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Skull and Facial Muscles - Anatomy & Physiology (view source)
Revision as of 17:41, 16 July 2010
, 17:41, 16 July 2010→Bones of the Skull
==Bones of the Skull==
==Bones of the Skull==
[[Image:Pig skull dorsal.jpg|thumb|right|150px|Pig skull (nuchal crest, nasal bone, frontal bone, pareital bone, zygomatic process of the temporal bone and coronoid process of the mandible labelled) - Copyright nabrown RVC]]
[[Image:Pig skull dorsal.jpg|thumb|right|150px|Pig skull (nuchal crest, nasal bone, frontal bone, pareital bone, zygomatic process of the temporal bone and coronoid process of the mandible labelled) - Copyright nabrown RVC]]
'''Occipital Bone (os occipitale)'''
*Forms the nuchal wall
*Forms the nuchal wall
*Forms the foramen magnum
*Forms the foramen magnum
*Basilar part (pars basilaris)
*Basilar part (pars basilaris)
**Caudal base of the cranium
**Caudal base of the cranium
**Hypoglossal canal
**Hypoglossal canal
'''Sphenoid Bone (os sphenoidale)'''
[[Image:Pig skull ventral view.jpg|thumb|right|150px|Ventral view pig skull (vomer, occipital condyle, sphenoid, pterygoid bone, hamulus labelled)- Copyright nabrown RVC]]
[[Image:Pig skull ventral view.jpg|thumb|right|150px|Ventral view pig skull (vomer, occipital condyle, sphenoid, pterygoid bone, hamulus labelled)- Copyright nabrown RVC]]
*Forms the base of the neurocranium
*Forms the base of the neurocranium
*Composed of a body and wings
*Composed of a body and wings
*Bones separated by cartilage which ossifies with age
*Bones separated by cartilage which ossifies with age
*Presphenoid (os praespenoidale)
*Presphenoid (os praespenoidale)
**Rostrally
**Rostrally
**Optic chiasma
**Optic chiasma
**Optic canal
**Optic canal
*Basisphenoid (os basispenoidalis)
*Basisphenoid (os basispenoidalis)
**Caudally
**Caudally
**Alar canal (rostral and caudal alar foramen)
**Alar canal (rostral and caudal alar foramen)
'''Temporal Bone (os temporale)'''
*Composed of squamous, petrosal and tympanic parts
*Composed of squamous, petrosal and tympanic parts
*Lateral wall of the cranial cavity
*Lateral wall of the cranial cavity
*Articulates with the frontal, pareital and sphenoid bones
*Articulates with the frontal, pareital and sphenoid bones
[[Image:Zygomatic arch.jpg|thumb|right|150px|Zygomatic Arch (Dog) - Copyright nabrown RVC]]
[[Image:Zygomatic arch.jpg|thumb|right|150px|Zygomatic Arch (Dog) - Copyright nabrown RVC]]
**Joins the temporal process of the zygomatic bone to form the zygomatic arch
**Joins the temporal process of the zygomatic bone to form the zygomatic arch
**Forms the articulating surface of the [[Mastication#Jaw Articulation|temporomandibular joint]]
**Forms the articulating surface of the [[Mastication#Jaw Articulation|temporomandibular joint]]
*Articular tubercle present
*Articular tubercle present
*Mandibular fossa present
*Mandibular fossa present
*Occipital process and retrotympanic process surrounds the external acoustic meatus
*Occipital process and retrotympanic process surrounds the external acoustic meatus
*Petrosal part encloses the inner ear
*Petrosal part encloses the inner ear
**Internal acoustic meatus present
**Internal acoustic meatus present
**Styloid process present which attaches the [[Hyoid Apparatus - Anatomy & Physiology|hyoid apparatus]]
**Styloid process present which attaches the [[Hyoid Apparatus - Anatomy & Physiology|hyoid apparatus]]
**Stylomastoid foramen present
**Stylomastoid foramen present
*Tympanic part is the ventral section of the temporal bone
*Tympanic part is the ventral section of the temporal bone
**Tympanic bulla present
**Tympanic bulla present
**Musculotubal canal where tensors of the [[Soft Palate - Anatomy & Physiology#Musculature and Innervation|soft palate]] originate
**Musculotubal canal where tensors of the [[Soft Palate - Anatomy & Physiology#Musculature and Innervation|soft palate]] originate
'''Frontal Bone (os frontale)'''
*Paired
*Paired
*Joined by the interfrontal suture
*Joined by the interfrontal suture
*Between the cranium and the face
*Between the cranium and the face
*Encloses the frontal sinuses
*Encloses the frontal sinuses
*The nasal and lacrimal bones border the frontal squama section
*The nasal and lacrimal bones border the frontal squama section
**Forms the zygomatic process laterally
**Forms the zygomatic process laterally
**Temporal line present which extends into the external sagittal crest
**Temporal line present which extends into the external sagittal crest
**Cornual processes in [[Horn - Anatomy & Physiology|horned]] ruminants
**Cornual processes in [[Horn - Anatomy & Physiology|horned]] ruminants
*The nasal section is the rostral part of the frontal bone
*The nasal section is the rostral part of the frontal bone
*Orbital part is perforated by the ethmoidal foramen
*Orbital part is perforated by the ethmoidal foramen
**Medially the dorsal oblique muscle of the eyeball attaches
**Medially the dorsal oblique muscle of the eyeball attaches
*Temporal part provides the muscle attachments for the temporalis muscle
*Temporal part provides the muscle attachments for the temporalis muscle
[[Image:Pareital Bone.jpg|thumb|right|150px|Parietal bone, occipital bone and external acoustic meatus (Horse) - Copyright nabrown RVC]]
[[Image:Pareital Bone.jpg|thumb|right|150px|Parietal bone, occipital bone and external acoustic meatus (Horse) - Copyright nabrown RVC]]
'''Parietal Bone (os parietale)'''
*Paired
*Paired
*Forms the dorsolateral wall of the cranium
*Forms the dorsolateral wall of the cranium
*Occipital bone caudally
*Occipital bone caudally
*Frontal bone rostrally
*Frontal bone rostrally
*Composed of a pareital plane, temporal plane and a nuchal plane (in the ox)
*Composed of a pareital plane, temporal plane and a nuchal plane (in the ox)
*Internally the grooves and ridges correspond with the gyri and sulci of the brain
*Internally the grooves and ridges correspond with the gyri and sulci of the brain
*Interpareital bone between the occipital bone and the pareital bone
*Interpareital bone between the occipital bone and the pareital bone
**Fuses with age
**Fuses with age
'''Ethmoid Bone (os ethmoidale)'''
[[Image:Nasal Cavities.jpg|thumb|right|150px|Nasal Cavities - Copyright David Bainbridge]]
[[Image:Nasal Cavities.jpg|thumb|right|150px|Nasal Cavities - Copyright David Bainbridge]]
*Forms part of the cranial and facial parts of the skull
*Forms part of the cranial and facial parts of the skull
*Located deep in the orbit
*Located deep in the orbit
*External lamina consists of the roof plate, floor plate and paired orbital plates
*External lamina consists of the roof plate, floor plate and paired orbital plates
*The ethmoid bone is separated from the cranial cavity by the cribiform plate
*The ethmoid bone is separated from the cranial cavity by the cribiform plate
**Numerous small foramina where the olfactory nerve ([[Cranial Nerves - Anatomy & Physiology|CN I]]) passes through
**Numerous small foramina where the olfactory nerve ([[Cranial Nerves - Anatomy & Physiology|CN I]]) passes through
*The perpendicular plate splits the ethmoid into two halves
*The perpendicular plate splits the ethmoid into two halves
*The ethmoid larbyrinth prodrudes from the ethmoid tubes
*The ethmoid larbyrinth prodrudes from the ethmoid tubes
**Composed of two rows of ethmoturbinates and air filled ethmoidal meatuses
**Composed of two rows of ethmoturbinates and air filled ethmoidal meatuses
**Secondary ethmoturbinates may also be present
**Secondary ethmoturbinates may also be present
*Ethmoturbinates divided into endoturbinates and ectoturbinates
*Ethmoturbinates divided into endoturbinates and ectoturbinates
**The first endoturbinate forms the dorsal nasal conchae
**The first endoturbinate forms the dorsal nasal conchae
**The second endoturbinate froms the middle nasal conchae
**The second endoturbinate froms the middle nasal conchae
*The endoturbinates form 3 nasal meatuses
*The endoturbinates form 3 nasal meatuses
**Dorsal nasal meatus
**Dorsal nasal meatus
**Ventral nasal meatus
**Ventral nasal meatus
'''Nasal Bone (os nasale)'''
[[Image:Ethmoid Turbinates.jpg|thumb|right|150px|Ethmoid Turbinates (Dog) - Copyright nabrown RVC]]
[[Image:Ethmoid Turbinates.jpg|thumb|right|150px|Ethmoid Turbinates (Dog) - Copyright nabrown RVC]]
*Paired
*Paired
*Forms the roof of the nasal cavity
*Forms the roof of the nasal cavity
*Dorsal nasal conchae attach to the ethmoidal crest on the internal surface
*Dorsal nasal conchae attach to the ethmoidal crest on the internal surface
*Rostral suture form the apex
*Rostral suture form the apex
*Between the nasal and incisive bones is the nasoincisive notch
*Between the nasal and incisive bones is the nasoincisive notch
'''Lacrimal Bone (os lacrimale)'''
*Forms part of the lateral wall of the face and orbit
*Forms part of the lateral wall of the face and orbit
*Situated near the medial canthus
*Situated near the medial canthus
*It articulates with the frontal bone, zygomatic bone and maxilla
*It articulates with the frontal bone, zygomatic bone and maxilla
**Also articulates with the nasal bone in ruminants and the horse
**Also articulates with the nasal bone in ruminants and the horse
**Also articulates with the palatine bone in carnivores
**Also articulates with the palatine bone in carnivores
*Composed of an orbital and facial part separated by supra- and infraorbital margins
*Composed of an orbital and facial part separated by supra- and infraorbital margins
*The nasolacrimal duct is present by the margin of the orbital surface
*The nasolacrimal duct is present by the margin of the orbital surface
*Ventral oblique muscle attaches caudal to the margin of the orbital surface
*Ventral oblique muscle attaches caudal to the margin of the orbital surface
*Nasal surface forms the boundaries of the maxillary and frontal sinuses
*Nasal surface forms the boundaries of the maxillary and frontal sinuses