There are different ways to inject i.a., but the posterior approach is most likely the more practical one.
Make sure you analyzed the clinical image and that your diagnosis is correct before performing this technique.
The main indication is a shoulder arthritis stage III
PATIENT'S POSTURE The patient lies prone on the couch, his arm by his side, his elbow flexed 90° and his forearm under his abdomen.
PRODUCT 2 ml triamcinolone acetonide (10 mg/ml)
SYRINGE 2 cm syringe
NEEDLE 0.7x50 mm (22 G 2)
TECHNIQUE The thumb of the free hand is put on the acromian angle (right angle between the acromion and the spine of the scapula). The index finger of the same hand is put on the coracoid process. The line joining both fingers crosses the glenoid cavity. The needle is thrust in just underneath the thumb, aimed at a point just lateral to the coracoid process. A first resistance is felt when piercing the capsule of the joint, a second one on impingement against the articular cartilage. Now the intra-articular injection is given. If a resistance is encountered on injecting, the needle is withdrawn a few millimetres, after which the injection becomes possible.