Which muscle arises from 4th pharyngeal arch?
(a) Cricothyroid(Ref. Scott Brown, 8th ed., Vol 3; 884)We can remember it as the only muscle supplied by external laryngeal nerve (the 4th pharyngeal arch nerve) is cricothyroid hence derived by 4th arch.Rest all the muscles are derived by 6th arch nerve as they are supplied by 6th arch nerve, the recurrent laryngeal nerve.
Cricothyroid
Cricoarytenoid
Posterior cricoarytenoid
Thyroarytenoid
Larynx