Function of Skeletal
Support
Protection
Movement
Storage
Hemopoiesis
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206 Bones
Ligaments
Cartilage
Osteocytes: Bone cells
Calcium slats give bone its hardness
Collagen provides strength and limited
flexibility
Structure of Bones
Compact Bone
Spongy Bone-
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Cortical Bone aka Compact Bone
◦ Dense
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Haversian System:
◦ Osteon: basic structural unit
◦ Lamellae: concentric rings that make up each osteon
◦ Haversian Canal: space that surrounds blood venule,
arteriole, nerve.
◦ Lacuna: space/cave with in matrix (contain oestocytes)
◦ Haversian canaliculus: tiny passages throughout bone
matrix (connect to larger canals called Haversian canals)
◦ Volkmann’s Canal : connects to Haverian canals.
Contains small blood vessels
Bone Structure
Cortical Bone
Compact
trabeculae
B
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R
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Cancellous Bone aka Spongy Bone
◦ Located at the ends of bones
◦ Lines the medullary marrow cavity
◦ Trabeculae: interspersed columns of bone matrix
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Layer of fibrous tissue that surrounds bone
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Functions:
◦ Layer of defense to protect from infection
◦ Forms new bone cells
◦ Full of nerves and blood vessels to aid in
nourishment of bone
◦ Attachment for tendons and ligaments
◦ **Due to these various functions the orthopedic
surgeon will approximate the periosteal layer when
incised
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Canal that runs down the middle of bone
Contains semisolid tissue Red Bone Marrow
◦ Located in the spaces of spongy bone found in the
ends of long bones, sternum, vertebrae, and ribs
◦ In adults RBM is replaced with yellow bone marrow
◦ Functions: production of erythrocytes, leukocytes,
and platelets
◦ Endosteum: fibrous layer of tissue that lines
medullary cavity
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Osteoprogenitor (osteogenic) Cells:
◦ Stem cells of skeletal tissue
◦ Composes the Inner layer of periosteum and the
single layer of endosteum
◦ Functions: formation of fetal bone and repair of
fractures
◦ Differentiate into Osteoblasts (good blood supply)
and Chondroblasts (limited blood supply)
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Osteoblasts:
◦ form bone matrix
◦ Develop into osteocytes
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Osteocytes:
◦ responsible for maintaining bone matrix
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Osteoclasts:
◦ Breakdown and resorption of bone
◦ Activated by parathyroid hormone
◦ Differentiated from blood monocytes
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Skelton is initially composed of cartilage and
gradually replaced with bone via two methods
◦ Intramembranous Ossification: Develops flat bones
of the cranium, facial bones, Mandible and clavivle
◦ Endochondrial Ossification: long bones, etc. (the
rest of the bones) Cartilage > Bone
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Located at the junction between the diaphysis
and each epiphysis
Area of growth (allows bone to lengthen)
Around age 16-25 Epiphyseal plate ossifies
marking full maturity (end of growth)
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Bones undergo a lifetime of remodeling and
adapting to stress
Remodeling maintains bone structure and
strength as well as ensures constant supply of
calcium to the body
Osteoclasts absorb bone that is then replaced by
new compact bone
When low blood calcium levels are detected
parathyroid hormone releases and stimulates the
osteoclasts
When normal blood calcium levels are reached
the thyroid releases calcitonin. Calcitonin inhibits
osteoclasts and stimulates osteoblasts (negative
feedback loop)
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Hormonal influence
Exercise: weight-bearing exercise is important in
maintaining bone strength
Osteoporosis: results when bone matrix is lost
faster then replaced
Nutrition: key factor in maintenance of normal
bones
Scurvy: results form a deficiency in vitamin C,
shaft of long bone becomes thin and fragile
predisposing the person to fractures
Rickets: results form vitamin D deficiency, causes
poorly calcified, semiriged bones that bend
under bodies weight (bowed legs, knock-knees)
Types of Bone
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Long:
Short
Flat
Irregular
Sesamoid
Structure of Long
Bones
 Diaphysis –
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Medullary Canal –
EpiphysesArticular Cartilage
Periosteum –
Endosteum –
Types of Bone
Short Bones
 Carpals (wrist bones)
 Tarsals (ankle bones)
 Cube shaped
 Equal length
 Equal width
Types of Bone
Structure of Short Bones
 Spongy Texture
 Bone surface thin layer of
compact
bone
 Cubed shaped
 Equal Length
 Equal Width
Types of Bone
Flat Bones
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Cranial Bones
Sternum
Ribs
Scapula
Types of Bone
Structure of Flat Bones
Thin
 Two parallel plates of compact bone
 Compact bone encloses spongy bone
Flat Bones
Types of Bone
Irregular
Bone
 Vertebrae
 Facial Bones
Types of Bone
Structure of Irregular
Bones
 Complex shapes
 Vary in amount of Spongy and
compact bone
Irregular
Bones
Types of Bone
Sesamoid Bones
 Can be found in the wrist
 Patella
Types of Bone
Structure of Sesamoid Bones
 Compact bone on the outside
 Spongy bone on the inside
Sesamoid Bone
Types of Bone
Other Types of
Bone
Wormian Bones- small bones found
between certain cranial bones
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Appendicular Skeleton
Axial Skeleton
Condyle
Epicondyle
Crest
Distal
Proximal
Foramen
Fossa
Fovea
Head
Trochanter
Tubercle
Tuberosity
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Articulation: where the ends of two bones
meet to form a joint
◦ Immovable
◦ Slightly movable
◦ Freely movable
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Synarthrosis: immovable joint
◦ Suture lines
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Amphiarthrosis: slightly movable joint
◦ Symphysis pubis
◦ Vertebral cartilage
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Diarthrosis: freely movable joint
◦ Synovial joints
JOINTS
JOINTS
JOINTS
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Menisci:
flat discs of tough fibrocartilage located
between the ends of two articulating bones
◦ Ex. Knee – lateral and medial menisci
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Bursae:
Small fluid filled sacs
◦ Commonly found between tendons and bony
prominences. Cushion and aid in movement
LIGAMENTS
Ligaments- A white band of fibrous connective
tissue. Connects Bone to Bone
TENDONS
Tendons- Bands or cords of fibrous
connective tissue that connect muscle to
bone
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Ball-and-Socket Joint:
◦ Widest range of motion
 Hip and shoulder joints
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Gliding Joints:
◦ Twisting and side to side movements
 Carpals and tarsals
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Hinge Joints:
◦ Allow only extension and contraction (movement in only
two directions)
 Elbow
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Pivot Joints:
◦ Rotational movement around a central axis
 Atlas and Axis
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Condyloid Joints:
◦ Condyle articulates with a fossa
 Tempromandibular Joint
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Saddle Joints:
◦ Allows great mobility (flex, extend, abduct, adduct,
circumduct)
 Thumb and Trapexium
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Flexion- reduces the angle of the joint
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Extension- increases the angle of a joint
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Rotation- spins one bone relative to another
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Circumduction- moves the distal end in a
circle while the proximal end stays relatively
stable
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Abduction- moves away from the midline
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Adduction- moving toward the midline
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Supination- pointing a body part upward
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Dorsiflexion: bending the foot upward at the
ankle joint
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Plantar Flexion: Bending the foot downward
at the ankle joint
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Eversion: turning the foot outward at the
ankle joint
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Inversion: turning the foot inward at the ankle
joint
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Origin: muscle end attached to the
immovable end of one bone
Insertion: muscle end attached to the
movable end of the bone
**When the muscle contracts the muscle
fibers draw the insertion toward the origin,
causing joint movement
Table 6-3 Pg. 106-107
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Scoliosis: crooked-back
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Kyphosis: Hump-back
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Lordosis: Sway-back
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Kyphoscoliosis: hump-back and crookedback
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Compound (Open Fracture): fractured bone
pierces the skin
Simple (Closed Fracture): fracture that does
not pierce the skin
Complete: fracture line continuous through
bone
Incomplete (Partial): may bend on one side
and break on the other (ex. Greenstick
fracture)
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Linear: fracture runs parallel to the axis of the
bone
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Spiral: fracture line curves around the bone
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Transverse: fracture line is across the bone
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Pott’s Fracture: break of the lower fibula
Classification of Fractures
COLLES
A fracture of the distal end
of the radius in which the
distal fragment is displaced
posterioraly
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Avulsion: Bone and other tissues are pulled
from normal attachments
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Bucket Handle: Dual vertical
fractures on the same side of
the pelvis
Comminuted: Fracture with
more than two pieces of
bone fragment
◦ Butterfly: butterfly-shaped
pieces of fractured bone
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Compound (open):
broken end of bone
has penetrated skin
exposing bone
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Depressed: occurs
when bone is driven
inward
Displaced: bone ends
are out of alignment
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Greenstick: bone splits longitudinally and is
not a complete break
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Impacted: broken
ends of bone are
forced into
eachother
Intra-articular: bones
inside a joint are
fractured
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Oblique: occurs at an
oblique angle across
bone
Spiral: fracture that
curves around bone
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Simple: fracture is in normal anatomic
position and the skin is not borken
Spontaneous: occurs without trauma
Stellate: fracture occurs at central point in
which additional breaks in bone radiate form
the central point
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Transverse: horizontal
fracture through the bone
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Heals in approx. 8-12 weeks
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Inflammatory Stage:
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Cellular proliferation stage:
◦ Bone ends must be aligned
◦ Site of injury must be completely immobilized (case,
external or internal fixation)
◦ Begins when fracture occurs & lasts approx. 2 days
◦ Hematoma forms
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Begins approx. 3rd day
Macrophages: debridement
Fibrin mesh forms (seals the approximated edges)
Ingrowth of capillaries and fibroblasts begins
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Callus formation:
◦ Lasts 3-4 weeks
◦ Cartilage, immature bone, and fibrous tissue
provide stabilization to the fracture site
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Ossification Stage:
◦ Lasts 3-4 months
◦ Bone calcifies completing union of bone ends
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Remodeling:
◦ return of homeostasis
◦ Bone is mature and resumes all normal functions
AXIAL SKELETON
Skull
Cranium
Ear Bones
Facial Bones
Spine
Thorax
Hyoid Bone
•Vertebrae
•Ribs, Sternum
AXIAL SKELETON
28 bones in the
skull
8 Cranial Bones
6 ear
bones
(ossicles)
14 Facial Bones
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Cranium (8 bones), face (14 bones), and
middle ear (6 bones)
Sinuses are spaces within some of the cranial
bones
Sutures are immovable joints between cranial
bones
Fontanels are soft spots on a baby’s skull
Skull, Facial
Malleushammer
Incus-Anvil
Stapes-Stirrup
Pg. 239
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Do men and women have the same number of
ribs?
YES!!
Spine, Vertebrae
26 Bones
7 Cervical
12 Thoracic
5 Lumbar
Sacrum
Coccyx
APPENDICULAR SKELETON
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Male:
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Larger skeleton
Pelvis is funnel-shaped and narrow
Pelvic inlet is narrow
Larger hipbones
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Female:
Wider pelvis to accommodate childbirth
Smaller skeleton
Wider hips
Pelvis is broad and bowl shaped to accommodate
fetus
◦ Pelvic inlet and outlet is wider
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