IN THE NAME OF ALLAH. The Skull 22 bones joined together by sutures Cranial bones surround cranial...
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Transcript of IN THE NAME OF ALLAH. The Skull 22 bones joined together by sutures Cranial bones surround cranial...
IN THE NAME OF ALLAH
Facial Bones with glasses onFacial Bones with glasses on
The Skull
• 22 bones joined together by sutures
• Cranial bones surround cranial cavity– 8 bones
• Facial bones support teeth & form nasal cavity & orbit– 14 bones
Frontal Bone
• Forms forehead and part of the roof of the cranium
• Forms roof of the orbit• Contains frontal sinus
Parietal Bone
• Forms cranial roof and part of its lateral walls
• Bordered by 4 sutures– coronal, sagittal, lambdoid
and squamous
• Marked by temporal lines of temporalis muscleTemporal lines
Temporal Bone
• Forms lateral wall & part of floor of cranial cavity– squamous part
• zygomatic process
• mandibular fossa & TMJ
– tympanic part• external auditory meatus
• styloid process
– mastoid part• mastoid process
• mastoid notch– digastric muscle
Petrous Portion of Temporal Bone
• Forms part of cranial floor– separates middle from
posterior cranial fossa
• Houses middle and inner ear cavities
Openings in Temporal Bone
Occipital Bone
• Foramen magnum holds spinal cord
• occipital condyles
Sphenoid Bone
• Lesser wing
• Greater wing
• Body of sphenoid
• Medial and lateral pterygoid processes
Sphenoid Bone
• Body of the sphenoid– sella turcica contains deep
pit (hypophyseal fossa)
– houses pituitary gland
• Lesser wing– optic foramen contains optic
nerve & ophthalmic a.
Sphenoid Bone
• Sphenoid sinus
Ethmoid Bone
• Between the orbital cavities• Forms lateral walls and roof of nasal
cavity• Cribriform plate & crista galli• Ethmoid air cells form ethmoid sinus• Perpendicular plate forms part of
nasal septum• Concha or turbinates on lateral wall
Ethmoid Bone
• Superior & middle concha• Perpendicular plate of nasal
septum
Maxillary Bones• Forms upper jaw
– alveolar processes are bony pointsbetween teeth
– alveolar sockets hold teeth
• Forms inferomedial wall of orbit– infraorbital foramen
• Forms anterior 2/3’sof hard palate– incisive foramen– cleft palate
Locations of Paranasal Sinuses
• Maxillary sinus fills maxillae bone• Other bones containing sinuses are frontal, ethmoid &
sphenoid.
EthmoidMaxillarySphenoid
Frontal
Palatine Bones
• L-shaped bone• Posterior 1/3 of the hard
palate • Part of lateral nasal wall• Part of the orbital floor
Zygomatic Bones
• Forms angles of the cheekbones and part of lateral orbital wall
• Zygomatic arch is formed from zygomatic bone and zygomatic process of temporal bone
Lacrimal Bones
• Form part of medial wall of each orbit
• Lacrimal fossa houses lacrimal sac in life
Nasal Bones
• Forms bridge of nose and supports cartilages of nose
• Often fractured by blow to the nose
Inferior Nasal Conchae
• A separate bone
Vomer
• Inferior half of the nasal septum
• Supports cartilage of nasal septum
Mandible• Only bone of the skull that can move
– jaw joint formed between mandibular fossaof temporal bone & condyloid process
• Holds the lower teeth• Attachment of muscles of mastication
– temporalis muscle onto coronoid process
– masseter muscle onto angle of mandible
• Mandibular foramen• Mental foramen
• Auditory ossicles– malleus– incus– stapes
• Hyoid bone– suspended from styloid
process of skull by stylohyoid muscle and ligament
– greater & lesser cornua
Bones Associated With the Skull
Major Skull Cavities
• Cranial cavity holds brain• Orbit contains eyeball &
extraocular muscles• Ethmoid sinus• Nasal cavity• Maxillary sinus• Oral cavity
Cranial Fossa
• 3 basins that comprise the cranial floor or base– Anterior cranial fossa
– Middle cranial fossa
– Posterior cranial fossa
The Skull in Infancy & Childhood
• Spaces between unfused skull bones called fontanelles– filled with fibrous membrane
– allow shifting of bones during birth & growth of brain in infancy
• 2 frontalle bones fuse by age six– metopic suture
Norma Verticalis
Norma Frontalis
Norma Occipitalis
Norma Lateralis
Norma Basalis