The 'Syringe' Technique

A Hands-Free Approach for the Reduction of Acute Nontraumatic Temporomandibular Dislocations in the Emergency Department

Julie Gorchynski, MD; Eddie Karabidian, MSC; Michael Sanchez, MD


J Emerg Med. 2014;47(6):676-681. 

In This Article

Material and Methods

Study Design

This was a prospective convenience sample study.

Setting and Selection of Study Participants

This study was conducted in the emergency departments (EDs) at two university teaching hospitals with an annual ED census of 62,000 and 108,000. Thirty-one consecutive adult subjects that presented to the ED for acute nontraumatic TMJ dislocations during 2008–2011 were enrolled. These subjects represented a convenience sample population because two emergency physicians performed all the reductions. This maintained standardization because all the reductions were performed in the same manner. A focused history was taken from all subjects that included the mechanism of dislocation, time of dislocation, and prior history of dislocations.

New Technique

The technique we propose is effective and may be rapidly performed. The only piece of equipment utilized in our technique is a 5-mL or 10-mL syringe. With the patient in a sitting position, the physician places the syringe between the posterior upper and lower molars or gums on the affected side. The patient is asked to gently bite down and grasp the syringe as the patient is instructed to roll the syringe back and forth, resulting in the reduction of the dislocated TMJ. Selection of the syringe size varies with each patient. The size depends upon the distance between the upper and lower molars or gums and the patient's ability to open the mouth on the affected side to accommodate the syringe size. The mechanics of our technique utilize the syringe as a rolling fulcrum upon which the mandible and maxilla apply slight downward pressure as the syringe is grasped between the teeth or gums. As the molars or gums roll over the syringe, it produces a gliding motion as the mandible slides posteriorly. The condyle that is displaced anterior to the articular eminence of the temporal bone moves posteriorly to allow the condyle to slip gently back into its normal anatomical position. The masseter, pterygoid, and temporalis muscles work in concordance to allow relocation of the condyle and reduction of the TMJ (Figure 1). If the dislocation is bilateral, by reducing one side, the other side reduces spontaneously.

Figure 1.

(A) Dislocated temporomandibular joint (TMJ) where the condyle is displaced anterior to the articular eminence with syringe placement between the posterior molars. (B) Gliding of the mandible posteriorly as the molars roll over the syringe. (C) Normal TMJ with syringe placement. Z = zygomatic bone, C = condyle.


Anatomically, the pterygoid, masseter, and temporalis muscles enable the mandible to open and close the jaw. The lateral (external) pterygoid muscle lowers the mandible and opens the jaw as the medial (internal) pterygoid, masseter, and temporalis muscles close the jaw (Figure 2). The jaw-opening muscles are designed to generate velocity and displacement, whereas the jaw-closing muscles have a special structural design that produces a significant amount of downward force.[7] When the jaw is dislocated, these muscles generate a considerable amount of localized tension. The special structural design of the jaw-closing muscles produces a greater force when closing the jaw.[7] Due to the great strength of the jaw muscles, the intraoral or external approach for manual reduction typically requires procedural sedation for the EP to overcome the extreme force and strength of the jaw-closing muscles, as well as to provide comfort to the patient. Conversely, our technique utilizes the patients' own jaw muscle strength to glide the condyle back to its normal anatomical position without any additional external or intraoral forces applied by the EP.

Figure 2.

Represents the intervention of the jaw-opening and jaw-closing muscles. (A) The medial pterygoid (MP), masseter (M), and temporalis (T) muscles close the jaw. (B) The lateral pterygoid (LP) muscle lowers the mandible and opens the jaw.

New Method

There are numerous advantages of utilizing our technique. Reduction of the TMJ is easily achieved within a matter of minutes and is highly effective. It is also a hands-free technique that is comfortable for the patient. Because there is no external or intraoral manipulation of the mandible by the EP, inadvertent mandibular fractures are prevented and the risk of bite injuries to the EP is completely eliminated.[1,2,5,6] Our technique eliminates procedural sedation and intravenous analgesia for successful reduction.