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Mastication (view source)

Revision as of 19:23, 30 July 2008

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*Digastricus muscle

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**Origin: paracondylar process of occipital bone

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**Origin: paracondylar process of [[Skull and Facial Muscles - Anatomy & Physiology#Occipital Bone (os occipitale)|occipital bone]]

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**Insertion: angle of mandible

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**Insertion: angle of [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]]

**Two bellies:

***Caudal half from the second visceral arch innervated by facial nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN VII]])

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*Masseter muscle

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**Origin: maxilliary region of skull and zygomatic arch

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**Origin: [[Skull and Facial Muscles - Anatomy & Physiology#Maxilla|maxilliary]] region of skull and zygomatic arch

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**Insertion: wide area on caudal side of mandible

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**Insertion: wide area on caudal side of [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]]

**Several divisions

**Unilateral and bilateral contraction

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*Lateral Pterygoid muscle

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**Origin: pterygopalatine region of skull

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**Origin: [[Skull and Facial Muscles - Anatomy & Physiology#Pterygoid Bone (os pterygoideum)|pterygopalatine]] region of skull

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**Insertion: lateral aspect of mandible

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**Insertion: lateral aspect of [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]]

**Also protrudes jaw (one-sided contraction)

*Medial Pterygoid muscle

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**Origin: pterygopalatine region of skull

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**Origin: [[Skull and Facial Muscles - Anatomy & Physiology#Pterygoid Bone (os pterygoideum)|pterygopalatine]] region of skull

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**Insertion: medial aspect of mandible

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**Insertion: medial aspect of [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]]

**One-sided contraction to close jaw

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**Origin: lateral surface of cranium

**Insertion: coronoid process

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**Pulls mandible dorsally

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**Pulls [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] dorsally

**Also pulls mandible rostrally (overbite) and caudally (underbite)

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'''Temperomandibular Joint'''

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*Articulation between the condylar process of the mandible and the mandibular process of the skull

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*Articulation between the condylar process of the [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] and the mandibular process of the skull

*Compartmentalised joint for rotational movement and lateral slide (grinding)

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'''Mandibular Symphasis'''

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*Rostral end of mandible

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*Rostral end of [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]]

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*Fibrous joint bewteen the left and right halves of the mandible

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*Fibrous joint bewteen the left and right halves of the [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]]

*Only in dogs and ruminants

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*Precise occlusion

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*Mandibular bones can move apart independently by rotation

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*[[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|Mandibular]] bones can move apart independently by rotation

*Stops jaw breakages (Canid)

Nabrown

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