Osteology of H&N Flashcards
What is the cranium divided into and how many bones are in each part
Neurocranium - 8 bones
Viscerocranium - 14 bones
What does the neurocranium consist of
Calvaria
Cranial floor
Cranial cavity
What are the bones of the calvaria
Parietal
Occipital
Frontal
Sphenoid
Temporal
What structures are found between calvaria bones - what do they do and what are their names
Sutures join calvaria bones together
Coronal, sagittal and lambdoid sutures
Sutures are serrated, immobile fibrous joints that interlock to make it hard for the bones to dislocate
What are found at the joining of suture lines - name and describe them
Fontanelles
Anterior fontanelle - between coronal and sagittal. Fuses to form bregma
Posterior fontanelle - between sagittal and lambdoid. Fuses to form lambda
What is the importance of the fontanelles
Allow for alteration of the skull during childbirth so it can fit through the birth canal
Allows for growth of infant brain
Describe the structure of the calvaria bones
Inner and outer table layers of compact bone separated by the diploe (spongy bone)
What happens if an artery between the inner table and periostium is damaged and haemorrhage occurs
Blood from the artery causes the periostium to strip away from the inner table as far as the margins of the bone sutures
This results in extra-dural haemorrhage
What is the pterion and why is it significant
Pterion is the thinnest part of the calvaria where many suture lines join - on lateral sides
It is significant as a # at this site may injure the anterior branch of the middle meningeal artery
How is the cranial floor divided
Floor is divided into anterior, middle and posterior cranial fossae
What are the bones of the cranial floor - what structures are found on the bones
Frontal bone - orbital plates, gap for ethmoid, supraorbital ridge
Ethmoid bone - cribriform foramina and cribriform plate
Sphenoid bone - lesser and greater wings, body, sella turcica
Temporal bones - petrous
Occipital bone - foramen magnum
What bones form the viscerocranium
Nasal bones
Zygomatic bones
Maxilla bones
Mandible
Lacrimal bones
Vomer
Palatine bones
Inferior nasal conchae
What is the supraciliary arch
Sharp bony ridge lying just above the orbital margin
What are the types of intracranial haematomas
Epidural
Extradural
Subdural
Describe the types of skull fractures
Linear # - single line away from point of injury. No bone displacement
Comminuted # - multiple # lines with fragments. Fragments may or may not displace inwards towards brain - depressed vs non-depressed
What is a basilar skull fracture
of the cranial floor
Occurs when significant force is transmitted through the vertebral column to the skull base, fracturing the cranial floor
What are the signs of a basilar skull fracture
Battle’s sign
Raccoon eyes
Haemotympanum
CSF rhinorrhoea
CSF otorrhoea
Epistaxis
What are the common facial bones to fracture
Nasal bones
Zygomatic bones
Mandible
What should you do when looking at an x-ray of a fractured mandible
Look for more than one fracture line - there will normally be more than one # line if mandible #ed
If trauma occurs to supraorbital ridge or supraciliary arch, what will be seen
Splitting of the skin as these areas are very tough so are unlikely to fracture
What osteological features are found on the fronal bone
Supraorbital ridge
Supraorbital notch/foramen
Orbital plate
What osteological features are found on the ethmoid bone
Crista galli
Cribriform plate
Perpendicular plate
Superior and middle conchae
Cribriform foramina
What osteological features are found on the sphenoid bone - name structure which pass through
Body
Lesser and greater wings
Clinoid processes
Sella turcica
Hypophyseal/pituitary fossa
Pterygoid processes
Superior orbital fissure - occulomotor nerves and muscles run through
Optic canal - optic nerves pass through
Foramen rotundum - maxillary branch of trigeminal
Foramen ovale - mandibular branch of trigeminal
Foramen spinosum - middle meningeal artery
What osteological features are found on the temporal bone
Squamous part
Zygomatic process
Petrous part
Mastoid process
Styloid process
Articular fossa for mandible
External and internal auditory meatus
Foramen lacerum
Carotid canal
Stylomastoid foramen
What osteological features are found on the occipital bone
External occipital protuberance
Superior nuchal line
Articular condyles for atlas (Occipital condyles)
Clivus
Foramen magnum
Hypoglossal canal
Jugular foramen
What osteological features are found on the mandible
Body
Ramus
Angle
Coronoid process
Condylar process
Mental protuberance
Mental foramen
Mandibular foramen
What three fossa are found on the lateral sides of the skull
Temporal fossa
Infra-temporal fossa
Pterygopalatine fossa
What bones make up the skull
Spenoid bone
Zygomatic bones
Lacrimal bones
Temporal bones
Occipital bone
Frontal bone
Nasal bones
Mandible
Maxillae
Ethmoid bone
Vomer
Parietal bones
Palatine bones
Inferior nasal conchae
