For this injection, we always use a spinal needle due to the large amount of soft tissue covering the posterior aspect of the glenohumeral joint.

The entry site is the posterior shoulder 2 cm inferior and 1 cm medial to the posterolateral tip of the acromion. Always direct the needle toward the tip of the coracoid process for accurate placement into the glenohumeral joint (Fig. 2-3).

Aspirate a small amount of synovial fluid to confirm placement and continue with aspiration or injection.

A “soft spot” exists overlying the posterior glenohumeral joint and is an excellent way to confirm that you have a good starting point (Fig. 2-4).

Use your free hand to palpate the tip of the coracoid process anteriorly to assist in guiding the needle into the joint space. By aiming the needle toward your digit on the coracoid, you will increase the accuracy of placement.

Position the patient in a seated posture to allow access to the posterior portion of the shoulder. If the patient is unable to sit, then position lateral decubitus with the affected shoulder up.

Typically a 1.5-inch needle is the sufficient to access the subacromial space.

The entry site is the posterior shoulder 2 cm inferior and 1 cm medial to the posterolateral tip of the acromion.

The needle is directed cephalad into the subacromial space. We place our free hand on the acromioclavicular joint and aim just lateral to this point. Once the needle has pierced the skin, direct it just under the acromion toward the acromioclavicular joint (Fig. 2-5).

The injection should flow easily. If resistance is felt, redirect the needle as it may be embedded in the rotator cuff.

A soft spot exists just inferior and medial to the posterolateral tip of the acromion, which marks the entry point for the subacromial space.

An additional access point to the subacromial space is lateral. To find this, mark the anterior and posterior tips of the acromion. Next palpate the triangular depression between the clavicle, acromion, and scapular spine. The entry point exists at a spot bisected by a line connecting the tips of the acromion and the apex of this triangle. Direct the needle under the acromion and inject in a similar fashion to the posterior approach (Fig. 2-6).

Position the patient in a seated posture. Since the AC joint is small, a 22G needle is used to aid in tactile feedback. With experience, a finer needle can be used to enter the joint.

To locate the entry site, palpate the distal clavicle until a small depression is felt; this is the AC joint. The entry site is the superior aspect of the AC joint just above this depression. With a slight lateral-to-medial inclination, the needle pierces the skin and joint capsule (Fig. 2-7).

Positioning the patient’s arm behind the back opens the anterior portion of the AC joint, which can make it easier to palpate and enter (Fig. 2-8).

If the needle is advanced too far, it is possible to pierce the inferior AC joint capsule entering the subacromial space.