12 year-old boy with a bone fracture injury

background

physiology

anantomy

type of bones

long bones

flat bones

Irregular bones

Sesamoid bones

Short bones

Wormian

greater in length than width

Elongated, cylindrical shaft ( diaphysis)

Most common bone shape,( all finger bones)

Length nearly equal to width.


carpal and tarsals

thin surfaces

surface for muscle attachment,

in top of skull, scapulae, sternum, ribs,

Protects underlying soft tissues

vertebrae, ossa coxae (hip bones), several bones in skull (ethmoid, sphenoid, temporal)

doesnt fit any other category

patella (kneecap)

bones that sometimes develop within tendons

used for leverage

stability and support

Regions

diaphysis

Elongated, usually cylindrical shaft (middle ),

Provides leverage and weight support,

Compact bone,

Medullary cavity (hallow)

within the diaphysis,

Contains red bone marrow in children,

Contains yellow bone marrow in adults,

(Epiphysis) each end of long bone

Proximal epiphysis (closest to body trunk),

Distal epiphysis (farthest from trunk),

Composed of

outer layer of compact bone

inner layer of spongy bone

Articular (hyaline)cartilage ( in the outer layer)

Covers the joint surface,

Reduces friction,

Absorbs shock in moveable joints,

outer layer compact

inner layer spongy

main two types of bones

compact bone

spongy bone

Trabeculae- network of matrix spikes,

Osteocytes (housed in lacuna) no concentric circles,

Trabecula form along lines of stress to provide strength to bone,

light so that mucles can move bone with ease

epithelial disk is here

usually has red bone marrow

composed of osteons

components

Canaliculi

Osteocytes

Concentric lamellae,

Central canal,

channel at center of osteon ,

Blood vessels and nerves enter through this central channel ,

Concentric rings of calcified matrix,

Surround central canal,

Mature bone cells,

Found in lacunae,

Maintain bone matrix,

Tiny, interconnecting channels that

travel through lamellae and connect from, lacunaes to the central canal,

Allow exchange between blood vessels and osteocytes,

Perforating canals( haversian canals)

Blood vessels and nerves travel through ,

connect osteons to osteons

covering and linings of bones

Periosteum is a tough membranous sheath that covers the outer surface of the bone, anchored to bone by collagen fibers

Endosteum covers the internals of the bone within the medullary cavity

types

Inner cellular layer

Outer fibrous layer of dense irregular CT

Protects bone from surrounding structures,

contains blood,lymph vessels,nerves that nourish compact bone,

Attachment site for ligaments and tendons,

Inner cellular layer

osteogenic cells

osteoblast ( bone builder)

osteoclast ( polisher)

contains osteogenic cells

osteoblasts

Covers all internal surfaces of bone within medullary cavity,

osteoclasts

–Stem cells from mesenchyme, will become an osteoblast

only bone cells that divides (One will be a stem cell (mesenchyme)and the other will be an osteoblast)

Makes and secretes goo : collagen matrix (organic) that attracts calcium salts (inorganic) to form a new bone

might become trapped within the matrix, and become osteocytes

osteocytes purpose is to maintain mineral concentration

big, multinuclear, phagocytic cells,

Derived from fused blood stem cells,

Involved in bone resorption ( sanding off wood),

types of fractures

Simple-closed,

Compound-open (through skin),

transverse fracture- straight across,

Spiral fracture- spiral often from a twisting action,

Comminuted fracture- more than 2 pieces,

impacted fracture-one fragment driven into another,

greenstick fracture- incomplete break with splintering,

incomplete – not all the way through,

complete- all the way through,

fissured fracture- Incomplete horizontal ( a crack),

healling

steps

Fibrocartilagenous: Internal and external callus forms

Fracture hematoma ( from clotted blood )

Cartilage replaced by trabecular bone ( spongy)

6-8 hrs

From chondrocytes in endosteum and periosteum,

secrete a fibrocartilaginous matrix between the two pieces

creates hyaline cartilage and the surrounding bone breaks off ( now stabile)

Osteoclasts resorb dead bone

Osteogenic cells become active and divide to make osteoblasts,

Osteoblasts adjacent to callus makes trabeculae (spongy) via endochondral ossification,

remodeling

several weeks

Compact bone replaces spongy bone,


48 hrs

side note: on remodeling

Resorption of old bones

5-10% of skeleton replaced yearly,

Influenced by hormones and mechanical stress (exercise ( helps bone become stronger))

Forms by:

direct

indirect

flat bones

Intramembranous Ossification

Osteoblasts group into clusters, and ossification centers form,

Osteoblast secrets osteoid which traps osteoblasts which turns them into osteocytes,

Trabecular matrix and periosteum form,

Compact bone develops above trabeculae which crowds blood vessels and it condenses into red marrow,

long bones

endochondral ossification

Mesenchymal cells differentiate into chondrocytes,

The cartilage model and the perichondrium forms,

Capillaries penetrate cartilage. Perichondrium transforms into periosteum. (Periosteal collar develops) Primary ossification center develops,

Cartilage and chondrocytes continue to grow at ends of the bone,

Secondary ossification centers develop( at the ends of the bone )

Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage,

side note on epiphyseal plate

found in the middle of the Epiphysis and Diaphysis

On epiphyseal side the cartilage grows,

On diaphyseal side, bone grows ( bone grows in length),

area of hyaline cartilage in immature bone where ossification occurs

called Interstitial growth

once all the cartilage is replaced with bone it becomes the epiphyseal disc

side note : on growth

growth on diameter is appositional growth ( modeling)

Osteoclasts resorbs bone on the endosteum,

osteoblasts produce new bone tissue beneath the periosteum,

increased diameter of the medullary cavity, called modeling,

he was running and fell forward, landing on his right arm

only eats unhealthy food

lactose intolerant

hotdogs

spaghetti

burgers

junkfood etc

doesn't eat /drinks dairy

little calcium intake (or vitamin D)

low intake of

calcium

Vitamin K,

Fluoride,

Omega 3 fatty acids,

Magnesium

injury

fracture

humerus

comminuted

compound

raw material

helps in bone remodeling, growth, healing

Calcium,

Vitamin K,

Vitamin D,

Magnesium,

Flouride,

Omega 3 fatty acid,

regulator of calcium intake

helps bone be built and rebuilt

in conjuction with vitamin k stimulates the transformation of fracture site stem cells to bone building osteoblast

in conjuction with vitamin d stimulates the transformation of fracture site stem cells to bone building osteoblast

helps bind calcium to bone ( helps bone mineralization )

makes the bone have tensile strength

decrease inflammation that may interfere with osteoblast function.

in bones' structure. Strengthens bone and enamel of teeth

in structure of bones

aid in absorption and metabolism of calcium

treatment

surgery

upper arm

needs antiobiotics

post surgery

is going to need pain reliever

since it the humerus,to keep it place he is going to need an arm cast

Do to horrible diet he has a low income of calcium,magnesium,flouride,omega 3 fatty acid, vitamin D. and vitamin K his healing will be slower than most children

would need to change diet to more leafy greens, and certain fish such as salmon to bring his required nutrients/vitamins up ( additional examples include nuts and beans for magnesium, some OJ for vitamin D etc)

needed to put the bone back in place and close the wound to stop infections and antibodies from further entering the body

needs to clean out wound (remove the small fragments )

elbow

need fixation of the fracture fragments with plates, screws or pins.

need fixation of the fracture fragments with plates, screws or pins

although he has a horrible diet he is still a child and the bones are smaller and has a dense periosteum

means his bones will heal faster ( thicker periosteum = more chondrocytes ) ( with a proper nutritional diet his chondrocytes can attract calcium and other nutrients and form "new" bone

going to need rehablitaion to:

joint motion

flexibiity

restore muscle strength

well include excercising

for further info on the covering and lining as well as spongy and compact bone on long bones see upper branches.