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Lecture

Health Sciences 2300A/B Lecture Notes - Nasal Concha, Ethmoid Bone, Inferior Orbital Fissure


Department
Health Sciences
Course Code
HS 2300A/B
Professor
Jamie Melling

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2 shades of bone- axial skeleton (blue), arm limbs make up the appendicular skeleton
Girdles are also very important
Hip girdle is less mobile than the shoulder girdle
Bones are not dead tissue very much alive
Different risk for males and females for bone with regards to bone density
Females reach about 80% of what males do, 80% more than enough and good
Graphs are similar until around 50- menopause occurs and lack of estrogen required to
increase bone density is lost
If you start around 20-30 exercising an proper diet to attain very high levels of bone
density, the eventual fall will start from a higher level, may only fall down to 60%
Normal group don’t really fall to a high risk area - exercising and proper diet
If at the time of menopause you introduce exercise and proper diet you can move into
simply low risk an not the normal high risk
LEC 4: The Boney Skeleton
September-07-12
6:22 PM
Lectures Page 1

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Skeleton gives upright posture an stable form
Muscle attachment sites- allow us to be mobile
Re bone marrow produced in flat bones (hip ) different than long bones (femur, humerus,
arms, lower leg) which contain yellow bone marrow (simply fat)
Hemopoietic tissue- bones that produce red blood cells, i.e. flat bones
Bones store calcium, to bleed out when the body needs it
Buffer- substance that allows a return to homeostasis, maintain a stable level of calcium
When blood becomes too acid it hinders the ability for them to carry calcium - proper
blood pH
Inside a bone in the vertebrae would be solid and surrounding porous
Solid bone- compact bone , porous bone- spongy bone
In interior of bone protected by compact bone
Spongy bone - "trabecular" web-like
Long bone- central cavity filled with yellow bone marrow, taller than wide - femur,
humorous
Short bones- tiny bones seen in wrist or ankle
Flat bones- very thin, red bone marrow- skull, breast plate (sternum)
Irregular bones- vertebrate
Sesamoid bone- sits within a tendon that’s what makes a sesamoid bone (patella aka
knee cap), bone is wrist which is very small and lies within a tendon
Bones can be described by morphology
Different types of bones inside bones
Spongy bone in the middle that creates a cavity in the center of the bone with yellow bone
marrow, cavity exists also to lighten bones, if solid would be very heavy , helps bones
reduce stress and transfer force reduce and risk of fracturing
Compact bone is made up of many pillars within (osteons) extend length down the long
access of the bone
Each osteon has multiple rings, concentric lamellae are cheeks for bone layered around a
central space (central canal)
Pillars tightly packed together in compact bone running the length and working to resist
tension from move
Femur supports weight of upper body
Fibre orientation making up bone in extracellular matrix, from subsequent layers of
lamellae the fibres are perpendicular from each other as you move from one layer to next
Fibres resist twisting fractures of bone an overall crack propagation (movement of a crack
through a bone), every time a breakage in one layer of lamellae the fibres orientated in
opposite layer of crack from next lamellae, crack follows easier path
Bone is light an strong due to osteon an structural matrix, within bones central canals exist
where vessels due, many canals
Bones of skull are referred to as "flat bones" which are flat and thin, organized in this
Lectures Page 2

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Bones of skull are referred to as "flat bones" which are flat and thin, organized in this
manner to be very light
Forces pushing on egg with fingers is distributed over the egg
Trauma to skull is distributed around
Thin bones protecting body's most important organ, skull is very strong like an eggshell- is
you center fingers on two points of the egg very hard to break
Not all joints are meant to move, especially not in the skull
Different from amphiarthrodial (slightly movable- ribs to vertebral column, must
move when we inhale) or diarthrodial joints (very movable-knee)
Bones are either cranial bones or facial which are joined together (articulate) via sutures,
fibrous solid joints called synarthrodial joints which are strong and immovable
False- not completely enclosed by bone
Mostly in the skull is true foramen
Major structure within skull is foramina- hole within a bone which is completely enclosed
by bone, many seen in skull 85 (must know 15)
Cranium - 6 actual bones but two of the bones are paired with makes a total of 8
Cranium is made up of bones that create the cranial cavity, protective case within which
the skull lies
Facial bones also part of the skull- do not contribute to cranial cavity but make up face
Paired bone
Resembles a wall
2/3 of cavity is made up of these bones
Mid-Sagittal suture connects the two halves
Parietal bone
Unpaired (only 1) makes up the last 1/3 of cavity, forehead, superior portion of the eye
Suture articulating two parietal bones and frontal bone is called the frontal/coronal suture
Frontal none
Unpaired bone on the posterior end of the skull
Portion of the brain lies within the occipital portion is the cerebellum
Superior and inferior neutral line that moves out horizontally - neutral lines stem off external
occipital protuberance (bump on back of skull)serve as an attachment point for a ligament
(ligementum neuche)
Occipital Bone
Paired bone
Houses the cavity for the ear, xigomatic process (cheekbone) projection off of the bone which is
called a process- articulates with a facial bone
Inferior portion - mastoid (breast-like structure) process, serves as an attachment for ligaments
Two mastoid processes- prominent bump on the bone
Styloid (column- like structure) process- attachment for ligaments and muscles
Temporal Bone
Resembles a bat, wings like a bat and spans an entire with of the skull, large
Unpaired
Sphenoid
Cube-like bone , sits on superior surface of the nasal cavity, portion of this bone form inferior
surface of the cranial cavity
Unpaired
Ethmoid
that divides the temporal and parietal bone is known as the squamous suture, scale like pattern of
the squamous suture
Between temporal bone and occipital bone is the occipital-temporal suture
Parietal bone and occipital bone- lambdoid suture, it resembles a portion of the lamda symbol
Suture
Known as the boxers temple, weak spot to be punched, risk for injury
Small artery behind pterion- middle meningeal artery - feeds layers of the brain with blood and
when puncture forces potential for bleeding out (hematoma)
Pterion- point of articulation between parietal, frontal, sphenoid and temporal , point where all skull
bones meet
"Time", where people have gray hair
Facial bones include bones no apart of cranial cavity
Only two bones unpaired in the face- mandible , vomer
Houses the lower teeth
Mandible
Paired bone, houses upper teeth, articulate each other at a suture
Maxillae
Paired bone on the medial orbit (eye orbit) , lacrimal fossa lies on it and a small bit on the
maxillae (small hole in the lacrimal fossa is where the tear duct lies, takes away fluid from
the eyes)
Lacrimal
Bump on the nose
Majority of a nose is made up of cartilage
Nasal
"inferior nasal concha", Paired bone
Snail-like bone - twist to them and penetrate into the nasal cavity
Help direct air as we take it in/out of the nose & reduce dead space (foreign material can
come in, good to reduce this space and possibility)
Concha
Don’t need to know facial sutures
Sutures of the cranium are landmarks on the skull to know what lies bellow
Lectures Page 3
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