Bone Flashcards
What is Periosteum?
- tough Fibrous membrane round the outer surface of the bone not covered by the articular surface
- delivers blood and nutrients to the bone. Is able to form new bone - good for healing fractures
- has an outer fibrous layer (mostly collagen) and inner cellular layer (osteoblasts).
What is compact bone (cortical bone)?
- forms hard outer shell around most bones and forms the cortex
- formed from osteons
- protection, support and acting as a calcium store when needed
What is cancellous bone (trabecular bone)?
- porus, vascularised and contains red bone marrow, in the epiphyses (end) of long bones
- can be converted to compact bone by osteoblasts (this takes place during embryo formation)
- storage of bone marrow, light weight, adds stength and flexability, mineral store
What is the medullary cavity?
- hollow region within diaphysis filled with yellow marrow
- endosperm = membranous lining where bone remodelling occurs
- red and white blood cells are formed here
What is the function of the greater trochanter?
- provides attachment for gluteal muscles
- provides extensors of hip with long lever arm
What is the function of the lesser trochanter?
- provides insertion for iliopsoas muscle
What is the function of the trochanteric fossa?
- lies between trochanter and femoral neck
- site of insertion for small rotor muscles of the hip
What is the function of the medial and lateral condyles?
- provides an attachment for collateral ligaments of the stifle
- provide patella stability and articulation of the tibia
What is the function of the extensor fossa?
- gives origin to the long digital extensor and peroneus tertius
What is the function of the patella?
- sesamoid bone developed within the insertion of the quadriceps femoris
What is the function of the intercondyler fossa?
- separates the 2 condyles
- articulation of the tibia and seats stabilisation ligaments in the knee
What is the function of the trochlea?
- articulates with the patella
What are the 3 parts of bone tissue?
- Matrix
- Cells
- Vascular spaces
What is the organic part of the matrix (osteoid)?
- contains type 1 collagen for flexibility, water, glycoproteins, proteoglycans and bone sialiproteins
- synthesised by osteoblasts
- mineralisation front = point where osteoid becomes bone tissue
What is the inorganic part of the matrix?
- minerals inc. calcium and phosphorus
- 60-70% of bones dry mass
- radio opaque
What is an osteoblast?
- derived from mesenchymal stem cells
- synthesise and secrete osteoid
- active in mineralisation
What is an osteocyte?
- within matrix
- interconnected by dendritic processes
- derived from osteoblasts
- reside in lacunae connected by canaliculi
What is an osteoclast?
- bone resorption
- large multinucleate
- release protons = acidic = demineralisation
- secrete proteases to destroy organic matrix
- derived from bone marrow
What type of ossification involves formation of a cartilaginous precursor?
- endochondral
What type of ossification is involved in formation of bones of the skull?
- intramembranous
What type of ossification results in formation of woven bone that is later replaced by lamellar bone?
- intramembranous
What type of ossification involves differentiation of mesenchymal stem cells into osteoblasts?
- intramembranous
What type of ossification is involved in growth in length of bones?
- endochondral
What type of ossification is involved in width of long bones?
- intramembranous
Where does endochondral ossification take place?
- physes/ growth plates = increase length of long bone
- epiphyses = increase in size link with joint cartilage growth
- cuboidal bones of carpus and tarsus
- repair of fractures (same as bone growth = no scar)
What is the diaphysis?
- Shaft of long bone
What is the metaphysis?
- flared region adjacent to epiphysis
What is the epiphysis?
- rounded end of bone
What is the axial skeleton?
- the bones forming the axis/ centre of the animal
What is the appendicular skeleton?
- regions that are attached e.g bones of forelimb
What are visceral bones?
- develop in soft tissues away from rest of the skeleton
e.g Os penis in dog and cat
Os cordis in heart of ruminants
What is chondral ossification?
- bones ossify from cartilage precursor
e. g most limb bones - humerus, radius etc
What is membranous ossification?
- bones ossify directly from mesenchymal cells
e. g scapula and most bones of skull
Chondral ossification bones
- found in load bearing areas
- often have specific fail/fracture configurations
Membranous ossification bones
- found in non-load bearing areas
- fracture configuration = pebble on sheet of ice
Long bones
- cylindrical shape
- main part of bone is a column providing strength, expanded ends providing transfer of load
- resist compression when loaded, act as levers and resist tension during muscle contraction
- e.g humerus, femur, radius, tibia
Short bones
- many sides, similar dimensions throughout (length, breadth, height)
- found in groups of bones that act to transmit and disseminate forces through joints (distribute weight and force more evenly and reduce concussive forces)
- one surface is always non-articular – for ligament attachment and vasculature
- e.g carpal and tarsal bones
Irregular bones
- have various jutting processes for muscle and ligament attachment
- e.g vertebral bones
Flat bones
- act as attachment for soft tissues and protect underlying tissues
- e.g skull, scapula, pelvis and ribs
Pneumatic bones
- bones that contain air spaces = light weight
- flat bones of skull
Sesamoid bones
- provide additional strength and reduce wear over joints
- e.g redirect course of tendon (patella)
What is the function of the greater and lesser tubercles?
- muscle attachment
What is the function of the olecranon?
- allows movement and attachment of the ulnar
What is the function of the head of the humerus?
- articular surface
What is the function of the deltoid tuberosity?
- ridge (muscle attachment)
