Transcript 19--last 4 cranial nerves

Dr. Ahmed Fathalla Ibrahim
LAST 4 CRANIAL NERVES
GLOSSOPHARYNGEAL NERVE
GLOSSOPHARYNGEAL NERVE
•
•
•
Types of fibers: mixed
Sensory ganglia: superior & inferior
Exit from cranial cavity: through jugular
foramen
• Course in neck:
1. Descends between internal jugular vein &
internal carotid artery
2. Curves around stylopharyngeus muscle &
runs between internal & external carotid
arteries
3. Crosses stylopharyngeus & runs between
hyoglossu & genioglossus muscles to
reach the tongue
GLOSSOPHARYNGEAL NERVE
• Branches:
1. Lingual: carries general & taste sensations
from posterior 1/3 of tongue
2. Pharyngeal: carries sensory fibers from
pharynx
3. Tonsillar: carries sensory fibers from
palatine tonsils
4. Muscular: to stylopharyngeus muscle
5. Tympanic: carries sensory fibers from
tympanic cavity & inner surface of
tympanic membrane, forms a plexus from
which arises the lesser petrosal nerve
carrying preganglionic parasympathetic
fibers to parotid gland
6. To carotid sinus & body
GLOSSOPHARYNGEAL NERVE
• Applied anatomy: pain of tonsilitis may
be referred to middle ear through
glossopharyngeal nerve because the
nerve supplies both structures
VAGUS NERVE
VAGUS NERVE
• Types of fibers: mixed
• Sensory ganglia: superior & inferior
• Exit from cranial cavity: through jugular
foramen
• Course in neck:
1.Descends between internal jugular vein
& internal carotid artery
2.Continues in carotid sheath between
internal jugular vein & common carotid
artery
3.At root of neck, crosses subclavian
artery to reach the thorax
VAGUS NERVE
• Branches:
1. Pharyngeal: contains motor fibers from
cranial part of accessory nerve to: all
pharyngeal (except stylopharyngeus) & all
palatine (except tensor palati) muscles
2. Superior laryngeal: divides into: internal
laryngeal: carries sensory fibers from larynx
(above vocal folds) & general & taste
sensations from vallecula + external
laryngeal: carries motor fibers to
cricothyroid muscle
3. Recurrent laryngeal: carries sensory fibers
from larynx (below vocal folds) & motor
fibers to all laryngeal muscles (except
cricothyroid)
VAGUS NERVE
• Branches:
4. Auricular: carries sensory fibers from
external auditory meatus & outer
surface of tympanic membrane
5. Meningeal: to dura of posterior cranial
fossa
6. Cardiac
ACCESSORY NERVE
ACCESSORY NERVE
•
•
1.
2.
•
Types of fibers: motor
Elements: formed of:
Cranial part: emerging from medulla
Spinal part: formed by fusions of
roots emerging from upper 5 or 6
cervical segments of spinal cord then
enters cranial cavity through foramen
magnum & joins cranial part
Exit from cranial cavity: through
jugular foramen
ACCESSORY NERVE
• Course in the neck: both parts separates
after emergence from cranial cavity
1. Cranial part: is distributed along pharyngeal
& recurrent laryngeal branches of vagus
2. Spinal part:
• Descends between internal jugular vein &
internal carotid artery
• Curves backward, superficial to internal
jugular vein then deep to sternomastoid (to
reach posterior triangle of neck
• Passes superficial to levator scapulae the
deep to tapezius
• Supplies motor fibers to sternomastoid &
trapezius
PHARYNGEAL PLEXUS OF
NERVES
• Site: on lateral surface of middle
constrictor
• Formation: by pharyngeal branches of:
1.Vagus (carries cranial part of accessory
nerve)
2.Glossopharyngeal
3.Superior cervical sympathetic ganglion
HYPOGLOSSAL NERVE
• Types of fibers: motor
• Exit from cranial cavity: through
hypoglossal canal
• Course in neck:
1.Descends between internal jugular vein
& internal carotid artery
2.Curves forward superficial to: internal
& external carotid arteries, lingual
artery, hyoglossus & genioglossus
• Branches: motor to all muscles of
tongue except palatoglossus