Lecture 2. General Concepts of Bones and Joints

33% organic compounds (collagen) + 67% inorganic compounds (minerals)

what is the general composition of a bone

allow flexibility

significance of the organic component of bones

provide strenght and ridgitiy

significance of the inorganic component of bones

it is when a young animal can fracture their bone but not break it all the way due to the high organic content of their bones

what is a greenstick fracture and why is it significant

Actual green stick mostly bends some cracks

axial skeleton

what skeletal aspect includes the body, head, ribs, spine, and tail

appendicular skeleton

what skeletal aspect includes the thoracic and pelvic limbs

heterotopic skeleton

what skeletal aspect includes structures that aren't true bone but more just calcified structures (Os penis)

Total average number of bones

321

1. 3 ceneters of ossification, 1 at each epiphysis and 1 at the diaphysis

2. contains a medullary cavity

3. typically part of the limbs

classification of a long bone

Epiphysis

Diaphysis

Epiphysis

1. squareish shape

2. no medullary cavity

3. typically in manus or pes

classification of a short bone

1. expanded in two directions

2. no medullary cavity

classification of a flat bone

what is special about the pneumatic bones

characterisitic of flat bones that have air filled spaces in the skull for the paranasal sinuses

classification of irregular bones

falls into no other class

what aspect of bone is labeled 1

Proximal epiphysis

what aspect of bone is labeled 2

diaphysis

distal epiphysis

what aspect of bone is labeled 3

growth plate/physis

what aspect of bone is labeled 4

metaphysis

what aspect of bone is labeled 6

Articular surfaces are covered by

Articular cartilage

spongey bone (softer marrow filled)

what bone aspect is being indicated internally by 1

compact bone (thick and hard cortex)

what bone aspect is being indicated internally by 2

nutrient foramen where bone gets blood supply

what bone aspect is being indicated internally by 3

meddulary cavity for marrow (ONLY IN LONG BONES)

what bone aspect is being indicated internally by 4

ribs are what type of bone they done not have a medular cavity

flat bone

spongey bone (softer marrow filled)

what aspect of this femur is 1

meddulary cavity for marrow (ONLY IN LONG BONES)

what aspect of this femur is 2

compact bone (thick and hard cortex)

what aspect of this femur is 3

cortex will get thicker the closer you are to the diaphysis/shaft and thin out as you move to the epiphysis

what is true of the cortex thickness in a bone

dense fibrous membrane on outer surface of bone that helps to grow and expand bone

periosteum

vascular membrane that lines the inner surface of the bone. inner mudullary cavity, trabeculae of spongy bone and central canals of bones

endosteum

used at articular surface of bones to protect the joints and blends seamlessly w/ periosteum and fibrous joint capsule

hyaline articular cartilage

hyaline articular cartilage

what part of the joint does the blue arrow point to

periosteum

what part of the joint does the red arrow point to

joint capsule

what part of the joint does the green arrow point to

richly vascularized active hemopoietic gelatinous tissue in bones full of RBCs towards the epiphysis of long bones (prominent in young)

significance of the red marrow in bones

inactive marrow that becomes very fatty with age and remains in the diaphysis/shaft. Hemopoietic potential is “inactive”

significance of yellow marrow in bones

they can only be found in the femur

what is special about the trochanter of bones

fossa and grooves

what are the two forms of depressions in bones

initial cartilage base is resorbed and ossifies with age throughout the bone and the growth plates allowing elongation and hardening. Areas within this model that initially start to mineralize are called centers of ossification

how does the process of ossification occur in bones

primary ossification

what form of ossification occurs before birth in the diaphysis of bones

secondary ossification

what form of ossification occurs after birth at the epiphysis and large eminences of bones

via intramembranous ossification using a sheet of connective tissue (within a membrane) rather than cartilage

also occurs under the periosteum as bones grow in diameter

how do flat bones undergo ossification

under the periosteum

where do long bones undergo intramembranous ossification

1. gets nutrients into the bones via the nutrient artery

2. can resemble oblique fracture on RADs

3. is where panosteitis will first show signs

why is the nutrient foramina so significant

sesamoid bone what does sesamo mean:

seed looks like the seed

the patella is the largest seasmoid bone and helps to reduce tendon friction against bones and avoid ripping the tendon

what is the significance of the circled structure in the stifle joint