Little boy sustains bone fractures to right arm

Simple (closed)

Running and fell forward onto his right arm

Diet is hot dogs and junk food

Lactose Intolerant/Calcium deficiency

Anatomy of Long Bones

Regions

Diaphysis

Medullary Cavity

Epiphysis

Distal

Proximal

farthest away from trunk

closest to thrunk

each end of long bone

hollow, cylindrical space within diaphysis

the shaft of the long bone

Linings/Coverings

Periosteum

Endosteum

tough sheath two layers

perforating fibers

anchoring the periosteum made of collagen fibers

incomplete layer covers all internal surfaces in the medullary cavity

Cells of Bones

Osteoprogenitor

Osteoblasts

Osteoid

Osteocytes

Osteoclasts

semisolid organic form of bone matrix

break down bone material

lost bone making ability maintain bine matrix and detect mechanical stress

synthesizing and secreting osteoids

stem cells derived from mesenchyme mature into osteoblasts

Bone Formation

Compact Bone Anatomy

Central Canal(CC)

Concentric Lamellae

Lacunae

Canaliculi

tiny interconnected channels letting osteocytes share nutrients

rings of bone connective tissue(CT) surround central canal gives strength and resilience

lets blood vessels and nerves run through lying in the middle of a osteon

small spaces that hold osteocytes

Osteons

small cylindrical structures subunit of compact bone

Perforating Canals

run perpendicular holds blood vessels and nerves help connect several CC within osteons

Circumferential Lamallae

rings of bones internally or externally

Interstitial Lamallae

incomplete leftovers

Anatomy of Spongy Bone

Trabeculae

open lattice of narrow rods and plates

Parallel Lamallae

bone matrix

Endochondral Ossification

1.) the fetal hyaline cartilage model develops

Hyaline cartilage(HC) becomes bones in the body except flat bones

2.) Cartilage calcifies, and a periosteal bone collar forms

3.) The primary ossification center forms in the diaphysis

4.) Secondary ossification centers form in the epiphysis

5.) Bone replaces almost all cartilage, except the articular cartilage and epiphyseal cartilage

6.) Lengthwise growth continues until the epiphyseal plates(EP) ossify and form epiphyseal line(EL)

bones grow into puberty until EP turns into EL

almost all HC turns to bone excepts some cartilage stays behind in joints

Secondary Ossification centers are created calcified cartilage pushed out creates a hollow cavity

periosteal bud extends from periosteum into cartilage shaft primary ossification centers remains of calcified cartilage are blueprints

chondrocytes start hypertrophy and resorb some cartilage starts to calcify blood vessels start to grow osteoblast start secreting osteoid. osteoid hardens

chondroblasts secret cartilage matrix and HC model forms Chondrocytes trapped in lacunae and perichondrium surround cartilage

Bone Growth

Interstitial Growth

1.) Zone of resting cartilage

composed of small chondrocytes distributed throughout resembles mature HC secures the epiphysis to EP

2.) Zone of proliferating cartilage

chond. undergo rapid mitotic cell division aligned in stacks parallel to diaphysis

3.) Zone of hypertonic cartilage

Chond. cease dividing & begin to hypertrophy wall of lacunae thin b/c chind. resorb matrix

4.) Zone of calcified cartilage(c.c)

composed of 2-3 layers of chond. Minerals deposited b/t columns of lacunae calcification destroys chond. and make matrix appear opaque

5.) Zone of ossification

walls break down b/t lacunae in the columns forming longitudinal channels spaces invaded by capillaries and osteoprogenitor cells new matrix is deposited on remaining c.c matric

Appositional Growth

occurs within periosteum osteoblasts produce and deposit bone matrix within layers parallel to surface external circumferential lamellae they increase # structure increases in diameter

Bone Remodeling

adding on new bone tissue and removal of old bone tissue throughout life

1.) A fracture hematoma forms

fracture tears blood vessels causing bleeding-fracture hematoma(fh) blood is clotted in the space

2.) A fibrocartilaginous (soft) callus forms

FH is reorganized into active growing CT fibroblasts create collagen fibers that help connect broken ends Chondroblasts from dense regular CT forming a fibrocartilaginous callus(FC) lasts 3 weeks

3.) A hard(bony) callus forms

osteoprogenitor cells in areas adjacent to FC become osteoblasts and produce primary bone forms hard callus grow and thicken over few months

4.) The bone is remodeled

final phase hard callus lasts 3-4 months osteoclasts remove excess bony material compact bone replaces primary bone fracture usually leaves thickening some do not

Raw Materials

Hormones

these help grow/repair or inhibit growth

Growth Hormone

Thyroid Hormone

Calcitonin

Calcitriol

Parathyroid Hormone

Sex Hormones

Glucocorticoids

Serotonin

increase bone loss impair bone growth when chronically high levels of glucocorticoids

increases blood calcium levels by encouraging bone resorption by osteoclasts

stimulates liver for IGF causes cartilage proliferation at EP resulting in bone elongation

stimulates bone growth by stimulating metabolic rate of osteoblasts

promotes calcium deposition and inhibits osteoclast activity

stimulates absorption of calcium ions from SI into blood

stimulates osteoblasts; promote EP growth and closure

inhibits osteoprogenitor cells from differentiating into osteoblasts when chronically high levels of serotonin

Epiphyseal Plate

Location

Metaphysis

sandwiched b/t the diaphysis and epiphysis

growing bone thing layer of HC provides continued lengthwise growth

Epiphyseal Line

thin defined area of compact bone

Classification of Fractures

Fractures

breaks in a bone

Stress Fractures

thin breaks

Pathologic Fracture

weakened by disease

Simple fracture

broken bone does not break skin

Compound Fracture

one or both ends break the skin

Avulsion

complete severing of a body part

Colles

fracture of distal end of lateral forearm

Comminuted

bone splintered into several small pieces b/t main parts

Complete

bone broken into two or more pieces

Compound (open)

broken ends of bone protrude through skin

Compression

bone is squashed

Depressed

broken part forms a concavity

Displaced

fractured bone parts are out of anatomic alignment

Epiphyseal

epiphysis is separated from diaphysis at the EP

Greenstick

partial fracture; outside breaks other side is bent

Hairline

fine crack in which sections are aligned

Impacted

one fragment of bone firmly driven into other

Incomplete

partial fractures extend only partway across bone

Linear

parallel to long axis of bone

Oblique

diagonial fracture

Pathologic

weakened by disease

Pott

fracture is at distal ends of tibia and fibula

Simple (closed)

does not break the skin

Spiral

spiral around axis of long bone

Stress

thin fractures due to repeated stressful impact

Transverse

at a right angle to the long axis of bone

Right elbow

Fracture

just needs to be reset/ a cast put on

needs calcium and Vitamin D supplements/change in diet to help with regrowth

Right Upper Arm

Comminuted Compound Fracture

needs surgery to reset bones in proper alignement

couple of weeks to heal

change in diet to aid in regrowth

age may play in not letting the bone grow completely

may take a month or two to heal