Head Flashcards
What structures are transmitted through the jugular foramen?
p. 736 3 compartments separated by transverse septa of dura ANTERIOR COMPARTMENT - glossophagryngeal nerve - inferior petrosal sinus MIDDLE COMPARTMENT - vagus nerge - accessory nerve POSTERIOR COMPARTMENT - termination of sigmoid sinus
What is the relationship between pia mater and underlying brain? What about cerebral arteries?
Like periosteum to bone, nowhere does any structure intervene between pia mater and underlying nervous tissue, even in deepest fissures and sulci.
Fuses with epineurium of cranial nerves.
Arteries lie in loose sheaths of pia.
What structures traverse the subarachnoid space?
- all cranial nerves
- all spinal nerves
- arteries and veins of brain and spinal cord
Structures connecting surface of brain with foramina necessarily pass through subarachnoid space (p718)
What are Arachnoid Villi?
Areas of arachnoid herniating through holes in the dura where CSF “oozes” back into blood
Most numerous in superior sagittal sinus and its “blood lakes”
Collect into arachnoid granulations
See p769 fig 7.16
Where is the jugular foramen?
Formed between deep jugular notch of petrous temporal bone and shallow jugular notch of occipital bone
Smaller carotid foramen anteriorly with tympanic canaliculus in between
p 832 fig 8.5
What are the subarachnoid cisterns?
Large spaces between brain and base of skull
- cerebromedullary cistern (cisterna magnum) between cerebellum and posterior surface of medulla
- pontine cistern between clivus and front of pons/medulla
- interpeduncular cistern: between dorsum sellae and cerebral peduncles roofed by floor of third ventricle
- chiasmatic cistern: above optic chiasm beneath rostrum of corpus calossum
https://images.wikia.com/ranzcrpart1/images/a/a5/Anatomy-of-meninges-ventricles-cerebrospinal-fluid-29-728.jpg
Where is the internal acoustic meatus and what does it contain?
Directed laterally in posterior surface of obliquely set petrous bone
contains
- vestibulocochlear nerve (CN VIII)
- facial nerve (CN VII),
- labyrinthine artery
- vestibular ganglion
What bones form the orbit?
RIM: Frontal, maxilla and zygomatic
Frontal Maxila Zygomatic Sphenoid Ethmoid Lacrimal Palatine
What are the contents of the optic canal?
Optic nerve
Ophthalmic artery
What structures are transmitted via the superior orbital fissure?
Lacrimal nerve (V1) Frontal nerve (V1) Trochlear nerve (CNIV) Superior branches of CNIII Nasociliary branch of ophthalmic nerve (V1) Inferior division of CN III Abducens nerve (CNVI) Superior ophthalmic vein
Lazy French Tarts Sit Nakedly in Anticipation
What structures are transmitted via the inferior orbital fissure?
Zygomatic nerve of CNV2 Infraorbital nerve of CNV2 Inferior ophthalmic vein Infraorbital artery Sympathetics
https://radiopaedia.org/articles/inferior-orbital-fissure-contents-mnemonic?lang=us
What are the borders of the nasopharynx?
The oropharynx?
Base of skull to lower border of soft palate fig 6.21 p 603
Lower border of soft palate to upper border of epiglottis.
Where are the pharyngeal tonsils? What is their other name?
ADENOIDS
On the posterior wall of the nasopharynx
What is the role of cricopharyngeus?
Closure of cricopharyngeus prevents air from being sucked into upper oesophagus when intrathoracic pressure falls.
Where is the opening of the auditory tube in the pharynx?
Above the soft palate in the lateral wall of the nasopharynx. Protected by tubal cartilage and contains tlymphatic tissue (tubal tonsil)
Levator palati underlying
Where are the palatine tonsils located?
What are some nearby important structures?
Palatopharyngeal fold behind, palatoglossal fold in front
Floor is lower part of superior constictor (+ some palatopharyngeus fibres)
Glossopharyngeal nerve crosses lower part of bed runnning oblique down and forwards passing under the lower border of constrictor.
Facial artery separated by superior constrictor from medial surface
Mucosa separates tonsil from uvula
ICA: 2.5cm from internal carotid posterolateraly separated by fat and connective tissue.
Where does a peritonsillar abscess occur?
Outside of the capsule of the tonsil, usually on the lateral surface
What structures are derived from the 2nd pharyngeal arch?
Cranial nerve VII (facial nerve)
Muscles of facial expression
What are the muscles of the eyelids and what supplies them?
- orbicularis oris (palprebral)
- levator papebra superioris/occipitofrontalis (considered scalp and orbital muscles)
NS: temporal/zygomatic CNVII
What are the muscles of the nostrils and what supplies them?
- compressor naris
- dilator naris (arising from maxilla)
- procerus
- levator labii superioris alaeque nasi
- depressor septi
NS: zygomatic/buccal branches CNVII
Describe the function and nerve supply of orbicularis oris
- narrowing of mouth
NS: buccal/marginal mandibular CNVII
damage causes drooping
What is the origin, function and nerve supply of buccinator?
Origin: jaws opposite 1st molar teeth, pterygomandibular raphe (interdigitating with superior constrictor) converging on the modiolus
Functions to return bolus of food from cheek pouch to molar
NS: buccal CNVII
p. 572 fig 6.11
List the branches of the facial nerve and their main functions.
Temporal: wrinkle forehead Zygomatic: blinking Buccal: emptying cheek pouch Marginal mandibular: elevating lip/smile Cervical: fan out neck
p. 575
What is the only area of the face not supplied by the trigeminal nerve and what is it supplied by?
Angle of the mandible
Supplied by greater auricular nerve
p. 545
How are the nuclei of pain vs regular touch arranged regarding the face?
pain: onion skin with centre cranial and forehead/chin caudal
touch: as per the facial nerves
fig 6.13
What are the landmarks that help distinguish between areas of sensory supply to the face?
occipital above the lateral edge of eye, maxillary below
maxillary above lateral edge of lip, mandibular below
Where does the lymph of the face drain?
- submental nodes: chin and tip of tongue
- submandibular nodes: facial tissue from forehead to floor of mouth
- preauricular nodes: temple, orbital contents, cheek
Eventually these all drain to deep cervical nodes
Which structures pass superficial to hyoglossus from superior to inferior?
- lingual nerve
- submandibular duct
- hypoglossal nerve
Which structures pass deep to hyoglossus from superior to inferior?
- glossopharyngeal nerve
- stylohyoid ligament
- lingual artery
Describe the venous drainage of the cerebellum.
into the closest venous sinus to that region
- superior and posterior: straight and transverse sinus
- inferior: inferior petrosal sinus, sigmoid and occipital sinus
accessory vein called superior vermis can drain into great cerebral vein
What are the 3 unique features of the trochlear nerve?
- decussation IN midbrain
- exits DORSAL to fourth ventricle
- smallest cranial nerve
At what levels are the decussations of the cerebellum?
inferior colliculi of midbrain
pons
Which structures form the floor of the fourth ventricle?
medial eminience facial colliculus (abducens nerve nucleus, facial nerve runs over it) stria medullaris (border between pons and medulla)
What are the 7 sections of the internal carotid artery?
- cervical
- petrous
- lacerum
- cavernous
- clinoid
- ophthalmic
- communicating
What are the superior and inferior colliculi responsible for respectively?
Superior: preliminary processing of visual stimuli and vertical gaze centres
Inferior: preliminary processing of auditory stimuli
What is the periaqueductal gray matter for?
control center for descending pain modulation
What is the tegmentum?
What are some structures in there?
Region between cerebral aqueduct and cerebral peduncles
- red nuclei at level of superior colliculus
- reticular formation
- substantia nigra
- medial lemniscus for vibration and proprioception
- spinothalamic tract for pain and temperature
What demarcates the cerebellar peduncles from the pons proper?
The exit of the trigeminal nerve
Where is the corticospinal tract, where does it decussate?
Cerebral peduncles
Decussates at the level of the pyramids in the medulla
Which nerves come off the brain stem at the level of the midbrain? At what level?
Occulomotor nerve (between posterior cerebral artery above and superior cerebellar artery below) Trochlear nerve (dorsally below inferior colliculus)
Which cranial nerves exit at the level of the pons?
CNV
at pontomedullary junction
CNVI
CNVII
CNVIII
What are the role of the olives in the medulla?
Lateral to pyramids on ventral pons
Contain inferior olivary nucleus to regulate motor coordination and learning
What are the cranial nerves associated with the medulla?
exiting lateral to olives
CNIX (glossopharyngeal)
CNX (vagus)
CNXI (accessory)
(medial to all 3 above between olives and pyramids)
CNXII (hypoglossal)
What is the course of the facial artery?
- comes anteriorly off external carotid
- hooks over posterior belly of digastric to touch subamandibular gland
- goes superiorly over inferior border of mandible at anterior border of masseter
- deep to dilators of lips up towards medial angle of eye
Which arteries supply the temple and forehead respectively?
Why is this important?
Temple: superficial temporal (and transverse facial)
Forehead: supraorbital and supratrochelar branches of opthalmic artery
Anastomose freely between eachother and establish communication between internal and external carotid systems.
p 578
What is the final venous drainage of the face?
Angular vein at medial canthus becomes facial vein.
Facial vein accompanies facial artery to border of mandible.
What are the origins, insertions, functions and nerve supply of the medial pterygoid?
Origin: medial surface of the lateral pterygoid plate
Insertion: pterygoid tuberosity on the inner surface of the mandibular angle
NS: CNV3 (medial pterygoid branch)
Function: elevates the mandible (jaw closure) and moves it forward (protrusion).
What are the origins, insertions, functions and nerve supply of the lateral pterygoid?
lateral surface of the latera pterygoid plate
Superior head: infratemporal crest of the sphenoid to the articular disc of the temporomandibular joint
Inferior head: pterygoid process of sphenoid to the condylar process of mandible
NS: CNV3 (lateral pterygoid branch)
Function: bilateral activation of the lateral pterygoid causes protrusion, whereas the unilateral contraction moves the mandible laterally (laterotrusion)
Where do the lobes vs isthmus of the the thyroid lie? (at which level)
isthmus in front of 2-4th tracheal rings
lobes from thyroid cartilage to 6th tracheal ring
What fascia envelopes the thyroid gland?
What muscles are direct relations to it?
enveloped in pretracheal fascia
lateral surface is in contact with sternothyroid and sternohyoid
medial surface in contact with cricothyroid, inferior constrictor, and cricopharyngeus
What is the relationship of the thyroid gland to the recurrent laryngeal nerves?
at the medial surface of thyroid, nerves lie in/in front of groove between trachea and oesophagus
lie close to the inferior thyroid artery or between the branches
nerves divide into two branches at level of isthmus
a “non-recurrent” laryngeal nerve is easily injured
What is a “Killian’s Dehisence” and what is its importance?
fig 6.36
Junciton between oblique fibres of thyropharyngeus and horizontal fibres of cricopharyngeus is a weakness at the posterior pharyngeal wall.
Common site of pharyngeal diverticulum
What are the structures associated with the pharyngeal arches?
1st: trigeminal nerve structures
- muscles of mastication
- tensor tympani/tensor palati
- mylohyoid
- ant belly of digastric
2nd: facial nerve structures
- stapedius
- muscles of facial expression
- stylohyoid
- posterior belly of digastric
3rd: glossopharyngeal nerve structures
- carotid sinus
- stylopharyngeus
4th: vascular structures (subclavian vein, aortic arch), constrictor muscles of pharynx and VAGAL nerves
6th: recurrent laryngeal nerve and its structures, pulmonary arteries, ductus arteriosus
What muscles make up the “strap muscles”
Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid
All lie below the hyoid
Where does the parotid gland open?
On a low papilla opposite the 2nd upper molar tooth
How many teeth does the adult human have?
32 4 x central incisors 4 x lateral incisors 4 x canines 8 x premolars 12 x molars
Which nerves are responsible for the afferent and efferent pathways of the gag reflex?
Lasts p635
Afferent: Glossopharyngeal to nucleus tractus soiltarius
Efferent: Vagal
What structures pass through the foramen ovale?
Otic ganglion V3 Accessory meningeal artery Lesser petrosal n Emissary veins
OVALE
