Diagnostic Imaging L3-Bone

drhartz's version from 2017-09-04 01:24

Essentials for Radiographic technique

Question Answer
what are the essential techniques?1. exposure
2. high definition film
3. postioning
4. at least 2 orthogonal projections
5. additional projections
6. centering/collimation
7. labeling
8. General Anesthesia
9. use same projection & exposure for follow up studies
what is in the ID when labeling film?patients name
owners name
case number
location of examination
in equine px remember to indicate what?what limb is radiographed
where should limb markers be placed?dorsal/cranial to the limb or lateral to the limb

bone anatomy

Question Answer
ends of bone are called?epiphysis
bone between epiphysis and diaphysismetaphysis
shaft or center of a bonediaphysis
what is the physis? where is it located?growth plate between epiphysis and metaphysis
how does the physis appear on a radiograph? why is this? what is it made of?radiolucent line - soft tissue opacity - cartilaginous

bone tissue

Question Answer
what is cortical bone & where is it located?Cortical bone forms the cortex, or outer shell, of most bones
what is the medulla of bone ?central cavity of bone shafts where red bone marrow is stored
what is periosteum where is it located on the bone?dense layer of vascular connective tissue covering the bones cortex except at the surfaces of the joints.
what is endosteum where is itthin layer of vascular connective tissue that lines the medullary cavity
what is the nutrient foramen? what does it look like on radiograph? what should you not mistake it for?1. entrance/exit of medullary blood supply 2. gap in cortex with a sclerotic border (increased opacity/thick) 3. do not mistake as a fracture line
3 sources of blood supply to the bone1. centrifugal from medullary artery (2/3 blood supply) 2. periostal vessels of periosteum 3. epiphyseal vessels present in immature skeleton before closure of growth plate
what are 2 active parts of the bone that respond to trauma with callus formation?periosteum and endosteum
woven bone type
growth rate?
when is it formed?
disorganized structure
rapid rate of formation
formed in fetal life and skeletal repair (callus)
more lucent than cortical bone
fracture callus is what bone type?woven bone
in fracture repair callus(woven bone) is replaced bylamellar bone
lamellar bone type
growth rate?
when is it formed?
orderly structure
slow rate of formation
formed in cortical and cancellous/trabecular bone
dense bone tissue --> opaque
cancellous/trabecular/spongy bone.. density, fx, trabeculated with?lacks density, provides shock absorption for joints (subchondral bone), trabeculated with marrow spaces
what is subchondral bone?bone layer below the cartilage in a joint

bone development

Question Answer
Intramembranous ossification occurs where?flat bones (skull) & diaphysis
callus formation is intramembranous or endochondral bone formation?intramembranous
intramembranous bone is produced by what? cartilage precursor?periosteum , NO
endochondral ossification occurs where? cartilage precursor?physis (growth plate) & epiphyseal secondary center of ossification , YES

centers of ossification

Question Answer
where is the epiphyseal secondary center of ossification? beneath surface of articular cartilage
primary ossification center - where is the growth? what produces the growth?diaphyses, produced by periosteal appositional growth
secondary ossification center - where is the growth? what produces the growth?epiphysis, growth plate with cartilage tissue
tertiary ossification center - also called? where is the growth? does not contribute to bone _____?apophyseal centers, sites of attachment of tendons, NOT for bone LENGTH
during growth the metaphysis width is the same as the _____? the site of marked modeling in width is called the _____?diaphysis, cutback zone
in order to grow shaftward the metaphysis has a marked modeling in width called the cutback zone. what does it look like?straight then flared at growth plate. site of modeling has a roughened cortical periosteal border that should not be mistaken for pathology
apopyseal growth plates are most commonly seen in (3)tibial tuberosity in stifle, olecranon process, greater trochanter of femur
apopyseal centerssupraglenoid tubercle of scapula
deltoid tuberosity of humerus
olecranon process
medial epicondyle of humerus
greater trochanter of femur
tibial tuberosity
tuber coxae
tuber calcis
what should you know about carpal/tarsal bone ossification?chondral template ossification = cartilagenous templates - ossify from center and become more square with maturity
trauma or error in physeal plates can cause what?premature closure - problem in joined bones (radius/ulna) where physeal plates much grow them at some time - leads to curved appearance and joint problems

bones on radiograph

Question Answer
evaluate 6 things on radiographanatomy , joints, bone alignment , bone architecture, periosteal rx, soft tissue changes
causes of inc. opacity in bone (4)1. bone proliferation 2. sclerosis of trabecular bone 3. periosteal / endosteal new bone 4. callus
causes of dec. opacity in bonebone lysis / resorption / destruction
mixed patterns of opacity have (2) at the same timeproduction and lysis
periosteal rx/proliferation: new bone growth on outside of bone / periosteum
Question Answer
endosteal rxproliferation of new bone inside of cortex
causes of endo/periosteal rx (3)response to injury - 1. trauma 2. infection 3. neoplasia
periosteal rx appearance is influenced by (4)1. thickness of periosteum (how active is that bone) 2. blood supply in overlying soft tissue 3. age of px 4. species
inc blood supply from inflammation causes periosteal rx how?inc growth bc inc blood supply to area
does trauma with dec blood supply (degloving) causes periosteal rx?not much rx will occur bc not much blood supply from tissue
which species have greater periosteal rxbovine and equine
what age group has inc periosteal rx?young - periosteum is loosely attached and more responsive
types of periosteal rx1. smooth well defined 2. parallel/lamellar "onion skin" 3. brush border,columnar,palisading,spicular 4. radiating starburst 5. amorphous
if periosteal rx is smooth and solid - indicates?healing
Lamellar periosteal rxnew lucent bone that looks layered "onion skin"
palisading brush border periosteal rxnew lucent bone that extends from periosteum at right angles in bristle-like formation
what is a typical presentation of benign hypertrophic osteopathic Maries dz ?Palisading brush border periosteal rx
amorphous periosteal rx? malignant?no pattern is recognized, no
codman triangleperiosteum is lifted from lesion or tumor "ski jump"- in association with neoplasms but not always
how must you adjust exposure of radiographs with soft tissue changes? why?- inc exposure -- get a better look at boney proliferation
massive localized soft tissue swelling is indicative ofmass or growth
massive localized soft tissue swelling is not indicative of vascular just edema, why?vascular problems will not be focal

Benign vs Malignant

Question Answer
what is zone of transition? what can it tell us? interface between destruction/production and healthy bone.... can indicate benign or malignant
defined clear margin = what zone of transitionshort zone of transition
ill defined margins = what zone of transitionlong zone of transition --> permeative lesion
defined clear zone/margin suggests what type of lesionbenign nonaggressive lesion
indistinctive zone/margin suggests what type of lesionmalignant aggressive lesion