2) Osteology of the H&N Flashcards
What are the bones that make up the cranium?
Calvaria: Frontal Parietal (2) Occipital Ethmoid
Cranial base:
Sphenoid
Temporal (2)
What do the bones of the calvaria (vault of skull) consist of?
2 layers of compact bone
separated by a layer of bone marrow (Diploe)
What do the bones of the cranial base articulate with?
Atlas (C1)
Facial skeletion
Mandible
Name the 3 sutures that join the bones of the cranium
Coronal
Sagittal
Lamboidal
Name 5 sites the skull is prone to fracture
Foramen magnum Anterior cranial fossa Middle cranial fossa (weakest) Posterior cranial fossa Squamous temporal bone & inner parts of Sphenoid wing
Describe some of the symptoms of skull fractures
Bleeding from wound, ear, nose, around eyes
bruising, draining of CSF from ears/nose
swelling, confusion, convulsions, drowsiness & lots more
Name 7 types of skull fracture
Depressed Linear Calvarial Comminuted Contrecoup (counterblow) Simple Compound Basal Skull
What is a depressed fracture?
Severe, localised blow
localised indentation
fragment of bone may compress or injure underlying brain
What is a linear calvarial fracture?
Trauma to Calvaria
Results in radiating linear fractures away from point of impact in 2 or more directions
What is a comminuted fracture?
The bone is broken into several pieces
What is a contrecoup (counterblow) fracture?
No fracture occurs at point of impact
Fracture occurs at opposite side of cranium
What is a simple fracture?
Break in the bone without damage to the skin
What is a compound fracture?
Break in, or loss of, skin & splintering of the bone
+ brain injury & bleeding
What is a basal skull fracture?
Fracture of base of skull
Presents with Battle’s sign (ecchymosis -bruising - of the mastoid process of the temporal bone)
What is the Pterion?
H-shaped junction of 4 bones
lateral aspect of skull
thinnest part of calvaria
Bone fragments from fracture may rupture middle meningeal artery > extradural haemorrhage
Which 4 bones make up the pterion?
Frontal
Parietal
Sphenoidal (greater wing)
Temporal
How might infection spread from the scalp to the skull?
Superficial veins of the scalp > Emissary veins > Diploic veins > Intracranial venous sinuses
May cause osteomyelitis
Name the foramen of the calvaria (6)
Foramen magnum Foramen ovale Foramen spinosum Foramen lacerum Carotid canal Jugular foramen
Name the 9 bones that make up the facial skeleton
Frontal Zygomatic (2) Maxilla (2) Palatine (2) Nasal (2) Lacrimal (2) Inferior concha (2) Vomer Mandible
What is the function of the Frontal bone?
Forms the skeleton of the forehead
Part of the floor of the cranial cavity
Roof of the orbit
Just above orbital margin is a sharp bony ridge - Supraciliary Arch
What is the function of the Zygomatic bones?
Cheek bones
Lie on inferolateral sides of the orbit
What is the function of the Maxillae?
Makes up large part of upper facial skeleton
Form upper jaw (fixed to cranial base)
What is the function of the Mandible?
Movable as it articulates with the cranial base
TMJ
Name some common facial fractures
Car accidents, fistfights, falls
commonly involve nasal bones
Maxillofacial fractures - massive facial trauma
hard blow to lower jaw, fracture of neck of mandible (TMJ dislocation)
