Lab 2 Flashcards
what are the immovable joints in the skull called?
sutures
bones of the skull provide …
muscle attachment sites and protection
facial bones provide …
- attachment for muscles of facial expression
- framework of face
- support for digestive and respiratory system entrances (nose and mouth)
What are the three unique features of the skull?
- Sutures
- Paranasal sinuses
- Fontanels
What are sutures?
an immovable joint which holds most skull bones together
What are Paranasal sinuses?
4 paired air-filled spaces around nasal cavity
What do paranasal sinuses do?
lined by mucous membranes which produce secretions to clear infections and debris, then drain into nasal cavity. Also are resonating chambers that intensify sound (eg speech)
What are fontanelles?
soft spots in infants skulls
How many bones make up the entire skull and what is their function?
22 bones; protect special sense organs and brain
What two bone groups are there in the skull?
Cranial bones and Facial bones
How many cranial bones are there?
8 cranial bones forming the cranial cavity
Name the cranial bones
Frontal, 2 parietal, 2 temporal, occipital, sphenoid and ethmoid.
How many facial bones are there?
14 facial bones forming the face
Name the facial bones
2 nasal, 2 maxillae, 2 zygomatic, 2 lacrimal, 2 palatine, 2 inferior nasal conchae, 1 vomer, 1 mandible
what does the frontal bone form?
the forehead
what do the parietal bones form?
sides/ roof of cranial cavity
what do the temporal bones form?
lateral aspects and floor of cranium
What does the occipital bone form?
posterior part and most of base of cranium
Which bone is in contact with ALL other cranial bones?
Sphenoid
which bone increases the surface area of the nasal cavity?
Ethmoid; traps air particles and humidifies the inhaled air
what facial structure do the nasal bones form?
bridge of nose
What do the maxillae form?
Forms the upper jawbone and most of hard palate. Also separates nasal and oral cavities.
Which bones form the cheekbones?
the zygomatic bones
which bones are the smallest facial bones and form medial wall of orbit?
Lacrimal bones
what is the proper name for the jawbone?
the mandible
what are foramen?
holes which allow veins, ligaments and nerves to pass through
what is a fissure?
narrow groove between bones which blood vessels or nerves pass through
what is a fossa?
a shallow depression for glands/ tissue
Where is the lacrimal sac found?
the lacrimal fossa
what is the largest and strongest bone of the skull?
mandible
what separates the nasal cavity into right and left nostrils?
the nasal septum
what is the only movable bone in the skull?
mandible
which two bones does the mandible articulate with?
the temporal bones
which bone is NOT attached to any other bones?
the hyoid bone
What is the function of the hyoid bone?
supports tongue, attachment site for muscles of tongue, neck and pharynx, keeps larynx (voice box) open
What are the seven bones that make up the orbit?
Sphenoid; Ethmoid; Lacrimal; Frontal; Palatine; Maxillary; Zygomatic
which bone separated the nasal cavity from the brain cavity?
Ethmoid
What do sinuses do?
membrane-lined cavities, secrete mucus, helps protect respiratory system from irritants/ infection
Why is the ethmoid more susceptible to infection?
due to it being one of the paranasal sinuses, and has many holes which filter air particles that are inhaled.
Which bone does the pituitary gland sit in?
Sphenoid bone (specifically in the Sella Turcica)
which bone is described as butterfly shaped?
Sphenoid bone
what is one issue that ay occur in sinuses?
Thrombosis (blood clots) which may cause embolism
What are fontanels and what do they eventually form?
Areas of unossified tissue, eventually replaced with bone to become sutures
what is the function of fontanels?
provide flexibility to the foetal skull, allowing skull to change shape as it passes through the birth canal. Also brain growth.
What is Craniosynostosis?
Premature cranial suture fusion. Causes abnormal skull shape, disabilities. Severity depends on which/ how many fontanels are affected
What are the 4 paired sinuses?
Frontal sinus; maxillary sinus; ethmoid sinus; sphenoid sinus
Sinusitis may occur if which complex is blocked?
Obstruction of Osteomeatal complex
What connects the paired sinuses to the nasal cavity?
Ostia (small openings)
Roles of sinuses:
- immunological defence
- lightening of skull
- increase SA for smell (olfaction)
- increasing voice resonance
- buffer against head trauma
- humifying & heating inhaled air
- regulating intranasal pressures
Which group of muscles arise from bone and insert into skin?
muscles of facial expression
What is the main nerve innervating muscles of facial expression?
Facial nerve (VII cranial nerve)
what is Bell’s palsy?
facial paralysis due to damage of CN VII (e.g. infection)
Which muscle closes the eye?
Orbicularis oculi
Which muscle opens eye/ raises eyelid?
Levator palpebrae superioris
Which muscle puckers the mouth?
Orbicularis oris
Which muscle forms portion of cheek & assists with whistling, blowing, sucking& chewing?
Buccinator
Where do extrinsic muscles of eye insert?
into sclera (white of eye)
Where do most extrinsic eye muscles arise?
from the Annulus of Zinn
What are the fastest and most precisely controlled muscles in the body?
Extrinsic muscles of the eye
How many rectus muscles of the eye are there?
4; lateral, medial, superior, inferior
How many oblique muscles of the eye are there?
2; inferior and superior
Which cranial nerves supply the extrinsic muscles of the eye?
Oculomotor (CN III), Trochlear (CN IV), Abducens (CN VI)
Which extrinsic muscles of the eye are supplied by Oculomotor (CNIII)?
superior, medial, inferior rectus and inferior oblique
Which extrinsic muscle of the eye is supplied by Trochlear (CNIV)?
Superior oblique
Which extrinsic muscle of the eye is supplied by Abducens (CNVI)?
Lateral rectus
adduction of eye =
eye moves inwards (towards nose)
abduction of eye =
eye moves outwards (away from nose)
Intorsion of eye =
rotation of eye towards nose
Extortion of eye =
rotation of eye away from nose
Which EOM muscles arise from the Annulus of Zinn?
All except the inferior oblique.
What is the Annulus of Zinn?
a ring of fibrous tissue which surrounds the optic nerve
What is the trochlea?
a loop of fibrous tissue that the super oblique tendon passes though.
What is the only EOM innervated by CN IV (trochlear)?
superior oblique
