Head & Neck: Skull, Face, Eye & Ear Flashcards
What is the skull composed of? & what are the 2 parts?
- Composed of 22 bones
- Divided into two parts:
o Neurocranium
o Viscerocranium
How many bones is the neurocranium composed of? & function?
8
houses brain
How many bones is the viscerocranium (facial bones) composed of? & function?
14
houses organs of face
What are the bones of the Neurocranium?
Two paired bones (n=4) 1. Parietal
2. Temporal
Four singular bones (n=4)
3. Frontal
4. Occipital
5. Sphenoid
6. Ethmoid
Describe the Newborn skull and Sutures/Fontanelles
- Flat bones of the neurocranium are separated by narrow seams of connective tissue called sutures
- At points where more then one bone meets is called a fontanelle
(imp. for when babies are born (helps to tell if something is wrong with them & is imp. to be overlapped (cone head when born)
What is a fontanelle?
At points where more then one bone meets
Anterior fontanelle closes by ____ months and posterior closes by ____ months of age
18
2
What is Craniosynostosis?
- Premature closure of one or more CRANIAL SUTURE
- 1 in 2500 live births
- More common in males
Early closure of _______ ______ results in skull becoming long and narrow (scaphocephaly; 57% of cases)
sagittal suture
Early closure of _____ _____ results in skull becoming short (brachycephaly; 30 % of cases)
coronal suture
What is the Craniosynostosis treatment? What are the benefits?
- Corrected by surgery (>1 yr)
- Molding helmet worn
- help protect skull as it corrects itself
- help mould skull in a rounded shape
What is flat head in babies?
when baby lies on back for too long but isn’t a premature closure of sutures
What are the bones of the Viscerocranium?
Bones of the Viscerocranium (n=14): Six Paired bones (n=12)
1. Nasal
2. Zygomatic
3. Lacrimal
4. Maxilla
5. Inferior conchae (*independent bones - gives underlying shape)
6. Palatine
Two Singular bones (n=2)
7. Vomer
8. Mandible (*develops as 1 bone - not 2 that come together)
Describe the muscles of facial expressions
- From skull to skin
- Sphincters and dilators (closing & opening various places)
- 17 different muscles of facial expression
- *All innervated by the FACIAL NERVE (CN VII) (exits via the STYLOMASTOID FORAMEN) - 1 main gland that splits to go to other places
Facial expressions are all innervated by the…
Facial nerve (CN VII) (exits via the stylomastoid foramen)
- 1 main gland that splits to go to other places
Muscles of Facial Expression: Frontalis
- ELEVATES eyebrows and WRINKLES skin on forehead; PROTRACTS scalp
- Expression: Surprise/Curiosity
Muscles of Facial Expression: Orbicularis Oculi (orbital sphincter)
Closes the eyelids
- Protection
- Moistens eyes by
spreading tears
Blinking, Sleeping, (both use palpebral - passive closing) Winking, Squinting (both use orbital & palpebral)
2 parts: Orbital part & Palpebral part (refers to eyelid)
Muscles of Facial Expression: Orbicularis Oris (oral sphincter)
Closes oral fissure
* Compresses and protrudes lips
(kissing)
* Resists distention (when blowing)
Attaches into the ANGLE OF THE MOUTH
Muscles of Facial Expression: Buccinator
- Compresses cheeks against teeth
- Works with tongue to keep food
out of oral vestibule - Resists distention when blowing; suckling
(sits behind mouth)
*NOT a muscle of mastication
babies get big buccinator muscles when they’re eating
How would you test facial nerve function?
Facial expressions!
Frontalis - crease up the forehead
Orbicularis - keep eyes closed against resistance
Elevators & Depressors of the lips - reveal the teeth
Orbicularis Oris - squeeze lips together
(have to do all of these to see if facial nerve is working/functioning)
What is Botox?
Botox is botulinum toxin, produced by the bacteria Clostridium botulinum
Powerful neurotoxin that prevents neurotransmitter release and paralyzes muscles (i.e. paralyzing facial nerves - so it’s smooth)
What is Botox used to treat? What about cosmetically?
Used to treat muscle stiffness, muscle spasms, excessive sweating, overactive bladder, or loss of bladder control, and chronic migraine headaches
Cosmetically used to reduce the appearance of wrinkles by paralyzing muscles of the face
What are the Muscles of Mastication?
Mastication = Chewing
Four Muscles:
1. Temporalis
2. Masseter
3. Lateral Pterygoid
4. Medial Pterygoid
(1st two are Superficial & last 2 are Deep)
What are Muscles of Mastication innervated by?
Innervated by the MANDIBULAR BRANCH (CN V3) of the TRIGEMINAL NERVE
- only CN that does motor function
Functions of the Muscles of Mastication: Close mouth
Masseter, Temporalis, Medial pterygoid
Functions of the Muscles of Mastication: Open mouth
Lateral pterygoid (pulling it anteriorally)
Functions of the Muscles of Mastication: Protrusion
Lateral pterygoid, Masseter, Medial pterygoid
(pull open jaw forward)
Functions of the Muscles of Mastication: Retrusion
Temporalis
(pull jaw backwards)
What is the External Carotid Artery?
Supplies blood to the head OUTSIDE of the cranium
Anastomoses between the internal & external carotid artery
What are the branches of the External Carotid Artery?
Branches:
1. Superior Thyroid a.
2. Ascending Pharyngeal a.
3. Occipital a.
4. Lingual a. (goes to tongue)
5. Facial a.
6. Posterior Auricular a.
7. Maxillary a.
8. Superficial Temporal a. (see it on side of forehead when someone mad it sticks out for ex)
Left Internal Carotid a.
Left External Carotid a.
Left Common Carotid a.
What are the Veins of the Face?
- Superficial Temporal vein
- Maxillary vein
- Retromandibular vein
(Ant. & Post. Branches)
- vein that’s behind mandibular - Facial vein
4a. Angular vein - Internal Jugular
- Posterior Auricular vein
- External Jugular
*study slide 19
What is the Orbit?
houses the eyes
- Comprised of 7 bones
- Floor and medial wall are thin (sinuses) while roof and lateral wall are strong
What are the 7 bones that the Orbit is comprised of?
- Frontal
- Ethmoid
- Palatine
- Lacrimal (has hole that drains)
- Maxilla
- Sphenoid
- Zygomatic
Describe Orbital Blowout Fractures
- Fracture of an orbital wall with an intact orbital margin
- Commonly occurs in FLOOR OF ORBIT formed by maxilla
- Often present with EXOPHTHALMOS (protrusion of eye from orbit)
TREATMENT: Reconstruction with titanium mesh
(floor blowouts b/c v. thin spot)
What are the Fissures & Foramina?
Optic Canal
- CN II, Ophthalmic A (comes through it)
Supraorbital Notch
- Supraorbital Nerves & Vessels
Nasolacrimal Canal
- Nasolacrimal Duct (tears drained from eye to nose)
Infraorbital Foramen
- Infraorbital Nerve & Vessels (pop out here - exit)
Inferior Orbital Fissure
- Infraorbital Nerve & Vessels (enter)
Superior Orbital Fissure
- CN III, CN IV, CN V1, & CN VI, Superior & Inferior ophthalmic veins
What are the functions of eyelids?
- Protect from injury, irritation, & excess light 2. Maintain moist cornea (b/c it doesn’t get any nutrients from things other than tears)
What are the Orbital Muscles to Eyelid?
- Orbicularis Oculi
o ORBITAL part: close eye TIGHTLY
o PALPEBRAL part: close eyelid GENTLY - Levator Palpebrae Superioris (LPS)
o Elevates superior eyelid
o Innervation: Oculomotor Nerve (CN III)
(*only have muscle for upper lid not lower b/c lower can open by gravity)
What is the Lacrimal Apparatus?
LACRIMAL GLAND produces lacrimal fluid (tears)
Lacrimal fluid drains through LACRIMAL PUNCTA and LACRIMAL CANALICULI to LACRIMAL SAC
NASOLACRIMAL DUCT then conveys fluid from lacrimal sac to nasal cavity
(from lateral side to medial side of body)
Runny nose when crying is caused by tears draining through the ______ ____ into nasal cavity
nasolacrimal duct
Parasympathetics: _______ lacrimal gland secretion - ______ Nerve (CN ____)
STIMULATE
FACIAL
VII
Sympathetics: ______ production of tears – ______ ________ ____
DECREASE
T1-2 Sympathetic chain (any symp. are coming from T1-2 always!)
What are the 3 layers of the eyeball?
- Outer fibrous layer
- Middle vascular layer
- Inner layer
Outer fibrous layer of eyeball contains:
Sclera, Conjunctiva & Cornea
Middle vascular layer of eyeball contains:
Choroid, Iris, & Ciliary Body
Inner layer of eyeball contains:
Retina