Classification Of Bones Flashcards
Typical long bones
Humerus radius ulna femur tibia and fibula with two secondary epiphyses
Miniature or short long bones
Have one epiphysis like metacarpals metatarsals phalanges
Modified long bones
Have no medullary cavity like clavicle
Transmits weight from appendicular skeleton to axial skeleton
Short bones
Cuboid
Scaphoid
Eg tarsal and carpal bones
Flat bones
Shallow plates
Sternum ribs scapula
Bones in vault of skull
Irregular bones
Hip bone, bones in the base of the skull eg sphenoid and first and second cervical vertebrae
Pneumatic bones
Large spaces lined by epithelium Maxilla sphenoid ethmoid Make the skull light in weight Help in resonance of voice Air conditioning chambers for inspired air Improves timbre of voice
Sesamoid bones
Bony nodules embedded in joint capsules or tendons
Have no periosteum, medullary cavity and haversian system and ossify after birth
Related to an articular or non articular surface
Surfaces of contact are covered with hyaline cartilage and lubricated by a synovial membrane
Patella in the tendon of quadriceps femoris
Pisiform in tendon of flexor carpi ulnaris
Function of sesamoid bones
To resist pressure
To minimise friction
To alter the direction of pull of the muscle
To maintain local circulation, protect the vessels and nerves
Accessory bones
Are not always present
Ununited epiphyses from extra centres of ossification
Eg sutural bones of skull
Cervical ribs lumbar ribs
Compact bone is present in the ——- of Long bones
Shaft / diaphysis
Wolfs law
Bone formation is directly proportional to stress and strain
Cancellous or spongy bone is found in
Epiphyses of long bone
Lamellae of compact bone
Arranged to form Haversian system
Lamellae of compact bone
Arranged to form haversian system
Bone marrow of compact bone
Yellow
Stores fat after puberty
Bone marrow of cancellous bone
Red
Produces RBCs granular WBCs and platelets
Periosteum
thick fibrous membrane
Outer fibrous layer
Inner cellular layer-osteogenic
Periosteum united to bone by sharpeys fibres- strong over tendons and ligaments
According to number of epiphsyis
Simple: ends of long bones develop form many epiphyses-these fuse independently eg femur
Compound ends of bones develop from many centres which unite to form a single epiphysis which fuses with the shaft eg humerus
Based on function
Pressure epiphysis Atavistic Ephiphysis Traction ephiphysis Aberrant epiphysis Compound epiphysis
Pressure epiphysis
Articular and takes part in transmission Of weight
Eg head of humerus
Lower end of radius
Traction epiphysis
Non Articular
Does not take part in transmission of weight
Provides attachent to tendons which exert a traction on the epiphysis
Ossify later than pressure epiphyses
Eg trochanter of femur and tubercles of humerus
Atavistic epiphysis
Phylogenetically an independent bone
Becomes fused to another bone
Eg coracoid process of scapula
Os trigonum of talus
Aberrant epiphysis
Not always present
Eg epiphysis at the head of the first metacarpal and the bases of other metacarpal bones
Compound epiphysis
2-3 smaller epiphysis join to form a compound epiphysis
Joins the shaft
Eg epiphysis of head greater and lesser tubercle of humerus join to form a compound epiphysis which joins that shaft
Traction epiphysis
Non Articular
Does not take part in transmission of weight
Provides attachent to tendons which exert a traction on the epiphysis
Ossify later than pressure epiphyses
Eg trochanter of femur and tubercles of humerus
Atavistic epiphysis
Phylogenetically an independent bone
Becomes fused to another bone
Eg coracoid process of scapula
Os trigonum of talus
Aberrant epiphysis
Not always present
Eg epiphysis at the head of the first metacarpal and the bases of other metacarpal bones
Compound epiphysis
2-3 smaller epiphysis join to form a compound epiphysis
Joins the shaft
Eg epiphysis of head greater and lesser tubercle of humerus join to form a compound epiphysis which joins that shaft
Diaphysis
Elongated shaft of the bone
Develops from primary centre of ossification
Receives blood supply from nutrient artery
Diaphysis
Elongated shaft of the bone
Develops from primary centre of ossification
Receives blood supply from nutrient artery
Metaphysis
Epiphyseal ends of diaphysis are called métaphyses
Zone of active growth
Before epiphyseal fusion, metaphysis is richly supplied with blood through end arteries forming hair pin bends
Common site of osteomyelitis because bacteria/emboli are trapped In hair pin bends causing infarction
After epiphysis fusion, vascular communications are established between metaphysical and epiphysial arteries
Intracapsular metaphysis
Both ends of humerus
Extracapsular Metaphysis
Upper and lower ends of radius and ulna
Epiphyseal plate of cartilage
Separates epiphysis from metaphysis
Proliferation of cells in cartilaginous plate- lengthwise growth of bone
Nourished by epiphysial and metaphysial arteries
The nutrient artery enters through the ———- runs through cortex and divides into ascending and descending branches which turn down to form
Nutrient foremen
Hair pin bends
