CHA101L Quiz 6

Labs 12 and 13

Cribriform plate

* Horizontal plate of bone covered with small holes

Crista galli

* Vertical plate of bone in the median plane to which the falx cerebri is attached

Identify

* Cribriform plate of ethmoid bone
* Optic canal
* Foramen rotundum
* Foramen lacerum
* Foramen ovale
* Foramen spinosum
* Internal acoustic meatus
* Jugular foramen
* Hypoglossal canal
* Foramen magnum

Longitudinal cerebral fissure

* Divides the cerebrum into right and left cerebral hemispheres

Lateral sulcus

* Largest valley visible from a lateral aspect
* Separates the temporal lobe from the parietal and frontal lobes

Central sulcus

* Lies on the lateral surface of the cerebrum
* Begins near the midpoint of the lateral sulcus, travels superiorly to reach the longitudinal cerebral fissure
* Serves as the boundary between the frontal and parietal lobes

Precentral vs. postcentral gyrus

* Pre - immediately anterior to the central sulcus and contains the primary motor cortex
* Post - immediately posterior to the central sulcus and contains the primary sensory cortex

Upper motor neuron paralysis

* Stroke in the area of the pre/post central gyrus cause the upper motor neuron signals toward the spinal cord to be lost
* If upper motor neuron is lost, conscious control of movement, particularly skilled movement, is lost

Olfactory nerve (CN I)

* Exit: cribriform plate of the ethmoid bone
* Function: sensory - smell

Sign/symptom of olfactory nerve dysfunction

* Anosmia (lack of smell)

Optic nerve (CN II)

* Exit: optic canal
* Function: sensory - vision

Sign/symptom of optic nerve dysfunction

* Various types of blindness

Oculomotor nerve (CN III)

* Exit: superior orbital fissure
* Function:
* motor - to levator palpebrae superioris muscle and all extraocular muscles (except superior oblique and lateral rectus)
* parasympathetic - to sphincter pupillae and ciliary muscles

Sign/symptom of oculomotor nerve dysfunction

* Strabismus (abnormal alignment of the eye)
* Mydriasis (abnormal dilated pupil)
* Ptosis (drooping eyelid)
* Diplopia (double vision)

Trochlear nerve (CN IV)

* Exit: superior orbital fissure
* Function: motor - to superior oblique muscle

Sign/symptom of trochlear nerve dysfunction

* Diplopia (double vision)

Ophthalmic nerve (CN V1)

* Branch of the trigeminal nerve (CN V)
* Exit: superior orbital fissure
* Function: sensory - from skin above the eye and cornea

Sign/symptom of ophthalmic nerve dysfunction

* Neuralgia (intense pain due to nerve damage) or anesthesia of appropriate skin region
* Loss of corneal blink reflex

Maxillary nerve (CN V2)

* Branch of the trigeminal nerve (CN V)
* Exit: foramen rotundum
* Function: sensory - from skin between the eye and lips

Sign/symptom of maxillary nerve dysfunction

* Neuralgia (intense pain due to nerve damage) or anesthesia of appropriate skin region

Mandibular nerve (CN V3)

* Branch of the trigeminal nerve (CN V)
* Exit: foramen ovale
* Function:
* sensory - from anterior 2/3 of tongue (via lingual nerve), and skin over the mandible
* motor - to muscles of mastication, mylohyoid, anterior belly of the digastric, tensor tympani, and tensor veli palatini muscles

Sign/symptom of mandibular nerve dysfunction

* Loss of general sensation to anterior 2/3 of tongue
* Neuralgia (intense pain due to nerve damage) or anesthesia of appropriate skin region
* Chewing difficulty

Abducens nerve (CN VI)

* Exit: superior orbital fissure
* Function: motor - to lateral rectus muscle

Sign/symptom of abducens nerve dysfunction

* Medial (internal) strabismus (eye move towards midline)
* Diplopia (double vision)

Facial nerve (CN VII)

* Exit: internal acoustic meatus
* Function: motor - to muscles of facial expression

Sign/symptom of facial nerve dysfunction

* Facial paralysis or palsy (Bell’s palsy)

Chorda tympani

* Branch of the facial nerve (CN VII)
* Function:
* sensory - taste from anterior 2/3 of tongue
* parasympathetic - to sublingual and submandibular glands

Sign/symptom of chorda tympani dysfunction

* Loss of taste to anterior 2/3 of tongue
* Reduced salivation

Parasympathetic branches of the facial nerve (CN VII)

* Function: parasympathetic - to lacrimal gland
* Dysfunction: loss of lacrimation (crying)

Vestibulocochlear nerve (CN VIII)

* Exit: internal acoustic meatus
* Function: sensory - hearing and balance (innervates semicircular ducts, utricle and saccule)

Sign/symptom of vestibulocochlear nerve dysfunction

* Hearing loss
* Loss of equilibrium

Glossopharyngeal nerve (CN IX)

* Exit: jugular foramen
* Function:
* sensory - taste from posterior 1/3 of tongue and general sensation from oropharynx
* motor - to stylopharyngeus
* parasympathetic - to parotid gland

Sign/symptom of glossopharyngeal nerve dysfunction

* Loss of taste and general sensation to posterior 1/3 of tongue
* Dysphagia (difficulty swallowing)
* Loss of gag reflex
* Loss of salivation from parotid duct

Vagus nerve (CN X)

* Exit: jugular foramen
* Function:
* sensory - sensation from viscera of neck, thorax, and abdomen, and taste from epiglottis and palate
* motor - muscles of larynx, pharynx, and palate
* parasympathetic - to viscera of neck, thorax, and abdomen

Sign/symptom of vagus nerve dysfunction

* Dysphagia (difficulty swallowing)
* Dysphonia (difficulty speaking/hoarseness)
* Sagging soft palate
* Uvula deviates to normal side
* Aspiration pneumonia
* Loss of visceral reflexes
* Tachycardia
* Decrease GI motility
* Decreases HCl
* more…

Accessory nerve (CN XI)

* Exit: jugular foramen
* Function: motor - to sternocleidomastoid and trapezius muscles

Sign/symptom of accessory nerve dysfunction

* Weakness in turning head and shrugging shoulders

Hypoglossal nerve (CN XII)

* Exit: hypoglossal canal
* Function: motor - to muscles of the tongue (except palatoglossus)

Sign/symptom of hypoglossal nerve dysfunction

* When protruded, tongue deviates to the side of the lesion

Confluence of sinuses

* The connecting point of the superior sagittal sinus, straight sinus, and transverse sinus

Drain into the hiatus semilunaris

* Frontal, maxillary, and anterior ethmoid sinuses

Roots

* Stylo →
* Palato →
* Mylo →
* Genio →
* Glossus →
* Hyo →

Roots

* → Styloid process
* → Soft palate
* → Molar
* → Chin
* → Tongue
* → Hyoid bone

Genioglossus muscle

* Innervation: CN XII
* Actions: Helps to protrude tongue

Styloglossus muscle

* Innervation: CN XII
* Actions:
* Helps to elevate and retract tongue
* Helps to create trough for swallowing

Hyoglossus muscle

* Innervation: CN XII
* Actions: Helps to depress and retract tongue

Palatoglossus muscle

* Innervation: CN X
* Actions:
* Helps elevate posterior aspect of tongue
* Helps form anterior arch

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Mylohyoid muscle

* Innervation: CN V3
* Actions: raises hyoid during swallowing

Geniohyoid muscle

* Innervation: CI (spinal nerve) via CN XII
* Actions:
* Draws hyoid up and forward during chewing
* Helps open mandible

Anterior belly of digastric muscle

* Innervation: CN V3
* Actions:
* Stabilizes hyoid during swallowing
* Swallowing, chewing, speech, breathing
* Lower mandible and elevate hyoid during swallowing

Posterior belly of digastric muscle

* Innervation: CN VII
* Actions:
* Swallowing, chewing, speech, breathing
* Lower mandible and elevate hyoid during swallowing

Stylohyoid muscle

* Innervation: CN VII
* Actions: raises hyoid during swallowing