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Chapter Objectives
- Describe the functions of the skeletal system.
- Compare the structures and functions of compact and spongy bone.
- Discuss bone growth and development, and account for variations in the internal structure of specific bones.
- Describe the remodeling and repair of the skeleton, and discuss homeostatic mechanisms responsible for regulating mineral deposition and turnover.
- Name the components and functions of the axial and appendicular skeletons.
- Identify the bones of the skull.
- Discuss the differences in structure and function of the various vertebrae.
- Relate the structural differences between the pectoral and pelvic girdles to their various functional roles.
- Distinguish among different types of joints and link structural features to joint functions.
- Describe the dynamic movements of the skeleton and the structure of representative articulations.
- Explain the relationship between joint structure and mobility, using specific examples.
- Discuss the functional relationships between the skeletal system and other body systems.
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Acetabulum
a vinegar cup: acetabulum of the hip joint
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Ad-
toward, to: adduction
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Amphi-
on both sides; amphiarthrosis
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Arthros
joint; amphiarthrosis
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blast
Precursor; osteoblast
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circum-
around:circumduction
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Clavius
Clavicle;clavicle
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concha
shell:middle concha
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corona
crown;coronoid fossa
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Cribrum
Sieve: cribriform plate
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gennan
To produce: esteogenesis
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gompgosis
a bolting together: gomphosis
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Infra-
beneath; infraspinous fossa
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lacrimae
tears: lacrimal bones
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lamella
thin plate:lamellae of bone
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malleolus
little hammer: medial malleolus
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meniscus
cresent: menisci
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porosus
Porous; esteoporosis
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stylos
pillar; styloid pillar
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supra-
above:supraspinous fossa
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sutra
a sewing together: suture
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Teres
cyndrical: ligamentum teres
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trabecula
wall: trabeculae in spongy bone
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Vertere
to turn:inversion
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Skeletal System includes
- bones of the skeleton
- cartilages
- joints
- ligaments
- and other connective tissue that stabilize or connect them.
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Skeletal System Has 5 primary functions
- Support
- Storage
- Blood cell production
- Protection
- Leverage
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Bone or (osseous tissue) is a supporting connective tissue that
Contains specialized cells and a matric that consists of extracellular protein fibers and a gorund substance.
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Calcium phosphate accounts for...
- 2/3 of the weight of bone.
- Remaining third is contained os osteocytes, collagen fibers and other cell types that only make up 2% of the mass of a bone.
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4 general shapes of bones
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Long bones
- Are longer then they are wide
- Humerous and femur are examples
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Short bones
dimensions are roughly equal in size
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Flat Bones
are thin and relatively broad
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Irregular bones
Have complex shapes that do not fit easily into any other category
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A long bone from top to bottom is:
Proximal epiphysis , Diaphysis, distal epiphysis
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Diaphysis
Central shaft, that covers a central marrow cavity that contains bone marrow, which is a loose connective tissue
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Epiphyses
The expanded portions at each end of a long bone, are covered by articular cartilages.
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Each epiphysis of a long bone articulates with an adjacent bone at a joint
Growth of an immature long bone occurs at the juctions between the epiphyses and diaphysis
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Two types of visible bone tisue
- Compact bone (dense bone) relatively solid
- Spongy bone (cancellous bone) resembles a network of bony rods or struts separated by spaces.
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Periosteum
Covers the outer surface of the bone
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The fibers of tendons and ligaments intermingle with those of the periosteum, and attach skeletal muscles to bones and one bone to another
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Cellular Endosteum
- lines the marrow cavity and other inner surfaces
- Is active during bone growth and whenever repair or modeling is underway
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Osteocytes
bone cells contained in small pockets called lacunae.
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Lacunae is found
between narrow sheets of calcified matric that are known as lamellae
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Canaliculi
Small channels that radiate through the matrix and interconnect lacunae and link them to nearby blood vessels.
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Haversian system, Osteon
basic functional unit of compact bone, osteocytes are arranged in concentric layers around a central canal or Haversian canal that contains one or more blood vessels.
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Perforating canals
provide passageways for the linking of blood vessels of the central canals with those of the periosteum and marrow cavity
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Spongy bone
- Has a different lamellar arrangement and no osteons.
- the lamellae froms rods or plates call trabeculae
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Branching of the thin trabeculae create an open network. canaliculi that radiate from the lacunae of spongy bone at the exposed surfaces of the trabeculae , where nutrients and wastes diffuse between marrow and osteocyts
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A layer of compact bone covers surfaces everywhere except
inside joint capsules where articular cartilages protect opposing surfaces
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Cells in bone
- Osteocytes
- Osteoclasts
- Osteoblasts
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Osteocytes
Mature bone cells. Maintain normal bone structure by recycling calcium salts in the bony matrix around themselves and by assisting in repairs
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Osteoclasts
Giant cells with 50 or more nuclei. acids and enzymes secredted by osteoclasts dissolve the bony matrix and release stored minerals through osteolysis or resorption.
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Osteolysis or resoption
helps regulate calcium and phosphate concentrations in body fluids
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Osteoblasts
- Are the cells responsible for the production of new bone.
- Osteoblasts produce new bone matrix and promote deposition of calcium salts in the organic matrix.
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Osteogenesis
production of new bone
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Ossification
Process of replacing other tissues with bone
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Calcification
depostion of calcium salts occurs during ossification , but it can also occur in tissues other than bone
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Endochondrial ossificaiton
bone replaces existing cartilage
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Intramembranous ossification
begins when osteoblasts differentiate within embryonic or fetal fibrous connective tissue.
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the place where Ossification first occurs
an ossification center
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Steps of Endochondrral ossificaiton
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Chonodrocytes at the center of the growing cartilage model enlarge and then die as the matrix calcifies
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Steps of Endochondrral ossificaiton
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Newly dervrived osteoblasts cover the shaft if the cartilage in a thin layer of bone
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Steps of Endochondrral ossificaiton
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Blood vessels penetrate the cartilate. New osteoblasts from a primary ossification center.
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Steps of Endochondrral ossificaiton
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The bone of the shaft thickens and the cartilage near each epiphysis is replaced by shafts of bone.
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Steps of Endochondrral ossificaiton
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Blood vessels invade the epiphyses and osteoblasts form secondary centers of ossification
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Appositional growth
While the bone elongates, its diameter enlarges as its outer surface
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Stopping ages for epipheseal cartilages in arms and legs
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Vitamen D3 is converted to what in the kidneys after processed in the liver
Calcitriol which is a hormone that stumulates the absorption of calcium and phosphate ions in the digestive tract
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Rickets
is a conditon marked by softening and bending of bones that occurs in growing children, due to a dificiency of Vitamen D3
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Scurvy
- Dificiency in vitamen C
- Reduction of osteoblast production that leads to weak and bittle bones
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Remodeling
18% of protein and mineral comonents are removed and replaced each year through this process
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Calcium
- Is the most abundant mineral in the body
- typical body caonts 1-2 kg of calcium
- 99% in the skeleton
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Calcium concentration in body fluids
- Increase- by 30%muscles become relatively unresponsive
- Decrease-by 35% muscles become so excitable that convulsions may occur
- Decrease by 50- Death
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Parathyroid hormone (PTH) and calcitriol
- work together to elevate calcium levels in body fluids
- they are opposed bu calcitonin which depresses calcium levels in body fluids
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Steps in repair of a fracture
1
Immediately after the fracture,extensive bleeding occurs. over a period of several hours, a large blood clor or fracture hematoma develops
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Steps in repair of a fracture
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An internal callus forms a network of spongy bone unites the inner edges and external callus of cartilage and bone stabilizes the outer edges.
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Steps in repair of a fracture
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The cartilage of the external callus has been replaced by bone and struts of spongy bone now unite the broken ends. Fragments of dead bone and the areas of bone closest to the break have been removed and replaced.
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Steps in repair of a fracture
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A swelling initially marks the location of the fracture. over time, this region will be remodeled, and little evidence of the fracture will remain.
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General types of skeletal/Joint injuries
joints, sprains, subluxations, dislocations, and fractures.
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Sprain
Injury that stretches or tears one or more ligament within a joint
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Sprain
Grade I
- Minor or incomplete tear
- Ligament is painful and tender but no laxity
- swelling/ecchymossis minimal
- joint is stable
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Sprain
Grade II
- Significant but incomplete tear
- there is laxity, but an endpoint which no further opening of the joint occurs
- swelling/ecchymosis moderate to severe
- joint is unstable but intact
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Sprain
Grade III
- Complete tear/ total failure of ligaments involved.
- no endpoint is felt during exam
- pain and muscle spasm can mask a grade III sprain.
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Subluxation
- Partial dislocation
- is a partial displacement of a bone end from its position withinn a joint capsule
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Dislocation
- Is a complete displacement of bone ends from normal position within a joint.
- Joint often fixes in an abnormal postion with noticeable deformiy.
- this injury occurs when bones of the joint move beyond their normal range of motion with great force.
- danger of entrapping,compressing or tearing blood vessels and nerves
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Fracture
- Is an injury that interrupts the structural integrity of a bone
- Either Traumatic or Pathological fracture(requires very little trauma
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Traumatic Fractures causes:
- Direct blow
- Angular(Bending forces)
- Axial loading
- Twisting (torque) stress
- or any combo
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Pathologial fractures
- lytic metastatic (cancerous) lesions,
- fractures through benign bone cysts
- vertebral compression fractures
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Salter-Harris System
Classifies growth plate injuries
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Salter-Harris Type I
- the fracture line runs through the physis. There is usually little, if any seperation of the epiphysis from the rest of the bone
- least severe
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Salter-Harris Type II
The entire epiphyss and a portion of the metaphysis are broken off. the fracture line runs through the physis and into the metaphysis
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Salter-Harris Type III
Portion of the epiphysis is broken off. Tje fracture lime rums through the physis into the epiphysis, and the joint.
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Salter-Harris Type IV
A portion of the epiphysis and portion of the metaphysis are borken off. The fracture lines through the metaphysis, physis, epiphysis and into the joint.
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Salter-Harris Type V
The epiphyseal plate is compressed, usually through an axial loading type force. These injuries are difficult to diagnose and found retrospectively
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Fracture classifications
in the field and xray
- Open
- closed
- Greenstick
- torus
- transverse
- oblique
- spiral
- comminuted
- segmental
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open fracture
through the skin
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Closed fracture
not through the skin
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Greenstick fracture
- almost exclusive to children
- one side of the bone is broken and ther other side is bent.
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Torus fracture
- almost exclusive
- there is localized buckeling or swelling of the cortex
- with little to no displace of the bone itself
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Transverse fracture
a transverse fracture is a fracture line perpendicular to the long axis of the bone
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Oblique fracture
the break extends obliquely to the long axis of the bone
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spiral fracture
- also called torsion fracture
- occurs when twisting force to a long bone
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communited fracture
bone fractures with fragments in the fracture site
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segmental fracture
Multiple fracture sites
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impacted fracture
axial loading force is applied to the bone which drives the bone ends to fracture site together
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colles' fracture
Fork forearm fracture
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Supracondylar fracture
- fracture of the distal humerous just above the elbow
- high complecation rate with nerve and vasculature
- can fracture growth plate
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Hip Fracture classifications
- Intracapsular
- Extracapsular
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Intracapsular
- Capital
- subcapitol
- transcervical
- basicervical
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extracapsular
- trochanteric
- introchanteric
- subtrochanteric
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Lefort I
- limited to the macilla at the level of the nares
- only the hard palate and upper mouth move with gentle palpation and mobilization
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Lefort II
Triangulat fracture line extends across the ridge of the cheets into hte orbits of eyes
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Le fort III
- the facial skeleton is separated from the skull
- Crainial-facial dislocation
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Steps of fracture healing
- Inflammatory
- Reparative
- Remodeling
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Osteopenia
Inadequate ossification
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Osteoporosis
Condition that produces a reduction in bone mass great enough to compromise normal function.
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bone markings/ surface features
depressions and openings indicate sides where blood vessels and nerves run alongside or penetrate the bone.
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Skeletal system consists of
- 206 separate bones
- axial
- appendicular
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Axial Skeleton
- Forms the longitudinal axis of the body
- 80 bones
- 22 bones of the skull, 7 assiciated bones (6 auditory ossicles and hyoid bone)
- Thoracic cage- 24 ribs and sternum
- 26 bones of the vertebral column
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Appendicular skeleton
- 126 appendicular bones
- 32 associated with each upper limb
- 31 with each lower limb
- Limbs
- pectoral/ pelvic girdles which attach the limbs to the trunk
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Surface features of bone/General/Anatomical/Description
Elevations and projections
Process
Any projection or bump
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Surface features of bone/General/Anatomical/Description
Elevations and projections
Ramus
Extension of a bone that makes an angle with the rest of the structure
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Surface features of bone/General/Anatomical/Description
processes formed where tendons or ligaments attach
Trochanter
Large, rough projection
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Surface features of bone/General/Anatomical/Description
processes formed where tendons or ligaments attach
Tuberosity
Smaller, rough projection
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Surface features of bone/General/Anatomical/Description
processes formed where tendons or ligaments attach
Tubercle
small, rounded projection
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Surface features of bone/General/Anatomical/Description
processes formed where tendons or ligaments attach
crest
prominent ridge
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Surface features of bone/General/Anatomical/Description
processes formed where tendons or ligaments attach
line
low ridge
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Surface features of bone/General/Anatomical/Description
processes formed where tendons or ligaments attach
spine
pointed process
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Cranium encloses the
Crainial cavity which is a fluid filled chamber that cushins and supports the brain
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Frontal bone
forms the forehead and the roof of the orbits
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supraorbital foramen
- is an opening the pierces the bony ridge abouve each orbit and forms a passageway for blood vessels and nerves passing to orfrom the eyebrows and eyelids
- aka the supraorbital notch
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Frontal sinius
make the cranium lighter and produce muscus that cleans and moistens the nasal cavities
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infraorbital foramen
is an opening for a major sensory nerve from the face
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parietal bone
is the posterior to the frontal bone. together the parietal bones form the roof and superior walls of the crainium
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False ribs
8-12 do not attach to sternum
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