Gross 2 Cranium and Cranial Nerves Flashcards
How many bones make up the Neurocranium?
8 bones
- Calvaria superiorly
- Cranial base inferiorly
How many bones make up the Viscerocranium?
15 bones
What is the Mandibular Foramen?
An opening where the Inferior Alveolar Nerve (Branch off Mandibular Nerve {V3}) enters the bone.
(posterior mandible)
What is the Mental Foramen?
This is for the Mental nerve
- The Terminal branch off Inferior Alveolar Nerve.
What are the structures where the Maxillary Bones come together and fuse?
- Intermaxillary Suture
- InterPalatine Suture
What contents go through the InfraOrbital Foramen?
- Infraorbital Nerve (off of Maxillary N {V2 of Trigeminal N.})
- Infraorbital Artery (Off of Maxillary Artery)
- Infraorbital vein
What contents go through the Incisive Foramen?
- Nasopalatine Nerve (Off of Maxillary Nerve {V2 of Trigeminal N.})
- Sphenopalatine Artery (Off of Maxillary Artery
What contents go through the Greater Palatine Foramina?
- Greater Palatine Nerve (Off of Maxillary Nerve {V2 of Trigeminal})
- Greater Palatine Artery
What contents go through the Lesser Palatine Foramina?
- Lesser Palatine Nerve (Off of Maxillary Nerve {V2 of Trigeminal})
- Lesser Palatine Artery
Why is the Ethmoid Bone important?
Contains the Cribriform Plate, This is the Nesting Site for Olfactory Nerve (CN I)
Describe the Frontal Bone.
- Contains a Squamous part: which forms outline of forehead
- Contains a Orbital Part: which is part of orbit and bridge of the nose
- Has the Supraorbital Foramina
What contents go through the Supraorbital Foramina?
- Supraorbital Artery
- Supraorbital Vein
- Supraorbital Nerve (comes off the Frontal nerve which is a branch from the Ophthalmic Nerve (V1) of Trigeminal)
What openings are on the Sphenoid bone?
-Optic Canal
- Superior Orbital Fissure
- Foramen Rotundum
- Foramen Ovale
What Nerve(s) go through the Optic Canal?
Optic Nerve (CN II)
What nerve(s) go through the Superior Orbital Fissure?
- Oculomotor (CN III)
- Trochlear N (CN IV)
- Ophthalmic Nerve (V1) which has branches: Lacrimal N. , Frontal N., and Nasociliary N. (All from Trigeminal Nerve (CN V)
- Abducens (CN VI)
What opening(s) are there in the Temporal Bone?
- Internal Auditory/Acoustic Meatus
What nerve(s) go through the Internal Auditory/Acoustic Meatus?
- Facial Nerve (CN VII)
- Vestibulocochlear Nerve (CN VIII)
What opening(s) are there in the Occipital Bone?
- Jugular Foramen
- Foramen Magnum
- Hypoglossal Canal
What contents go through the Jugular Foramen?
- Internal Jugular Vein
- Glossopharyngeal Nerve (CN IX)
- Vagus Nerve (X)
- Spinal Accessory (CN XI) {exits}
What contents go through the Foramen Magnum?
- Vertebral Arteries
- Spinal Accessory (CN XI) {re-enters}
- Spinal Cord
What contents go through the Hypoglossal Canal?
- Hypoglossal Nerve (CN XII)
What is the function of Olfactory-CN I?
Special Sensory
- Smell from nasal mucosa
Where does the Olfactory-CN I exit?
The Cribriform Plate of the Ethmoid bone
What are Olfactory-CN I dysfunctions?
Anosmia (Loss of smell)
- Can be caused by upper respiratory infections, sinus disease, and head trauma
What is the function of Optic-CN II?
Special Sensory
- Vision (Transmitted from the retina to the visual cortex)
Why is the Sella Turcica Important?
This houses the Pituitary Gland
Where does the Optic-CN II exit?
Optic Canal
What is the pathway for vision?
- Retina
- Optic nerve
- Optic canal
- Optic chiasm
- Optic tract
- Lateral Geniculate Nucleus
- Visual cortex (Occipital Lobe)
What would happen if there was a lesion to the Right Optic Nerve/Canal?
Monocular Blindness
(The right eye will be blind, losses both nasal and temporal visual fields of ipsilateral eye)
What would happen if there was a lesion to the Right Optic Chiasm?
Bitemporal Hemianopsia
(Reduces peripheral vision, losses temporal vision)
What would happen if there was a lesion to the Right Optic Tract?
Homonymous Hemianopsia
(Eliminates vision from the left temporal and right nasal visual fields)
Commonly observed in patients with strokes
What is the function of Oculomotor CN-III?
Somatic Motor
- Motor to Superior/Inferior/Middle Rectus and Inferior Oblique
(This rotates the eyeball superiorly, inferiorly, and medially) - Motor to Levator Palpabrae Superioris
(Raises superior eyelids)
Visceral Motor
- Constricts pupil and accommodate lens of eye
Where does the Oculomotor CN-III exit?
Superior Orbital Fissure
What are the Oculomotor CN-III dysfunctions?
Somatic Motor
- The affected eye will be positioned down and out, the superior eyelids will not keep the eye completely open
Visceral Motor
- Affected eye does not constrict (Meaning if you shine a light on it the pupil remains large)
If someone has a Right Oculomotor (CN-III) Palsy, what would happen when they are looking straight (Primary Position)?
The right eye will turn downward and outward (Towards the right side)
If someone has a Right Oculomotor (CN-III) Palsy, what would happen if they try to look/gaze to the right?
The eye will have a squint
(The eye will only squint because they eyeball is already turned downward and outward)
If someone has a Right Oculomotor (CN-III) Palsy, what would happen if they try to look/gaze to the left?
They would be unable to adduct the right eye, and the angle of the squint will be larger, creating double vision further apart
What is the function of Trochlear (CN-IV)?
Motor
- To Superior Oblique
(This depresses, medially rotates and abducts eye)
Where does the Trochlear (CN-IV) exit?
Superior Orbital Fissure
What are the Trochlear (CN-IV) dysfunctions?
- The eye will be in adduction, lateral rotation, and elevation
What is the function of Trigeminal (CN-V)?
Both:
Sensory
- Head (Face, teeth, mouth, nasal cavity)
Motor
- Masseter, Temporalis, Medial Pterygoid, Lateral Pterygoid, Mylohyoid, Anterior belly of Digastric, Tensor veli palatini, Tensor Tympani
What are the 3 Somatic Sensory nerves for Trigeminal?
V1: Ophthalmic
V2: Maxillary
V3: Mandibular
(Look at pic from BB)
What is the function of Ophthalmic (V1), and what are the 3 branches?
Sensory Nerve to the skin of Forehead and nose
Branches
- Frontal Nerve: Forehead
- Nasociliary Nerve: Eye and nose
- Lacrimal Nerve: Sensation of, and tear production through lacrimal gland (Parasympathetic)
What is the function of Maxillary (V2), and what are the four branches?
Sensory nerve
Branches
- Zygomatic Nerve: Temporal and Zygomatic bone area
- Superior Alveolar N. : Upper Teeth
- Infraorbital N. : Skin below the eye
- Greater/Lesser Palatine and Nasopalatine N. : Glands on roof of mouth
The Mandibular Nerve (V3) is a mixed nerve, what are the branches and their functions from the Motor portion? (5)
Motor: (Muscles of Mastication)
- Nerve to Medial Pterygoid: Medial Pterygoid M.
- Nerve to Lateral Pterygoid: Lateral Pterygoid M.
- Deep Temporal N. : Temporalis M.
- Masseteric N. : Masseter M.
- Mylohyoid N. : Mylohyoid and Anterior Digastric M.
The Mandibular Nerve (V3) is a mixed nerve, what are the branches and their functions from the sensory portion? (4)
Sensory:
- Auriculotemporal N. : Area anterior to ear and temporal bone
- Buccal N. : Skin over cheek and lateral jaw
- Lingual N. : Anterior Tongue
- Inferior Alveolar N. : Lower Teeth, and floor of mouth
- Turns into Mental Nerve: Skin over chin and lower lip
What is the function of Abducens (CN-VI)?
Somatic Motor
- Lateral Rectus
(This directs gaze laterally; looking lateral)
Where does Abducens (CN-VI) exit?
Superior Orbital Fissure
What happens if there is a dysfunction to the Abducens (VI)?
The eye will be placed medially, wont be able to look laterally
What is the pathway for Facial (V)?
- Firstly it runs through the Internal Acoustic Meatus and out the Stylomastoid Foramen
What are the functions of Facial (CN-VII)? (4)
Both Sensory and Motor:
Somatic Motor
- Facial Expressions muscles
- Muscles of scalp, stapedius, stylohyoid, posterior belly of digastric
Special Sensory
- Taste of anterior 2/3 tongue (Chorda Tympani), Palate (Greater Petrosal)
Sensory
- Skin over external auditory meatus
Visceral Motor
- Parasym, submandibular and sublingual salivary glands, lacrimal gland and glands of nose and palate
What happens if there is a dysfunction to the Facial (CN-VII)?
Facial Paralysis
What are the nerve(s) the innervate the muscles of facial expressions?
Facial (Mainly)
Oculomotor: (Just one muscle) Levator palpabrae superioris {This raises superior eyelid}
What nerve innervates the Occipitofrontalis (frontalis belly), Corrugator Supercilli, and Obicularis oculi?
The Temporal Branch of the Facial Nerve
What nerve innervates the Orbicularis Oculi?
The Zygomatic Branch of the Facial Nerve
What nerve innervates the Occipitofrontalis (Occipital belly)?
The Posterior Auricular Branch of the Facial Nerve
What nerve innervates the Platysma?
The Cervical Branch of the Facial Nerve
What nerve innervates the Procerus, Nasalis, Levator Labii Superioris Alaequae Nasi, Obicularis Oris, Levator Labii Superioris, Zygomatic Major/Minor, Buccinator, Risoris, and Levator Anguli Oris?
The Buccal Branch of Facial Nerve
What nerve innervates the Depressor Anguli Oris, Depressor Labii Inferioris, and Mentalis?
The Mandibular Branch of Facial Nerve
What is Bells Palsy?
A sudden and Temporary UNILATERAL damage to the Facial Nerve.
- Due to swelling and inflammation
*This affects motor and visceral function along distribution of Facial nerve, and No affects to sensation**
What is the function of Vestibulocochlear (CN-VIII)?
Special Sensory
- Hearing, Equilibrium, and motion
Has 2 parts:
- Vestibular Nerve Innervates:
–Vestibular Apparatus (Semicircular canals, Utricle, and Sacule). {Position and Movement sense} - Cochlear Nerve Innervates:
–The Cochlea (involved with hearing)
Where does the Vestibulocochlear (CN-VIII) exit?
Exits through the Internal Acoustic Meatus
Then it separates into Vestibular N. and Cochlear N.
What is the dysfunction of the Vestibulocochlear Nerve?
Vertigo
What is the function for Glossopharyngeal (CN-IX)?
Both Motor and Sensory:
Somatic Motor
- Stylopharyngeus (Swallowing)
Visceral Motor
- Parasympathetic to Parotid Gland
Visceral Sensory
- Parotid Gland, Carotid Body and Sinus, Pharynx, and Middle Ear
Special Sensory
- Taste Posterior 1/3 of tongue
- Carotid fibers: carotid sinus baroreceptors
Somatic Sensory
- Cutaneous sensation from external ear
What are the dysfunctions of the Glossopharyngeal (CN-IX)?
- Loss of taste on posterior 1/3 of tongue
- Loss of sensation on affected side of soft palate
Can result in loss of bitter and sour taste and impaired swallowing
What are the functions for Vagus Nerve (CN-X)?
Both Motor and Sensory
(Its the main parasympathetic nerve, 90% of Parasympathetic nerve fibers are carried by CN X)
- Somatic Motor
- Visceral Motor
- Visceral Sensory
- Special Sensory
- Somatic Sensory
The Vagus Nerve (CN-X) is a mixed nerve, what are the functions of the Somatic Motor?
Somatic Motor
- Muscles of Pharynx (Except stylopharyngeus {CN IX}), intrinsic muscles of larynx, muscles of palate (Except Tensor Veli Palatine {V3}) and striated muscle in superior 2/3 of esophagus
The Vagus Nerve (CN-X) is a mixed nerve, what are the functions of the Visceral Motor? (5)
Visceral Motor
- Parasympathetic smooth muscle and glands of trachea, bronchi, digestive tract, coronary arteries, and nodes of conductive system of heart
The Vagus Nerve (CN-X) is a mixed nerve, what are the functions of the Visceral Sensory? (9)
Visceral Sensory
- Form base of tongue, pharynx, Larynx, Trachea, Bronchi, Heart, Esophagus, Stomach, and Small Intestine to left Colic Flexure
The Vagus Nerve (CN-X) is a mixed nerve, what are the functions of the Special Sensory?
Special Sensory
- Taste from Epiglottis and Palate
The Vagus Nerve (CN-X) is a mixed nerve, what are the functions of the Somatic Sensory?
Somatic Sensory
- From Auricle, External Acoustic Meatus, Cranial Fossa
What are the dysfunctions of the Vagus (CN-X)?
- Dysphagia: Swallowing difficulties
- Dysphonia: A voice disorder that causes an abnormal voice quality
- Aphonia: You can’t make yourself heard because your voice sounds hoarse, or you can’t speak above a whisper
- Respiratory Stridor: Noisy breathing that occurs due to obstructed air flow through a narrowed airway
What is the function of the Spinal Accessory (CN-XI)?
Somatic Motor:
- SCM
- Trapezius
What are the dysfunctions of the Spinal Accessory (CN-XI)?
- Atrophy of Trapezius
- Drooping shoulder
- Inability to retract or elevate scapula
- Weakness in turning head to opposite side
What is the function of the Hypoglossal (CN-XII)?
Somatic Motor:
- Intrinsic and Extrinsic muscles of the tongue
What are the dysfunctions of the Hypoglossal (CN-XII)?
- Deviation toward affected side: (If right side is affected the tongue will deviate to right side)
- Atrophy of tongue
- Dysarthria: Where you have difficulty speaking
