From the Research
The landmark for a posterior glenohumeral injection is the point 1.5 cm below the scapular spine, mid-way between the posterior lateral acromial corner and the posterior axillary crease, as this approach has been shown to have a high accuracy rate of 97% in a study published in 2013 1. To perform the injection:
- Palpate the posterior aspect of the shoulder to locate the scapular spine and the posterior lateral acromial corner.
- Identify the point 1.5 cm below the scapular spine, mid-way between the posterior lateral acromial corner and the posterior axillary crease.
- Clean the area with an antiseptic solution.
- Insert the needle perpendicular to the skin at this point, aiming slightly superiorly and medially.
- Advance the needle until you feel a slight "pop" as it enters the joint space, or use a bone touch technique to ensure accurate placement. This approach is preferred because it provides reliable access to the glenohumeral joint while minimizing the risk of injury to surrounding structures. When performing the injection, use a 20-25 gauge needle, 1.5-3.5 inches long, as used in the study 1. The choice of medication depends on the clinical indication but typically includes a combination of a local anesthetic (e.g., lidocaine 1%) and a corticosteroid (e.g., triamcinolone acetonide 40 mg). Always aspirate before injecting to ensure the needle is not in a blood vessel. Some studies have suggested alternative approaches, such as the anterosuperior technique 2 or the anterior approach 3, but the posterior approach with a bone touch technique has been shown to have a high accuracy rate and is a reliable method for glenohumeral joint injection. It is also worth noting that the depth from the skin to the joint capsule can vary between individuals, and using a longer needle may increase the risk of penetrating the joint capsule, as shown in a study published in 2012 4.