Post on 18-Jan-2016
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