Bones of the Skull

Sutures immovable joints found only between bones of the skull coronal - found between the frontal and the two parietal bones sagittal - between the two parietal bones lambdoid - between the parietal and occipital bones squamous - between the parietal and the temporal bones

Fontanels (little fountain) infancy membrane filled spaces found between cranial bones at birth eventually replaced by bone (about age 2) Functions: - enable the fetal skull to modify shape during birth process - permit rapid growth of brain during

Neurocranium (cranial bones) frontal parietal temporal sphenoid ethmoid occipital

Frontal unpaired (single bone) forms anterior part of the cranium (forehead) roof of the orbits most of anterior part of cranial floor smooth portion between orbits - glabella each bony ridge perforated by - supraorbital foramen contains frontal sinuses

Frontal supraorbital foramen glabella

Parietal paired, posterior to frontal bone forms sides and roof of cranium bones meet at midline to form - sagittal suture posteriorly, bones merge with occipital bone to form - lambdoid suture lateral sides of skill merge with temporal bone to form - squamous suture

Parietal sagittal suture lambdoid suture

Temporal paired forms sides and base of skull has pit or depression - mandibular or glenoid fossa (site of articulation with mandible) sharp projections on underside - styloid process

Temporal (cont.) rounded projection at back: - mastoid process has canal on lateral sides - external auditory meatus suture that connects occipital with parietal - lambdoid suture

Temporal (cont.) zygomatic process projecting from inferior - articulates with temporal process of zygomatic bone zygomatic process of temporal bone and temporal process of zygomatic bone make up zygomatic arch

Temporal glenoid lamboid fossa suture external zygomatic auditory meatus zygomatic process styloid process mastoid process

Sphenoid single bone wedge or butterfly shaped situated on cranial floor central depression called sella turcica - surrounds pituitary gland articulates with cranial bones

Sphenoid

Ethmoid single anterior part of cranial floor between orbits anterior to sphenoid posterior to nasal bones primary supporting bone of nasal cavity

Ethmoid

Occipital single posterior and base of cranium (base and back) has large opening called foramen magnun (through which spinal cord passes) occipital protuberance is midway between top and foramen magnum occipital condyles articulate with atlas

Occipital

Viscerocranium (facial bones) nasal vomer inferior nasal conchae lacrimal maxilla palatine zygomatic mandible

Nasal paired oblong bones side by side in midline forms bridge of nose major portion of the nose consists of cartilage

Vomer single, triangular in lower back of nasal cavity forms portion of septum partition of two nasal chambers

Inferior Nasal Conchae (KONG-ke) paired thin, spongy looks rolled or coiled lateral wall of each nostril function to increase interior surface area of the nose also called turbinate bones

Lacrimal (lacrima = tear) paired thin bones in anterior wall of orbit inner angle of eye directly behind frontal process of maxilla lacrimal duct passes through smallest of facial bones

lacrimal nasal conchae vomer

Maxillae paired bones join at midline to form upper jaw articulates with all bones of face except mandible form part of floor of orbits form lateral walls and floor of nasal cavity contain inferior orbital foramen contain maxillary sinus which empty into nasal cavity

Maxillae (cont.) forms most of hard palate contains alveolar process - arch that contain alveoli (sockets) for maxillary (upper) teeth contains palatine process - horizontal projection on maxilla anterior 3/4 of hard palate maxillary bones unite before birth

Cleft Palate Cleft Lip failure of palatine processes to unite at about 10-12 weeks of embryonic development repair - between age one and age 2 Cleft Lip split in the upper lip repair - first year of life

Palatine Bones paired L-shaped form posterior portion of hard palate part of the floor and lateral wall of the nasal cavity small portion of floors of the orbits

Palatine Bone

Zygomatic paired form prominences of the cheeks part of lateral wall and floor of each orbit also known as malars temporal process of zygomatic bone projects posteriorly and articulates with zygomatic process of temporal bone - together form zygomatic arch

Mandible (mandere = to chew) single bone, lower jaw largest, strongest facial bone only movable bone of skull (except ear ossicles) contains alveolar process - arch that contain alveoli (sockets) for mandibular (lower) teeth

Mandible (cont.) body; curved horizontal portion two perpendicular portions: (rami) condyloid process articulates with temporal bone coronoid process attaches to temporalis muscle mandibular angles mental and mandibular foramen

zygomatic maxilla mandible

Hyoid Bone (hyoedes = U-shaped) single bone does not articulate with any other bone suspended from styloid process by ligaments and tendons located in neck between mandible and larynx supports tongue; attachment for muscles of neck and pharynx consists of body and projections often fractured during strangulation