Anatomy and imaging head and neck Flashcards
What is the 1st cranial nerve?
The olfactory nerve
How does cranial 1 enter the skull?
Through the cribriform plate and ethmoid bone
What is the 2nd cranial nerve?
The optic nerve
What is the 3rd cranial nerve?
Occulomotor nerve
What is the deep origin of occulotor nerve?
Motor nucleus: supply extraocular muscles
Parasympathetic nucleus: edinger westphal nucleus (ciliary ganglion)`
How does the 3rd cranial nerve exit the brain?
From the anterior surface of the idbrain in the interpeduncular fossa
What is the 4th cranial nerve?
Trochlear nerve
What is the deep origin of cranial 4?
FRom the trochlear motor nucleus in the lower part of the midbrain (superior oblique muscle)
What is the superficial attachment and exit from brain of cranial 4 nerve?
The nerve appears on the back of midbrain (the right nerve comes from the left nucleus and vice versa)
What is the cranial nerve 6?
Abducent nerve
What is the origin of cranial 6>
Abducent motor nucleus in the pons (lateral rectus muscle)
What is the superficial attachment ad exit from brain?
At the lower border of pons near the midline
What is the 5th nerve?
Trigeminal nerve
Where does nerve 5 arise from?
Lateral aspect of pons by 2 roots (sensory and motor roots)
What are the divisions of the trigeminal nerve and where do they exit from?
1.Opthalamic division exit through superior orbital fissure
2.Maxillary division exit through foramen rotundum
3.Mandibular division exit through foramen oval
What is the 7th cranial nerve?
Facial nerve
What type of nerve is the facial nerve?
mixed (motor, sensory and parasympathetic)
What is the origin of the facial nerve?
Emerges at lower end of pons (pontocerebellar junction)
What does the facial nerve exit through?
Stylomastoid foramen from the skull
What is the origin of the facial nerve?(cranial nerve nuclei)
1.Motor: facial motor nucleus in the pons
2.Parasympathetic: Superior salivary nucleus in the pons
3.Special sensory= taste: Nucleus solitarius in the medulla
What are the intracranial branches of facial nerve?
Greater petrosal nerve
Chorda tympani
Nerve to stapedius
What are the extracranial branches of facial nerve?
Nerve to posterior belly of digrastic & stylohyoid
Posterior auricular
Branches within the parotid gland
Where does hypoglossal nerve exit from?
Hypoglossal canal
Where do cranial nerves 9, 10, 11 exit from?
Jugular foramen
what is the type of nerve of nerve IX?
Motor, sensory, parasympathetic
What is the motor origin of the cranial nerve IX?
Nc ambiguus
What is the other origin of the cranial nerve IX?
Taste sensation posterior 1/3 of tongue: Solitary nucleus
Parasympathetic to parotid: Inferior salivary nucleus
What are the sensory branches of cranial nerve IX?
Tonsillar
Lingual
Pharyngeal
Carotid
What type of nerve is cranial nerve X?
Mixed
What is the origin of cranial nerve X?
Motor : Nucleus ambiguus
Parasympathetic: Dorsal nucleus of vagus
Sensory nucleus: Nucleus solitarius
What are the branches of the vagus nerve?
Meningeal branch
Auricular branch
Two cardiac branches
(Motor) pharyngeal branch
Laryngeal branch
What does the pharyngeal branch of cranial nerve X innervate?
Supplies all muscles of pharynx except stylopharyngeus (9th) and all muscles of the soft palate except tensor palati (5th)
What is the course of the Recurrent laryngeal branch?
The right RL hooking around the subclavian artery
The left RL hooking around the arch of aorta
What are the clinical symptoms of Blow out?
Diplopia
Infra orbital nerve parasthesia
Enophthalmos
Enophthalmos
Edema
Ecchymosis
What are the layers of eyelid?
1.Skin devoid of fat
2.Muscle: Orbicularis occuli and levator palpebrae superioris
3.Fibrous tarsal plate
4.Conjunctiva
What is the function of the tarsal plate?
Stiffen the eyelid
What is the tarsal plate formed off?
Fibrous tissue
How is the tarsal plate connected to the orbital margin?
By the orbital septum
Medial and lateral palpebral ligaments connect the tarsal plates to the sides of the orbit
What are the types of palperal gland infection?
Stye: inflammation of the eyelid associated with a small collection of pus
Chalazion: Small, painless, lump or swelling that appears on your eyelid by a blocked meibomian or oil gland
What structures pass through the orbital canal?
Optic nerve, opthalmic artery
What structures pass superior to orbital fissure?
Live Free To See No Insult At all
Lacrimal, Frontal, Trochlear, Superior division of occulomotor, Nasociliary, Inferior division of occulomotor, Abducent
Which bones are affected in an orbital blow out fracture?
Zygomatic and maxillary
What happens in an orbital blow out?
A rapid increase in intraorbital pressure resulting in a blowout fracture of the thin orbital floor. In severe comminuted fractures of the orbital floor the orital soft tissues may herniate into the underlying maxillary paranasal sinus
What is the conjunctiva?
A continuation of the epithelium of the coreathat lines the deep surface of the eyelid and exposed part of the eye.
WHat are the reflections of the conjunctiva?
The superior and inferior fornix
What is the pathway that a tear takes?
Exits through the opening of the lcrimal canaliculi called lacrimal punctum into the lacrimal canaliculi and than into the lacrimal sac and goes down through the nasolacrimal duct
What caues dry eye?
Injury of facial nerve at brainstem (cerebelloponine angle)
Which nerve innervates the lacrimal gland?
Lacrimal nerve V1
What is the pathway of the lacrimal nerve V1?
Lacrimatory nucleus in brainstem to facial nerve to greater petrosal nerve relaying athe pterygopalatine ganglia into the zygomatic branch of maxillary nerve v2 to the lacrimal nerve
What is the insertion and origin of the extrinsic muscles?
Origin: Tedinous ring and bones of the orbit
Insertion: The sclera
Where does the LPS go from to?
Froom: roof of orbit
To: Upper eye lid
What is the action of the Levator palpebrae superioris?
Elevates upper eye lid
What is the origin of recti?
Tendineous ring of zinn
What are the extrinsic muscles of the eye?
4 rectus
Superior rectus
Lateral rectus
Inferior rectus
Medial rectus
2 Oblique
Superior oblique
Inferior oblique
What is the origin of the 4 recti?
Common tendinous ring
What is the insertion of the recti?
Sclera
What is the origin of the superior oblique?
Roof of the orbit –> pulley (trochlea)
What is the insertion of the superior oblique?
Eye ball behind the equator
What is the origin of the inferior oblique?
Floor of the oribit (medial)
What is the insertion of the inferior oblique?
Eye ball behind the equator (lateral)
What direction does the eyeball look when using the inferior oblique?
laterally upwards
What direction does the eyeball look when using the superior oblique?
Laterally and downwards
What direction does the eyeball look when using the lateral rectus?
look laterally
What direction does the eyeball look when using the medial rectus?
look medially
What direction does the eyeball look when using the superior rectus?
Look medially upward
What direction does the eyeball look when using the inferior rectus?
Look medially downwards
What is the action of uperior and inferior Recti?
Adduction plus elevation and depression
What is the action of the superior and inferior obliques?
Actions opposite of their name (SO= depress, IO=elevate)
Abduction
What is the action of the superior oblique and rectus?
Intorsion
What is the action of the inferior oblique and rectus?
Extorsion
Which muscles move the eye from side to side?
Medial & lateral recti
What are the intraoccular muscles and what are their innervations?
1.Constrictor pupillae (Parasympathetic)
2.Dilator pupillae (sympathetic)
3.Ciliary (parasympathetic)
What do the sympathetic fibers supply ?
The smooth part of the levator palpebrae superioris, so LPS has double nerve supply
What are the occulomotor superior divisions?
Superior rectus and levator palpebrae
What are the occulomotor inferior division?
Medial rectus, inferior rectus and infrior oblique
Which nerves innervate most of the muscles?
Cranial nerve III Occulomotor
Which nerve innervates superior oblique muscles?
Cranial nerve IV (trochlear)
Which nerve supplies the laterl rectus ?
Cranial nerve VI (Abducent)
What are the sensory nerves of the orbit?
optic
Trigeminal opthalmic:
Lacrimal
Frontal
Nasociliary
What is the motor nerves of the orbit?
Oculomotor III
Trochlear IV
Abducent VI
What is the course of the optic nerve?
Axons of nerve cells of retina
Pierce sclera 3 mm medial to posterior pole
Backward & medially –> optic canal–> middle cranial fossa –> optic chiasma
where does the inner ear lie?
In the petrous temporal bone between the medial ear and the bottom of the internal auditory meatus
What is the inner ear formed off?
1.bony labyrinth
2.Membranous labyrinth
