What is bone?
- bones are organs made up of more than one tissue
- bone tissue, cartilage tissue, nervous tissue, dense connective tissue proper, muscle tissue, and epithelial tissue are all tissues that make up bone
What are the functions of bone?
- support: supportive framework of the body
- protection: number of areas of skeleton are specifically for protection of some organs (heart, lungs, brain)
- anchorage: bones provide a solid anchor for other structures
- mineral/growth factor storage: calcium is a big mineral-many other minerals, bone is a dynamic structure that can store things within for when needed
- blood cell formation and triglyceride (fat) storage: happens in marrow with bones
- hormone production: lets nervous system know what is going on in the bones
What is included in the axial skeleton?
skull, ribs, spine, sternum
- it is the main axis in which rest of the body moves
What is included in the appendicular skeleton?
shoulder girdle, upper limb, pelvic girdle, lower limb
- parts that are attached to axial skeleton
shapes of bone
Long bone- wider at each end, narrow shaft, long skinny structure
Short bone- cube shaped
Flat bone- flat and sometimes a little curved
Irregular bone (vertebra)- spine bone, don’t match any other description
Sesamoid bone (patella)- not completely flat structure, tend to be very small, largest ones are the knee caps (patella), not attached directly to other bone, found in areas which are wear and tear
- sesamoid bone is usually tucked into tendon-> add extra structural integrity in tendons that live a rough life
- tendon= connective tissue that attaches muscle to bone
What is compact bone?
is the dense outer layer of bone and appears smooth and solid
- very strong and solid
What is spongy bone?
- is the internal layer of bone
- trabeculae (stripes of bone in spongy bone) form honeycomb-like structure
- contains marrow (can store more stuff)
Structure of long bone
- proximal and distal epiphysis: wider part of bone closer to core of body, thinner compact bone wall
- articular cartilage: spongy bone that contains red bone marrow in epiphysis, gives shock absorbent surface
- Epiphyseal line: divides epiphysis above from diaphysis below
- Metaphysis: area between epiphysis and diaphysis
- diaphysis: narrow shaft, thick compact bone wall, contains spongy bone
- Medullary cavity: contains yellow bone marrow in adults, has spongy bone and more opening, lots of marrow
- Hyaline cartilage: long bones have hyaline cartilage (at either end), adds softer shock absorbent surface compared to rest of the bone
- Metaphysis is where growth occurs in bone
- Epiphyseal line is made of cartilage as a child up until about age 20, it will slowly turn to bone-> how bones get longer as you grow
- when you reach full growth height, cartilage ossifies (turns into bone)
Where is marrow located?
within spongy bone
- in long bone, medullary cavity has marrow
What is red marrow?
- where there is blood cell production
- located in trabecular cavities of long and flat bones
What is yellow marrow?
- where there is fat storage- important resource
- can turn back into red marrow in adults in server anemia (in adult bone)
Facts about marrow
- newborns have all red marrow because you have to make all red blood cells fresh-> take red marrow
- as you age, red marrow starts to be replaced by yellow marrow
- in adults, you find red marrow in only flat bone and epiphysis of long bone
- if you have a problem with red blood cells (delivering oxygen to cells), yellow can turn back to red in some bone
- decrease in red blood cells or decrease in oxygen to cells is called anemia
- short, regular, or sesamoid bones don’t hold much marrow
What is cartilage in the skeleton?
- cartilage is highly resilient and very good at resisting compression ( 2 things pressing against each other like bone)
- cartilage has a lot of water in it , making it highly resilient
What is hyaline cartilage?
- it provides support with flexibility and resilience
- is more abundant in the skeletal cartilage
- located in the articular (joints- where 2 bones connect), costal (ribs), and respiratory
- each of the ribs is joint to breast bone by hyaline cartilage
- respiratory tube cartilages in neck and thorax are covered in hyaline cartilage
What is elastic cartilage?
- has more elastic fibres compared to hyaline
- better able to stand up to repeated bending
- located in the external ear and nose, and epiglottis (going to bend and rise back up to keep food out)
What is fibrocartilage?
- has great tensile strength (lots of thick collagen fibers), very strong
- located in sites that are subject to both pressure and stretch like menisci of knee (joint), intervertebral discs-> allow spine to bend), and pubic symphysis (interpubic disc)- important for females when giving birth
Cartilage in the growing skeleton
- cartilage makes up most of the fetal skeleton (hyaline cartilage), cartilage grows very fast (cells divide and grow quickly then can turn into bones fast)- ossification (growth of bones) starts to begin at about at 8 weeks in fetus and continues
- resilient and elastic (lots of water)
- ideal for fast growth
- no nerves or blood vessels (avascular)
- if you damage cartilage it will be very slow to heal, especially in joints
What is the fracture classification?
Non-displaced: bone ends retain normal position (bone ends in original position)
Displaced: bone ends out of alignment (ends of bone are not aligned)
Complete: bone is broken only part of the way through
Incomplete: bone broken only part of the way through (hairline fracture)
Closed (simple): bone does not penetrate skin
Open (compound): bone penetrates skin
What is a comminuted bone fracture?
- when a bone is splintered, crushed, or broken into pieces
- small bone fragments present at the fracture
What is a greenstick fracture?
- only occurs in children because their bones aren’t fully ossified, and still have some cartilage
- partial fracture, one side of the bone will be broken, other side bends
What is an impacted fracture?
- when one end of the bone is forcefully driven into the other end of the bone
- jamming motion
What is a pott fracture?
- ankle fracture
- maliolie (bumps on either side of the ankle) breaking, happens when you jump and land awkwardly or if you twist the ankle
What is a colles fracture?
- fracture of the distal end of the radius (thumb side) wrist
- happens when you break fall with your hands
What is a closed (external) reduction fracture repair?
physician manually coaxes bone ends back into position
- aggressive movement
- reduction is putting fracture into alignment before healing
