CHA101L Quiz 6

Labs 12 and 13

Cribriform plate

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

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