Jaw Thrust Maneuver: Primary Muscles Used
The jaw thrust maneuver primarily uses the lateral pterygoid muscles and the suprahyoid muscle group (including the digastric muscles) to displace the mandible anteriorly and open the airway. 1
Anatomical Basis of the Jaw Thrust
The jaw thrust works by anteriorly displacing the mandible, which in turn pulls the tongue forward and away from the posterior pharyngeal wall, thereby opening the upper airway. This mechanical action relies on specific muscle groups:
Primary Muscles Activated
Lateral pterygoid muscles: These muscles attach to the mandibular condyle and articular disk, and when the jaw is thrust forward, they are the primary muscles responsible for anterior mandibular displacement 1, 2
Suprahyoid muscle group: This includes the digastric, geniohyoid, mylohyoid, and stylohyoid muscles, which work together to depress and protract the mandible during jaw opening movements 1, 3
Digastric muscles: These muscles play a particularly important role in jaw opening and are activated bilaterally during the jaw thrust maneuver, with EMG studies showing their involvement in mandibular depression and anterior movement 3
Clinical Application Context
When to Use Jaw Thrust
For trauma patients with suspected cervical spine injury, use jaw thrust without head tilt as the primary airway opening maneuver 4
The jaw thrust produces significantly less cervical spine movement (mean 4.8° flexion-extension) compared to head tilt-chin lift (14.7°), making it the safer choice when spinal injury cannot be excluded 1, 5
Research demonstrates that jaw thrust results in less angular motion in all planes and less displacement at unstable C1-C2 injuries compared to head tilt-chin lift 5
Important Caveats
If jaw thrust fails to adequately open the airway and allow effective ventilation, switch to head tilt-chin lift maneuver, as maintaining a patent airway takes priority over theoretical spinal movement concerns 4
The jaw thrust can be technically difficult in patients with limited mandibular mobility or macroglossia, such as those with Duchenne muscular dystrophy 4
A rare but documented complication is vagal stimulation from pain induced by the jaw thrust, which can cause severe bradycardia or even transient asystole, particularly in patients emerging from anesthesia 6
The two-handed E-C technique with head fully extended produces comparable tidal volumes to jaw thrust, but involves more cervical spine movement 7