Head Flashcards
Which bones form the pterion?
-Temporal
-Parietal
-Sphenoid
-frontal
What is the clinical significance of the pterion?
-Middle meningeal artery runs behind it
-Trauma can result in extradural haematoma
What are the layers of the scalp?
-Skin
-Connective tissue
-Aponeurosis
-Loose areolar tissue
-Periosteum
What age do the cranial sutures ossify by?
-18-24 months
What happens if cranial sutures are fused at birth?
-Craniosynostosis
-Can result in developmental abnormalities
By which age does the mastoid bone develop?
2 years
What are the diploic veins of the skull?
Veins that drain the diploic space of the skull to the dural venous sinuses
Tear to which vessel might cause subdural haematoma?
Cerebral vein and bridging veins
5,29,32
5,27,29,32
What type of joint is the TMJ? What are its articulating surfaces
Bicondylar, synovial hinge joint
Articulating surfaces:
-Head of mandible
-Mandibular fossa of temporal bone
-Artiular tubercle (of temporal bone)
A condyloid joint (also called condylar, ellipsoidal, or bicondylar) is an ovoid articular surface, or condyle that is received into an elliptical cavity. This permits movement in two planes, allowing flexion, extension, adduction, abduction, and circumduction.
Mouth open
What movements does the mandible do, what muscles carry out each?
What muscles are involved in opening mouth?
DLGM
-Digastric
-Lateral pterygoid
-Geniohyoid
-Mylohyoid
Location and contents of foramen ovale
Location:
-Sphenoid bone
Contents
-Otic ganglion
-V3 branch trigeminal
-Accessory meningeal artery
-Lesser petrosal nerve
-Emissary veins
Location and contents of foramen spinosum
Location
-Sphenoid bone
Contents
-Middle meningeal branch of mandibular nerve
-Middle meningeal artery
Foramen rotundum location and contents
-V2
Location
-Sphenoid bone
Foramen lacerum
Location:
-Sphenoid bone
Contents:
-ICA (passes along superior surface but does not traverse it)
-Vidian nerve (nerve of pterygoid canal–> formed by union of deep petrosal and greater petrosal )
-Artery of the pterygoid canal
Vidian nerve innervates pterygopalatine ganglion: parasympathetic to nasal and lacrimal glands. Greater petrosal provides parasympathetic from facial nerve
Location and contents of optic canal
Location:
-sphenoid bone
Contents
-Optic nerve + 3 layers of dura –> meningeal infection is seen as papilloedema
-Opthalmic artery
-Sympathetic nerves
Superior orbital fissure location and contents
Location:
-Sphenoid bone
Contents
-Superior and inferior division oculomotor nerve
-Trochlear nerve
-All 3 branches V1 (NFL)
-Abducens nerve
-Superior and inferior ophthalmic veins
Carotid canal
Location
–> temporal bone
Contents: ‘side’
–> sympathetic plexus around artery
–> internal carotid artery
–> deep petrosal nerve
–> emissary veins
Location and contents of jugular foramen
Location:
-Temporal bone
Anterior compartment: inferior petrosal sinus
Intermediate: 9,10,11
Posterior: sigmoid sinus (becoming IJ), meningeal branches from occipital and ascending pharyngeal arteries
Stylomastoid foramen location and contents
-Stylomastoid artery
-Facial artery
Foramen magnum
Bone: occipital bone
Contents:
-Arteries: vertebral arteries forming basilar artery, anterior and posterior spinal arteries
-Veins: spinal veins
-Nerve: Spinal part of accessory nerve (ascends up and joins cranial part of accessory nerve to exit via jugular foramen)
-Soft tissue: End of medulla and beginning of spinal cord, meninges
Identify:
-Trigeminal impression for trigeminal ganglion
-Squamous part of temporal bone
-Tegmen Tympani
-Frontal crest
-Clivus
-Groove for transverse sinus
-Internal occipital protuberance
-Hypoglossal canal
- What is the cranial nerve track on the clivus?
- What juvenile structure forms the clivus?
- Abducens nerve
- Spheno-occipital synchondrosis
What are the benign tumours of the posterior cranial fossa
-Haemangioblastoma
-Acoustic neuroma
-Ependymoma
-Ependymoblastoma
What muscles attach to the styloid process
-Styloglossus
-Stylopharyngeus
-Stylohyoid
What are the causes of lytic skull lesions?
-Lytic skeletal metastasis
-Multiple myeloma
-Paget’s disease
-Sarcoidosis
-Osteomyelitis
-Haemangioma
Identify the anterior cranial fossa and its borders
Anterior/lateral border:
-Inner surface of the frontal bone
Posterior medial:
-Limbus of sphenoid bone: the limbus is a bony ridge that forms the anterior border of the prechiasmatic sulcus (a groove running between the right and left optic canals).
Posterior lateral:
-Lesser wings of sphenoid bone
Floor:
-Frontal bone, ethmoid bone, anterior aspect of body and lesser wing of sphenoid bone
Foramina
-Anterior ethmoid foramen
-Posterior ethmoid foramen
Describe the boundaries and contents of the middle cranial fossa
Anterior and lateral: lesser wing of sphenoid bone
Anterior and medial: limbus of sphenoid bone
Posterior and lateral: Superior border of petrous part of the temporal bone
Posterior and medial: dorsum sellae of sphenoid bone
Floor:
-Body and greater wing of sphenoid
-squamous and petrous parts of the temporal bone
Contents
–> temporal lobe
Identify the borders of the posterior cranial fossa
Anteromedial: dorsum sellae of the sphenoid bone
Anterolateral: superior border of petrous part of the temporal bone
Posterior: internal surface of the squamous part of the occipital bone
Floor:
–> mastoid part of the temporal bone
–> squamous, condylar and basilar parts of occipital bone
Where are the cavernous sinuses?
There are two cavernous sinuses lying either side of the sella turcica
Where do the cavernous sinuses drain blood from and to?
From:
-Superior ophthalmic vein
-Facial veins
-Emissary veins from pterygoid plexus
-Sphenoparietal sinuses
To:
-Superior and inferior petrosal sinuses
-IJV
-Intercavernous sinus
Contents of the cavernous sinus
Lateral wall:
-Oculomotor
-Trochlear
-Ophthalmic (V1)
-Maxillary (V2)
Within cavernous sinus itself:
-internal Carotid
-Abducens (6)
What is the clinical significance of the cavernous sinus?
Cavernous sinus thrombosis
-Infections from danger area of face (drained by ophthalmic and facial veins) can spread to the cavernous sinus as they are valveless and cause cavernous sinus thrombosis
What are the signs of cavernous sinus thrombosis?
-Painful swelling of the eye
-CN palsy of 6, 3, 4, V1, V2
Describe cavernous sinus syndrome
-Cavernous sinus syndrome is most often caused by cavernous sinus tumours
-Diagnosis is based on signs of pain, ophthalmoplegia, proptosis, trigeminal nerve lesion (ophthalmic branch) and horner’s syndromes
What are the paired dural venous sinuses?
-Sphenoparietal
-Superior petrosal
-Sigmoid
-Cavernous
-Transverse
-Inferior petrosal
What are the unpaired dural venous sinuses?
-Superior sagittal
-Inferior sagittal
-Straight
-Occipital
-Anterior intercavernous
-Posterior intercavernous
-Basilar venous plexus
What is the major vein draining the brain parenchyma
Great cerebral vein
Describe the location of the straight sinus
Junction between tentorium cerebelli and the falx
What is the blood supply to temporalis muscle
Deep temporal (anterior and posterior) from maxillary arteryW
What supplies the scalp over the temporalis?
Superfiical temporal artery from ECA
What are the regions drained by pre-auricular lymph nodes?
-Upper half of face
-Temporal region
-Auricle and external auditory meatus
-Gums
What is the roof of the middle ear?
Tegmen tympani
How do middle ear infections enter the skull?
Direct erosion of tegmen
May also spread to mastoid air cells causing mastoiditis
