Can we or can we not palpate the inferior lateral pterygoid (IFL) muscle as part of our exam for our patients suffering from Orofacial Pain? I will provide some references below that seem to give evidence to support either viewpoint. However, I have to say following the Head, Neck and Jaw Cadaver Dissection Course with Dr. Tanaka that I hosted at Freedom Physical Therapy Services the weekend of July 19-21, 2019; the consensus was you cannot palpate the inferior lateral pterygoid (IFL). On the cadaver specimens, we had the honor to learn from, and we were unable to palpate it.
Fig 1. Medial Pterygoid (1), Inferior Lateral Pterygoid (2),
Superior Lateral Pterygoid (3)
When I lecture in class, I still feel there is value in noting pain intraorally in the vicinity of the Lateral Pterygoid as an objective sign. If it is painful to palpation, as our patients progress and feel better, we find the tenderness eases and eventually goes away.
- From an anatomic point of view, it is nearly impossible to reach the IFL muscle with the palpating finger. However, one of the studies I included felt if the superficial fascicle of the medial pterygoid was absent, you could reach the IFL on a few of their subjects.
- The high frequency of false-positive results is presumed to be due to palpation of the medial pterygoid muscle.
- The IFL muscle palpation technique cannot be considered to be a reproducible, clinical procedure because of the high interindividual variability of the examiners.
- The limitations of these cadaver studies are associated with the examination of nonvital tissues, which might differ in compressibility when compared with living tissues due to the lower temperature, absent blood flow, and initial process of autolysis or saprophytic decomposition.
Fig 2. Attachment Sites: Anterior Head of the Medial Pterygoid (1), Posterior Head of the Medial Pterygoid (2), Inferior Head of Lateral Pterygoid (3), Superior Head of Lateral Pterygoid (4). It became apparent during our cadaver course when palpating for the IFL, and we were only able to reach and contact the anterior head of the medial pterygoid.
Let me know your thoughts!! I would love the feedback!
- Clinical anatomy and palpability of the inferior lateral pterygoid muscle. Stratmann U, Mokrys K, Meyer U, Kleinheinz J, Joos U, Dirksen D, Bollmann F. J Prosthet Dent. 2000 May;83(5):548-54.
- Evidence – The intraoral palpability of the lateral pterygoid muscle – A prospective study. Stelzenmueller W, Umstadt H, Weber D, Goenner-Oezkan V, Kopp S, Lisson J. Ann Anat. 2016 Jul;206:89-95.
- Palpation of the lateral pterygoid region in TMD–where is the evidence? Türp JC, Minagi S. J Dent. 2001 Sep;29(7):475-83.
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As I explored this question with Mike in the Cadaver class, it occurred to me that on the specimens was the first time I have ever palpated muscles directly. We are always palpating muscles through layers of skin, fascia and oftentimes through other muscles. The layers of gluteus max, med and min are a good example. Therefore, if we are indirectly influencing the inferior lateral pterygoid and getting excellent results, that is what matters most in treating our patients.
What you are palpating intraorally that most practitioners mistake is to neither LP or MP it is temporal tendon insertion on the medial aspect of the coronoid process