John Davenport was a music major in college and now pastors a small church. He notices that for the past two years he can no longer reach his typical upper notes. When he tries to sing he develops tightness in his left neck as if he is straining. When I listen to him glide from his lowest note to his highest note that he can reach, he has only a one octave range. His uppermost note is C4, or middle C on the piano. This is an incredibly small range, especially for a trained singer. His upper notes have a tight quality. Basically he is unable to reach any falsetto.
During the endoscopic examination, I asked him to glide up from his lowest note to his highest note and I notice that his vocal cords do not change length. Something is preventing his cricothyroid (CT) muscle from working. Either the superior laryngeal nerves which supply the CT muscle are not working, or the CT joint is frozen in position. The joint can be viewed with a CAT scan, which I order.
He has developed arthritis of his cricothyroid joint. Consequently when he tries to contract his CT muscle, the frozen joint prevents movement and stretching of the vocal cords. This also explains the discomfort in his neck on the left side as these muscles try to work overtime. We discuss, but don’t pursue, trying to mobilize the joint surgically. Everything in the x-ray should be symmetric. The large white area on the left side of the CAT scan images is the arthritis in his joint. The right side joint is normal.
When he tries to contract his CT muscle, the frozen joint prevents movement and stretching of the vocal cords — reducing a trained singer to just one octave of range with no falsetto whatsoever.
What you learned
- The cricothyroid joint allows the CT muscle to rock the cricoid and thyroid cartilages relative to each other, stretching the vocal cords to produce higher pitches and falsetto.
- Arthritis of the cricothyroid joint freezes this movement — vocal cords cannot change length on command, collapsing the pitch range to the lower chest voice only.
- The differential diagnosis for loss of falsetto includes SLN paresis (nerve not firing) and CT joint fixation (nerve fires but joint cannot move) — CT imaging distinguishes the two.
- Neck pain or tightness on the left side during high-note attempts suggests the left CT muscle is straining against a fixed joint, a symptom that can help localize the problem before imaging.