Cranial Nerves + Autonomics Flashcards
Function of CN1
Olfactory nerve: special sensory - smell
Fxn of CN2
Optic nerve: special sensory - vision
Fxn of CN3
Oculomotor n:
- Somatic motor to inferior rectus, superior rectus, inferior oblique, and medial rectus
- Visceral motor to ciliar muscles & sphincter pupillae muscles
Fxn of CN4
Trochlear n: motor to superior oblique muscle
Fxn of CN5
Trigeminal n.
- Sensory: face, eyes, teeth, sinuses, nasopharynx, oral cavity, nasal cavity, etc…. (most of face)
-
Motor:
- Muscles of mastication (medial tperygoid, lateral pterygoid, masseter, temporalis)
- Mylohyoid
- Anterior belly of digastric
- Tensor tympani
- Tensor veli palatini
Fxn of CN6
Abducens n
Motor: external rectus muscle
Fxn of CN7
Facial nerve:
-
Branchial motor to
- facial muscles
- stapedius
- stylohyoid
- posterior belly of digastric
-
Visceral (parasympathetic) motor: secretomotor to
- All salivary glands except parotid gland
- Mucous glands in oral & nasal cavity
- Lacrimal gland
- Special sensory - taste (anterior 2/3 of tongue)
- Somatic sensory - part of ext acoustic meatus & deep auricle
Fxn of CN8
Vestibulocochlear nerve: special sensory to inner ear- hearing & balance
Fxn of CN9
Glossopharyngeal n.
Motor
- Branchial- pharyngeal musculature
- Visceral (parasympathetic) motor - secretomotor to the parotid gland
Sensory
- Visceral - carotid body and sinus
- Special - taste (posterior 1/3 of tongue)
- Somatic - posterior 1/3 of tongue, oropharynx, palatine tonsil, middle ear, pharyngotympanic tube, and mastoid air cells
Fxn of CN10
Vagus nerve
Motor: heart, lungs, bronchi, GI tract
Sensory: heart, lungs, bronchi, trachea, larynx, pharynx, GI tract, external ear
CN11
Spinal accessory n: motor to SCM & traps
Fxn of CN12
Hypoglossal n: motor (GSE) to intrinsic muscles of tongue (hypoglossus, styloglossus, genioglossus)
The cranial nerves are numbered according to..
anterior to posterior
Foramina through which the cranial nerves exit
The trigeminal nerve [V] innervates facial structures derived from which pharyngeal arch?
First
The facial nerve [VII] innervates facial structures derived from which pharyngeal arch?
Second arch
Fxn of components of CN5
-
Ophthalmic nerve [V1] enters the orbit; SENSORY
- Supra orbital & supratrochlear n: upper eyelid, forehead, scalp
- Infratrochlear n: medial upper eyelid, side of nose, medial angle
- Lacrimal n: lateral upper eyelid, lateral angle
- External nasal n: anterior part of nose
-
Maxillary nerve [V2]: SENSORY
- Zygomatictemporal branch: small area of temples
- Zygomaticofacial branch: skin over zygomatic bone
- Infraorbital nerve: lower eyelid, cheek, side of nose, upper lip
-
Mandibular nerve [V3]: MOTOR & SENSORY
- Auriculotemporal n: large area of temples; ext acoustic meatus; ear drum
- Buccal nerve: cheek
- Mental nerve: lower lip & chin
Sensory innervation of the face and scalp by the three divisions of the trigeminal nerve, the cervical plexus, and cervical dorsal rami.
- Trigeminal branches previously discussed
- Greater occipital (C2 ramus): back of scalp
- Third occipital (C3 ramus): back of neck
- Transverse cervical (C2-3 ramus): side of neck
- Lesser occipital & greater auricular (cervical plexus, C2-3): posterolateral side of head behind ear
Branches of the ophthalmic nerve in the orbit and their distribution (green)
Supra orbital & supratrochlear n: upper eyelid, forehead, scalp
Infratrochlear n: medial upper eyelid, side of nose, medial angle
Lacrimal n: lateral upper eyelid, lateral angle
External nasal n: anterior part of nose
How does sensory and motor part of the mandibular n enter the infratemporal fossa?
-
Sensory portion drops between the tensor veli palatini & upper head of lateral pterygoid muscle
- All branches of V3 originate in the infratemporal fossa.
- The small motor root of the trigeminal nerve [V] passes through the foramen ovale and joins the sensory part
Name all the branches of the mandibular nerve and the nerve types
- Meningeal branch - sensory
- Nerve to medial pterygoid - motor
- Anterior trunk - mostly motor
- Buccal (sensory*)
- Masseteric
- Deep temporal
- Nerve to lateral pterygoid
- Posterior trunk - mostly sensory
- Auriculotemporal
- Lingual
-
Inferior alveolar
- Gives n. to mylohyoid (motor*)
Meningeal branch of V3 supplies sensory innervation to
- Dura mater of middle cranial fossa
- Mastoid cells that communicate with middle ear
N to medial pterygoid supplies motor to
deep surface of the medial pterygoid muscle
The auriculotemporal nerve carries what fiber types and to where?
- Postganglionic parasympathetic and sympathetic GVE’s to the parotid gland
-
Sensory GSA’s to the
- temporomandibular joint
- skin of auricle
- scalp
What is the lingual nerve’s main function?
Sensory branch that carries general sensation from the anterior 2/3 of the tongue
Relationship between lingual nerve (from V3) & chorda tympani (from CN7)
The lingual n (carries general sensation from anterior 2/3 of tongue) is joined high in the infratemporal fossa by the chorda tympani (carries taste from same area).
Chorda tympani’s preganglionic parasympathetic fibers go through the submandibular ganglion, which hangs off the lingual n in the floor of the oral cavity. Then, it either reenters the lingual n to run with it, or it goes straight to glands.
Describe the inferior alveolar nerve’s fxns
- Mostly sensory, but has one motor branch: nerve to mylohyoid innervates the mylohyoid muscle and anterior belly of digastric
- Innervates lots of teeth before dividing into terminal branches:
- Mental nerve: innervates lower lip & skin
- Incisive branch: innervates canine & incisor teeth
Course of facial nerve
- Starts in the pons with a large motor root and a small sensory root
- The roots leave through the internal acoustic meatus, and enter the facial canal where they
- Fuse
- Form the geniculate ganglion
- Give rise to the greater petrosal n, n. to stapedius, and chorda tympani.
- Leave the canal via the stylomastoid foramen right behind the temporal bone’s styloid process.
- Gives off the first extracranial branch: the posterior auricular nerve, which gives motor innervation to the posterior belly of the digastric muscle and the stylohyoid muscle.
- Main trunk goes to parotid gland, where it doesn’t inervate it, but terminates into 5 branches (TZBMC) that innervate facial expression muscles
- Temporal, Zygomatic, Buccal, Marignal mandibular, cervical
Course of glossopharyngeal nerve
- Medulla oblongata
-
Jugular foramen, gives off tympanic nerve
- Superior and inferior/petrous ganglia right outside contain the cell bodies of the sensory fibers
- Down the neck, anterolateral to internal carotid artery
- Gives off motor branches to the stylopharyngeus muscle
- Gives rise to carotid sinus nerve that gives sensation to carotid sinus and body
- Enter the pharynx and divide into lingual, tonsil, and pharyngeal branches.
Course of hypoglossal n
- Medulla oblongata
- Runs across posterior cranial fossa in the subarachnoid space
- Hypoglossal canal
- Travels in a sheath with branch from the cervical plexus that conducts fibers from C1/C2 spinal nerve roots
- Goes down to the mandible, crossing the int & ext carotid arteries
- Tongue : hyloglossus, styloglossus, and genioglossus muscles
Innervation of parotid gland
- Sensory - auriculotemporal
- Parasympathetic innervation (increase salivation)
- Glossopharyngeal n > otic ganglion > auriculotemporal n
- Sympathetic innervation (decrease salivation): superior cervical ganglion
