Shoulder Anatomy
The basic anatomy of the shoulder includes the clavicle and acromion bones, the coracoid process, the supraspinatus and infraspinatus muscles, and the subacromial bursa. The subacromial bursa separates the supraspinatus tendon from the acromion. This bursa aids in the motion of the supraspinatus tendon of the rotator cuff in overhead activities.
Bursitis and Tendinitis Defined
Subacromial bursitis is a condition caused by inflammation of the bursa. If the tendons of the shoulder are inflamed, it is called tendinitis. These conditions are often treated with physical therapy, anti-inflammatory medications, or injections.
Performing the Injection
After obtaining consent from the patient, the injection site is marked about 2 cm below the posterolateral corner of the acromion. To find this site, define the posterior and lateral borders of the acromion and find the site hwere these borders meet. The injection site is 2 cm below this meeting point. The injection site is then disinfected with betadine. The tip of the needle will enter the marked target site and aim towards the superior aspect of the acromion, which the needle will be underneath. At that point, aspiration or injection is done accordingly. For steroid injections, I prefer using 5 mL of 1% Lidocaine and 1 mL of a steroid solution.
