Skull Flashcards
Which bones form the pterion?
Frontal
parietal
Temporal
Sphenoid
What is the clinical significance of the pterion?
The middle meningeal artery runs behind it, injury at this location can lead to extradural haematoma
What are the layers of the scalp?
Skin
Connective tissue
Aponeurosis of occipitofrontalis muscle
Loose areolar tissue
Periosteum
Temporalis muscle will also be encountered during pterional burr holes
At what age do the cranial sutures ossify?
18-24 months
What is the condition called if cranial sutures are fused at birth?
craniosynostosis
At which age does the mastoid bone develop?
2 years
What are the diplopic veins?
Veins found in the skull which drain the diplopic space to the dural venous sinus
Tears to which vessel may cause subdural haematoma
Cerebral vein and bridging veins
What type of joint is the Temporomandibular joint?
Bi-arthrodial hinge (synovial) joint
What are the articulating surfaces of the TMJ?
Head of the mandible
Mandibular fossa of the temporal bone
Articular tubercle (from the squamous part of the temporal bone)
What movements can be made by the TMJ?
Protrusion
Elevation
Depression
Retraction
Side to side
What are the muscle of mastication?
Masseter
Temporalis
Medial and Lateral pterygoid
Which muscles are responsible for opening of the mouth
DLGM
- Digastric
- Lateral pterygoid
- Geniohyoid
- Mylohyoid
Where is the foramen ovale and what are its contents?
Sphenoid bone
Otic ganglion - runs under the ovale
Mandibular nerve V3
Accessory meningeal artery
Lesser petrosal nerve
Emissary veins
Where is the foramen spinosum and what are its contents?
Sphenoid bone
Middle meningeal artery
Meningeal branch of the mandibular nerve
Where is the foramen rotundum and what is its contents?
Sphenoid bone
Maxillary nerve (V2)
Where is the foramen lacerum located and what are its contents?
Sphenoid bone
ICA - passes along its superior surface but does not traverse it
Nerve of the pterygoid canal - deep petrosal nerve and superficial greater petrosal nerve
artery of pterygoid canal
Where is the optic canal and what is its contents?
Sphenoid bone
Optic nerve and 3 layers of dura
Ophthalmic artery
Sympathetic nerves
Where is the superior orbital fissure and what are its contents?
Sphenoid bone
Oculomotor nerve
- superior and inferior divisions
Trochlear nerve
Abducens nerve
Superior and inferior ophthalmic veins
Ophthalmic branch of CN V
- lacrimal, frontal and nasociliary branches
Where is the carotid canal and what are its contents
Temporal bone
Sympathetic plexus around arteries
Internal carotid artery
Deep petrosal nerve
Emissary veins
Where is the jugular foramen and what are its contents?
Temporal bone
Inferior petrosal sinus
Glossopharyngeal, vagus and accessory nerves
Sigmoid sinus (becoming IJV) and some meningeal branches from the occipital and ascending pharyngeal arteries
Where is the stylomastoid foramen and what are its contents?
Temporal bone
Stylomastoid artery
Facial nerve
Where is the foramen magnum and what are its contents?
Occipital bone
Vertebral arteries
anterior spinal artery
posterior spinal artery
Spinal root of XI
lower end of the medulla
Tectorial membranes
Apical ligaments of the dens
Which cranial nerve track can be found on the clivus?
Abducens
What is the juvenille structure which forms the clivus
Spheno-occipital synchondrosis
Name some benign tumours of the posterior cranial fossa
Haemangioblastoma
Ependymoma
Acoustic neuroma
Ependymoblastoma
Which muscles attach to the styloid process?
Styloglossus
Stylohyoid
Stylopharyngeus
Name some causes for lytic skull lesions
Lytic skeletal metastasis
Sarcoidosis
Paget’s disease
Multiple myeloma
Osteomyelitis
Haemangioma
What are the boundaries and contents of the middle cranial fossa?
Anterior - lesser wing of sphenoid and anterior clinoid process
Posterior - petrous part of temporal bone and dorsum sellae
Laterally - Squamous part of the temporal bone
Temporal lobe
What are the boundaries of the posterior cranial fossa and which bones form it?
Anterior - apex of the petrous part of the temporal bone
Posterior - occipital bone
Lateral - squamous and mastoid parts of the temporal bone
occipital and temporal bones
Where do the cavernous sinuses drain blood from?
superior ophthalmic veins
facial vein
emissary vein from pterygoid plexus
sphenoparietal sinuses
Where do the cavernous sinuses drain blood to?
Superior and inferior petrosal sinuses
IJV
Intercavernous sinus
What are the contents of the cavernous sinus?
Lateral wall components
- Oculomotor nerve
- Trochlear nerve
- ophthalmic nerve
- Maxillary nerve
Contents of the sinus
- Internal carotid artery (and sympathetic plexus)
- abducens nerve
What is the clinical significance of the cavernous sinus?
Ophthalmic and facial veins drain the dangerous area of the face. They are also valveless vessels therefore any infection drained from this area can spread to the cavernous sinus leading to cavernous sinus thrombosis
What are the signs of a cavernous sinus thrombosis?
Painful swelling of the eye
3rd, 4th, 5th and 6th nerve palsies
Gradual loss of vision
What is the most common cause of cavernous sinus syndrome?
Cavernous sinus tumours
What are the signs of cavernous sinus tumours?
Pain, ophthalmoplegia, proptosis, trigeminal nerve lesions and Horner’s syndrome
Name the paired dural sinuses
Middle meningeal
Sphenoparietal
Superior petrosal
Sigmoid
Cavernous
Transverse
Inferior
Petrosquamous
Name the unpaired dural sinuses
Superior sagittal
Inferior sagittal
Straight
Occipital
Anterior intercavernous
Posterior intercavernous
Basilar venous plexus
What are the tributaries of the superior sagittal sinus?
Parietal emissary veins
Superior cerebral veins
scalps veins
cavernous sinus through superior anastomotic veins
meningeal veins
veins of the frontal sinus
diplopic veins
Name the tributaries of the straight sinus
Superior cerebellar veins
Few tributaries from flax cerebri
Name the tributaries of the Inferior sagittal sinus
Veins draining the limbic lobe
medial frontotemporal lobe
genu of the corpus callosum
deep cerebral veins
What are the tributaries of the transverse sinus?
Inferior cerebellar veins,
superior petronsal sinus
inferior cerebral veins
anastomotic veins
diplopic veins
Name the tributaries of superior petrosal sinus
Cerebellar
inferior cerebral
tympanic veins
Name the tributaries of the sigmoid sinus
Mastoid and condylar emissary vein
cerebellar veins
internal auditory vein
What is the major vein draining the brain parenchyma?
Great cerebral vein
Describe the blood flow from the superior sagittal sinus to the IJV
Superior sagittal sinus > confluence of sinuses > transverse sinus >sigmoid sinus > IJV
Describe the location of the straight sinus
Tentorium cerebelli and flax junction
What is the blood supply of temporalis muscle
Deep temporal artery - (anterior and posterior) branches from the maxillary artery
What artery supplies the scalp over the temporalis muscle?
Superficial temporal artery from ECA
