Question: New Jersey Subscriber Answer: It's likely that either 20550 (Injection[s]; single tendon sheath, or ligament, aponeurosis [e.g., plantar "fascia"]) or 20551 (... single tendon origin/insertion) applies to the sacral crest injection, but you may want to check with the physician before you actually file the claim. Because the sacrum has many ligament and tendon attachments, it's possible that he could be injecting those structures rather than a muscle at the sacral crest.