Anatomy Flashcards
1
Q
what are the choanae
A
posterior nasal apertures. Closed off during swallowing by the soft palate meeting the superior constrictor muscle.
2
Q
What are the 3 parts of the septum
A
- Perpendicular plate/extension of the ethmoid bone (where falx cerebri runs forward).
- Septum cartilage
- Vomer bone
3
Q
Role of the conchae
A
Increase S.A. of nasal cavity so more efficient at heating and humidifying the air as it passes to the lungs.
4
Q
What are the conchae made from
A
superior and middle part of ethmoid bone
5
Q
What does the superior meatus drain
A
posterior ethmoidal sinus/cells
6
Q
What does the middle meatus drain
A
Via the infundibulum = Frontal sinus.
Via the hiatus semilunaris = Anterior ethmoidal sinus/cells and maxillary sinuses.
7
Q
What does the inferior meatus drain
A
nasolacrimal duct
8
Q
Respiratory epithelium
A
Pseudostratified columnar ciliated epithelium + goblet cells
9
Q
How does the mucoperiosteum act to warm air in the nasal cavity
A
Very rich in blood vessels which swell when increased blood flow and reduce the volume of nasal cavity so make it warmer.
10
Q
Blood supply of nasal cavity
A
Ophthalmic artery = upper and front parts of midline septum.
Facial artery = upper hard palate and lower parts of the septum.
Maxillary artery = posterior septum and lateral wall.
11
Q
Role of sinuses
A
Lighten skull weight and add resilience to the skull
12
Q
Maxillary sinus
A
V thin bone b/w it and upper molars - careful when extracting to avoid fistulas.
High ostium so mucous accumulates before it can be cleared.
13
Q
Frontal sinus
A
Drains above maxillary sinus in middle meatus = cross infection
14
Q
Sphenoidal sinus
A
Drains into the sphenoethmoidal recess above the superior conchae.
15
Q
Innervation of the nasal cavity
A
Infraorbital nerve = skin of the nose, lower eyelid, cheek, top lip.
Post-ganglionic fibers = glands, air sinuses, gingivae
16
Q
Endothelial structure of the lymph ducts
A
Overlapping endothelial cells allow fluids to move in but not flow out.
17
Q
What does the right lymphatic duct drain
A
The right side of the body, above the waist only.
18
Q
What does the thoracic duct drain
A
All of the body apart from right side above the waist.
19
Q
Where does the thoracic duct empty
A
Venous blood supply, between the left subclavian and jugular veins.
20
Q
Superficial lymphatic vessels are found above which muscle
A
Sternocleidomastoid, and along external jugular.
21
Q
Lymph nodes that drain into the deep cervical nodes
A
Pre-auricular, submental and submandibular node.
22
Q
Lymph nodes that drain to the superficial nodes
A
Post-auricular and occipital node.
23
Q
Face lymphatic nodes and areas they drain
A
Pre-auricular (drains eyelids, cheeks, and part of scalp)
Post-auricular (drains posterolateral scalp)
Submental (drains chin, tip of tongue, bottom lip, floor of mouth, incisors)
Submandibular (face, gingivae, teeth and tongue)
Occipital (posterior scalp and neck)
24
Q
Which lymphatic nodes drain the scalp
A
Post-auricular, pre-auricular and occipital
25
Which lymphatic nodes drain the teeth
Submandibular (apart from incisors which are drained by the submental)
26
What is the midline raphe (tongue) and why is it important
Impervious lymph border at anterior 2/3 of tongue. Means cancer can't spread from one side of tongue to the other through the lymph vessels. Deficient at tip and posterior 1/3 of tongue.
27
Which lymph node drains anterior 2/3 of tongue
```
Directly = deep cervical nodes
Indirectly = submental and submandibular nodes
```
28
Which lymph nodes drain posterior 1/3 of tongue
the Jugulodigastric node of the deep cervical chain
29
Which lymph node drains tip of the tongue
Submental node then to jugulo-omohyoid node
30
Bones that make up the roof of the orbit
Frontal bone
| Lesser wing of the sphenoid bone
31
Bones that make up the medial wall of the orbit
Lacrimal bone
Ethmoid bone
Maxilla bone
Body of the sphenoid bone
32
Bones that make up the lateral wall of the orbit
Zygomatic bone
| Greater wing of the sphenoid bone
33
Bones that make up the floor of the orbit
Maxilla bone
Palatine bone
Zygomatic bone
34
Openings into the orbit
Superior orbital fissure
Optic canal
Inferior orbital fissure
35
What structures are in the superior orbital fissure
CN 3,4,5 (V1)
| Superior ophthalmic vein
36
What structures are in the optic canal
```
CN 2 (Optic nerve)
Ophthalmic artery
```
37
What structures are in the inferior orbital fissure
```
CN 5 (V2)
Inferior ophthalmic vein
```
38
Where do all 4 rectus muscles originate from
Annulus of Zinn
39
What's a blow-out fracture of the eye and how does it happen
When the force on globe > strength of bones so the globe breaks/bursts through the bony orbit.
40
What is proptosis
Forward displacement of the globe caused by any bleeding or growth in the orbit. Can cause compression of vessels and nerves here.
41
What is the role of the tarsal plate
Next to the globe, connective tissue which gives strength and structure.
42
Which muscles open the upper eyelid
Levator and Muller muscles
43
Which muscles close the upper eyelid
Orbicularis oculi
44
Which muscles open the lower eyelid
Lower Muller muscle
45
Which muscles close the lower eyelid
Orbicularis oculi
46
What glands are found in the orbit/globe
Meibomian glands - Sebaceous/secretes oil to stop tears evaporating and to lubricate.
Glands of Zeis - secrete oil onto lashes
Gland of Moll - Apocrine/sweat gland onto the skin.
47
What is the conjunctiva and its functions
Thin translucent mucous membrane over the globe.
Functions =
1. Lubrication (goblets cells secrete mucous)
2. Physical barrier - immunological defence.
48
Globe nerve innervations and their functions
CN II - sight, accomodation and pupil reflex
CN III - 4 extra-ocular muscles, upper levator muscle, iris muscles.
CN IV - superior oblique muscle
CN VI - lateral rectus muscle
CN VII - orbicularis oculi muscles, blink reflex
49
Action and innervation of the superior rectus muscle
CN III
| Elevates
50
Action and innervation of the medial rectus muscle
CN III
| Rotates globe medially
51
Action and innervation of the lateral rectus muscle
CN VI
| Rotates globe laterally
52
Action and innervation of the inferior rectus muscle
CN III
| Depresses
53
Action and innervation of superior oblique muscle
CN IV
| Depresses and rotates the eye laterally
54
Action and innervation of inferior oblique muscle
CN III
| Elevates and rotates the eye laterally
55
Movement of the arytenoids and how this affects phonation
Rotate around verticle axis: Inwards (adduction) and outwards (abduction).
Sliding: Medially (adduction) and laterally (abduction)
Tilting: Backwards (increase tension) and forwards (increase thickness, decrease tension).
56
Role of the conus elastus
Muscle covering the vocal folds and constrict the larynx vertically from the vocal folds to the cricoid.
57
Adduction definition
Closing
58
Abduction definition
Opening
59
Vocal folds open/close cycle
1. -->F F, vocal folds open
60
What about the vocal folds affects pitch
Length
Tension
Thickness
61
How can the pitch of a voice be altered
Tilting arytenoids backward or forwards
62
What happens to overused vocal folds
Hemorrhaging or nodules/growths on them = lower quality of sound.
63
Laryngeal muscles
```
Transverse and oblique interarytenoids
Posterior cricoarytenoids
Lateral cricoarytenoids
Thyroarytenoids
Cricothyroids
Vocalis
```
64
Action of lateral cricoarytenoids
Forcefully adduct the arytenoids e.g. during speech
65
Action of the cricothyroid muscles
Act on the cricothyroid synovial joint to make the initial movements. Move cricoid up, tipping arytenoids backward and increasing tension in vocal folds.
66
Action of the vocalis muscles
Make fine adjustments. Pad out the vocal folds and move arytenoids forward, decreasing tension in vocal folds.
67
What nerves innervate the larynx
Recurrent laryngeal nerve and superior laryngeal nerve (branches off vagus nerve)
68
What does the superior laryngeal nerve supply
Motor to cricothyroid muscles
| Sensory to mucosa above vocal folds
69
What happens if the superior laryngeal nerve is damaged
No cough reflex and hard to regulate pitch of voice.
70
What does the recurrent laryngeal nerve supply
Motor to all laryngeal musles apart from cricothyroid muscles (bilateral to interarytenoids)
71
What happens if the recurrent laryngeal nerve gets damaged
Harsh raspy voice bc vocal folds are tensed (due to cricothyroid muscles) and adducted (weak action from interarytenoids due to bilateral innervation)
72
Muscular tissue of pharynx
3 constrictor muscles (attached to the stylohyoid ligament) and 2 longitudinal muscles (palatopharyngeal and stylopharyngeal). Create a pressure wave to push food down into the stomach.
73
What are the 4 layers of tissue making up the pharyngeal wall
1. Areolar CT (buccopharyngeal fascia containing nerve and venous plexus).
2. Muscular tissue.
3. Fibrous tissue (attaches pharynx to the base of the skull and medial pterygoid plates).
4. Mucosa (respiratory = upper, remainder = SSE).
74
During swallowing, how does the mouth get closed off
Tongue moves up and meet hard palate
75
During swallowing, how does the nasal cavity get closed off
1. Superior constrictor muscle moves down to meet the soft palate
2. LVP and TVP move the soft palate up
3. Uvula moves up
76
During swallowing, how does the laryngeal opening get closed off
1. Hyoid bone and thyroid cartilage move up and forward (due to the action of geniohyoid and constrictor muscles) so epiglottis flops down and covers the opening.
2. Arytenoid cartilages move forwards and medially (due to the action of the laryngeal muscles) to close of the glottis using the vocal folds.
77
CN I (5 points)
1. Olfactory nerve
2. Foramen = Cribriform plate of the ethmoid bone
3. Enters = Nasal cavity
4. Sensory
5. Olfactory epithelium, allows for the sense of smell
78
CN II
1. Optic nerve
2. Foramen = optic foramen / canal
3. Enters = orbit
4. Sensory
5. Retina (vision) and a part of the accommodation and pupil reflexes.
79
CN III
1. Oculomotor
2. Foramen = Superior orbital fissure
3. Enters = Orbit
4. Motor
5. Target = eye and eyelid muscles internal and external.
80
CN IV
1. Trochlear
2. Foramen = Superior orbital fissure
3. Enters = orbit
4. Motor
5. Target = superior oblique muscle of the eye
81
CN V1
1. Opthlamic branch of trigeminal
2. Foramen = Superior orbital fissure
3. Region entered = orbit
4. Sensory
5. Skin and mucosa at and above orbit
82
CN V2
1. Maxillary branch of Trigeminal
2. Foramen = Foramen rotundum
3. Target = Pterygopalatine fossa
4. Sensory
5. Skin and mucosa from orbit to mouth e.g. palate, nasal cavity.
83
CN V3
1. Mandibular division of Trigeminal
2. Foramen = Foramen ovale
3. Enters = Infratemporal fossa
4. Mixed
5. Targets = M to M of M and mylohyoid and other head/neck muscles. S to skin and mucosa from mouth to chin and anterior 2/3 of tongue.
84
CN VI
1. Abducens
2. Foramen = Superior orbital fissure
3. Enters = orbit
4. Motor
5. Target = lateral rectus muscle
85
CN VII
1. Facial
2. Foramen = Internal acoustic meatus. Exits at stylomastoid foramen.
3. Enters = Temporal bone
4. Mixed
5. M = muscles of facial expression and head/neck muscles. S = taste to anterior 2/3 of tongue
86
CN VIII
1. Vestibulocochlear
2. Foramen = internal acoustic meatus
3. Enters = Temporal bone
4. Sensory
5. Targets = balance and hearing
87
CN IX
1. Glossopharyngeal
2. Foramen = Jugular foramen
3. Enters = Middle ear/infratemporal fossa
4. Mixed
5. Targets = M to stylopharyngeus muscle and parotid gland. S to the pharynx, middle ear, auditory tube and taste to posterior 1/3 of the tongue
88
CN X
1. Vagus nerve
2. Foramen = Jugular foramen
3. Mixed
4. M to pharynx, larynx, soft palate and thorax. S to larnx.
89
CN XI
1. Accessory nerve
2. Foramen = jugular foramen / formamen magnum
3. Enters = neck
4. Motor
5. Targets = sternocleidomastoid and trapezius muscles
90
CN XII
1. Hypoglossal nerve
2. Foramen = Hypoglossal canal
3. Enters = neck
4. Motor
5. All tongue muscles apart from palatoglossus (CN X)
91
Damage to CN III (and test)
Diplopia, lateral squint and dilated pupils.
| Test = see if the patient can follow pen across all visual fields.
92
Damage to CN II
Damage to optic tract = complex visual loss
Damage at optic chiasm = loss of temporal fields
Damage to optic nerve = blindness in that eye
93
Damage to CN VII
If after middle ear, taste and lacrimation are intact but facial expression lost on that side.
94
What does the facial nerve supply + what are the branches
Branches = Temporal, Zygomatic, Buccal, Mandibular, Cervical.
Muscles = Zygomaticus, Buccinator, Frontalis, Orbicularis Oculi and Oris, Lip depressors and elevators.
Secretomotor nerves to Lacrimal, Submandibular and Sublingual glands.
Taste to anterior 2/3 of tongue (Chorda Tympani)
95
Damage to CN VIII (and test)
Damage to cochlear or nerve = sensorineural hearing loss.
Test = high f tuning fork near the ear and if still not heard, on mastoid process. If only heard on mastoid process = conductive hearing loss only.
96
What does CN IX supply
```
M = stylopharyngeus and to the parotid gland
S = mucosa of the pharynx, posterior 1/3 of the tongue, middle ear and auditory tube.
```
97
Damage to CN IX
No gag reflex
98
What does CN X supply
```
M = muscles of the pharynx (constrictor muscles and palatopharyngeus), larynx (and soft palate
S = mucosa of the larynx
```
99
Damage to CN X (and test)
Damage to muscles of the palate (dysarthria/speaking problems), pharynx (dysphagia/problems swallowing) and larynx (dysphonia/problems making sounds).
Test = see if the patient can cough strongly and soft palate raises symmetrically when speaking.
100
Testing CN XII
See if the patient can stick out tongue without it deviating to one side.
101
3 things unique about the TMJ
1. The R and L synovial joints are connecting by bone so move together.
2. Articular surfaces of the joint are covered in fibrocartilage.
3. Articular disc separates the cavity into 2.
102
The ligaments found around the TMJ
Tempromandibular/ lateral ligament
Sphenomandibular ligament
Stylomandibular ligament
103
Borders of the posterior triangle (neck)
Clavicle, posterior border of sternocleidomastoid and anterior border of trapezius
104
Where does the external jugular vein drain blood from
Outside of skull, deep parts of face
105
What can make the external jugular vein stand out
Valsalva's maneuver (forced exhalation against resistance) and increased vena cava/central venous pressure e.g. due to right-sided heart failure.
106
The infrahyoid muscles
Thyrohyoid
Omohyoid (inferior and superior bellies)
Sternothyroid
Sternohyoid
107
Innervation of the infrahyoid muscles
Ansa Cervicalis from Cervical spinal nerves 1-3
108
Function of the infrahyoids
Depress the larynx and hyoid bone after swallowing
109
What does the carotid sheath contain
internal jugular vein
Common Carotid artery
Vagus nerve
110
What does the superior thyroid artery supply and what does it branch off
Branches off the eternal carotid and supplies the superior anterior aspect of the thyorid
111
What does the inferior thyroid artery supply and what does it branch off
Branches off the thyrocervical artery (from the subclavian) and supplies the inferior posterior aspect.
112
Why are tumours in the thyroid area v dangerous
Because they can compress the oesophagus or trachea
113
Borders of the anterior triangle (neck)
Anterior side of sternocleidomastoid, mandible and midline of neck.
114
What does the ansa cervicalis supply and which nerves does it branch off
Supplies the infrahyoid muscles and geniohyoid.
| Branches of the cervical spinal nerves 1-3 (part of the cervical plexus)
115
Main branches of CN V1
Frontal branch
Lacrimal branch
Nasociliary branch
116
Main branches of the cervical plexus and which nerves is it made up of
Made from Cervical spinal nerves 1-4
Main motor branches = ansa cervicalis and phrenic nerve (C3,4,5 keep the diaphragm alive)
Sensory branches = auricle nerve, transverse cervical nerves.
117
How to do an emergency cricothyroid stab/tracheotomy
Incision between the thyroid and cricoid cartilages and insert a tube.
118
What are the suprahyoid muscles
Mylohyoid muscle
Geniohyoid muscle
Stylohyoid muscle
Digastric muscle (anterior and posterior bellies)
119
The action of the suprahyoid muscles
Elevate the hyoid bone during swallowing.
120
Borders of the submandibular triangle
Anterior belly and posterior belly of digastric muscle and mandible.
121
Anatomy of the submandibular gland and its duct
Deep part hooks around posterior margin of the mylohyoid muscle.
Secretions travel in Wharton's duct
122
Branches of the external carotid artery
```
Some attendings like freaking out potential medical students.
SALFOPMS
Superior thyroid
Ascending pharyngeal
Lingual
Facial
Occipital
Posterior Auricular
Maxillary
Superficial temporal
```
123
Damage to the cervical sympathetic chain
Drooping of eyelid, no sweating/flush skin, constricted pupil = Horner's syndrome
124
What is the modiolus
Place at the corner of the mouth where 8 muscles meet.
125
What are the branches of the facial nerve and which branches supply the muscles of facial expression.
```
Temporal - frontal, orbicularis oculi
Zygomatic - orbicularis oculi
Buccal - buccinator, orbicularis oris, zygomaticus
Mandibular - mentalis
Cervical
```
126
The action of Masseter/ the deep and superficial part features
Closes mouth by elevating jaw. Has many origins so can retract and protrude jaw too. Deep part is more muscular and more for closing (verticle fibres). Superficial is more tendonous (for opening). Diff angels so the max force can be exerted through the whole range of movements.
127
Action of Temporalis
Closes jaw by elevating and retracting mandible. Weaker action than masseter.
128
Action of the Lateral Pterygoid
Opens mouth by protruding jaw - moves articular disc and condyle forward
129
Action of the Medial Pterygoid
Closes mouth by elevating jaw. Also protrudes jaw.
130
Origin of the buccal nerve, its path and what it supplies
From V3
Pierces masseter but doesnt supply it and enters mouth
Sensory to lower buccal and gingival mucosa.
Motor to lower temporalis and pterygoid muscles.
131
What does the mylohyoid nerve branch off and what does it supply?
Branch off V3, inferior alveolar nerve.
| Supplies mylohyoid muscle and anterior belly of digastric muscle.
132
Order of branching off V3
```
Mandibular nerve
Buccal nerve (with branches to M of M)
Auriculotemporal nerve
Lingual nerve (with Chorda Tympani)
Inferior alveolar nerve (with mylohyoid, inferior dental and mental nerve branches)
```
133
What does the inferior alveolar artery supply and what does it branch off.
Mandible, chin, lower teeth, mylohyoid muscle
134
What nerves can be found at level of bifurcation of common carotid into external and internal
Hypoglossal and Glossopharyngeal
135
What happens at the germinal centres of lymph nodes
Cells proliferate and mutate and differentiate
136
What are the 4 types of tonsils and type of epithelium.
```
Lingual tonsils (SSE)
Palatine tonsils (SSE)
Adenoids (Respiratory epithelium)
Tubal tonsils (respiratory epithelium)
```
137
What does the internal carotid artery supply
Goes directly to the brain
138
What vessel runs over the sternocleidomastoid muscle
External jugular vein
139
What is the role of the thyroid Isthmus
Connects the 2 lobes of the thyroid
140
What is the shape of the thyroid cartilage
A ring, incomplete posteriorly. Articulates w the cricoid cartilage anteriorly inferiorly.
141
What is the shape of the cricoid cartilage
Complete ring, bigger and flatter posteriorly.
142
Features of cervical vertebrae
Tranverse foramen
Bifid spinous process
Small body
143
Masseter
Origin = Zygomatic arch and process
Insert = Ramus, angle of the mandible and lateral surface of the coronoid process.
Action = elevates mandible (has many origins so can also protrude and retract mandible).
CN V3.
144
Temporalis
Origin = Temporal fossa
Insert = Coronoid process (down to retromolar fossa)
Action = Elevates and retracts mandible
CN V3.
145
Lateral Pterygoid
Origin = Lateral surface of lateral pterygoid plate
Insert = Articular disc and neck of condyle
Action = Protrudes mandible so opens the mouth.
CN V3
146
Medial Pterygoid
Origin = Medial surface of lateral pterygoid
Insert = Inner surface of angle of mandible
Action = Elevates mandible and protrudes.
CN V3
147
Jaw movements
Biting/insicing = Protrude jaw so incisors meet
Mastication = Depress mandible via infra and suprahyoid muscles. Lateral and medial excursion to allow cuspal contact.
Speaking
Limits of movements when yawning.
148
Lateral Excursion of mandible
1. Lateral pterygoid on balancing side contracts to move mandible to working side.
2. Temporalis on working side contracts so working side moves back slightly and balancing side moves medially.
149
TMJ movements
```
Some rotation around the axis of the condyle
Anterior movement (condylar guidance) onto the articular eminence.
```
150
Role of the articular disc
1. Joins lateral pterygoid to the lateral joint surface
2. Pulled forward by lateral pterygoid when the condyle moves forward onto the articular eminence so packs the joint and stabilizes it.
151
TMJ dislocation and how to fix it
When the condyle overshoots the articular eminence. Can only happen anteriorly (there's bone medially and the lateral pterygoid muscle laterally).
Can be fixed by applying downwards and backward force onto the mandible (needs to be done quickly or using muscle relaxants to stop them spasming or locking the jaw in place).
152
TMJ dysfunction
Mostly due to over-closing e.g. grinding teeth.
153
Meningeal Arteries - origin, foramen, location, supply
Branch off the maxillary artery (from the external carotid)
Foramen spinosum
Located in the extradural space and they mostly supply the cranium bones.
154
The Mater's
Dura Mater
Arachnoid Mater
Pia Mater
155
About the dura mater
One layer tightly bound to the cranium and one to the arachnoid mater.
Venous sinuses can be found here.
Creates the dural folds.
156
About the arachnoid mater
Covers the pia mater. Has extensions which run into the pia mater through the subarachnoid space.
157
About the pia mater
Thin layer, very tightly associated with the brain.
158
Dural folds and their functions
Stabilise and support the brain.
Falx Cerebri = Between the cerebrum hemispheres
Falx Cerebelli = Between the cerebellum hemispheres
Tentorium Cerebelli = between the cerebrum and cerebellum hemisphere.
159
Extradural space and consequences of a haemorrage here
A potential space above the Dura Mater containing the meningeal arteries.
As the dura mater is v tightly associated with the cranium, a hemorrhage here can't spread so causes a localized coning and increase in intracranial pressure. This can force the brain down and put pressure on the brain stem = v dangerous.
160
Subarachnoid space and consequeces of a haemorrage here
A real space, containing brain arteries, nerves and CSF (which reduces the brains apparant weight and cusions it).
Slower raise in intracranial pressure as the fluid can spread so less dangerous.
161
Venous drainage of the cranium
Venous blood drains into venous sinuses which follow the path of the dural folds and eventually drain into the internal jugular vein.
162
How do the venous sinuses connect to deep and superficial veins?
Via the orbit, pterygoid and pharyngeal venous plexuses and the emissary veins.
163
What are emissary veins and what problems are associated with them?
Veins that exit the cranium into the nasal sinuses. Have no valves so blood and infections can travel up the brain too.
164
Role of the Circle of Willis
Connects the internal carotid and vertobrobasilar systems.
| Provides an alternative blood supply if there's damage in one of the other vessels.
165
What does the anterior cerebral artery supply and what happens if it gets damaged?
Supplies the medial part of the frontal lobe.
| Damage = Loss of M and S function to opposite leg.
166
What does the middle cerebral artery supply and what happens if it gets damaged?
Supplies the lateral part of the hemisphere (apart from occipital lobe)
Damage = Loss of M and S function to opposite arm and side of the face (and speech).
167
What does the posterior cerebral artery supply and what happens if it gets damaged?
Supplied the medial and inferior part of the occipital and temporal lobe and visual cortex.
Damage = Blindness one 1 side of visual field.
168
Different types of strokes
Ischemic and hemorrhagic stroke
169
Ischemic stroke
A blocked brain artery. Brain function lost after the point of blockage.
170
Hemorrhagic stroke
Trauma, aneurysm etc can cause a tear in a brain artery (blood is toxic to brain tissue). Short-term effects are normally worse than long-term effects and function can return as mass of blood clot decreases.
171
Functions/benefits of CSF
Cushions and protects the brain.
Lightens the apparent weight of the brain.
Carries nutrients and hormones to the brain.
Takes metabolic waste products away from the brain.
172
Embryology time frame
Pre embryonic stage = 0-2.5 weeks
Embryonic stage = 2.5-8 weeks
Fetal stage = 8 weeks - 9 months
173
Post fertilization/early embryonic events
Gastrulation
Neurulation
Development of the pharyngeal arches
174
Gastrulation
Epiblast and hypoblast totipotent cells in the inner cell mass (surrounded by placental cells).
Epiblast cells move down and invaginate, pushing the hypoblast cells out the way.
3 embryonic/germ layers = Ectoderm, mesoderm and endoderm.
175
Neurulation
1. Another germ layer = Ectomesderm (derived from ectoderm but has properties of mesoderm)
2. Ectoderm thickens in the middle to form the neural plate.
3. Crease along the axis of the neural plate
4. Neural folds/plate move together and fuse = neural tube
5. The merged neural folds separate from neural tube = neural crest/epidermis.
6. Neural crest cells move to mesoderm and differentiate into diff types of cells.
176
The fate of the 4 embryonic germ layers
```
Ectoderm = Hair, the epidermis.
Mesoderm = Skeleton, muscles
Endoderm = Epithelium
Ectomesoderm = CNS, PNS
```
177
The 4 (out of 6) embryonic pharyngeal arches all contain ?
Arch bone/cartilage
Arch muscle
Arch cranial nerve
Arch artery
178
Embryonic pharyngeal arch 1
CN V
Muscles of mastication
Meckel's cartilage (= mandible, malleus and incus)
179
Embryonic pharyngeal arch 2
CN VII
Muscles of facial expression
Styloid process, part of the hyoid bone, Stapes
180
Embryonic pharyngeal arch 3
CN IX
Stylopharyngeus
Hyoid bone
181
Embryonic pharyngeal arch 4
CN X
Laryngeal and soft palate muscles
Laryngeal cartilages
182
Laryngeal muscles and their innervation
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Interarytenoids
Posterior cricoarytenoid
Lateral cricoarytenoid
Cricothyroid
Thyroarytenoids
Vocalis
All supplied by CN X (recurrent and superior laryngeal nerves)
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183
Interarytenoids
Adduct the vocal folds
| Recurrent laryngeal
184
Thyroarytenoids
Move the arytenoids forward, relaxing the vocal folds. Makes the initial movements.
Recurrent laryngeal
185
Posterior cricoarytenoids
Abduct the vocal folds
| Recurrent laryngeal
186
Cricothyroid
Acts on the cricothyroid synovial joint to move the cricoid up so it tilts the arytenoids backward and tenses the vocal folds.
Superior laryngeal.
187
Vocalis
Pads out the vocal folds and moves the arytenoids forward, relaxing the vocal folds.
Recurrent laryngeal
188
What does the recurrent laryngeal nerve innervate
M to all the laryngeal muscles (apart from cricothyroid)
189
What does the superior laryngeal nerve innervate
M to the cricothyroid muscle.
| S to laryngeal mucosa up to the vocal folds.
190
What are the pharyngeal muscles and their innervation?
Superior, middle and inferior constrictor muscles (CN X/pharyngeal plexus)
Stylopharyngeus (CN IX)
Palatopharyngeus (CN X/pharyngeal plexus)
191
What are the soft palate muscles and their innervation
LVP (CN X)
TVP (CN V3)
Palatoglossus (CN X)
Palatopharyngeus (CN X)
192
The action of the soft palate muscles
Palatoglossus/pharyngeus elevate the pharynx and larynx.
| LVP and TVP elevate and tense the soft palate.
193
Muscles of the tongue and their innervations.
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Extrinsic:
Palatoglossus
Genioglossus
Styloglossus
Hyoglossus
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Intrinsic:
Superior longitudinal
Inferior longitudinal
Transverse
Verticle
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All supplied by CN Xii apart from palatoglossus (CN X)
194
Palatoglossus
Elevates the posterior tongue / depresses the soft palate.
195
Styloglossus
retract the tongue and elevates the sides
196
Hyoglossus
Depresses the tongue and sides of the tongue and retract tongue
197
Genioglossus
Many actions e.g. protrusion and depression
198
Inferior and superior longitudinal tongue muscle action
Curl apex of tongue down (inferior) / up (superior)
199
Transverse tongue muscle action
Narrow and increase the depth of tongue.
200
Verticle tongue muscle action
Flatten and lengthen the tongue.
201
Attachments of the constrictor muscles
All attach to the pharyngeal raphe at the midline.
Superior = pharyngeal tubercule
Middle = stylohyoid ligament/hyoid bone
Inferior = thyroid cartilage
202
Venous drainage of the brain
Via the sinuses and then to the internal jugular vein.
Superior sagittal sinus
Inferior sagittal sinus
Straight sinus, transverse sinus, sigmoid sinus
203
Ventricles in the brain
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Lateral ventricle (main big one)
3rd and 4th ventricles (joined by the aqueduct)
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204
Type III la forte fracture complications
Can disrupt cranial floor so the brain is open to the outside via nose so can get infected.
