Download The Two Comedians, by Chris Peters Kaan Yücel M.D., Ph.D. 19

The Two Comedians, by Chris Peters
Kaan Yücel M.D., Ph.D.
19. November 2013 Tuesday
1.OSTEOLOGY
Gk, osteon, bone, logos, science
branch of medicine concerned with
the development and diseases of bone tissue
270 bones
222 bones
206 bones
Skeletal system divided into two functional/anatomical parts:
Axial skeleton
bones of the head, neck and trunk
Appendicular skeleton
bones of the limbs
including those forming the pectoral (shoulder) and pelvic girdles.
80 bones
126 bones
Bone
one of the hardest structures of the animal body
calcification of its extracellular matrix
some elasticity
results from the organic matter
great rigidity
results from their lamellous structures and tubes of inorganic calcium
phosphate
color in a fresh state
pinkish-white externally, deep red within.
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The skeleton is composed of cartilages and bones.
Cartilage
resilient, semirigid form of connective tissue
forms parts of the skeleton where more flexibility is required.
articulating of bones participating
in a synovial joint capped with
articular cartilage
provides smooth, low-friction, gliding surfaces for
free movement
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The skeleton is composed of cartilages and bones.
Cartilage
resilient, semirigid form of connective tissue
forms parts of the skeleton where more flexibility is required.
articulating of bones participating
in a synovial joint capped with
articular cartilage
provides smooth, low-friction, gliding surfaces for
free movement
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Blood vessels do not enter cartilage avascular
Diffusion
bone /cartilage in the skeleton
changes as the body grows
younger a person the more cartilage
bones of a newborn are soft and flexible because mostly composed of cartilage.
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The skeleton is composed of cartilages and bones.
The amount and kind of extracellular fibers in the matrix
depends on the type of cartilage.
Heavy weightbearing areas or areas prone to pulling forces
More collagen fibers, less flexible cartilage.
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Functions of cartilage
1. support soft tissues
2. provide a smooth, gliding surface for bone articulations at joints
3. enable the development and growth of long bones.
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Types of cartilage
1. Hyaline
most common, matrix w/ moderate amount of collagen fibers articular surfaces of bones
2. Elastic
large number of elastic fibers external ear
3. Fibrocartilage
limited number of cells & ground substance amidst substantial amount of collagen fibers intervertebral discs
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Bones function as
supportive structures for the body
protectors of vital organs
reservoirs of calcium and phosphorus
levers on which muscles act to produce movement
containers for blood-producing cells
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TYPES OF BONES
according to their shape gross anatomy
1) Long bones
2) Short bones
tubular humerus in the arm
cuboidal
tarsus (ankle) carpus (wrist)
3) Flat bones
protective functions
flat bones of the cranium protect the brain
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Classification of Bones
4) Irregular bones
various shapes other than long, short, or flat
bones of the face
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Classification of Bones
5) Sesamoid bones
patella or knee cap
protect the tendons from excessive wear
often change the angle of the tendons as they pass to their attachments.
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Long bones develop by replacement of hyaline cartilage plate
endochondral ossification
a shaft diaphysis - two ends epiphyses
Metaphysis
a part of the diaphysis adjacent to the epiphyses.
Diaphysis encloses the marrow cavity.
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2 types of bones according to histological features
compact bone & spongy (trabecular) bone
relative amount of solid matter
# & size of the spaces they contain
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All bones have a superficial thin layer of compact bone
around a central mass of spongy bone
except where the spongy bone is replaced by a medullary (marrow) cavity.
Spongy bone
found @ expanded heads of long bones + fills most irregular bones.
Compact bone
forms outer shell of all bones + shafts in long bones.
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Spongy (cancellous) bone consists of thin threads of bone
trabeculae
The orientation of the trabeculae is modelled by the mechanical
stress to which the bone is exposed
Wolff's law
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Architecture & proportion of compact and spongy bone
vary according to function
Compact bone
provides strength for weight bearing.
.
Fig. 11. (a) Frontal section of the humerus head of a younger person (male, 32 years). The
superior border of the medullary cavity is marked by the dotted line. The arrows point to the
very thin lamella of compactbone in this region. (b) Frontal section of the humerus head of an
aged person (female, 97 years). The superior border of the medullary cavity is marked by the
dotted line. Notice that the very thin lamella of compactbone (arrows) is not supported by
spongious osseous substance.
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Bone Markings and Formations
 Bone markings appear wherever tendons, ligaments, and fascias are
attached or where arteries lie adjacent to or enter bones.
 Other formations occur in relation to the passage of a tendon (often
to direct the tendon or improve its leverage) or to control the type of
movement occurring at a joint.
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Arises from the bony floor &
overlying temporal fascia
attaches
superiorly superior temporal
line
inferiorly lateral & medial
surfaces of the zygomatic
arch
Insertion: Coronoid process of
mandible & ramus of mandible
Elevation and retraction of mandible
Linear elevations
Line (in Latin linea), crest (in Latine crista)
Crista galli
(crest of the cock)
in the anterior part of the skull
Superior temporal line
Inferior temporal line
in the skull
Round elevations
tubercule (small eminence), protuberance (swelling)
Tubercle of a rib
External occipital protuberance
rear side of the head (skull)
Sharp elevations
spine, process
Spinous process of a vertebra
Styloid process
in the skull
Rounded articular areas
head, condyle
Head of the mandible
Condylar process
Depressions
fossae (small depression), groove (sulcus, long narrow depressions)
Submandibular fossa
Costal groove
Foramen
Hole
Mental foramen
Foramen magnum
in the skull
Canal
a foramen having length
Optic canal
in the skull
in the orbita where the eye is located.
Meatus
a canal entering a structure
External auditory meatus
Vasculature and Innervation of Bones
 Bones are richly supplied with blood vessels.
 Veins accompany arteries.
 Nerves accompany blood vessels supplying bones.
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ACCESSORY BONES
Accessory (supernumerary) bones develop when additional
ossification centers appear and form. extra bones.
Many bones develop from several centers of ossification, and the
separate parts normally fuse.
Sometimes one of these centers fails to fuse with the main bone,
giving the appearance of an extra bone.
HETEROTOPIC BONES
Bones sometimes form in soft tissues where they are not
.
normally present (e.g., in scars).
Horse riders often develop heterotopic bones in their thighs
(rider's bones), probably because of chronic muscle strain
resulting in small hemorrhagic (bloody) areas that undergo
calcification and eventual ossification.
CHANGES IN BONES & BONE FRACTURES
Trauma to a bone may break it. For the fracture to heal properly, the
.
broken ends must be brought together,
approximating their normal
position. reduction of a fracture.
Fractures are more common in children than in adults.
CHANGES IN BONES & BONE FRACTURES
Immediately after a fracture, the patient suffers severe local pain and
is not able to use the injured part. .
Deformity may be visible if the bone fragments have been displaced
relative to each other.
OSTEOPOROSIS
decreases in the organic & inorganic components of the bone by aging
.
Bones become brittle, lose their elasticity,
and fracture easily.
Bone scanning is an imaging method used to assess normal and
diminished bone mass.
(BONE) SCINTIGRAPHY
metabolic activity of bone and its affinity to uptake a detectable marker
image can be captured
by a scan
.
a wide range of indications ranging from sports related injuries to
detection of metastasis (spreading of cancer) to the bones.
BONE DENSITOMETRY
(DEXA, DXA)
enhanced form of x-ray technology
. used to measure bone loss
most often used to diagnose osteoporosis
effective in tracking the effects of treatment for osteoporosis and
other conditions that cause bone loss.