Lecture 2: Cranial Nerves and Craniofacial Autonomics Flashcards
(94 cards)
1
Q
What CN’s are above pons, in the pons, in medulla, and are medial?
A
4 CN are above pons (I, II, III, IV)
4 CN are in pons (V, VI, VII, VIII)
4 CN are in medulla (IX, X, XI, XII)
4 CN nuclei are medial (III, IV, VI, XII) - Factors of 12, except 1 and 2
2
Q
What is CN I; pathway; synapses; injury?
A
- Olfactory = sensory
- Pathway: cribiform plate of ethmoid bone
- Synapse in olfactory bulb –> piriform cortex
- Injury: anosmia
3
Q
The afferent fibers of which CN do not go to the thalamus?
A
CN I
4
Q
What is CN II; function; pathway; arises from where?
A
- Optic N = special sensory
- Sight
- Pathway: optic canal of the sphenoid bone
- Arises from the diencephalon
5
Q
What are the three nerves to the Ocular muscles and which CN do they arise from?
A
1) Trochlear N (CN IV)
2) Abducent (CN VI)
3) Oculomotor (CN III)
6
Q
How do the somatic motor efferent fibers of CN III (oculomotor) move the superior rectus m, medial rectus m, inferior rectus m, inferior oblique m., and levator palpebrae of the eyes?
A
- Superior rectus m. (up)
- Medial rectus m. (medial)
- Inferior rectus m. (inferior)
- Inferior oblique m. (superior rotation)
- Levator palpebrae (elevates eyelid)
7
Q
What are the parasympathetic motor (visceral efferent) effects of CN III (oculomotor) on the sphincter pupillae and ciliary muscle?
A
- Sphincter pupillae: pupillary constriction
- Ciliary muscle - for near vision
8
Q
Which CN’s innervate the motor functions of the lateral rectus m and superior oblique ms. of the eye?
A
Lateral rectus m = CN VI
Superior Oblique = CN IV
Mnemonic: SO4LR6
9
Q
What CN is affected here?
A
- Right oculomotor (CN III) nerve palsy
- Downward and outward gaze, dilated pupil, eyelid manually elevated due to ptosis
- Only CN IV and VI are functioning
10
Q
What CN innervates the superior oblique m. of the eye and what type of movement?
A
- CN IV (trochlear)
- Turns eye down/in
- Used when reading/going down stairs
11
Q
What is characteristic of trochlear (CN IV) palsy?
A
- Eye tilted outward
- Unable to look down/in (stairs, reading)
- Tucking chin and head tilting away from affected side (to compensate)
12
Q
What CN innervates the lateral rectus m. of the eye and what kind of movement?
A
- CN VI (abducens)
- Lateral movement of the eye
13
Q
What is characterisitic of abducens nerve palsy?
A
- Diplopia (double vision)
- Can’t laterally move (look out) affected eye
14
Q
What are the sensory and motor functions of the Trigeminal (CN V)?
A
Sensory (touch-pain-temp) to face
- 3 divisions: opthalmic (V1), maxillary (V2), mandibular (V3)
Motor: muscles of mastification (chewing)
- Mandibular (V3)
- Part of corneal reflex (sensory input via V1)
15
Q
What is the corneal reflex and the CN involved?
A
- Touch eye with Q-tip
- Input sensoes by V1 of CN V
- Transmit to CN VII (bilaterally)
- CN VII (facial n.) -> blink
16
Q
What provides the sensory input for each of the three colors in this image?
A
Orange = Opthalmic (CN V1)
Blue = Maxillary (CN V2)
Green = Mandibular (CN V3)
17
Q
What are the 4 main sensory branches that arise from the Opthalmic nerve (V1)?
A
1) Lacrimal
2) Frontal
3) Nasociliary
4) Meningeal branch (from the tentorium cerebelli)
18
Q
What are the 6 main sensory branches that arise from the Maxillary nerve (V2)?
A
- Zygomatic
- Infraorbital
- Superior alveolar
- Nasociliary
- Palantine
- Meningeal
19
Q
What are the 5 main sensory branches that arise from the Mandibular nerve (V3)?
A
1) Buccal
2) Lingual
3) Inferior alveolar
4) Auriculotemporal
5) Meningeal (spinous)
20
Q
What are the 5 main motor branches that arise from the Mandibular nerve (V3)?
A
1) Medial ptergoid
2) Lateral pterygoid
3) Masseteric
4) Deep temporal
5) Mylohyoid
21
Q
What are the characteristics of Trigeminal nerve (CN V) palsy?
A
- Numb face (sensory)
- Weak jaw (motor) - deviates to affected side
22
Q
What is characteristic of Trigeminal (CN V) neuralgia?
A
- Recurrent, sudden sharp pains
- Tic douloureux (painful tic)
- So intense you wince
23
Q
Describe the route of the presynaptic parasympathetic fibers (secretomotor) of the facial n. (CN VII)?
A
Go to pterygopalantine ganglion via greater petrosal nerve and to anterior tongue and submandibular ganglion via chorda tympani
24
Q
What are characteristics of Facial (CN VII) palsy?
A
- Loss of corneal reflex (motor output)
- Loss of taste anterior 2/3 of tongue
- Hyperacusis (stapedius paralysis): pt cannot tolerate sounds
25
What is Bell's Palsy; how is it brought on; characteristics; how does it resolve?
- Idiopathic mononeuropathy of CN VII
- Sudden onset of facial paralysis
- Usually resolves in weeks to months
26
What is the function of CN VIII (vestibulocochlear); describe both portions and what occur with lesions to each of the regions?
- Special sensory
- Hearing, balance, equilibrium
**Cochlear portion:** hearing
- Lesions = loss of hearing, tinnitus
**Vestibular portion:** equilirum --\> compensatory eye movement
- Lesions = vertigo, nystagmus, vomiting, nausea
27
What type of innervation from CN IX and the important functions?
- Motor, sensory
- Taste/sensation **posterior 1/3** of tongue
- Salivation **(parotid gland)**
- **Carotid body and sinus (chemo- and baroreceptor)**
- **Stylopharyngeus**: elevates pharynx for swallowing/gagging
28
What does damage to the Glossopharyngeal (CN IX) lead to?
**Glossopharyngeal palsy**
- Loss of gag reflex
- Loss of taste posterior 1/3 tongue
- Loss sensation upper pharynx
**Hemodynamic effects**
- Trick body into thinking low BP
- Increase BP and vasoconstriction
29
What are the important function of the Vagus (CN X) in the head and neck?
- Taste, supra-epiglottic region
- Swallowing (dysphagia = vagus)
- Palate elevation
- Midline uvula
- Talking
- Coughing
30
What chemo/baroreceptors does the Vagus n vs. Glossopharyngeal n. play a role in?
Vagus (CN X) = **Aortic arch**
Glossopharyngeal (CN IX) = **Carotid body and sinus**
31
The nucleus solitarius is involved with what CN's and functions?
- Visceral **S**ensory information (i.e., taste, baroreceptors, gut distention)
- VII, IX, X
32
The nucleus ambigous is involved with what CN's and functions?
- **M**otor innervation of pharynx, larynx, upper esophagus (i.e., swallowing, palate elevation)
- IX, X, XI (cranial portion)
33
The dorsal motor nucleus is involved with what CN's and what functions?
- Sends autonomic (parasympathetic) fibers to heart, lungs, upper GI
- CN X
34
What is seen in Vagus (X) nerve palsy; what specifically with the Uvula?
- Hoarsness, dysphagia, dysarthria
- Loss of gag reflex
- Loss of sensation pharynx and larynx
- Weak side of palate collapse (lower)
- **Uvula** deviates **AWAY** from **affected side (U go away)**
35
What are the hemodynamic effects of Vagus n. palsy?
- Unopposed sympathetic stimulation of heart
- Increased HR
36
What is the most common cause of syncope (fainting); characteristics and triggers?
- **Vasovagal syncope**
- Trigger to vagus nerve: increase parasympathetic outflow via vagus
- Decrease HR, decrease BP --\> fainting
- Many **triggers** = hot weather, prolonged standing, pain, sight of blood
37
What kind of innervation from spinal accessory (CN XI) and functions?
- Motor (branchial type)
- Turning head
- Shoulder shrugging: SCM and Trapezius
38
What is seen with Spinal Accessory (CN XI) palsy?
- Difficulty turning head **toward normal** side (SCM)
- Shoulder droop (affected side)
39
What kind of innervation from Hypoglossal (CN XII), what are the functions?
- Motor
- Tongue movement
40
What is seen with Hypoglossal (CN XII) palsy?
- Protrusion of tongue **TOWARD** the **affected** side
- Opposite side pushes tongue away unopposed
41
What provides the general sensory innervation (pain, touch, pressure, temp) to the anterior 2/3, posterior 1/3, and tongue root?
Anterior 2/3: Mandibular branch (CN V3)
Posterior 1/3: Glossopharyngeal (IX)
Tongue root: CN X
42
What nerves are involved in lacrimation (tears) reflex, both sensory and output?
- Sense: V1
- Output: VII (tearing)
\*Damaged V1 --\> no reflex tears, but still have emotional tears
43
What nerves are involved in the gag reflex, both sensory and output?
Sensory: IX
Output: X (gagging)
44
What are the 4 superficial cervical nerves and what spinal segments does each come from?
1) Lesser Occipital (C2-C3)
2) Great Auricular (C3-C4)
3) Transverse Cervical (C3-C4)
4) Supraclavicular (C3-C4)
45
What is the ansa cervicalis; where is it found; what are its divisions; what does it innervate?
- Formed by a loop of nerve fibers from the **anterior rami of C1-C3**
- Embedded in the fascia of **carotid sheath**
- **Superior root** (C1-C2) leaves hypoglossal nerve
- **Inferior root** (C2-C3) crosses lateral to IJV
- Directly **innervates** all the **infrahyoid muscles**
**\*Travel with CN XII, but not a functional component of**
46
What occurs in unilateral vs. bilateral paralysis of the phrenic nerve?
- **Unilateral** causes few or no symtoms
- **Bilateral** characterized by exertional dyspnea, scaphoid abdomen which is not protruded during expiration; hyperactivity of the accessory respiratory muscles (heaving action)
47
General somatic afferent fibers innervate structures of what embryologic origin and what type of sensory info is relayed; primarily conveyed by what nerve?
- Ectodermal origin
- Pain, temperature, tactile, pressure and proprioception (**highly localized**)
- Primarily conveyed by **Trigeminal n. (CN V)**
48
General visceal afferent fibers innervate structures of what embryologic origin, what type of sensory info is relayed; what nerve has huge distribtution of these fibers?
- Endodermal origin
- Dull, aching, burning, **poorly localized** sensations
- **Vagus** nerve has a huge distribution of GVA fibers to the mucosa of posterior 1/3 tongue to the mid-portion of transverse colon
49
General somatic efferent fibers innervate structures of what embryologic origin; what structures specifically in the head?
- Myotomic origin
- Most muscles in the body/neck are of myotomic origin
- Only myotomic groups in head are **intrinsic muscles of tongue and extraocular muscles**
50
General visceral efferent fibers are components of what; innervate what structures?
- Components of the ANS, may be parasympathetic or sympathetic
- GVE fibers are associated w/ the **parasympathetic** fibers coursing in the **III, VII, IX, and X** cranial nerves
51
Special Visceral Afferent fibers innervate what structures; what 4 CN's are involved?
- Convey olfactory (smell) and taste information from organs derived from head **endoderm**
- **CN I** innervating olfactory epithelium (smell)
- **CN VII** innervating anterior 2/3 tongue (taste)
- **CN IX** innervating posterior 1/3 tongue (taste)
- **CN X** innervating epiglottis region (taste)
52
Special Visceral Efferent fibers innervate?
Muscles of **branchiomeric origin**, such as:
- Muscles of mastication (V)
- Facial expression (VII)
- Larynx and pharynx (X, except stylopharyngeus—IX)
- SCM and trapezius (XI)
53
Special Somatic Afferent fibers innervate what structures?
- Optic nerve (CN II) innervating the retina (vision)
- Vestibulo-cochlear nerve (CN VIII) innervating the cristae ampuallaris of semicircular ducts, maculae of the utricle, and saccule
54
What is the sensory nucleus for all sensation from the face?
- Trigeminal sensory nuclei
- ALL **GSA** fibers from CN's V, VII, IX, and X terminate in some part of this nucleus
55
What are the 3 nuclei of the trigeminal sensory nucleus and what information does each receive?
1) **Mesencephalic** nucleus of V receives **proprioception** info from facial muscles
2) **Main sensory** nucleus of V receives **precise tactile discriminaton** info from the face
3) **Descending nucleus** of V received **crude tactile pain, temperature** info from the face
56
What is the sensory nucleus for general sensations from the posterior 1/3 of the tongue to the mid-portion of the transverse colon; what type of fibers?
- Solitary nucleus (nucleus tractus solitarius, NTS)
- ALL **GVA** and SVA (taste) fibers
57
What is the sensory nucleus for the salivary, lacrimation, gag, and cough reflexes?
Solitary nucleus (nucleus tractus solitarius)
58
What are the 4 nucleus that make up the GSE column?
1) Oculomotor nucleus: innervates the **superior, inferior, and medial recti, inferior oblique,** and the **levator palpebrae superioris ms.**
2) Trochlear nucleus: innervates the **superior oblique muscle**
3) Abducens nucleus innervates the **lateral rectus m.**
4) Hypoglossal nucleus innervates **all** the muscles associated w/ the **tongue**, except **palatoglossus**
59
What is the Edinger-Westphal nucleus?
- Part of the **GVE parasympathetic column**
- Sends preganglionic fibers to **ciliary ganglion** via branches of **oculomotor nerve**
- The **ciliary ganglion** sends postganglionic fibers to the **ciliary muscles of the lens** and the **pupillary constrictor muscles**
60
What is the Superior Salivatory nucleus (VII)?
- Sends preganglionic fibers to the **sphenopalantine and submandibular ganglia.**
- **Sphenopalantine ganglion** sends postganglionic fibers to the **lacrimal gland**, and oral and nasal cavities
- **Submandibular ganglion** sends postganglionic fibers to the **submandibular and sublingual salivary glands**
61
What is the Inferior Salivatory nucleus (IX)?
- Sends preganglionic fibers to the **otic ganglion**
- The **otic ganglion** sends postganglionic fibers to the **parotid salivary gland**
62
What is the Dorsal Motor nucleus (X)?
- Sends preganglionic fibers to the **scattered ganglia** in the **larynx, pharynx, thorax, and abdomen**
- These ganglia send postganglionic fibers to various glands and smooth muscle in these regions
63
The spinal accessory nerve is partly deived from both the ______ and \_\_\_\_\_\_\_\_\_.
Medulla and spinal cord
64
The glossopharyngeal (IX), vagus (X), and spinal accessory nerves all exit where; what is their anatomical relationship to the parotid gland?
- Exit the **jugular foramen** at the **base of the skull** between the IJV and the internal carotid artery
- They are **retroparotid** at the level of the neck of the mandible
65
What's Vernet's Syndrome; what sign do you look for?
- A basilar skull fracture due to trauma may involve the jugular **foramen and result in ipsilateral IX, X, and XI paralysis**
- Look for **Battle's sign** (bruising behind the pinna and/or over the mastoid process)
- May be accompanied with "raccoon" eye
- Fractures of the base of skull require **a lot of force**, therefore, always examine for possible brain/spine injury
66
What is Collet's or Sicard's syndrome?
- May be due to an injury in the **retroparotid space**
- Involve ipsilateral paralysis of CN's IX-XII, and the cervical sympathetic trunk
67
The sympathetic trunk is located _______ to the \_\_\_\_\_\_\_\_, and ________ to the longus colli and capitus muscles.
The sympathetic trunk is located **posterior** to the **common carotid**, and **anterior** to the longus colli and capitus muscles.
68
Outside the cervical sympathetic trunk, there are no preganglionic sympathetic fibers in the \_\_\_\_\_\_\_\_.
Head
69
From the SVE column, fibers from the nucleus ambiguus exit the brainstem w/ cranial portion of \_\_\_\_\_\_, and anastomose with ________ at jugular foramen.
Fibers from the **nucleus ambiguus** exit the brainstem with cranial portion of **XI**, and anastomose with **vagus nerve** at **jugular foramen**
70
Where do the preganglionic sympathetic fibers to the head and neck originate and how do these fibers exit the spinal cord?
- Originate in preganglionic sympathetic cells bodies located in the **intermediolateral cell column** of the **1st and 2nd thoracic levels of spinal cord**
- Exit the spinal cord via the **ventral root**, travel through the **white ramus** to the **sympathetic trunk,** where they ascend for a vairable distance before terminating in one of the cervical sympathetic ganglia
71
Where do the postganglionic sympathetic fibers to the head and neck form plexuses and what do these fibers innervate?
- Form nerve plexuses on the surface of blood vessesl, or join with cervical or cranial nerves
- Innervate blood vessels, smooth muscle, and glands of the head and neck
72
What does the external carotid plexus consist of and what does it innervate?
- Postganglionic sympathetic fibers which course in the **tunica adventitia** of the external carotid and its branches
- Supplies the **glands of the neck**
73
The superior cervical ganglion is a large elliptical ganglion located where?
**Posterior** to the **internal carotid artery,** embedded in the prevertebral fascia at the level of **C1-C2** and on the surface of the longus capitus muscle at the level of C1
74
The superior cervical ganglion sends postganglionic fibers (axons) where?
- Upper cervical (C1-C3)
- Lower cranial nerves (IX-XII)
- Pharynx
- Carotid body and sinus
- Internal carotid nerve
75
The internal carotid nerve leaves the __________ and forms the \_\_\_\_\_\_\_\_\_.
The internal carotid nerve leaves the **supeior cervical ganglion** and forms the **internal carotid plexus**
76
What are the 4 major branches of the internal carotid plexus?
1) Perivascular plexuses
2) Sympathetic branch to the ciliary ganglion
3) Deep Petrosal nerve
4) Carotico-tympanic nerve
77
The middle cervical ganglion is located at what vertebral level and where does it send post-ganglionic fibers?
- At level of **C6** above the arch of the inferior thyroid artery
- Fibers to middle cervical nerves (C4-C6) and the **vertebral artery + its branches via the vertebral plexus**
78
The vertebral ganglion is located at what spinal level and near what artery; where does it send fibers?
- Level of **C7** anterior to the **vertebral artery**
- Send postganglionic fibers to the **sixth cervical nerve** and the **vertebral plexus**
79
What is Horner's Syndrome + the signs and symptoms?
- May be caused by Interruption of the **cervical sympathetic trunk**; **transection** of spinal cord **above** the level of **T1**; hemisection of the spinal cord above level of T1 (ipsilateral Horner's Syndrome)
- **Slight ptosis** of the upper lid due to paralysis of the tarsal muscle
- Mitosis or **pupillary constriction** due to paralysis of the dilator pupillae muscle
- **Anhidrosis and blushing** (vasodilation) of the skin on the face due to loss of sympathetic innervaton of the blood vessels
- **Enopthalmos** due to paralysis of the orbitalis muscle of Muller which has a slight protrusion function
80
The preganglionic parasympathetic axons course with cranial nerves \_\_\_\_\_\_\_\_?
III, VII, IX, or X
81
Where is the sphenopalatine (pterygopalantine) ganglion found?
Sphenopalatine fossa just inferior to the maxillary division of CN V ad lateral to the sphenopalatine fossa
82
The sphenopalatine (pterygopalatine) ganglion receives preganglionic parasympathetic fibers via what nerves?
- Greater petrosal nerve (a branch of the facial nerve)
- Vidian nerve
83
Where is the submandibular ganglion located and what nerves does it receive preganglionic parasympathetic fibers from?
- Adjacent to the **lingual nerve** at the level of the **third molar**
- Receives axons from the **chorda tympani nerve,** a communicating branch between the facial nerve and the lingual nerve
- The lingual nerve conveys the fibers to the ganglion
84
The otic ganglion receives preganglionic parasympathetic fibers from which nerve?
Lesser petrosal nerve, a branch of the glossopharyngeal nerve
85
Postganglionic parasympathetic axons from the otic ganglion will innervate which gland via which nerves?
Innervate the **parotid gland** via the auriculotemporal branches of the trigeminal nerve (CN V)
86
Dorsal motor nucleus of CN X supplies parasympathetic innervation to where?
- Heart
- Lungs
- LES
- Stomach
- Small intestines
- Proximal 1/2 of the colon
87
Describe the route of parasympathetic fibers that innervate the submandibular salivary gland?
- **Superior salivatory nucleus** sends preganglionic fibers, which course in the **chorda tympani nerve,** a branch of the facial nerve, and merge with the lingual nerve in the infratemporal fossa before reaching the **submandibular ganglion**
**- Submandibular ganglion** sends postganglionic fibers which innervate the submandibular and sublingual salivary glands
88
Describe the route of sympathetic innervation to the submandibular and sublingual salivary glands?
- Preganglionic sympathetic neurons are found in the **intermediolateral cell column**
- Facial plexus on the facial artery distributes postganglionic sympathetic fibers to the submandibular and sublingual salivary glands
89
Describe the route of sympathetic innervation to the parotid gland
- Preganglionic sympathetic neurons are found in the **intermediolateral cell column**
- **Caroticotympanic nerve** enters the middle ear cavity, forms part of the tympanic plexus, and exits as the lesser petrosal nerve
- Postganglionic fibers will course through the **lesser petrosal nerve,** foramen ovale, otic ganglion, an auricotemporal nerve before supplying postganglionic fibers to the parotid gland
90
Describe the route of parasympathetic innervation to the parotid gland.
- **Inferior salivatory nucleus** send preganglionic fibers from the lesser petrosal nerve, a branch of glossopharyngeal, to the **otic ganglion**
- Postganglionic fibers from the otic ganglion innervate the parotid gland via the auriculotemporal branches of the trigeminal nerve
91
Describe the route of sympathetic innervation to the lacrimal gland
- Preganglionic neurons are found in the **interomedial cell column**
- The **deep petrosal nerve** courses in the carotid canal, and joins with the greater petrosal nerve to from the Vidian nerve.
- Postganglionic sympathetic fibers distribute to the palate, nasal cavity, pharynx, orbit and lacrimal gland
92
Describe the route of parasympathetic innervation to the lacrimal gland
- **Superior salivatory nucleus** sends preganglionic fibers via the **greater petrosal nerve**, a branch of facial nerve, and then the **Vidian nerve** to the **Sphenopalatine ganglion**
- Postganglionic fibers from the ganglion will innervate the lacrimal gland, nasal cavity, nasopharynx, palate and orbit via the zygomatic nerve, a communicating branch between the maxillary/infraorbital and lacrimal nerves
93
Describe the route of sympathetic innervation to the eye.
- Preganglionic sympathetic neurons are found in the **intermediolateral cell column** of the thoracolumbar segments of the spinal cord.
- **Sympathetic branch** to the **ciliary ganglion** passes through the cavernous sinus, superior orbital fissure and the ciliary ganglion before terminating as short ciliary nerves to the eyeball
- These postganglionic fibers innervate the **dilator pupillae and tarsal muscles**
94
Describe the route of the parasympathetic innervation to the eye
- **Edinger-Westphal nucleus** sends preganglionic fibers via the short root of the oculomotor nerve which terminate in the **ciliary ganglion**
**-** Postganglionic fibers to the **ciliary muscles of the lens** and the **sphincter pupillae muscles of the iris**
