skull & cranial nerves Flashcards

1
Q

The cranium

A

Bones that form the skeleton of the head

  1. neurocranium- houses brain
    a. calvaria (skullcap)
    b. cranial base (basicranium)
  2. viscerocranium- facial bones that form:
    a. orbits
    b. nasal cavities
    c. upper jaw
    d. lower jaw (mandible)
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2
Q

Neurocranium consist of 6 parts and subparts

A
  1. frontal
  2. parietal (2)
  3. temporal (2)
    • mastoid process
    • styloid process
    • external acoustic meatus
  4. occipital
    • external occipital protuberance
  5. sphenoid
  6. ethmoid
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3
Q

sutures of neurocranium

A
  1. coronal- frontal & parietal
  2. lambdoid- parietal & occipital
  3. sagittal- R & L parietal
  4. squamous- parietal & temporal
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4
Q

intersections of cranial sutures

A
  1. bregma- sagittal & coronal
  2. lambda- lambdoid & sagittal
  3. Pterion- frontal, parietal, temporal, sphenoid
  4. asterion- parietal, occipital, temporal
  5. nasion- frontal & nasal bones
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5
Q

Other landmarks

  1. Glabella
  2. Vertex
  3. Inion
A
  1. Glabella-most anterior part of forehead
  2. Vertex- superior most point of neurocranium
  3. Inion- most prominent point of external occipital protuberance
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6
Q

Cranial Base & associated holes in bones

A
  1. Anterior fossa
    - cribriform plate (ethmoid)
  2. Middle fossa
    - optic foramen/ canal; sphenoid
    - superior orbital fissure; sphenoid
    - foramen rotundum; sphenoid
    - foramen ovale; sphenoid
    - foramen spinosum; sphenoid
    - foramen lacerum; sphenoid
  3. Posterior fossa
    - internal acoustic meatus; temporal
    - jugular foramen; btw temporal & occipital
    - hypoglossal canal; occipital
    - foramen magnum; occipital
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7
Q

sphenoid bone

A
  • the sphenoid & ethmoid bones form part of anterior cranial fossa, along with the frontal bone
  • sphenoid also comprises the floor of the middle cranial fossa
  • it is a key bone in cranial skeleton
  • it articulates with 8 bones
  • has central body, 2 wings laterally and 2 processes inferiorly
  • the sella turcica holds the pituitary gland (hypophysis) within it.
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8
Q

Viscerocranium contents

A
  1. lacrimal (2)
  2. nasal (2)
  3. maxillae (2)
  4. zygomatic (2)
  5. palatine (2)
  6. inferior nasal conchae (2)
  7. mandible
  8. vomer
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9
Q

other important holes in the face

A
  1. supraorbital notch/foramen (frontal)
  2. infraorbital foramen (maxilla)
  3. mental foramen (mandible)
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10
Q

CNS & PNS

  • sensory (afferent): somatic/general, visceral
  • motor (efferent): somatic motor, branchial motor, visceral motor
A

CNS- brain & spinal cord
PNS- sensory & motor neurons, clusters of neurons called ganglia and nerves connecting to the CNS

Sensory (afferent-going from external stimulants to the brain)

  1. somatic sensory (general)
    - touch, pain, pressure, temperature (skin)
    - proprioception (muscles, tendons, joints)
    - special sensory: hearing, balance, vision, olfaction
  2. visceral sensory (parasympathetic/sympathetic)
    - reflex or pain sensatins from viscera, glands, blood vessels
    - special sensory: taste

Motor (efferent- going from cranial/spinal nerves to organs)

  1. somatic motor
    - innervation of skeletal muscles (except pharyngeal arch derivatives)
  2. Branchial motor
    - innervation of pharyngeal arch muscles
  3. visceral motor (para/sympathetic)
    - innervation of smooth muscles, cardiac muscle, glands
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11
Q

overview of cranial nerves

A
  • nerves originating from brain or brainstem and exiting through foramina or fissures in the cranium
  • 12 pairs (CNI-XII) anterior to posterior
  • variously carrying nerve fibers for:
    1. somatic motor- movement of eyes, mastication, deglutition, respiration, vocalization, facial expression
    2. general sensory -pain, pressure, temperature to tissues
    3. special sensory- olfaction, vision, gustation, audition, equilibrium
    4. parasympathetic motor- to lacrimal, salivary, mucous glands, smooth muscles of eye
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12
Q

List the 12 cranial nerves

A
CN I- olfactory nerves
CN II- optic nerve
CN III- oculomotor nerve
CN IV- trochlear nerve
CN V- trigeminal nerve
CN VI- abducent nerve
CN VII- facial nerve 
CN VIII- vestibulocochlear nerve
CN IX- glossopharyngeal nerve
CN X- vagus nerve
CN XI- accessory nerve
CN XII- hypoglossal nerve
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13
Q

cranial nerves and its location

A
  1. foramina of cribriform plate- CN I olfactory
  2. optic canal- CN II optic
  3. superior orbital fissure
    - CN III oculomotor
    - CN IV trochlear
    - CN V1 opthalmic
    - CN VI abducent
  4. foramen rotundum- CN V2 maxillary
  5. foramen ovale- V3 mandibular
  6. internal acoustic meatus
    - CN VII facial
    - CN VIII vestibulocochlear
  7. jugular foramen
    - CN IX glossopharyngeal
    - CN X vagus
    - CN XI acessory
  8. hypoglossal canal- CN XII hypoglossal
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14
Q

CN I

  1. function-
  2. innervates-
  3. cranial exit-
A

Olfactory n.

  1. function- special sensory smell
  2. innervates- olfactory epithelium of superior nasal cavity
  3. cranial exit- cribriform plate of ethmoid
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15
Q

CN II

  1. function-
  2. innervates-
  3. cranial exit-
  4. Damage to:
    a. optic n.-
    b. optic tract-
    c. optic chiasm-
A

CN II- optic n.

  1. function-special sensory vision
  2. innervates-retina of the eye
  3. cranial exit-optic foramen; sphenoid bone
  4. Damage to:
    a. optic n.- blindness of one eye (anopsia)
    b. optic tract- loss of visual field on opposite side (homonymous hemianopsia)
    c. optic chiasm- loss of peripheral visual fields (bitemporal hemianopsia, tunnel vision)
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16
Q

CN III

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN III: oculomotor n.

  1. function/innervates-
    a. somatic motor- all eye muscles except superior oblique (CN IV) and lateral rectus (CN VI)
    - levator palpebrae superioris (muscle that raises eyelids)
    b. parasympathetic- constriction of pupils and change shape of lens (accomodation)
  2. cranial exit- superior orbital fissure of sphenoid
  3. complete paralysis of CN III leads to dilated pupils, ptosis (droopy eyelids), and inability to move eye upward, downward, medially
17
Q

CN IV

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN IV- trochlear n.

  1. function- somatic motor eye movement
  2. innervates- superior oblique muscle of the eye
  3. cranial exit- superior orbital fissure of sphenoid
  4. damage- injury to trochlear n, patients unable to look downward and inward; has difficulty walking downstairs
18
Q

CN VI

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN VI

  1. function- somatic motor eye movement
  2. innervates- lateral rectus muscle
  3. cranial exit- superior orbital fissure of sphenoid
  4. damage- patient has medial strabismus; unable to abduct the eye
19
Q

CN V (3)

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN V: trigeminal n.

CN V1- opthalmic division

  1. function-general sensory
  2. innervates- conjunctiva & cornea of eye, nasal cavity, skin of scalp, forehead, eyebrows, upper eyelid, part of nose
  3. cranial exit- superior orbital fissure of sphenoid
    - branches seen in orbit: lacrimal n, frontal n. (divides into supraorbital n. & supratrochlear n.)

CN V2- maxillary division

  1. function- general sensory
  2. innervates- lower eyelid, upper lip, gums, teeth, cheek, nose, palate, pharynx
  3. cranial exit- foramen rotundum (sphenoid)
  4. important branches: superior alveolar n. & infraorbital n.

CN V3- mandibular division

  1. function- general sensory, somatic motor
  2. innervates-
    a. sensory- skin over mandible, lower gums, teeth, lower lip, palate, anterior 2/3 tongue
    b. motor- muscles of mastication (temporalis, masseter, medial & lateral pterygoids); anterior digastric & mylohyoid mm.
  3. cranial exit- foramen ovale (sphenoid)
  4. important (sensory) branches:
    a. lingual n.
    b. inferior alveolar n.
    c. mental n.
20
Q

CN VII

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN VII- facial nerve

  1. function/ innervates-
    a. parasympathetic
    - submandibular salvary gland
    - sublingual salivary gland
    - lacrimal gland
    - mucous glands of nasal cavity, pharynx, palate
    b. special sensory- taste receptors on anterior 2/3 of tongue
  2. cranial exit-
    - into the internal acoustic meatus (temporal bone)
    - out of the stylomastoid foramen (temporal bone)
  3. damage
  4. function/innervates
    a. somatic motor
    - muscles of facial expression
    - stylohyoid m.
    - posterior digastric m.
  5. cranial exit
    - into internal acoustic meatus (temporal bone)
    - out of the stylomastoid foramen (temporarl bone)
21
Q

CN VII

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN VII- facial nerve

  1. function/ innervates-
    a. parasympathetic
    - submandibular salvary gland
    - sublingual salivary gland
    - lacrimal gland
    - mucous glands of nasal cavity, pharynx, palate
    b. special sensory- taste receptors on anterior 2/3 of tongue
  2. cranial exit-
    - into the internal acoustic meatus (temporal bone)
    - out of the stylomastoid foramen (temporal bone)
  3. damage
  4. function/innervates
    a. somatic motor
    - muscles of facial expression
    - stylohyoid m.
    - posterior digastric m.
  5. cranial exit
    - into internal acoustic meatus (temporal bone)
    - out of the stylomastoid foramen (temporarl bone)
22
Q

branches of facial nerve CN VII

A
  1. temporal
  2. zygomatic
  3. buccal
  4. mandibular
  5. cervical
23
Q

CN VIII

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN VIII- vestibulocochlear nn. (acoustic)

  1. function- special sensory balance and hearing
  2. innervates-
    - vestibule- receptors for motion & balance
    - cochlea- hearing receptors
  3. cranial exit- internal acoustic meatus of temporal bone
  4. damage- injured to middle cranial fossa
    - cochlear n- leads to tinnitus (ringing, buzzing) and deafness
    - vestibular n- vertigo & nystagmus
24
Q

CN IX

  1. function-
  2. innervates-
  3. cranial exit-
  4. damage
A

CN IX- glossopharyngeal n.

  1. function/ innervates-
    a. general sensory- posterior 1/3 of tongue, pharynx, palate, tonsil
    b. special sensory-
    - posterior 1/3 of tongue (taste)
    - carotid body (monitors blood oxygen levels)
    - carotid sinus (monitors blood pressure)
    c. parasympathetics- parotid gland
    d. somatic motor- stylopharyngeus m.
  2. cranial exit- jugular foramen
  3. important for gag reflex
25
Q

CN X

  1. function-
  2. innervates-
  3. cranial exit-
A

CN X- vagus n.

  1. function/ innervates-
    a. motor
    - muscles of pharynx, larynx, palate (except tensor veli palatini)
    b. general sensory- pharynx, tongue
    c. parasympathetics (and sensory)
    - abdominal & thoracic viscera
  2. cranial exit- jugular foramen
26
Q

CN XI

  1. function-
  2. innervates-
  3. cranial exit
A

CN XI- spinal accessory n.

  1. function- motor
  2. innervates- sternocleidomastoid m & trapezius m.
  3. cranial exit- jugular foramen
  4. damage
27
Q

CN XII- hypoglossal n.

  1. function-
  2. innervates-
  3. cranial exit-
A

CN XII- hypoglossal n.

  1. function- motor tongue muscles
  2. innervates- all muscles with gloss in name (except palatoglossus m.)
  3. cranial exit- hypoglossal canal (occipital)
  4. damage
28
Q

Acronym for 12 cranial nerves

Oh Once One Takes “The Anatomy Final”, Very Good Vacations Are Heaveny

A
O
O
O
T
T
A
F
V
G
V
A
H