MUSCLES OF MASTICATION ANDTHEIR EXAMINATION

UZMA JAN

BDS 3RD YEAR

ROLL NO 39

ORAL DIAGNOSIS &MEDICINE DEPARTMENT

EXAMINATION OF THE MUSCLES

Functional disorders of the masticatory muscles are probably the most common TMD complaint of the patients seeking treatment in the dental office.With regard to pain , they are second to odontalgia in terms of frequency.They are generally grouped in large category known as “masticatory muscle disorder”As with any pathologic state two major symptoms can be observed:1.Pain2.dysfunction

PAINCertainly the most common complaint in patients with masticatory muscle disorder is pain , which may range from slight tenderness to extreme discomfort.Pain felt in muscle tissue is called myalgia.It may arise from increased level of muscle use.Symptoms are usually associated with a feeling of muscle fatigue and tightness.

DYSFUNCTION

Usually it is seen as decrease in range of mandibular movement.When muscle tissues have been compromised by overuse , any contraction or stretching increases the pain.Therefore to maintain comfort , patient restricts movement within a range that doesnot increase the pain level.Clinically this is seen as inability to open mouth widely.

TEMPORALIS MUSCLE

It is a large fan shaped muscle that originates from temporal fossa and lateral surface of skull.Its fibers comes downward zygomatic arch and lateral surface of the skull to form a tendon that inserts into coronoid process and anterior border of ascending ramus.

It can be divided into three distinct areas:

Anterior portion : consists of fibers that are direcrted verticallyMiddle portion : contains fibers that run obliquely across lateral aspect of the skullPosterior portion : that are aligned almost horizontallyWhen temporal muscle contracts , it elevates mandible.

Anterior,Middle andPosteriorportions of thetemporalis muscleshould be palpated

Temporalis muscle can be seen and readily palpated throughout entire length and breadth when the patient’s teeth are firmly clenched.

MASSETER MUSCLE

ORIGIN:Superficial portion – anterior 2/3of lower border of zygomaticarchDeep portion – medial surface ofZygomatic archINSERTION:Lateral surface of ramus,Coronoid process, and angle ofmandibleFUNCTION:Elevates mandible, clenches teeth

Palpate multiple areas ofthe masseter muscle

As with temporalis muscle,it can be located when patient’s jaw are forcibly closed.the body of massetercan be palpated with thumb and index finger.index finger can palpate the entire body of masseter.

MEDIAL PTERYGOID / INTERNAL PTERYGOID

ORIGIN:Medial surface of lateral pterygoid plate and tuberosity of maxilla and can not be palpated

INSERTION:lower medial surface of ramus of mandible

FUNCTION:Elevation and protraction

Anterior part of insertion can be palpated by placing the finger at 45 degrees in the floor if the patients mouth near base of the relaxed tongue.The opposite hand can be used to extraorally to palpate posterior and inferior portions of insertion.Body of the muscle can be palpated by rotating the index finger upwards against the muscle to near its origin on the tuberosity.

LATERAL / EXTERNAL PTERYGOID

ORIGIN:It originates in two parts:Superior head from the greater wing of sphenoidInferior head the lateral surface of the pterygoid plate

INSERTION:Neck of condyle and articular disc of TMJ.

FUNCTION:protraction

PALPATION OF LATERAL PTERYGOID MUSCLE

The muscle is palpated by using the little or index finger and placing it lateral to maxillary tuberosity and medial to coronoid process.The finger presses upwards and inwards and a painful response can be determined .

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Lippert, L.S. (2011). Clinical Kinesiology and Anatomy, 5th ed. Philadelphia, PA: F.A. Davis.

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