30 June 2026 : Review article
Muscle-Specific Differences in Neuromuscular Block and Quantitative Neuromuscular Monitoring: A Narrative Review
Paweł Radkowski
ABCDEFG 1,2,3, Dawid Kamil Malicki BCDEF 4, Florian Trachte CDEF 5,6, Hubert Oniszczuk CDEF 7*
DOI: 10.12659/MSM.951168
Med Sci Monit 2026; 32:e951168
Introduction
Neuromuscular Conduction
Measurement of Neuromuscular Transmission Depending on Muscle Group: The TOF Method
Adductor Pollicis Muscle
Diaphragm
Muscles of the Arm and Forearm
Orbicularis Oculi Muscle
Corrugator Supercilii Muscle
Laryngeal Muscles
Pharyngeal Muscles
TOF-Cuff Measurements on the Lower Leg
Foot Muscles
Discussion
Future Directions
Conclusions
References
Table 2 Pharmacodynamic differences in neuromuscular blockade among muscle groups.
| Neuromuscular blocking agent | Muscle group | Relative ED50/ED95 compared with adductor pollicis | Onset and recovery characteristics | Key clinical implication |
|---|---|---|---|---|
| Rocuronium | Diaphragm | Higher ED50 and ED95 | Faster onset and faster recovery than adductor pollicis | Peripheral TOF may underestimate preserved diaphragmatic activity |
| Rocuronium | Adductor pollicis | Reference | Slower onset and slower recovery | Reliable site for recovery assessment |
| Pancuronium | Diaphragm | Approximately 2-fold higher ED50/ED95 | Faster recovery despite higher dose requirement | Increased risk of residual diaphragmatic activity at peripheral TOF=0 |
| Pancuronium | Adductor pollicis | Reference | Prolonged onset and prolonged recovery | Conventional monitoring site |
| Multiple NMBAs | Laryngeal muscles | Higher resistance than adductor pollicis | Rapid onset, early recovery | May explain movement or coughing despite peripheral block |
| Multiple NMBAs | Diaphragm | Higher resistance than peripheral muscles | Rapid onset, rapid recovery | Requires higher NMBA doses and careful reversal |
| ED50 – effective dose producing 50% neuromuscular block; ED95 – effective dose producing 95% neuromuscular block; NMBA – neuromuscular blocking agent; TOF – train-of-four. Relative ED50 and ED95 values indicate comparative dose requirements between muscle groups within the same study and do not represent equipotent doses across different neuromuscular blocking agents. “Faster” or “slower” onset and recovery describe temporal relationships relative to the adductor pollicis muscle under comparable anesthetic and monitoring conditions. Complete suppression of peripheral TOF responses (TOF=0) may coexist with preserved diaphragmatic or laryngeal activity. . | ||||