Bones2 Flashcards
5 functions of bone
- Support
- Protection
- Movement
- Mineral and growth factor storage
- Blood cell formation
- fat storage
- hormone production
3 types of cartilage and their locations
- Hyaline cartilage: costal cartilages
- Elastic Cartilage: epiglottis
- Fibrocartilage: pubic symphysis
4 classifications of bone and examples of each
- Long bone: femur
- Irregular bone: vertebra
- Flat bone: sternum
- Short bone: talus
Compact Bone
Smooth looking outer layer, has osteons, lamellar, canaliculi, and central canal
Spongy bone
Internal to compact bone also called trabecular bone, honey comb like, little flat prices of bone called trabeculae (little beams) in living bones the open spaces are filled with yellow or red marrow
Structure of a long bone list all parts
- Diaphysis: shaft
- Medullary cavity: center of diaphysis
- Epiphyses: ends of bone
- Articular cartilage: cartilage covering the epiphysis
- Spongy bone: porus bone tissue found at epiphyses
- Epiphyseal plate/line: where growth cartilage is at bottom of epiphyses
- Endosteum: membrane that covers the inside of bones
- Periosteum: membrane covering outside of bones
- Perforating fibers: connects periosteum to bones
- Nutrient arteries: deliver nutrients to bones
- Yellow bone marrow: found in adult medullary cavity
- Red marrow: found in epiphyses of long bones (femur and humerus)
Microscopic structure of compact bone
- Central canal: big hole in osteon
- Osteon: lamella+central canal
- Circumferential lamellae: lamellae forming outer layer of bone
- Perforating canal: verticle canal next to central canals
- Nerve,vein and artery
- Canaliculi: cracks around lacuna
- Osteocytes: bone cells in lacuna
Chemical composition of bone
Organic: bone cells and osteoid
- ostegenic cells, osteocytes, osteoblasts, osteoclasts. Osteoid=Glycoproteins,proteoglycans and collagen fibers
Inorganic: mineral salts
Calcium phosphate crystals
Endochondral ossification
A bone developes by replacing hyaline cartilage. The resulting bone is called a cartilage or endochondral bone
Except for clavicle all bones inferior to base of skull are formed by endochondral ossification
Intramembranous ossification
A bone develops from a fibrous membrane and the bone is called a membrane bone.
Forms the cranial bones and (frontal, parietal, occipital, and temporal bones) as well as clavicles. Most bones formed by this process are flat bones
How does endochondral ossification happen
- Bone collar forms around diaphysis of the hyaline cartilage model. Primary ossification center in mid diaphysis
- Cartilage in middle of diaphysis calcifies and develops cavities
- The periosteal bud invades the internal cavities and spongy bone forms
- The diaphysis elongates and a medullary cavity forms. Secondary ossification centers appear in the epiphyses
- During childhood and adolescence epiphyses ossify and the only cartilage left is in the epiphyseal plates and articular cartilage
How does intramembranous ossification happen?
- Mesenchymal cells cluster together and turn into osteoblasts. Ossification centers appear in the fibrous connective tissue membrane, osteoblasts make the first trabeculae of spongy bone.
- Osteoblasts secrete osteoid which calcifies in a few days. Osteoblasts become trapped and become osteocytes
- Bone forms in a woven manner instead of lamellae. Vascularized mesenchyme condenses on the outside of woven bone and becomes the periosteum
- Lamellar bone replaces woven bone just deep to the periosteum. The spongy bone’s vascular tissue becomes red marrow
Osteoblasts
Build bone
Osteocytes
Bone cells located in lacuna of compact bone. Maintains bone tissue
Osteoclasts
Break down bone. Look like snails
Bone growth
During infancy and youth bones lengthen by interstitial growth by growth of the cartilage of the epiphyseal plate until bone growth ends during or after puberty and the epiphyseal plate becomes the epiphyseal line
When and how does bone growth stops
At the end of adolescence chondrocytes in epiphyseal plate divided less often. The plates become thinner and thinner until they are entirely replaced by bone tissue. Longitunal bone growth ends when epiphysis and diaphysis fuse (called epiphyseal closure) only articular cartilage
When does epiphyseal closure happen
18 yrs in females, 21 in males
Bone remodeling
Also called Appositional growth. Is regulated by hormones and stress on the bone. Osteocytes detect stress osteoblasts secrete osteoid on one side of the bone which becomes calcified while on the other side osteoclasts reabsorb bone. Remodeling goes on through out life
Types of fractures
- Comminuted
- Compression
- Spiral
- Epiphyseal
- Depressed
- Greenstick
Comminuted fracture
- bone fragments into 3-4 pieces. Common in aged and brittle boned people
Compression fracture
- Bone is crushed
- Common in porous bones subjected to extreme trauma, such as a fall
Spiral Fracture
- ragged break occurs when excessive twisting forces are applied to a bone
- common sports fracture
Epiphyseal fracture
- Epiphysis and diaphysis separate at epiphyseal plate
- occurs where cartilage cells are dying and matrix is calcifying
Depressed fracture
- Broken bone portion is pushed inward
- typical of skull fracture
Greenstick fracture
- Bone breaks only part way like a green twig. Other side bends
- common in children whose bones are more flexible and contain organic matrix
Repair of fractures
- A hematoma forms
- Fibrocartilage callus forms
- Bony callus forms
- Bone remodeling occurs
Fracture classification
- position of the bone ends after fracture (non displaced and displaced fractures)
- completeness of break. If broke is broken through (complete fracture) if not (incomplete fracture)
- wether bone ends penetrate skin if fracture does it is a compound/ open fracture if not it is a simple/ closed fracture
Treatment of a fracture
- Reduction: put back in place
- in closed reduction bone is popped back in place
- in open reduction the bone is surgically put together with pins or wires.
- After a broken bone is reduced it is immobilized by a cast or traction to allow healing
Osteomalacia
Means soft bones. Includes a number of disorders in which bones are poorly mineralized. Osteoid is produced but mineral salts are not adequately deposited resulting in soft weak bones. It is called rickets in children. Causes pain on weight bearing bones. Results in bowed legs and other deformities in children. Caused by insufficient calcium or vitamin D in diet
Osteoporosis
Occurs most often in post menopausal women. Caucasian and Asians are affected more. Sex hormones keep osteoporosis at bay.
Risk factor for osteoporosis:
- petite frame
- not enough weight bearing exercise
- a diet poor in calcium and protein
- abnormal vitamin D receptors
- smoking
- hormone related conditions
Osteoporosis can occur at any age due to mobility, men can get osteoporosis when they have prostate cancer
Treatment of osteoporosis
- calcium and vitamin D supplements
- weight bearing exercise
- hormone replacement therapy ( can cause cancer, soy products)
- new drugs
Preventing osteoporosis
- get enough calcium while bones are increasing density
- carbonated and alcohol leaches minerals from bones, avoid said products
- plenty of weight bearing exercise throughout life
Osteogenesis imperfecta
A genetic condition present at birth. Body can’t make normal collagen. Leading to brittle bones, victims have frequent fractures and are usually short in stature
Hormonal regulation of bone growth
Epiphyseal plate growth is influenced by growth hormone released by the pituitary gland and moderated by thyroid hormones (proper proportions) At puberty sex hormones take over, spur growth then cause epiphyseal closure. Excess or deficits of hormone can cause abnormal growth
Achondroplasia
A congenital condition in which cartilage and endochondral bone growth are defective. The cartilaginous bones are short and membrane bones are normal size. A type of dwarfism
Bony spur
Abnormal projection from a bone due to bony overgrowth; common in aging bones.
Osteoaliga
Pain in bones
Osteitis
Inflammation of bony tissue
Osteomyelitis
Inflammation of the bone and marrow caused by pus forming bacteria, that enter the body through a wound or infection near the bone. Effects long bones commonly. Causes pain and fever, joint stiffness, bone destruction, shorter limb. Treatment; antibiotics, draining abscesses and removing dead bone fragments
Osteosarcoma
A form of bone cancer typically in the long bone of a 10-24 yr. old. Grows aggressively, painfully eroding the bone. Tends to metastasize to the lungs and cause secondary lung tumors. Treatment; amputation of affected or limb, followed by chemo therapy, and surgical removal of any metastases. Survival rate 50% if caught early
Pathologic fracture
Fracture in a diseased bone due to normal activities ( no physical trauma). Example: hip bone weakened by osteoporosis breaks while walking and causes a fall, rather than the person falling and breaking their hip
Traction
(Pulling) placing sustained tension on a body region to keep parts of a fractured bone in proper alignment.
4 spinal curvatures and how they curve
Cervical curvature; concave posteriorly
Thoracic curvature: convex posteriorly
Lumbar curvature; concave posteriorly
Sacral curvatures: convex posteriorly
What do the curvatures of the spine do?
Increase resilience and flexibility of the spine, allowing it to function like a spring, instead of a rigid rod
Three types of spinal abnormalities
- Scoliosis
- Kyphosis
- Lordosis
Scoliosis
(Twisted disease) abnormal lateral curvature of the spine that occurs most often in the thoracic region. Common in preteen girls. Severe cases result from abnormal vertebral structure, unequal lower limbs, or muscle paralysis. Treatment: body braces or surgery before bone growth ends to prevent further complications
Kyphosis
Hunchback a dorsally exaggerated thoracic curvature. Common in elderly, also caused by tuberculosis of the spine, rickets or osteomalacia
Lordosis
Swayback; accentuated lumbar curvature. Can be caused by spinal tuberculosis or osteomalacia . Temporary lordosis caused by potbellies and pregnancy
Stenosis of the lumbar spine
Lumbar spinal stenosis is a narrowing of the spinal canal in the lower back, known as the lumbar area.
This usually happens when bone or tissue—or both—grow in the openings in the spinal bones. This growth can squeeze and irritate nerves that branch out from the spinal cord .The result can be pain, numbness, or weakness, most often in the legs, feet, and buttocks.
It’s most often caused by changes that can happen as people age. For example:
Connective tissues called ligaments get thicker.
Arthritis leads to the growth of bony spurs that push on the nerves that branch out from the spinal cord.
Discs between the bones may be pushed backward into the spinal canal.
Symptoms may include:
Numbness, weakness, cramping, or pain in the legs, feet, or buttocks. These symptoms get worse when you walk, stand straight, or lean backward. The pain gets better when you sit down or lean forward.
Stiffness in the legs and thighs.
Low back pain.
In severe cases, loss of bladder and bowel control.You can most likely control mild to moderate symptoms with pain medicines, exercise, and physical therapy. Your doctor may also give you a spinal shot of corticosteroid, a medicine that reduces inflammation.
You may need surgery if your symptoms get worse or if they limit what you can do. Surgery to remove bone and tissue that are squeezing the nerve roots can help relieve leg pain and allow you to get back to normal activity. But it may not help back pain as much.
Chiropractic
A system of treating illness based on the belief that illness is caused by pressure on certain nerves caused by faulty bone alignment. The vertebral column is manipulated.a specialist in the field is called a chiropractor
Clubfoot
Common congenital defect soles of the feet face medially and the toes point inferiorly
Laminectomy
Surgical removal of a vertibral lamina; most often done to relieve symptoms of a ruptured disc
Orthopedist
A physician who specializes in restoring lost skeletal system function or repairing damage to bones and joints ( orthopedic surgeon)
Pelvimetry
Measurement of the dimensions of the inlet and outlet of the pelvis to determine if a baby can fit through
Spina bifida
(Cleft spine) congenital defect of the vertebral column in which one or more of the vertebral arches are incomplete; can affect neural functioning and encourage nervous system infections
Spinal fusion
surgical procedure involving insertion of bone chips or crushed bone to immobilize and stabilize a specific region of the vertebral column. Usually in the case of a vertebral fracture or herniated disc
What are the structural classification of joints?
- Fibrous
- Cartilaginous
- Synovial joints
Types of fibrous joints
- Suture
- Syndesmosis
- Gomphosis
Joint definition
Joint/articulation the sites where 2 or more bones meet. They give our skeleton mobility and hold it together
What are the functional classification of joints?
Functional classification is based on movement allowed
- Synarthroses; no movement
- Amphiarthroses; some movement
- Diarthroses; freely movable
The movement of the bone depends on the length of the fibers this is true of what?
Fibrous joints
Suture
A joint held together with very short interconnecting fibers, and interlocking bone edges.
Location: found only in skull
Synarthritic
Syndesmosis
Joint held together by a ligament. Fibrous tissue can vary in length, but is longer than sutures.
Location: ligament between tibia and fibula
Somewhat amphiarthritic
Gomphosis
Peg in socket fibrous joints. Periodontal ligament holds tooth in socket
Synarthritic
cartilaginous joints
The articulating bones are joined by cartilage. They lack a joint cavity and are not highly movable.
Two types:
- Synchondroses
- Symphyses
Synchindroses
A type of cartilaginous joint in which a bar or plate of hyaline cart. Unites the bone at a synchindrosis.
Synartheitic
Example: epiphyseal plates, joint between first rib and sternum
Symphyses
A type of cartilaginous joint where fibrocartilage unites the bone. The cart. Acts as a shock absorber and permits limited movement.
Amphiartrotic
Example: pubic symphysis, intervertebral discs
How are joint mobility and stability related?
The more stable the less movable and vice versa
Synovial joints
“Joint eggs” joints in which articulating bones are separated by a fluid filled joint cavity. This arrangement allows for free movement. All are freely movable diathroses
Structure of synovial joints
- Articular cart.; covers bone ends
- Joint cavity; area around joint contains synovial fluid
- Articular capsule: 2 layered articular capsule. Outside fibrous layer DICT, inside synovial layer
- Synovial fluid:occupies free space in cavity
- Reinforcing ligaments: reinforce joint
- Menisci: pad of fibrocartilage separating articular surfaces
- Fatty pads: cushioning pads between the fibrous layer and the synovial membrane
Do synovial joints have a lot of nerves and blood vessles?
Yes
What are the types of synovial joints?
- Plane
- Hinge
- Pivot
- Condylar
- Saddle
- Ball and socket
Pretty much all synovial joints function how?
They are diarthrotic
Articular discs/ menisci do what?
Improve fit between articulating bone ends, making the joint more stable and minimizing wear and tear on joint surfaces
Bursae
bags of lubricant that act as “ball bearings” reduce friction between adjacent structures during joint activity. Flattened fibrous sacs lined with synovial fluid. They occur where ligaments, muscles, skin, tendons or bones rub together
Tendon sheath
An elongated bursa that wraps around a tendon subjected to friction, like a hotdog in abun. Common where several tendons are crowded together
What are the factors influencing stability of synovial joints in order of importance?
- Muscle tone
- Ligaments
- Articular surfaces
Types of movements allowed by synovial joints and do them
- Gliding
- Angular movements:
- flexion
- extension
- abduction
- adduction
- circumduction - Rotation
- Special movements:
- supination
- pronation
- dorseflexion
- plantar flexion
- inversion
- eversion
- protraction
- retraction
- elevation
- depression
- opposition
Plane joint
- Nonaxial movement
- gliding
- intercarpal joints/ intertarsal, joints between vertebral and articular surfaces
Hinge joint
- Uniaxial movement
- flexion and extension
- elbow joints and interphalangeal joints
Pivot joint
- Uniaxial movement
- rotation
- proximal radioulnar joints, atlantoaxial joint
Condylar joint
- Biaxial movement
- flexion/extension and adduction/abduction
- knuckles and wrist joints
Saddle joint
- Biaxial movement
- flexion/extension and adduction/abduction
- proximal thumb joint
Ball-and-socket joint
- only joint with multiaxial movement
- flexion/extension, abduction/adduction, and rotation
- shoulder and hip joints
Common joint injuries
- Cartilage tear
- Sprain
- Dislocation
- Bursitis
- Tendinitis
- Arthritis
- osteo
- rheumatoid
- gout - Lyme disease
Cartilage tears
Happens during sports or vigorous activity. Tears usually occur in the meniscus when it is subjected to compression and shear stress. Does not heal well. Part of the meniscus may need to be surgically removed
Sprains
When a ligament which is reinforcing a joint is stretched or torn. Common in ankles, knees and lumbar region. Partially torn ligaments will heal themselves, but takes a long time due to poor vascularization. When completely torn it may need to be sewn together, replace with a graft or immobilized for a period of time
Dislocations
When bones are forced out of alignment. Usually accompanied by sprains, inflammation and difficulty moving the joint. Shoulder fingers and thumbs most affected. Must be reduced. Multiple dislocation of the same joint is common due to stretched out joint capsules and ligaments
Bursitis
Inflammation of the bursa, caused by a blow or friction.
Tendinitis
Inflammation of the tendon sheaths, caused by overuse.
Arthritis
Over 100 joint damaging diseases. Pain, stiffness and swelling of the joint. Acute arth. Caused by bacteria. Chronic forms include osteo, RA and gout
Osteoarthritis
The most common form of arth. Wear and tear arth. Common in the elderly
Rheumatoid arthritis
Type of arthritis cause by autoimmune disease. Happens in episodes.
Gouty arthritis
Caused by crystals of Uric acid in soft joint tissues due to slow excretion of Uric acid or over production. Men are more affected. Can destroy a joint. Medicine available to prevent it. Patients advised to avoid food containing purine nuclaic acids in food and to drink a lot of water.
Lyme disease
An inflammatory disease caused by a bacterial infection from a tick bite. Often results in joint pain and arthritis especially in the knees.
An umineralized band of gauzy looking bone matrix on top of the calcification front
Osteoid Seam
a layer of bone tissue that is calcifying. Underneath the osteoid seam
Calcification front
