Unit 1: Head and Neck Flashcards
CN I
- olfactory nerve
- sensory (sensation of smell)
- goes through olfactory foramina of the cribriform plate of the ethmoid bone; synapses on the olfactory bulb
- receptors in the nasal cavity (olfactory epithelium)
- transmitted directly through cortex (not thalamus)
Olfactory Bulb
bilateral to the crista galli, lies within the cribriform plate
CN II
- optic nerve
- sensory (detection of visual stimuli)
- goes through the optic canal of the sphenoid bone then crosses at optic chiasm
- receptors in the retina
Optic Chiasm
found at sella turcica of sphenoid bone
Optic Tract
continuation of visual sensory fibers from the optic chiasm to the thalamus (LGN)
Optic Radiations
projection fibers traveling from thalamus to V1 (primary visual cortex) in occipital lobe
CN III
- oculomotor nerve
- motor (control of muscles that move the eye in orbit, voluntary eye movements, constriction of the pupil, eye tracking)
- originate in midbrain, exit the skull through superior orbital fissure of the sphenoid
CN IV
- trochlear nerve
- motor (down and medial eye movements)
- originates in midbrain, exits the skull through superior orbital fissure of the sphenoid
CN V
- trigeminal nerve
- mixed
- 3 branches: ophthalmic (V1), maxillary (V2), mandibular (V3)
CN V1
- ophthalmic branch
- sensory (sensory information from orbital structures and upper third of face)
- passes through superior orbital fissure of the sphenoid
CN V2
- maxillary branch
- sensory (sensory information from the middle third of the face; innervates upper facial features such as lower eye lid, upper lip, etc.)
- enters skull through the foramen rotundum of the sphenoid
CN V3
- mandibular branch
- mixed
- sensory: sensation of lower third (teeth, lower gums, etc.)
- motor: muscles of mastication
- travels through foramen ovale of the sphenoid and mental foramen of the mandible
CN VI
- abducens nerve
- motor: eye movements (abduction of eye; up and laterally)
- originates in pons, leaves the skull through the superior orbital fissure of the sphenoid
CN VII
- facial nerve
- mixed
- sensory: taste
- motor: facial expressions
- enters through the internal acoustic meatus of the temporal bone; emerges from skull through the stylomastoid foramen
CN VIII
- vestibulocochlear nerve
- sensory: balance + equilibrium (receptors in semicircular canals) and hearing (receptors in cochlea)
- exits skull at internal acoustic meatus
CN IX
- glossopharyngeal nerve
- mixed
- sensory: information from posterior portion of the tongue + pain
- motor: muscles that elevate the larynx and pharynx during swallowing
- exits the skull via the jugular foramen
CN X
- vagus nerve
- mixed (largely involved in autonomic function)
- sensory: innervation of skin on head and sensation of heart, etc.
- motor: muscles for swallowing, digestive tract, heart, etc.
CN XI
- accessory nerve
- motor: movements of the head and neck; innervates the sternocleidomastoids and trapezius
- exits the skull via the foramen magnum/jugular foramen
CN XII
- hypoglossal nerve
- motor: innervates intrinsic and extrinsic muscles of the tongue (speaking, swallowing, etc.)
- exits the skull via the hypoglossal canal
how many bones does the neurocranium have?
6: 2 parietal bones, 2 temporal bones, frontal bone, occipital bone
how many bones does the viscerocranium have?
8:
- 2 centred on the midline: vomer, mandible
- 6 are bilateral: maxillae, inferior nasal conchae, palatine, zygomatic, lacrimal bones
what are the landmarks of the frontal bone?
- nasal part
- squamous part
- orbital part
- supraorbital margin/superciliary arch
- supraorbital foramen
- frontal sinus (prevents bones from drying out because of its mucosal lining)
- anterior cranial fossa
what is the function of the supraorbital margin/superciliary arch?
- forms the eyebrow ridge
- contains the supraorbital foramen
what are the landmarks of the occipital bone?
- external occipital protuberance
- external occipital crest
- superior nuchal lines
- inferior nuchal lines
- occipital condyles
- condyloid (condylar) fossa
- groove for transverse sinus
- groove for superior sagittal sinus
- internal occipital crest
- posterior cranial fossa
what are the foramina of the occipital bone?
- foramen magnum
- hypoglossal canal
what is the function of the superior nuchal lines?
origin of the trapezius + occipitalis and insertion of the sternocleidomastoids
where does the flax cerebri attach?
groove for superior sagittal sinus of the occipital bone, the frontal crest of the frontal bone, and the crista galli of the ethmoid bone
where does the tentorium cerebelli attach?
groove for transverse sinus of the occipital bone
where does the flax cerebelli attach?
internal occipital crest of the occipital bone
what is the function of the occipital condyles?
attaches to the atlas
what is the function of the foramen magnum?
- entrance/exit of the vertebral arteries, which provide blood to the brain (cerebellum, posterior cortex, brainstem) and spine
- entrance/exit of spinal cord
- admits passage of the brainstem (medulla oblongata) and the accessory nerve (XI)
what is the function of the hypoglossal canal?
- pathway for the hypoglossal nerve (XII)
what are the landmarks of the sphenoid bone?
- greater wing
- lesser wing
- medial pterygoid plate
- lateral pterygoid plate
- body of sphenoid
- sella turcica
what is the function of the lateral pterygoid plate?
origin of medial pterygoids (medial side) and lateral pterygoids (lateral side)
what are the holes/foramina of the sphenoid bone?
- foramen rotundum
- foramen ovale
- foramen spinosum
- superior orbital fissure
- optic canal
what is the function of the body of the sphenoid?
houses the sphenoidal sinuses
what is the function of the sella turcica?
contains the pituitary gland (also called the pituitary fossa)
what is the function of the foramen rotundum?
passage for the maxillary branch of the trigeminal nerve (V2)
what is the function of the foramen ovale?
passage for the mandibular branch of the trigeminal nerve (V3)
what is the function of the superior orbital fissure?
passage of the oculomotor (III), trochlear (IV), ophthalmic branch of trigeminal (V1), and abducens (VI) cranial nerves
what is the function of the optic canal?
passage of the optic nerve (II)
what are the landmarks of the ethmoid bone?
- crista galli
- cribriform plate
- perpendicular plate
- nasal conchae
what is the function of the crista galli?
attachment point for flax cerebri
what is the function of the cribriform plate?
passage for olfactory nerves that turn into CN I at the olfactory bulb
what is the function of the perpendicular plate?
constitutes part of the nasal septum
what is the function of the nasal conchae?
increase surface area of the nasal cavities for warming and humidification of air passing into the lungs
what are the landmarks of the temporal bone?
- squamous part
- petrous part
- mastoid process
- styloid process
- mandibular fossa
- zygomatic process
- middle cranial fossa
what are the holes/foramina of the temporal bone?
- external acoustic meatus
- foramen lacerum
- carotid canal
- jugular foramen
- stylomastoid foramen
- internal acoustic meatus
what is the function of the mastoid process?
insertion of the sternocleidomastoid and filled with air cells to equalize pressure in the middle ear
what is the function of the styloid process?
attachment point for stylohyoid
what is the function of the external acoustic meatus?
tube connecting inner and outer ear
what is the function of the foramen lacerum (and carotid canal)?
passage for the internal carotid artery
what is the function of the jugular foramen?
passage for the glossopharyngeal, vagus (X), and accessory (XI) nerves + internal jugular vein
what is the function of the stylomastoid foramen?
passage for the facial nerve (VII)
what is the function of the internal acoustic meatus?
passage for the facial nerve (VII) and the vestibulocochlear nerve (VIII)
what suture separates the frontal bone from the parietal bone?
coronal suture
what suture separates the bilaterally paired parietal bones?
sagittal suture
what suture separates the parietal bones from the occipital bone?
lambdoid suture
what is the intersection between the coronal and sagittal sutures called?
bregma
what is the junction of the lambdoid and sagittal sutures called?
lambda
what are the landmarks of the mandible?
- body
- angle
- ramus
- coronoid process (anterior)
- condyle (head/condyloid process) (posterior)
- alveolar part
what is the function of the angle?
insertion of the medial pterygoid
what is the function of the ramus?
insertion of the medial pterygoid and masseter
what is the function of the coronoid process?
insertion of the temporalis
what is the function of the condyle (head/condyloid process) ?
insertion of the lateral pterygoid
what is the function of the alveolar part of the mandible?
origin of the buccinator and articulates with teeth for support
what are the foramina of the mandible and their functions?
- mandibular foramen
- mental foramen
- both are passages for the trigeminal nerve (V)
what are the landmarks of the maxillae?
- frontal process
- body
- zygomatic process
- alveolar process
- maxillary sinus
- palatine process
what is the function of the frontal process of the maxilla?
- origin of the orbicularis oculi
- origin of the medial palpebral ligament
what is the function of the alveolar process of the maxilla?
houses teeth
what is the function of the palatine process?
forms the hard palate
what are the maxillae joined together by?
intermaxillary suture
what is the function of the prefrontal cortex?
executive function
what runs through the sylvian fissure?
middle cerebral artery
what is the precentral gyrus also known as?
primary motor cortex
what is the postcentral gyrus also known as?
primary somatosensory cortex
how are the precentral/postcentral gyri organized and what are their differences?
- medial = lower limb and lower extremities
- lateral = upper limb and face
- primary somatosensory cortex contains genital sensory information
what divides the parietal lobes from the occipital lobe?
parieto-occipital sulcus
what is the lateral parietooccipital line?
the imaginary line that connects the parieto-occipital sulcus and the pre-occipital notch, separating the lobes
where is Broca’s area located?
inferior portion of the frontal lobe
where is Wernicke’s area located?
inferior parietal lobe/posterior temporal lobe
what is the cingulate gyrus?
limbic lobe
what is the limbic lobe’s function and its structures?
- crucial role in emotional processing, memory formation, and regulation of basic instincts and drives such as hunger, thirst, and sexual behavior
- includes the amygdala, hippocampus, hypothalamus, thalamus
what is the calcarine sulcus?
location of the primary visual cortex
how is the visual field organized on the calcarine sulcus?
- superior to sulcus represents inferior visual field
what is the paracentral lobule?
medial extension of the precentral and postcentral gyri
what are the structures of the brainstem?
- midbrain
- pons
- medulla oblongata
- cerebellum
what is the function of the midbrain?
relays sensory and motor information between higher brain centres and spinal cord
what is the function of the pons?
bridge between the cerebellum and the rest of the brain + relaying information from cortex to cerebellum, resulting in coordinated movement
what is the function of the medulla oblongata?
- autonomic centre (heart rate, breathing, etc.)
what is the function of the cerebellum?
balance and smooth, coordinated movement
what are the 3 white matter tracts discussed?
- corona radiata
- internal capsule
- corpus callosum
what are the types of communication fibers?
- association (within hemisphere)
- commissural (between hemispheres)
- projection (lower to higher brain centres)
what is the function of the corona radiata?
projection fibers carrying sensory and motor information to and from the brain
what is the function of the internal capsule?
couples cerebral cortex to deeper structures of the brain + divides thalamus and basal ganglia
what is the function of the corpus callosum?
commissural fibers connecting the hemispheres
what is the basal ganglia composed of?
- caudate nucleus (C-shaped)
- lentiform nucleus (bean)
what is the lentiform nucleus composed of?
- putamen
- globus pallidus (medial to putamen)
what is the role of the thalamus?
relay station and integrative hub for sensory information; gateway for sensory modalities and their respective cerebral areas
what is the role of the basal ganglia (nuclei)?
regulation of voluntary motor control + suppression of involuntary movements + reward centre
what arteries make up anterior circulation?
- common carotid arteries
- internal carotid arteries
- external carotid arteries
- middle cerebral arteries
- anterior cerebral arteries
what are characteristics of the common carotid arteries?
- left CC directly bifurcates into its divisions after aortic arch
- right CC is first the brachiocephalic trunk off the aortic arch which divides into the subclavian artery and the right CC, then bifurcates into internal and external divisions
what does the internal carotid pass through to enter the skull and what does it branch into?
- carotid canal of the petrous portion of the temporal bone
- branches into the anterior and middle cerebral arteries
how do the external carotid arteries project?
laterally
what do the middle cerebral arteries supply?
the lateral surface and temporal poles of the brain
- runs along the sylvian fissure
what do the anterior cerebral arteries supply?
medial and superior surfaces and frontal pole of the brain
what connects the anterior cerebral arteries?
anterior communicating artery
what arteries make up posterior circulation?
- posterior communicating arteries
- vertebral arteries
- posterior inferior cerebellar arteries (PICA)
- basilar artery
- anterior inferior cerebellar arteries
- pontine arteries
- superior cerebellar arteries
- posterior cerebral arteries
what does the posterior communicating artery do?
connects the internal carotid artery to the posterior cerebral artery
where do the vertebral arteries originate?
subclavian arteries
how do the vertebral arteries enter the skull?
through the foramen magnum
what do the posterior inferior cerebellar arteries (PICAs) supply?
medulla oblongata and the inferior aspect of the cerebellum
what does the basilar artery supply?
carries blood to the back of the brain (brainstem, cerebellum, occipital lobe)