In this article, we review ways to assess muscle tenderness and pain. Common abnormalities of the masticatory muscle include injection induced myositis, myofascial taut band, trigger point, hypertrophy, spasms, etc.
Note: Prior to each procedure, introduce yourself to the patient, explain the purpose of the examination, obtain consent, and be sure to meet infectious control standards.
Relative Tenderness Assessment
With all muscles that you palpate there are two methods. First is the relative tenderness assessment which is done using a standard anatomic location and a standard pressure level. The locations are described below for each muscle. The pressure to be used is 2 kg of pressure with one finger for 2 seconds. While palpating, ask the patient to rate the pressure as none, mild, moderate or severe.
Note: calibrate yourself periodically with a pressure algometer to make sure you are palpating with the right pressure on both hands.
Related Reading: Reliability and Usefulness of the Pressure Pain Threshold Measurement in Patients with Myofascial Pain
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Trigger Point Assessment
The second aspect of a muscle palpation assessment is to palpate across the muscle with your fingers to identify any taut bands. This involves sliding the overlying skin back and forth across the muscle. Taut bands will be evident if it is present and once you find the band, you move up and down the band applying firm pressure while asking the patient to report the most tender point in the band. Once found, this point needs to be compressed for 5 seconds (with 2 kg pressure) to see if the pain radiates or refers.
Related Reading: TMJ Assessment: Jaw Range of Motion, Noise, and Tenderness
1. Deep Masseter Muscle Palpation
This site is anterior and inferior to the lateral condyle pole, posterior to the posterior edge of the superficial masseter, and beneath the zygomatic arch. Palpate the deep masseter for tenderness using a none, mild, moderate or severe scale.
2. Superficial Masseter Muscle Palpation
This site is beneath the zygomatic arch and the muscle is angled back towards the angle of the mandible. Palpate the superficial masseter for tenderness using a none, mild, moderate or severe scale.
3. Anterior Temporalis Muscle Palpation
The anterior temporalis muscle is best palpated at the hair line and opposite the eyebrow. Palpate the anterior temporalis for tenderness using a none, mild, moderate or severe scale.
4. Posterior Temporalis Muscle Palpation
This site is just above the pinna or the ear and its direction is posterior from the coronoid process. Palpate the posterior temporalis for tenderness using a none, mild, moderate or severe scale.
Related Reading: How to Conduct a Cranial Nerve Examination
5. SCM (Sternocleidomastoid) Muscle Palpation
This site is from the manubrium of the sternum (sterno-) and the clavicle (cleido-), and has an insertion at the mastoid process of the temporal bone of the skull. Palpate the sternocleidomastoid muscle for tenderness using a none, mild, moderate or severe scale.
6. Temporalis Muscle Tendon Palpation:
The temporalis muscle tendon is at the coronoid process just beneath the zygomatic process and is accessed by having the mouth open. Palpate the temporalis muscle tendon for tenderness using a none, mild, moderate or severe scale.
7. Lateral Pterygoid Muscle Functional Exam
Test the lateral pterygoid muscle for proper function. The lateral pterygoid muscle cannot be palpated but you can assess the function of this muscle by asking the patient to protrude the jaw.
8. Medial Pterygoid Palpation
Palpate the medial pterygoid muscle both intraorally and extraorally. The origin of the medial pterygoid muscle is located on the inner surface of the pterygoid plate behind the maxilla.
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