“Which Side Is Paralyzed?” Is the Wrong Question
When a vocal cord doesn’t move well, the doctor’s reflex is to call it a paralysis leading to a next question, which is almost always which side?
I think that easily can lead to the wrong conclusion, because it was the wrong question.
Paralysis is a conclusion about a whole nerve, yet injuries often may affect only one branch, a partial injury, an injury in the past, with reinnervation that may or may not have gone where it was supposed to go. “Which side is paralyzed” cannot describe that. So instead of asking whether something is paralyzed, fix your eyes on one particular structure and ask what that structure does during a given task.
One important structure is the vocal process. The tasks can be subdivided into inspiration, expiration, and phonation.
This visual method is why I think visual neurolaryngology can be as accurate as EMG for working out what happened inside a larynx. Which one you reach for depends on your equipment and your familiarity with each.
The lateral cricoarytenoid muscle fires twice in an ordinary exam — during expiration, and during phonation. Two chances and two ways to assess it. So record breathing, not just voice. And when you record both sides, the opposite side becomes your control: compare timing, compare the arc of rotation, compare whether closure is complete.
Many examiners look only at the membranous cords, an asymmetric larynx might still appear symmetric and one will call it normal — but the overcompensating side may hide the weak one. To see the angle of the joints you have to get into the posterior commissure, which means topical anesthesia and an endoscope underneath the arytenoids. This posterior commissure view is the sine qua non for this diagnosis.
There is also the question of whether the vocal process is rotating or simply being dragged. A cord pulled toward midline by the interarytenoid may resemble an active LCA muscle. Watching the angulation of the joint rather than the cord edge is what separates them.
And pitch matters, because the cricothyroid compensates. Record high, medium, and low in the same exam and you will watch the asymmetry grow as pitch drops. The overcompensating healthy side may hide this gap in a typical exam. This compensation is why a patient with a minor injury sounds fine in the morning and poor by evening — the overworked compensating side fades after being used all day.
None of this requires new equipment. Recording breathing, slowing the video down, watching one structure repetitively in isolation, and being willing to replace a fast conclusion with a slower and more precise one is available to any examiner with patience and curiosity.
The lecture below works through four cases this way. It was recorded for World Voice Day, April 2026.
If you want to go further with this, the Portland Diagnostic Laryngology Workshop this year runs October 9–10, 2026 at the University Club of Portland. Two days, small groups, hands-on lab sessions, CME credit. Instead of working on surgery, we work on finding the things that might eventually need it. Registration is open.
