Jaw Dislocation
Joe Lex, MD, FACEP, MAAEMClinical Professor of Emergency Medicine
Department of Emergency MedicineTemple University School of Medicine
Philadelphia, PA USA [email protected] @JoeLex5
Odds & Ends
• Mandere (L): to chew• Late Latin: mandibula• Middle French: mandible (late 14th C.)• NOT just a “hinge joint”–Hinge joints allow movement in only one
plane: ankle, elbow, and knee
BALL ANDSOCKET
CONDYLOID(ELLIPSOID)
SADDLE
HINGE PIVOTMovement in two planes: flexion, extension, adduction, abduction, circumduction
BALL ANDSOCKET
CONDYLOID(ELLIPSOID)
SADDLE
HINGE PIVOT
Like condyloid joint but no axial rotation; movement only in sagittal and frontal planes
Some Anatomy
• Inferior compartment allows rotation of condylar head around an instantaneous axis of rotation
• First ~20mm of mouth opening• Then mouth can no longer open without
superior compartment of TMJ active
Some Anatomy
• After 20 mm, not only is the condylar head rotating within the lower compartment, but the entire apparatus translates
• Feel translation by putting your fist against your chin, then try to open your mouth more than 20 mm
Some Anatomy
• Resting position of TMJ is not with teeth biting together
• Muscular balance and proprioceptive feedback allow a physiologic rest
• There’s an interocclusal clearance or freeway space of 2 to 4 mm
Some Anatomy
• Normal full jaw opening: 40-50 mm• Only mandible moves during jaw
movement• Normal mandible movements during
chewing are called excursions
Some Anatomy
• Two lateral excursions: left and right• Forward excursion: protrusion• Reversal of protrusion: retrusion
Traditional
• Most common: intraoral route• You: gloved with thick gauze taped
securely on both thumbs• Place thumbs on lower molars or on
ridge of the mandible intraorally, posterior to molars, with your fingers wrapped externally around mandible
Traditional
• With patient positioned so mandible is below level of your elbows, apply firm, slow, and steady pressure in a downward and posterior direction
• If bilateral reduction is not possible, you can reduce one side at a time
Traditional
• You may need procedural sedation• You may need intravenous analgesia• You may get bitten
A New Concept
The “Syringe” Technique: A Hands-Free Approach for the Reduction of Acute Nontraumatic Temporomandibular Dislocations in the Emergency DepartmentJulie Gorchynski, Eddie Karabidian, Michael SanchezThe Journal of Emergency Medicine, Volume 47, Issue 6, December 2014, Pages 676–681
Wow – really??
• 31 patients with acute nontraumatic TMJ dislocation
• 30 had successful reduction• 24 were reduced in less than 1 minute• No recurrent dislocations at 3 day follow-
up
Technique
• Patient in sitting position• Place syringe between posterior upper
and lower molars or gums• Have patient gently bite down and roll
syringe back and forth
Technique
• Syringe size depends on distance between upper and lower molars / gums and patient’s ability to open mouth
• Syringe acts as rolling fulcrum • As molars / gums roll over syringe
mandible glides posteriorly
Technique
• Anterior displaced condyle moves posteriorly
• Masseter, pterygoid, and temporalis muscles work in concordance
• Condyle slips gently back into its normal anatomical position
Advantages
• No procedural sedation• No intravenous analgesia• Technique is simple and fast• Technique is comfortable to patient• Significantly reduced time in ED• Lower cost: no procedural analgesia,
critical care monitoring or nursing care