4Bones of the SkullThe skull bones are made up of external and internal tables of compact bone separated by a layer of spongy bone called the diploe.
5The skull has 22 bones, excluding the ossicles of the ear. COMPONENT PARTSThe skull has 22 bones, excluding the ossicles of the ear.Except for the mandible, which forms the lower jaw, the bones of the skull are attached to each other by sutures, are immobile, and form the cranium.
72.Lower anterior part-the facial skeleton (viscerocranium). Subdivisons1.The cranium can be subdivided into: an upper part the calvaria, which surrounds the cranial cavity containing the brain(Neurocranium).2.Lower anterior part-the facial skeleton (viscerocranium).
8The cranium consists of the following bones, two of which are paired Frontal bone: 1Parietal bones: 2Occipital bone: 1Temporal bones: 2Sphenoid bone: 1Ethmoid bone: 1
9The facial bones consist of the following, two of which are single: Zygomatic bones: 2Maxillae: 2Nasal bones: 2Lacrimal bones: 2Vomer: 1Palatine bones: 2Inferior conchae: 2Mandible: 1
10Frankfort horizontal line(anatomical position of Cranium) Horizontal plane represented by a line between Upper rim of the external auditory canal( auricular point), to the lower rim of the orbit( infraorbital point).FHL divides the head into upper and lower halves.
11External Views of the Skull Anterior View of the Skull(Norma frontalis)The anterior view of the skull includes the forehead superiorly, and, inferiorly, the orbits, the nasal region, the part of the face between the orbit and the lower jaw
22Fracture of the Pterion A hard blow to the side of the head may fracture the thin bones forming the pterion, producing a rupture of the anterior branch of the middle meningeal artery crossing the pterion
33Foramen of Anterior cranial fossa 1. Cribriform plate:olfactory nerves (CN-I)2. Foramen cecum: occasional small emissary vein from nasal mucosa to superior sagittal sinus.3. Anterior and posterior ethmoidal foramina: anterior and posterior ethmoidal nerves, arteries, and veins.
40Foramen of posterior cranial fossa Foramen magnum: medulla, the ascending portions of the spinal accessory nerve (XI), and the vertebral arteries.Internal acoustic meatus:facial (VII) and vestibulocochlear (VIII) cranial nervesJugular foramen: internal jugular vein (actually begins here), the glossopharyngeal (IX), the vagus (X) and the accessory (XI) nerves.Anterior condylar (hypoglossal) canal:hypoglossal (XII) nerve.
42Fractures of the Calvaria A depressed skull fracture is a break in a cranial bone (or "crushed" portion of skull) with depression of the bone in toward the brain.A compound fracture involves a break in, or loss of, skin and splintering of the bone.
43Contrecoup (counterblow) fracture No fracture occurs at the point of impact, but one occurs on the opposite side of the cranium.When a moving object impacts the stationary head, coup injuries are typical, while contrecoup injuries are produced when the moving head strikes a stationary object
44Fractures to the Maxilla and associated bones Le Fort I Fracture = Horizontal FractureLe Fort II Fracture = Pyramidal FractureLe Fort III Fractures = Craniofacial Separation