General Anatomy (Osteology) Flashcards
What is osteology?
- osteology is the study of bones
- bone is a living tissue. It has blood vessels, lymph vessels and nerves
- bones have an organic framework of fibrous tissue and cells among which inorganic salts are deposited
- bone matrix - contains inorganic salts, primarily calcium phosphate and some calcium carbonate, and collagen fibers.
- These and a few other salts are deposited in the framework of collagen fibers, a process called calcification or mineralisation.
- Mineral salts confer hardness of bone while collagen fibers give bone its great tensile strength.
- The process of calcification occurs only in the presence of collagen fibers.
How do bones work?
Bone structure is somewhat similar to reinforced concrete that contains structural metal reinforcement rods or bars. These metal reinforcements are commonly called rebar. Protein strands make up the rebar of bone. Calcium and phosphorus mineral crystals deposited around the protein strands are somewhat like the concrete poured around the rebar in reinforced concrete. The protein strands provide the tensile strength that holds everything together and the minerals provide the solid structure. If bones were made only of protein, they would be too flexible. If bones were made solely from minerals, the skeleton would be too brittle.
What is the skeleton divided in?
For the convenience of study, the skeleton is divided into axial and appendicular parts.
What is the axial skeleton?
The axial skeleton consists of 80 bones that form the axis of the body and which supports and protects the organs of the head, neck, and trunk.
• Skull
• Auditory ossicles
• Hyoid bone
• Vertebral column
• Thoracic cage
What is the appendicular skeleton?
The appendicular skeleton is composed of 126 bones of the upper and lower limbs and the bony girdles, which anchor the appendages to the axial skeleton.
• The shoulder girdle (the scapula and clavicle)
• The upper limb (the humerus, ulna, radius and bones of the hand)
• The pelvic girdle (the hip bone)
• The lower limb (the femur, tibia, fibula and bones of the foot)
What are the functions of the bones?
- support - Support the body. Eg. pelvis
- levers for muscles (movements / locomotion) - Muscles are attached to the bones. When muscles contract, the bones act as levers to allow movements. Eg. humerus
- protection to brain, heart, lungs, etc. - Bones protect important organs such as the brain, heart, and lungs. Eg. Skull, ribs
- production of blood cells - Blood cells (red blood cells, white blood cells, platelets are produced in the red marrow of bones). Eg. Vertebrae, sternum, pelvis
- storehouses for calcium and phosphorus - The calcium and phosphate can be released or stored in the bone to maintain constant concentration of these ions in body fluids. Eg. All bones
What are the two types of stem cells?
hemopoietic (which can produce blood cells) and stromal (which can produce fat, cartilage and bone)
What are the two types of marrow?
There are two types of bone marrow: red marrow (also known as myeloid tissue) and yellow marrow.
What does the red and yellow marrow contain?
Red blood cells, platelets and most white blood cells arise in red marrow; some white blood cells develop in yellow marrow.
What happens when there is severe blood loss?
the body can convert yellow marrow back to red marrow in order to increase blood cell production.
What does the bone matrix contain?
• Inorganic mineral salts provide bone’s hardness – hydroxyapatite (calcium phosphate) & calcium carbonate
• Organic collagen fibers provide bone’s flexibility – their tensile strength resists being stretched or torn
• Bone is not completely solid since it has small spaces for vessels and red bone marrow
– spongy bone has many such spaces
– compact bone has very few such spaces
What is the difference between spongy and compact bone?
Spongy
- area - makes up the inner cavity of the bones
- porosity - more
- also known as - cancellous tissue
- functional unit - trabeculae
Compact
- area - outer covering
- porosity - less
- also known as - cortical tissue
- functional unit - osteons
What is Diaphysis?
Long central shaft
What is epiphysis?
Rounded ends of long bones
What is epiphyseal plates?
Plates of cartilage, known as growth plates which allow growth in length childhood
What is a cancellous bone?
Where blood cells are made?
What is a compact bone?
Gives strength to the hollow part of the bone
What is the periosteum?
Ligaments and tendons attach to the periosteum
What is marrow cavity?
Where white blood cells are made
What are the classifications of bones?
• Every adult skeleton contains 206 major bones, which can be divided into six broad categories according to their individual shapes.
- Long bones (Eg. Humerus, phalanges)
- Flat bones (Eg. Cranium)
- Sutural bones (Eg. Cranial sutures)
- Irregular bones (Eg. Facial bones)
- Short bones (Eg. Tarsus and carpus)
- Sesamoid bones (Eg. Patella)
What do flat bones do?
Protect internal organs
- cranial bones
- scapulae
- sternum
- ribs
What do the long bones do?
Support weight and facilitate movement?
- humerus
- radius
- ulna
- metacarpal
- phalanges
- metatarsal
- tibia
- fibula
- femur
What are short bones?
Cube shaped
- tarsals
- carpals
What are irregular bones?
Complex shapes
- vertebrae
- sacrum
What are sesamoid bones?
Reinforce tendons
- patella
What are bone surface markings?
Markings are distinct features seen on a bone. They occur wherever fibrous tissue or muscle is attached to the bone.
What are the different types of bone markings?
- elevation
linear elevation – line, ridge, crest
rounded elevation – tubercle, tuberosity, malleolus, trochanter sharp elevation – spine, styloid process - facets
small, smooth, flat areas - depressions
small – pit or fovea
large – fossa
has length – groove or sulcus
when bridged by a ligament or a bone – notch or incisura foramen – perforation or hole
canal or meatus – perforation that has length. A canal has an orifice (os or ostium) at each end
What are periosteal arteries?
Accompanied by nerves supply the periosteum and compact bone
What are epiphyseal veins?
Carry blood away from long bones
What nerves accompany the blood vessels that supply bones?
The periosteum is rich in sensory nerves sensitive to tearing or tension
What are heterotrophic bone?
- HO is the process by which bone tissue forms outside of the skeleton usually in the soft tissue
- can be caused by surgery or trauma to the hips and legs
- most common examples are horse riders where they develop it in their thighs or buttocks
What is the difference between osteomalacia and osteoporosis?
- def - demineralization of the bones
- presence - adults
- signs and symptoms - weakness of the muscles and fragile bones
- causes - deficiency in vitamin D
- treatment - injections of vitamin D
- def - reduction of the bone mineral density
- presence - > or equal to 65 years women
- signs and symptoms - curving of the back and risk for fractures
- causes - deficiency in calcium and phosphorus, drugs, inherited, endocrine disorders, alcohol drinking.
- treatments - healthy lifestyle, calcium supplements and natural calcium diet
What are rickets and osteomalacia?
-Rickets - in children prior to epiphyseal fusion, vitamin D deficiency results in growth retardation associated with an expansion of the growth plate
-Osteomalacia - in adults the hypocalcemia and hypophosphatemia that accompany vitamin D deficiency result in impaired mineralization of bone matrix proteins
What is osteoporosis?
Osteoporosis is a bone disease that occurs when the body loses too much bone, makes too little bone, or both.
What happens as a result of osteoporosis?
bones become weak and may break from a fall or, in serious cases, from sneezing or minor
bumps. Osteoporosis means “porous bone.”
