Transcript KH 2220 Laura Abbott, MS, LMT

KH 2220
Laura Abbott, MS, LMT
Day 4
Muscles of the Skull
Meninges
• 3 protective layers of brain
• Dura Mater
– External; tough, thick covering
• Arachnoid Mater
– Web-like, shock absorption, intermediate
• Pia Mater
– Deep and vascular
• Meningitis – compression/pressure on
brain- usually involving the arachnoid mate
and pia mater
– 2 types: viral and bacterial (touch chin to
neck)
MENINGES
Subarachoid space contains cerebrospinal fluid
The Cranial Nerves
• There are 12 pairs of cranial nerves, each
designated by a name and a Roman numeral.
• Most cranial nerves are mixed, meaning they
have both sensory and motor fibers.
• The cell bodies of the motor fibers are situated
within the brain.
• The cell bodies of the sensory fibers are located
(for the most part) just outside the brain where
they cluster together into a ganglion.
I
Olfactory nerves
• sensory
• There are actually many tiny olfactory
nerves, each originating in the roof of the
nasal cavity and terminating in the
olfactory bulb.
• The olfactory nerves conduct impulses
from the nasal cavity to the olfactory area
of the cerebral cortex, which interprets
these impulses as smell.
II
Optic nerve
• Sensory
• The fibers of the optic nerve originate in
the retina (back of the eye).
• From there, the fibers conduct impulses to
the midbrain.
• From the midbrain, the impulses are
relayed to the visual area of the cerebral
cortex where the impulses are interpreted
as sight.
III Oculomotor nerve
• Mixed
• The sensory and motor fibers of this nerve
supply the muscles that produce movements of
the eye ball, as well as the eye lid muscles.
• It also supplies the iris (the sphincter muscle
through which light enters the eye) and the
ciliary muscles, which change the shape of the
lens to accommodate for near and far vision.
• Damage to this nerve may result in double
vision, dilated pupils, blurred vision, and droopy
eyelids (ptosis).
IV Trochlear nerve
• Mixed
• This is the smallest of the cranial nerves.
• Its sensory and motor fibers supply the
superior oblique muscles for oblique eye
movements.
V Trigeminal nerve
• Mixed
• This is the largest of the cranial nerves.
• It supplies the tissues of the face, eyes, nasal cavity, and
mouth.
• Sensory fibers conduct impulses for touch, heat, cold,
and pain (including tooth pain).
• Motor fibers supply the chewing muscles. Its name is
taken from the fact that it consists of three main
branches:
– The ophthalmic nerve (supplies the scalp, eyes, outer nose, and
nasal
cavity),
– the maxillary nerve (supplies the nasal cavity, palate, and upper
teeth)
– the mandibular nerve (supplies the lower jaw and teeth).
FYI
• Trigeminal Neuralgia is believed to be the
most severely painful condition there is. It
is caused by inflammation of the trigeminal
nerve.
• Pain may last for a few seconds of a few
minutes, but it may
occur many times
during the day.
• Severing the nerve just proximal to its
ganglion treats the most severe cases.
VI Abducens nerve
• Mixed
• The sensory and motor fibers of this nerve
supply the lateral rectus muscles for lateral
eye movements.
VII Facial nerve
• Mixed
• Sensory fibers conduct impulses from the
taste buds on the anterior two-thirds of the
tongue.
• Motor fibers supply the facial muscles.
FYI
• Bell’s palsy is a dysfunction of the facial nerve.
• The muscles are paralyzed on one side of the
face, and the person loses sensation on that
side of the face, the lower eyelid droops, the
corner of the mouth sags, there is partial loss of
taste, and the eyes tear constantly.
• The cause is unknown, symptoms could
disappear spontaneously, and massage can
help
VIII
Vestibulocochlear nerve
• Sensory
• Also known as the statoacoustic nerve and
auditory nerve.
• It originates in the ear.
• It has two portions:
– the vestibular portion conducts impulses which the
brain uses to get a sense of balance.
– The cochlear portion carries impulses to the auditory
area of the cerebral cortex which interprets the
impulses as “sound.”
• Damage to this nerve results in impaired hearing
(nerve deafness), dizziness, and nausea.
IX Glossopharyngeal nerve
• Mixed
• This nerve supplies the back of the
tongue
(glosso) and the throat (pharynx).
• Sensory fibers provide
general sensation for
these areas as well as taste information from the
back of the tongue.
• Sensory fibers originating from the carotid artery
gives the brain information about blood
pressure.
• Motor fibers supply swallowing muscles of the
throat.
• Damage to this nerve results in loss of gag reflex
and impaired ability to swallow and taste (sour
and bitter).
X Vagus nerve
• Mixed
• This nerve supplies most of the visceral
organs in the thoracic and abdominopelvic
cavity.
• Damage results in hoarseness, loss of
voice, difficulty in swallowing, and
impaired digestion.
• Innervates smooth muscle of heart and
lungs.
XI Accessory nerve
• Motor
• Motor fibers supply the
sternocleidomastoid muscle (SCM), traps,
and swallowing muscles.
• Damage may result in turning of the head
to one side (SCM) and impaired ability to
shrug shoulder (traps).
XII Hypoglossal nerve
• Motor
• Motor fibers supply muscles of the tongue.
• Damage results in impaired ability to
speak and swallow.
Pneumonic Device to Remember
Cranial Nerves:
•
•
•
•
•
•
•
•
•
•
•
•
Oh – Olfactory
Oh – Optic
Oh – Oculomotor
To – Trochlear
Touch – Trigeminal
And – Abducens
Feel – Facial
Very – Vestibulocochlear
Green – Glossopharyngeal
Veggies – Vagus
Ah – Accessory
Ha - Hypoglossal
Temporalis Muscle
• O: temporal fossa
SIDES OF SKULL
• I: coronoid process
of mandible
• A: Elevates
mandible
Frontalis
• O: frontal bone
• I: Skin of the
eyebrows
• Wrinkle eyebrows,
forehead elevation,
raise eyebrows
Occipitalis Muscle
• O: lateral 2/3 of
superior nuchal line
external occipital
protuberance
• I: galea aponeurosis,
over the occipital
bone
• A: draws back the
scalp to raise the
eyebrows and wrinkle
the brow
Masseter Muscle
• O: zygomatic process
and its arch
• I: angle and ramus of
mandible
• A: Closes jaw and
elevates mandible
• Unilaterally – moves jaw
to same side
Buccinator Muscle
• O: molar region of
maxilla and
mandible
alveolar near teeth
• I: orbicularis oris
• A: draws corner of
mouth lateral
(compresses
cheek/whistling/food
between teeth)
Orbicularis Oris
• O: maxilla and
mandible
• I: encircles mouth,
angles at mouth
• A: closes
mouth/kissing
muscle
Medial Pterygoid
• O: medial surface of lateral
pterygoid plate of the sphenoid
palatine bone pterygoid fossa
• I: inner surface of mandibular
ramus angle of the mandible
• A: closes the lower jaw
(clenches the teeth) ; can
protrude the mandible in
combination with the lateral
pterygoid
Lateral Pterygoid
• O: Superior head: lateral
surface of the greater wing of
the sphenoid; Inferior head:
lateral surface of the lateral
pterygoid plate
• I: neck of the mandibular
condyle; articular disk of the
TMJ
• A: deviates mandible to side
opposite of contraction (during
chewing); opens mouth by
protruding mandible