Osteology And Radiology Flashcards
How many bones are in the neurocranium?
8 bones
What can we divide the neurocranium into?
Calvaria (skull cap)
Base of skull
How many bones make up the viscerocranium?
14 bones
What is the only freely moveable joint in the skull?
Temporomandibular joint (TMJ)
The coronal suture is between which bones?
Frontal and parietal
The squamous suture is between which bones?
Squamous part of temporal bone and parietal
The sagittal suture is between which bones?
The 2 parietal bones
The lambdoid suture is between which bones?
Parietal and occipital
Where is the bregma?
The joining point of the 2 parietal bones and the frontal bone
(Anterior fontanelle)
Where is the pterion?
Joining point of frontal, parietal, temporal and sphenoid bones
(One either side)
Where is the lambda?
Joining point of 2 parietal bones and occipital bone
What are fontanelles?
Membranous areas of unfused skull (soft spots on baby’s head)
Will close in first 2 years of life
What are the purposes of the fontanelles?
Flexibility eases passage through birth canal
Allows for brain growth
Describe the structures of skull bone
Inner and outer table of hard bone
Area between called diploe = spongy bone
Where does the pituitary gland sit?
Sella turcica
What are the 4 sinuses called?
Frontal
Ethmoid
Maxillary
Sphenoid
What bones make up the hard palate?
Maxillary and palatine bones
What imaging would you use for a suspected skull fracture?
CT imaging
Bones show up very clearly
What is a lucid interval?
A period of time that can occur after a head injury where the patient is temporarily fine and then deteriorates rapidly
What colour is fresh blood on a CT?
White
What blood vessel is found just under the pterion?
Anterior branch of the middle meningeal artery
Where is an extra dural haemorrhage?
Between the skull periosteum and the outermost meningeal layer (dura mater)
What clinical signs are associated with a basilar skull fracture?
CSF rhinorrhoea
Clotted blood in middle ear
Raccoon’s eyes (extensive bruising)
Mastoid bruising
What is a Jefferson’s fracture?
Burst fracture of C1
Combination of anterior and posterior arch fractures
Due to axial compression
Can be unstable
What is a Hangman’s fracture?
Bilateral fracture of posterior arch of C2
Disruption of C2-3 junction
Due to hyperflexion of neck
High risk of C2 displacement and spinal cord damage
What are some features of osteoarthritis of the C spine?
Osteophytes Facet joint hypertrophy Disc herniation Disc space narrowing Sclerosis of end plates
Describe cervical spondylotic radiculopathy
Nerve root impingement
Dermatomal arm pain +/- mild weakness and sensory loss
Describe cervical spondylotic myelopathy
Spinal cord compression (or slipped disc)
Loss of function - often loss of fine motor skills in upper limbs
What is Battle’s sign?
Bruising over the mastoid process
What is haemotypanum?
Blood behind the ear drum
What are the most common bones to be fractured in the face?
Nasal
Zygomatic
Mandible
Through which foramen does the internal carotid artery enter the skull?
Carotid canal
Through which foramen does the middle meningeal artery enter the cranium?
Foramen spinosum
Through which foramen does the vertebral artery enter the skull?
Foramen magnum
How many fossae are in the floor of the cranial cavity and what do we call them?
3
Anterior, middle and posterior
What are the orbital plates?
Roof of the orbits
Formed by the frontal bone
In which bone does the cribriform plate reside?
Ethmoid bone
What is the crista gallis?
Bony, sharp prominence of ethmoid
Attachment point for dura matter
Blow to face can tear dura - CSF rhinorrhoea
What clinical sign will occur and why if we fracture the orbital plate?
Blood from within cranial cavity will move into tissue around the orbit
Raccoon’s eyes - periorbital ecchymosis
Which bone divides the anterior and middle fossae?
Sphenoid bone (lesser wing)
The sella turcica is in which bone?
Sphenoid
If we pass through the foramen rotundum where do we end up?
Pterygopalatine fossa
What important nerve passes through the foramen rotundum?
Maxillary branch of the trigeminal (V2)
Where do we end up if passing through the foramen ovale?
Infratemporal fossa
Which important nerve passes through the foramen ovale?
Mandibular branch of the trigeminal (V3)
What passes through the foramen lacerum?
In life nothing passes through it, covered in cartilage
Internal carotid passes over the top though
Where does the carotid canal run through?
Petrous part of the temporal bone
Which blood vessel runs into the cavernous sinus?
Internal carotid artery
How do we remember the 4 foramen of the cranial base?
ROLS
Rotundum, ovale, lacerum, spinosum
What forms the boundary between the middle and posterior fossae?
Petrous part of the temporal bone
Which nerves pass through the internal acoustic meatus?
Vestibulocochlear nerve Facial nerve (out at the stylomastoid foramen)
Which nerves pass through the jugular foramen?
Glossopharyngeal
Vagus
Accessory
