Radiographic Anatomy Flashcards
Properties of an X-ray
- travel straight lines at the speed of light
- diverge in space from the source
- cause certain crystals to flourecence
- cannot be detected by the human eye
- differential absorbtion
- cannot be refracted by lens
- produce biological effects
Clinical use
-harmful effects identified as ALARA
as low as reasonably achievable
Advanced Imaging
- computed tomography (CT)
- magnetic resonance imaging (MRI)
- Myelography (w/wout CT)
- diagnostic ultrasound
- nuclear medicine
- dual energy X-ray absorption (DEXA)
- mammography
Producing a radiograph
- minimal equipment: X-ray source->image recorder->subject
- xray beam travels from source, thru subject, to the film
Image formation
-x ray tube, source of electrons
-xray beam, focused source of photons based on density
-object, beam absorbed or passed based on density
-film, photons pass object to strike film with silver coating
Image - record of proton interactions
Xray Photons
produced when electrons hit the target
Xray photon interactions
xray photons penetrate object, absorbed or pass thru to hit film
Xray beam
- is cone shaped from a point source
- the most central portion is called central ray
- the central ray diverges less and gives the truest image
- typically the beam will be perpendicular to the film
Differential Absorbtion
- penetration dependant on density
- denser object=less penetration
- move beam striking film=dark
- less beam striking film=whiter
Tissue Density
- a product of type of tissue and thickness
- results in differential absorbtions
- increase tissue density = whiter
- decrease tissue dens = darker
Differential Absorbtion
black - Air (lungs, trachea,outside of body) fat (parietal fat, fascial fat) water (muscle, organs) bone (bone, atherosclerotic placing) metal (filling,markers,orthodevices)
X ray photon Pass thru
non dense object
air and soft tissue
immage apears blacker
radioleucent appearance
Xray photons absorbed
- by dense object
- metal and bone
- image appears white
- radioopaque appearance
Image Terminology
Projection
Body Position
Projection
Anteroposterior/Posteroanterior - x ray beam enters AP front to back or PA back to front
Lateral - x ray beam enters side project side of patient alone coronal plane and travels left to right, names for which side is against the film
Oblique - positioned on film so X-ray passes thru at 45 degree angle
Body Position
Upright - AP or PA or lateral
Recumbent - supine or prone or lateral
Oblique - right or left and anterior or posterior
Decubitis - laying on side and take PA or AP
Upright Positions
patient stands
allows for veal to postural information
chiros can use this to analyze upright lumbar and sacral
Recumbent
patient laying down
no reliable evaluation of postural elements
useful when patient is in a lot of pain
Minimum Diagnostic Series
- standard views required to evaluate an area
- variation by facility or circumstance
- add more views depending on case
- must take at least 2 views
- projection oriented 90 degrees to one another
- view 3D object in 2D
Choice of Postioning
place the structures closest to the film starts with standard series what structures you wish to visualize patients clinical presentation different diagnosis under consideration patients size patients protection (female pelvis)
Film Markers
Informational markers
Mitchell Markers
Name blockers
ID markers - Type of study, Clinic and Tech
Informational Markers
provide information about patient
provide information about the doctor and or facility
identifies side of patient or patient positioning
General marker rule
without a marker you cannot identify which side of the patient is the left and which is the right
Mitchell Markers
metal markers taped to cassette label anatomical side of patient label side of patient usually contains BB's BBs at centre of bubble and are gravity dependant
Markers are also used to ID
type of study
patient positioning
technologist
facility
Name Blocker
Patients name Patients gender Patients age Doctors name Facility where films were taken Date of study
View a Radiograph
composite shadowgram -profiles/shadows/outlines -structures added contrasting densities -superimposition in a profile vs on end
Composite Shadowgram
represents the sum of the densitites interposed b/w the beam source of the film
involves superimpostion of object and orientation of objects
Projection
orientation of beam, position of object will affect image
Superimposition
objects that lie on the same path
Collimation
shutters that block peripheral portions of beam limits area exposed to beam, uses most central portion of beam limits size of xray beam field uses smallest area possible decreases the scatter radiation decerases the patients dose acheives better dose tube light stimulate xray beam
Compat bone
Cortex outer shell of bone encloses meddulary bone covered by periosteum homogeneous density
Spongy Bone
Cancellous
network of trabecula
Long / Tubular Bone
Epiphysis - articular end of the bone
Metaphysis - tappering portion b/w the physis and the shaft
Diaphysis - shaft of the bone
Periosteum
fibrous layer of bone
membranous bone formation, attachment of tendonous and ligmanets
contains vascular supply
not distinguishable on a radiograph
Apophyses
tuberosity, tubercles, trochanters, processes, spinous processes
osseous projections
develop to support and resonce of forces
Radiographic Evaluation and Interpretation
differentiate normal from abnormal localize abnormality describe abnormality list pertinant positives/pertinant negatives give impression of clinial significance
Radiographic evaluation
have a systm
use the system every time
be thorough
Extent of Evaluation
you are legally responsible
evaluate the whole xray
evaluate for all pathologies/conditions
Method of Evaluation
A - alignment
B - Bone
C - Cartilage
S - soft tissue
Search Pattern
Steps in Evaluation
know the ABCS for each region
steps: - identify the study
- identify the informational markers
- note collimation, shielding and artifacts
- the the technical quatlity of the film
- evaluate anatomy using ABCS search pattern
Normal Anatomy
the first step om recognizing abnormalities on radiographs is to know the appearanfce of notmal radiographic anatomy
- each person is a unique anatomical entity
- anatomical variations exist that are normal or abnormal
- pathology ften alters anatomical structures
- may be present with no radiographically visible alterations in anatomical structures
Abnormal Anatomy
know pathology, learn patients history, ID patients clinical presentation put it all together, radiographs are not isolated, it represents patient
Method of Evaluation
compare one side to the other
compare one level to the adjacent lebels
Cervical Spine Standard Series
neutral lateral
AP lower cervical
APOM open mouth
Lateral Cervical (neutral lateral)
you want all 7 cervical vertebrae and have the base of the skull
head and neck in a neutral position (hard palate level)
The 5 Assessing Cervical Lines
Paravertebral Lines - rules of 2s and 6s
Anterior Body line - smooth curve, no interuptions
Posterior Body line- Georges line, eval vert bodies
Spinolaminar Line - line thru spinolaminar junction
Spinous Process Interspacing- spacing of SP’s
Atlantodental Interspace (Interval)
space b/w post aspect of C1 anterior tubercle and the anterior aspect of odontoid process
adults < 3mm
children 8-10yrs <5mm
McGregor’s Line
Posterior-superior margin of hard palate to inferior most surface of the occiput
tip of dens to the line: <10mm in females
Relevant soft tissues of the Lateral Cervical
pharyngeal air shadow laryngeal air shadow tracheal air shadow note calcification of cartilages posterior cervical soft tissues
AP lower cervical
used to visualize the structures of C3-C7 vertebral bodies
-good to also see the postior elements but they come in variavle in size
see the articular pillars and SP’s and other oblique structures
AP Open Mouth
used to visualize the structures of C0-C1 articulation and the C1-C2 joint space
- you also see the lateral masses of C1 and the arches
- odontoid process, paraodontoid notches, body of C2, skull, madible, and dental structures
Georges Line
Lateral spine (neutral, flexed, or extended) a line is drawn along the posterior aspect of the vertebral bodies to extrapolate across disc space -offset indicates anter or retrolithesis having a translation of >= 4mm as the indicator
Sagittal Dimention of Cervical Spine Canal
lateral cervical
posterior surface of mid vertebral body to spinolaminar junction
-there are minimum measurements for this one at each vertebral body
C1-16mm, C2-14mm, C3-13mm, C4-7-12mm
positive shows the patient may have canal stenosis
Atlantoaxial Alignment
seen on the AP open mouth
lateral mass of atlas should not overhang lateral margin of C2 superior facet (>1mm)
>=2mm overhang shows the patient may be suspect to a Jefferson’s fracture
this may be normal in children 4 years of age or younger
you can draw an X from one C0-C1 joint to the opposite C1-C2 joint and the and by doing the same on the other side you can determine rotation at the C1-C2 joint
Coronal Dimensions of the Cervical Spine
measure the shortest distance between the inner cortical margins of pedicles at given segment, cary by spinal level, evaluated for stenosis
Cervical Gravity Line
Lateral neutral cervical
vertical line drawn through the apex of odontoid process should pass through the seventh cervical vertebral body
gross assessment of where the gravitational stresses are acting at the C/T junction
Ruth Jackson stress lines on flex/extension can also assess stress focus
Angle of Cervical Curve
lateral cervical
two lines are drawn, one through and parallel to the inferior endplate of the 7th cervical body and the other through the midpoints of the anterior and posterior tubercles of the atlas
construct perpindiculars and measure the angle, normally 35 - 45 degrees
lack of lordosis may indicate trauma, muscle spasm, or degenerate disease
many stress lack of correlation between curve and symptoms
Prevertebral soft tissue
lateral cervical
space measured between the vertebral bodies and the air shadow of the pharynx, larynx and trachea
normally 10mm at C1
rules of 2’s and 6’s
C2 < 6mm
C6 < 22mm
increases with any soft tissue mass (hematoma, abscess or tumour)
