Expansion
PCA parts the cords apart
Mnemonic
“Posterior Cricoarytenoid: Please Come Apart”, the only abductor of the vocal cords.
- Every other intrinsic muscle adducts or tenses
- Bilateral loss therefore closes the airway and is life threatening, since the cords sit in the midline with nothing to open them
- Unilateral loss gives hoarseness and a weak cough, with the cord in the paramedian position
The tensor of the cords is cricothyroid, the only intrinsic muscle supplied by the external branch of the superior laryngeal nerve, so damage to it in thyroid surgery causes loss of high notes and a monotonous voice rather than frank hoarseness.
Expansion
- Posterior cricoarytenoid - the sole abductor, opens the cords
- All other intrinsic muscles - adductors or tensors, close or tighten the cords