Lanzhou University School of stomatology Mandibular Movements Lanzhou University School of stomatology

The features and rule of mandbular movement Nerve control of mandibular movement Rotation and slide Rule and variability Landmarks

Neural pathways of mandibular movements

下颌运动 sensory afferent pathway of mandibular movement Motor efferent pathway of mandibular movement Jaw reflexes 下颌运动

2.Control of mandibular movement

Factors of controlling mandibular moventments Anatomic factors: TMJ and occlusion posterior controlling factors: TMJ anterior controlling factors: Occlusion Physiological factors: nerve and muscles

3.Pattern and regions of mandibular movements

The form of mandibular movement opening movement closing movement protrusive movement retruding movement lateral movement The range of mandibular movement border movement Habitual opening and closing movement functional movement

3.1 Patterns of mandibular movements 3.1.1 Opening movement Little opening movement：18-25 mm Big opening movement：37-45 mm The biggest opening movement：yawn

The strength of opening movement Down and backward: Suprahyoid muscles Down and forward: lateral pterygoid muscle 

3.1.2 Closing movement Definition The strength of closing movement Temporal muscle, masseter muscle, medial pterygoid muscle Upper lateral pterygoid muscle

The normal signs of opening and closing movement Condyle Clicking, popping ； Mandibular Chin； Openning: >40 mm。

3.1.3 Protrusive movement Definition Primary functional movement The most protrusive position Upper joint space

The strength of protrusive movement Lower Lateral pterygoid muscle Masseter muscle Medial pterygoid muscle Temporal muscle Digastric muscle

The normal signs of protrusive movement Condyle TMJ Maxillofacial Mandible

3.1.4 Retruding movement Rightabout movement compare with protrusive movement The strength of retruding movement Temporal muscle Digastric muscle Upper Lateral pterygoid muscle

3.1.5 Lateral movement Definition Primary functional movement of mastication

Bennett movement and Bennett angle Bennet movement: working side, rotating, 1.5 mm Bennet angle: non-working side, 20°

The strength of lateral movement Non-working side: Lateral： Lower lateral pterygoid muscle Medial pterygoid muscle Working side: Temporal muscle Upper lateral pterygoid muscle 

3.2 Regions of mandibular movements 3.2.1 Border movement Lateral：10 mm Opening：50-60 mm protrusive：9 mm Retruding ：1 mm

3.2.2 Habitual opening and closing movement Tapping movement Recovery occlusal relationship

3.2.3 Functional movement Mastication Swallowing Speech

4. Recordings of mandibular movements

4.1 Landmarks and observation planes for recordings of mandibular movements Incisor point Condylar point Observation plane frontal plane sagittal plane horizontal plane

4.2 The history of studing on mandibular movement recording Anatomy：1773，Monro Take pictures： 1889，Luce 1907，Bennett 1960，Chick X-ray： 1936，Hildebrand Clinic Mechanical: Gothic archtracing magnetic resonance imaging （MRI）/computer tomography （CT） Electronic measure: Electronic pantograph

5. Traces of mandibular movements

5.1 Trace of mandibular movements sagittal plane ：Posselt

Horizontal plane MR1 MR2 IEC F

Frontal plane

Trace of habitual opening and closing movement sagittal plane