Rad Anatomy Flashcards
Discovery of x-rays
Wilhelm Conrad Roentgen in 1895
Properties of X-rays
- Travel in straight lines at the speed of light in a coneshape
- Diverge in space from the source
- Cause certain crystals to flouresce
- Cannot be detected by human senses
- Differentail absorption
- Cannot be refracted by a lens
- Produce biological effets
Clinical Use of X-rays
- Diagnostic application as early as 1895
- Medical use and chiropractic use
- Harmful effects identified
ALARA- 1994: As Low As Reasonably Acheivable
No such thing as a SAFE dose
When to Take X-rays
New patient or existing patient with a new complaint or an Existiing patient with **no or poor response **to treatment then:
Clinical History and Examination and Evaulation
What is the working clinical differential diagnosis or assessment?
Will radiographs help clarify or impact the Diagnosis and/or Prognosis and/or treatment?
If NO-there is no clinical need for diagnostic imaging then: NO DIAGNOSTIC IMAGING PERFORMED.
If YES-There is clinical justification for diagnostic imaging then: Do the benefits of imaging outweigh the risks to the patient? Then:
** If NO- **Then: NO DIAGNOSTIC IMAGING PERFORMED.
If YES- Then: Determine imaging modality most appropriate depending on patient presentation and differential diagnosis. Then:** DIAGNOSIS IMAGING PERFORMED**
Advanced Imaging
- Computed Tomography (CT)
- Magnetic Resonance Imaging (MRI)
- Myelography (with/without CT)
- Diagnostic Ultrasound
- Nuclear Medicine
- Dual Energy X- ray Absorptiometry (DEXA)
- Mammography
Producing Radiographs
Minimal equipment:
X-ray source
Image recorder (film)
Subject/patient
X-ray beam travels from the source, through the subject, to the film.
Image Formation
- X-ray tube- source of electrons
- X-ray beam- focused stream of photons directed at object
- Object- beam is absorbed or passes through depending on varying densities
- Film- photons that pass through object strike the film and react with silver coating to form an image
- Image- record of photon interactions
X-ray Photons
Produced when electrons hit the target
X-ray photon interaction
X-ray photons penetrate object and are absorbed or passed through an object and strike the film
X-ray Beam
- Beam is cone-shaped from a point source
- The most central portion is called the central ray
- The more central portion of the beam diverges leess; this gives the “truest” image
- Typically, the beam will be perpendicular to the film ( Beam 2)
- To view some structures, the beam may be angled
Radiographic Image
- Black, white nand shades of gray
- It’s all relative
Differential Absorption
- Penetration dependent on density
- Denser the oblect = less penetration
- More beam striking the film = the blacker
- Less Beam striking the film (more absorption) = whiterAir = black, H2O/Muscle = gray, Bone = white
Tissue Density
- A product of the type of tissue and the thickness of that tissue
- Results in differential absorption
- Increased tissue density = whiter area on film-More tissue quantity = whiter
- Decreased tissue density = darker area on film- Less tissue quantity = darker
Anatomic Densties
Photons in= the same amount of photons hit the tissues but only some continue through the tissues.
Bone- the least photons pass through the tissue therefore, shows up as the whitest image on the film.
Muscle- moderate amount of photons pass through the tissue therefore shows up as a gray image on the film
Air- the most photons pass through unobstructed by tissue therefore shows as the blackest image on the film.
Differential Absorption 2
Black→ Air (Lungs/ Trachea/ Outside the body)
Dark Gray→Fat ( Perirenal fat/ Fascial plane)
Gray→ Water ( Muscle/ Organs)
White/Light Gray→ Bone (Bone/ Atherosclerotic plaquing)
White→ Metal ( Filings/ Markers? Ortho devices)
X-ray Photons Passed Through
- Non-defense objects - Air and Soft tissue
- Image appears blacker
- Radiolucent appearance - Darker/ nothing
X-ray Photons Absorbed
- By dense object- Metal and Bone
- Image appears whiter
- Radiopaque appearance
Radiographic Densities
- Most radiolucent = least tissue density = most blackness on film
- Most radiopaque = most tissue density = most whiteness on film
Image Terminology
RADIOLUCENT- Readily allowing x-rays to pass through the object to strike the film.
- Appears blacker on x-ray film
- Ex. Lungs (soft tissue) are more RADIOLUCENT than bone( dense hard tissue)
RADIOPAQUE- Not permitting the transmission of x-rays though the object to the film.
- Appears whiter on the x-ray film
- Ex. Metal (dense hard material) is more RADIOPAQUE than bone
Positonal Terminology
PROJECTION- Most common
- Anteroposterior/ Posteroanterior-Visual: Front to Back/ Back to Front
- Lateral-Side View
- Oblique- Angled View through the body
Projection - AP/PA
Anteroposterior / Posteroanterior (AP/PA)
-The central ray enters the patient in a:
- Front to Back (AP) or
- Back to Front (PA) direction along the horizontal plane
- Options: AP or PA
- The spine is usually radiographed in the AP projection
- Ex. AP Thoracic- Beam projected on the anterior side of patient and posterior side of patient is against the film.
Projection - Lateral
-Lateral
- The x-ray beam enters the side of the patient along a coronal plane and travels Lt to Rt or Rt to Lt through the patient t the film.
- Options: Left lateral or Right lateral
- Example: Left Lateral Lumbar named for which side of the patient is against the film
- Left Lateral = Left side against film = X-ray beam travels from right to left though the patient.
Left Lateral = Beam→Rightside →Leftside →Film
Right Lateral = Beam→Leftside→Rightside→Film
Projection-Oblique
Oblique
- The patient is postiioned oblique to the film so that the central ray passes through the patient at a 45º angle to their coronal and sagittal planes.
- Options: Right Anterior Oblique ; Right Posterior Oblique; Left Anterior Oblique; Left Posterior Oblique
- Ex. Oblique Cervicals
Left or Right
and
Anterior or Posterior
Body Postion
**Upright- **AP or PA or Lateral
**Recumbent- **Supine or Prone or Lateral
**Oblique- **Right or Left and Anterior or Posterior
**Decubitus- **Any positon in the lying posiiton
Upright Positions
- Usually AP/ PA
- The patient is standing upright for the x-ray examination
- This allows for evaluation of postural information
- Many chiropractors utilize upright lumbar/pelvis films to evaluate for leg length inequalities
Recumbent Postions
- Usually Supine or Prone
- The patient is lying down for the x-ray examination
- No reliable evaluation of postural elements can be obtained from recumbent views ie. compression etc.
- The positoning is useful when the patient is in a lot of pain or when the patient is very large
Minimum Diagnostic Series- What X-rays to Take
- Standard views required to evaluate an area
- Minimal 2 views perpendicular to each other
- Some variation by facility or circumstance
- Add optional views depending on case
- Must take at least 2 views
- Projections oriented 90º to one another
- View 3-D object in 2-D
- Some body parts require more than 2 views for a minimal study
- Supplemental views outside the minimal series are used to better visualize specific structures
Minimal Diagnostics-Cervical Spine
Cervical Spine
Minimum Series:
- AP
- Lateral
- AP Open Mouth (Odontoid)
Supplemental Views:
- Obliques
- Flexion/Extension
- Lateral Bending APOM
- Pillars
Alternative Views:
- Swimmer’s
- Fuchs/Judd
Minimal Diagnostics- Thoracic Spine
Thoracic Spine:
- AP
- Lateral
Supplemental Views:
- Swimmer’s
Minimal Diagnostics- Lumbar Spine
Minimum Series:
- AP/PA
- Lateral
Supplemental Views:
- Axial AP/PA LS Spot
- Obliques
- Lateral L5/S1 Spot
- Flex/Extension
- Traction/ Compression
- Scanogram
Minimal Diagnostics- AP Full Spine
( For Scoliosis evaluation)
Minimum Series:
- AP Projection (initial exam)
- PA Projection (for subsequent exams)
Supplemental Views:
- Sectional Lateral
- APOM
Minimum Diagnostics- Sacrum
Minimum Series:
- AP
- Lateral
Minimum Diagnostics-Coccyx
Minimum Series:
- AP
- Lateral
Choice of Positioning
-In choosing what films to take and what projections, postions, views and methods to utilize, it is important to:
- Place the structures that you wish to visualize closest to the film
- Start with standard (minimal diagnostic) series
-Choices may be influenced by:
- What particular structures you wish t visualize
- The patient’s clinical presentation
- The differential diagnoses under consideration
- The patient’s size
- Patient protection (e.g., female pelvis)
Film Markers
- Informational Markers = made of metal taken with the x-rays indicate Lt or Rt images
- Mitchell Marker
- BBs in the Markers which indicate upright or recumbent body positioning in images
- Name Blockers = Patient’s and Dr.’s name
- Identification Markers – Type of Study
-Identification Markers– Clinic & Tech (where and who took the images)
Informational Markers
- Provide infrmation about the patient
- Provide information about the doctor and/ or facility
- Identifies side of patient or patient positioning
Mitchel Markers
- Metal markers
- Taped to film cassette (prior to exposure) L or R
- Label anatomical side of patient
- AP/PA and extremeties
- Label side of patient closest to film
- Laterals and Obliques
- Usually contain BBS
- BBS in center of bubble indicate a recumbent body position
- BBS are gravity dependent
- Concave surface- BBs in middle= recumbent; BBs on the bottom = upright or other
Markers
Markers may also identify:
- Type of study
- Patient positioning
- Technologist
- Facility
- Weight bearing
- Traction Position etc.
- Position of objective ER, MR, LR etc.
- Cervical Spine= Always AP view upright
Warning!
As a general rule:
Without a marker, you cannot identify which side of the patient is the left and which is the right!
Name Blocker
Usually on a sticker or exposed on the film will contain:
- Patients Name
- Patients Gender
- Patients Age
- Doctors Name
- Facility where films were taken
- Date of study
Viewing a Radiograph
-Composite shadowgram
- Profiles/Shadows/Outlines are detailed
- Structures add contrasting densities
- Superimposition and object orientation confuse the picture
- Think 3-D (Identify the object not the person being x-ray’d
- What is in profile and what is seen on end
The Whole Picture
-An X-ray beam penetrates the entire object through which it passes, creating and image of all the various aspects of that object and all objects that lie in the path of the beam.
Composite Shadowgram
- Squire explains radiographic images as a “composite shadowgram” that represent the sum of the densities interposed between the beam source and the film.
- Final image involves superimposition of objects and orientation of objects
Projection
- The beam travels some distance from the object it strikes until it reaches the film. The orientation of the beam-object-film will affect the location of shadows.
- If you face the sun your shadow will be behind you. If the sun is behind you, your shadow is in front of you.
Beam 1 Beam 2 Beam 3
A
B
C
Film__________________
A B c All c B A <—- more to edge of film
Image 3 Image 2 Image 1
Superimpositon
- Radiographic images of objects that lie in the same path of the x-ray beam will be superimposed in each other (on top of each other)
- The radiograph image is a representation of all the densities superimposed on one another. It is not possible to distinguish each density separate from the other densities
- The superimposition of objects is affected by their anatomical relationships.
- Superimposition is not affected by the order (AP vs PA) that the beam strikes the objects.
- Projection and superimposition are affected by the objects relationships to the central ray
- The central ray is simply the most central portion of the beam
- Ex. if the center beam, of the cone shaped beam, travels through the joint space then the true measure of the joint space will reflect on the film.
- If the angled part of the beam, of the cone shaped beam, travels through the joint space then a false measurement of the joint space will reflect on the film.
Distortion
- If the central part of the beam is angled to the object then the image will appear larger on the film than the actual size of the object.
- A “skycam view” = “Bird’s eye view” may make the image inidentifiable
Magnification
- If an object is closer to the source of the beam it will appear as a larger image on the film (Object Image Distance, OID)
- Transversly: if the same size object is further from the source of the beam it will appear as a smaller image on the film
Object size = Image size x Corection Factor
O= I x CF
CF = D (total distance of beam to film) x d (object distance from film) / D (total distance of beam to film)
Collimation
- Shutters (barn door) block periperal protions of beam ie narrows beam before it strikes image to reduce patient exposure
- Limits area exposed to beam; uses most central protion of beam.
- Light indicates the area the beam will strike directly
- Limits size of x-ray beam feild
- Use smallest area possible for good x-ray
- Decreases scatter radiation
- Decreases patient dose
- Achieves better detail
- Tube light simulates x-ray beam
- In Oregon-must show collimation on 3 sides
Bone: General Properties and Architecture
Compact Bone
-Compact Bone = Cortex
- Outer shell of bone
- Encloses the medullary bone
- Covered by periosteum
- Homogenous density of x-ray
Spongy / Cancellous Bone
- Spongy Bone = Cancellous Bone
- The network of trabeculae in the medullary portion of the bone
Periosteum
- The fibrous outer layer of bone
- Responsible for membranous bone formation, attachment of tendons and ligaments, and contains vascular supplies for the bone
- Not present on suraface of intra-articular bone (follows synovial membrane with the capsule)
- Normal periosteum not distinguishable on a radiograph
Categories of Bones
-Flat Bones: ribs, sternum scapula, cranium. iliac wing
-Short Bones/ Square Bones: carpals, tarsals, vertebrae
-Sesamoid Bones: embedded in tendons
-Long /Tubular Bones: femur, humerous, etc.
Long/Tubular Bones
-Epiphysis: The articular end of the bone; separarted from the rest of the bone by the physis (growth plate)
-Metaphysis: The tapering portion between the physis and the shaft (diaphysis); the site of growth and greatest metabolic activity
-Diaphysis: The shaft of bone; medullary cavity filled with red marrow
Apophyses
- Tuberosities, Tubercles, Trochanters, Processes, Spines/;Spinouses, etc.
- Osseous projections from the general shape of the bone which develop to support and in response to the forces at major ligament and tendon insertions and at articular surfaces
-Apophysis: Lateral superior of the femur ie greater trochantor
-Epiphysis: Medial superior of the femur ie. Head and Medial epicondyle
-Cortex: ie, denser part of shaft of femur
-Diaphysis: ie. shaft of femur
- Metaphysis: ie. superior part of femur anterior of head and superior to lthe distal end ie. the epicondyles
- Medullary Cavity: The core of the bone
- Trabecular Bone: the “spongy” part of boneat proximal and distal parts of bone.
Reading Films
- Differentiate normal from abnormal
- Localize abnormality
- Describe abnormality
- List perinent postives/pertinent negatives
- Give an impression of clinical significance
Radiographic Evaluation
-Have a systematic approach
- Have a system
- Use the system every time
- Be thorough
Extent of Evaluation
- You are legally responsible for ALL information
- Evaluate the whole x-ray
- Evaluate for ALL pathologies/conditions
- Read ALL the information on the film
- Read to the edges of the film
Method of Evaluation
-The search pattern often employed is the ABCs
- Alignment
- Bone
- Cartilage
- Soft Tissues
Alignment
-Evaluate structures
- Spatial relationship of structures
- Look for offset of articulate margins
- Evaluate structures for proper postion
- Make pertinent specific measurements (e.g., lines of mensuration, joint spaces, structural size, etc.)
Bone
-Evaluate all visualized bones for:
- Shape
- Size
- Cortical integrity
- Internal matrix (trabeculation)
- Radiographic density
- Specific structures
Cartilage
-Evaluate joint spaces:
- Joint shape
- Joint size
- Radiographic density
Soft Tissues
-Evaluate all soft tissues:
- Shape
- Size
- Position
- Radiographic density
Search Pattern
- The components of the ABCs are specific for each region of the body
- It is important to know which structures are most readily visualized on which particular projections / veiws
-Know your ABCs for each region
Steps in Evaluation
- Identify the study
- Identify the informational markers
- Note collimation, shielding and artifacts (if any)
- Note the technical quality of the film
- Evaluate anatomy using the ABCs search pattern
Step 1: The Study
-Identify the study:
- Anatomy visulaized
- Number of films
- Projections
- Use of contrast media
Step 2: The Information
- Identify informational markers:
- Name blocker
- Patient age
- Patient gender
- Date(s) of study
-Qualification of study
- Patient postion
- Type of study
-Note timing of certain studies
Step 3: Collimation
- Identify and take note of :
- Collimation
- Sheilding
- Artifacts
Step 4: Film Qualitly
-Evaluate the technical quality of the film:
- Diagnostic quality?
- Proper Positioning?
- Entire area visualized?
Step 5: Use a Search Pattern
- Evaluate the entire film
- Use a systematic approach
Normal vs Abnormal?
- Each person is a unique anatomical entity
- Anatomical variations exist that are normal and abnormal
- Pathology often alters anatomical structures and may be present with no radiographically visible alterations in anatomical strutures
Normal Anatomy
- The first step in recognizing abnormalities on radiographs is to know the appearance of normal radiographic anatomy
- KNOW YOUR GROSS ANATOMY
- Get experience reading normal radiographs
Abnormal Anatomy
-Know your pathology
- Learn patient’s health history
- Identify patient’s clinical presentation
- Put it all together
- Radiographs are not isolated
- Remember that the radiograph represents a patient
Method of Evaluation
- Compare one side to the other
- Compare one level to adjacent levels (spaces, curves, continium, normalities)
- Keep in mind the gradual changes in vertebrae from cervical to thoracic to lumbar to sacral
- Look @ nothing over 2 yrs old x-rays→ 7 yrs old –NO WAY
- 1 yr only if symptoms are the same but still “Iffy”
Cervical Spine
-Minimal diagnostic series?
- Neutral Lateral
- APLC (AP lower cervical)
- APOM (AP open mouth)
- Anatomy
- Roentgenometrics- Lines & Measurements
- Variant- Normalities
Lateral Cervical
- Upright
- Shoulder to film
- Indicate L or R
- Patient (coronal plane) perpendicular to film
- Cervical spine in neutral positon
- Beam perpendicular to film
- Want to see– Seven cervical vertebrae; base of skull (sella turcia)
- Head and neck in neutral positon
Hard palate level with horizontal (lower film edge)
-Good superimposition of R and L articular pillars = no rotation
Lateral Cervical ABCs–A
-Alignment
- Neutral positon
- Specific relationships
- Measurments
-Assess for Neutral Positon
- Use hard palate as reference
- Parallel to floor
- Shows neutral postion
- No flexion
- No extension
-Assess for Rotation
- Posterior Body Margin
- Angle of the Mandible
- Facets superimposed
Lateral Cervical ABCS—B
Bone
- Cortical margins
- Trabeculae patterns
- Shape of bones
- Size of bones
- Density of bones
- Specific Structures
Bone–Cortical Margins
- Cortical margins–lucidity and translucent
- Cortices intact
- Normal Thickness
- Decreased thickness
- Increased thickness
Bone–Trabecular Pattern
-Normal trabeculea –(small little white lines)
- Absent trabeculae
- Thinned trabeculae
- Thickened trabeculae
Bones–Shape of Bones
-Normal Shape–(shape they’re suspposed to be)
- Abormal shape but normal variant
- Abnormal shape due to pathology
Bones– Size of Bones
-Normal Size–(small vs larger)
- Abnormal size but normal variant
- Abnormal size due to pathology
Density of Bones
-Normal Density
- Decreased Density
- Increased Density
- Changes generalized
- Changes localized
Specific Structures- Regional
Responsible for ALL on film:
- Skull
- Face
- Jaw
- Atlas/ C1
- Axis/ C2
- C3-C7
- Soft Tissues of Neck
- Thorax
Lateral Cervical ABCS–C
-Cartilage
- Intervertebral Disc Spaces
- Zygapophyseal/Facet Joint Spaces
- Uncovertebral Joint Spaces (poorly visualized)
- Temporomandibular Joint Spaces
Assess 5 Cervical Lines
- Prevertebral Tissue
- Anterior Body Line-of bodies & V. Canal
- Posterior Body Line–of V. Canal
- Spinolaminal Junction-line of SPs & posterior of VC
- Spinous Process Interspacing
- Prevertebral Soft Tissue LIne
- Retropharyngeal
- Down to C2
Retrolaryngeal
C3 to C5
Retrotracheal
C6 and below
Rule of 2s and 6s
- @ C2 < 6mm —from VB to Tissue
- @ C6 < 22 mm–from VB to Tissue
- Anterior Vertebral Bodies
- Smooth Curve – form C1 inferior natural curve
- No interuptions
- Not as sensitive for vertebral displacement as Posterior Vertebral Body Line
- Posterior Vertebral Body Line
- AKA George’s Line
- Smooth Curve-Uninterurupted Line
- Evaluates VB Displacement
- Key Landmarkds
- Superior and Inferior body corners—of VBs
Spinolaminar Junction Line
- Extrapolate line through each spinolaminar junction–(most Ant. points of lines)
- Evalutes for displacemnet
- Spinous Process Interspaces
- Check for equal spacing between adjacent spinous processes of SPS
- Evaluates relative segmental postionting
Atlantodental Interspace
- Space between posterior aspect of C1 anterior tubercle and the anterior aspect of odontoid process
- Normal:
- Adults– < 3mm (ossicfication of bone)
- Children– < 5mm @ 8-10yrs
Dens to Foramen
- Mc Gregor’s Line
- Posterior-superior margin of hard palate to inferior-most surface of the occiput.
Tip of dens: < 10mm above Mc Gregor’s Line
Lateral Cervical ABCs—S
- Pharyngeal Air Shadow
- Laryngeal Air Shadow
- Tracheal Air Shadow
- Note calcificaton of cartilages (cricoid cartilage calcified– never means anything @ anytime in lifetime)
- Posterior Cervical Soft Tissues
- May see a Thyroid Sheild on film used to protect the Thyroid gland
AP Lower Cx
- Structures visualized on AP Cx: Centered @ C4 upwards 15º angle (camera to C4) to veiw C3 to C7
- C3-C7 VBs
- Posterior Elements
- Variable visulization
- SPs and articular pillars most consistent
- Other structures more oblique
- Uncinate processes and uncovertebral joint spaces
- Soft tissues of neck
AP Cervical ABCs– Alignment
- Alignment
- Primarily postural assessment: look at structures compared to midline and for bilateral symmetry
- Tracheal air shadow
- Spinous processes
- Lateral body margins
- Head position
- Vertebral endplates
- Clavicles
-Posterior Ribs –70% have a rib on C7 TPs should point upwards
Trachea
-Tracheal air shadow—see thru SPs
- Should be midline
- Constant diameter
- Laryngeal constriction- narrow when patient is holding their breath, open when patient is breathing
Spinous Processs
- Should be midline
- Form verticlal line–straight line
- Identify each level
- May need to identify one level and count seperately
Pedicles
- Should form verticle lines
- Equidistant from midline
- Count EVERY pedicle
- Not fully visualized
- Cancer likes to go to bone which will hide or make pedicle non-existent
Lateral Body Margins
- Basic line up: May be difficult to visualize due to superimpostion of posterior elements
- Equidistant from midline –uncinate processes bodies
- Vertical lines
Articular Pillars
- Lateral margins–sinusoidal lines of the whole image of spine
- Smooth sinusoidal lines
- Verical orientation
- Equidistant from midline
Head Position
- Level horizontally
- Assess for rotation
- Assess for lateral flexion- use angles of mandibles
Mandible
- Level horizontally: use angles of mandibles
- Not rotated
Vertebral Endplates
- Level horizontally
- Assess for lateral flexion
- Uncinate processes continuous with superior body margin
- Anterior bosy margins have inferior lipping: may give two lines for inferior (anterior and posterior)
Clavicles
- Look different than expected in a AP view
- Equidistant from midline
- Similar horizontal orientation
- Some magnification and distortion
Posterior Rib
- Should be horizontal
- Assess bilaterly
- Symmetrical in spacing and orientation
- Identify rib 1 by indentifying T1: TPS point superiorly (Cx TPs point inferiorly)
AP Cervical ABCs—Bone
- Compare Bones to each other
- Cortical margins
- Internal matrix and trabecular patterns
- Size, shpae, position, of all bones
- Compare structures bilaterally
- Compare structures to levels abouve and below
- Evaluate all osseous structures
Cortical Margins
- Evaluated cortical integrity
- Evaluate cortical thickness
- Should be smooth, even , and uninterupted
Internal matrix and trabeculea
- Evaluate density
- Evaluate definition of trabecular pattern
Size
- Evaluate size of each bone
- Evaluate size in relation to adjacent levels–progressive size
- Vertebrae getr progressively larger as cervical spone transitions into thoracic spine
Shape
- Evaluate shape of bones
- Evaluate shape relative to adjacent levels
Position
- Evaluate positon of all bones
- Evaluate position relative to adjacent bones
- Are changes abrupt or gradual?
- Compare bilaterally
- Evaluate side t side at each level
Osseous Structures
-Evaluate all osseous structures ( mastoid “bubbles”)
AP Lower Cx ABCs– Cartilage
- Intervertebral disc space—joint spaces
- Uncovertebral joint spaces
- Zygapophyseal / Facet joints
AP Lower Cx ABCs– Soft Tissue
- Lateral soft tissues
- Anterior soft tissues
- Calcified thyroid cartilage
- Lung apices ( trachea & lungs start at bottom of rib 1)— C4-C5 –Cricoid, Thyroid cartilage (lamina) seen also vertebral artery.
APOM (AP Open Mouth)
Structures best visualized on APOM:
- C0-C1 articulation
- C1-C2 joint space
- Lateral masses and arches of C1
- TPs of C1
- Odontoid process
- Paraodontoid notches
- Body of C2
- Skull, mandible, and dental structures
APOM ABCs–Alignment
- Base of Occiput and C1
- C1 lateral mass with C2 articular margins
- < 2mm offset
- Pseudosubluxation in children
- Paraodontoid space symmetry (space on either side of dens) in realtion to the condyler joints.
- “X” through the joints (condyler joints)
APOM ABCs—Bone
- Cortices
- Internal Matrix and trabeculation
- Size
- Shape
- Density
- Positoion
- Osseous structures (notice the lines of the anterior and posterior arch of the atlas which will be superimpposed over the dens).
APOM ABCs– Cartilage
- C0-C1 jooint spaces
- C1-C2 facet joint spaces
- Other visualized joints
APOM ABCs—Soft Tissues
- Soft Tissues
- Tongue shadow
- Superimpostion of teeth/dental appliances (over dens)
Flexion and Extension
Additional veiws:
Flexion and extension
- Taken to evaluste relative segmental mobility
- Special attention to atlanto-dental interspaces
- Indirectly evaluate transverse ligament integrity
- Same structures as Neutral Lateral Cx
- Assess 5 Cervical Lines
Cx Flexion and Extension
- Look at chin tuck on flexion
- Assess full extent of global motion
- Assess segmental motion
Cervical Obliques
- View intervertebral foramen (Primary focus)
- Always taken bilaterally
- Indications
- Radicular symptoms
- Suspected dislocation
- Further assessment of posterior elements
- Pedicles, lamina, pillars
Evaluation of Cx Obliques
- IVFs are visible
- Entire cervical spine is visible
Positioning of Obliques
- Right Anterior Oblique (RAO)
- Left Anterior Oblique (LAO)
- Right Posterior Oblique (RPO)
- Left Posterior Oblique (LPO)
Named by what is closest to fim
Orientation of Cervical IVFs
- 45º between sagittal and coronal planes
- 55º in lower Cx
- Oblique orientation
- Oriented “down and out in front”
- Know which IVF it is:
- RPO = LAO = Left IVF
- LPO = RAO = Right IVF
Vertebral Levels
IVFs seen between the vertebrae:
- C2-C3
C3-C4
C4-C5
C5-C6
C6-C7
Structures seen on Cx Oblilques
- Vertebral bodies
- Superior and inferior margins may be poorly visualized (slope posterior-superior to anterior-inferior)
- Pedicles, lamina
- One side profile, opposite side “on end”
- Articular pillars: one side forms IVF; opposite superimposed on vertebral body
- SPs behind spine
- TPs: IVF sode “on end”; opposite in front of spine
Intervertebral Foramen
Borders of the IVF
- Inferior margin of pedicle above
- Superior margin of pedicle below
- Posterior body margin (vertebra above)
- Uncinate process (vertebra below)
- Posterior margin of intervertebral disc
- Superior articular process (vertebra below)
- Gutter of the transverse process
Radiographic Measurements:
Lines, Angles, and Distances→
Cervical Spine→
McGregor’s Line
- Lateral skull/cervical
- Posterior hard palate to most inferior surface of the occipital bone
- Dens should not project more that 8mm above in males, 10mm in females
- Basilar impression (1º-occipitialization, platybasia; 2º-Paget’s dz, osteomalacia, fibrous dysplasia, rheumatoid arthritis) <–diagnosis
Chamberlins’s Line (FYI)
- Lateral skull/cervical
- Posterior hard palate to (posterior foramen magnum-differ from McGregor’s Line)
- Dens should not project above this line (3mm above may be normal; 7mm definitely abnormal)
- Basilar impression (same conditions as for McGregor’s line)–>diagnosis
Macrae’s Line (FYI)
- Lateral skull (no lateral flexion)
- Line from anterior to posterior borders of foramen magnum
- Perpendicular line through odontoid should intersect anterior ¼ of this line: may be indication of craniovertebral dislocation or odontoid fracture
- Inferior margin of occiput should lie at or below line: same significance as McGregor’s and Chamberlain’s
POWER’S INDEX: looking for→
(ANTERIOR ATLANTO-AXIAL DISLOCATION MEASUREMENT) (FYI)
- Lateral cervical spine; lateral skull
- Line from anterior foramen magnum to spinolaminar junction of C1 (B-P; second line from posterior foramen magnum to posterior margin of anterior tubercle (O-A)
- Ratio of B-P: O-A < 1 normal
- >/= 1 probably anterior atlanto-occipital diaslocation→diagnosis
ADI Atlantodental Interval
Measure in Neutral Pos. 1st
- Lateral cervical spine
- nuetral, flexion, extension
- Midpoint of posterior margin of anterior tubercle of C1 to nearest point on anterior margin of odontoid process
- Normal
- = 3mm in an adult
- = 5mm in a child
Indicates rupture of transverse ligament; C1-C2 instability (Do not adjust unless known about upper C instability)
George’s Line: Posterior Body Margin Line
- Lateral spine (Cx, Tx, Lx)
- neutral, flexion, extension
- A line drawn along the posterior aspect of the vertebral bodies, extrapolate across disc space
- Relationship of poteroinferior body corner to subjacent posterosuperior body corner
- Offset indicates antero-or retrolisthesis-posterior to one below (compare to eachother) “whiplash”
- Translation >/= 4mm between two views may indicate instability
Spinolaminar Junction Line: Posterior Cervical Line
- Lateral spine (CX,Tx, Lx)
- neutral, flexion, extension
- The most anterior point of the spinolaminar juction is identified at each level: these points are conneted
- Offset indicates antero- or retrolisthesis ADI→diagnosis
Sagittal Dimension of the Cervical Spinal Canal
- Lateral cervical Posterior surface of midvertebral body to spinolaminar junction
- Minimums: (Varies by level)
- C1 - 16mm
- C2 - 14mm
- C3 - 13mm
- C4-C7 -12mm
-Indicator of canal stenosis; Further evaluate with CT or MRI→diagnosis
Atlantoaxial Alignment
- AP open mouth
- Lateral mass of atlas should not overhang lateral margin of C2 superior facet (>1mm)
- (>/m 2mm) overhang suspect Jefferson’s fracture, odontoid fracture, alar ligament instability of rotatory atlantoaxial instability
- May be normal in children 4 years of age or younger
- “X” drawn with lines form one C0-C1 joint through opposite C1-C2 gives general idea of symmetry, rotation at C1-C2
Coronal Dimensions of the Cervical Spine
Interpediculate Distance
- Measure shortest distance between inner cortical margins of pedicles at given segment; vary by spinal level; evaluates for stenosis
- See chart page 168, Essentials of Skeletal Radiology
Cervical Gravity Line
- Lateral neutral cervical
- Verticla line drawn through the apex of the odontiod 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 flexion/extension can also assess stress focus
Angle of Cervical Curve
- Lateral cervical
- Two lines ae drawn, one through and parallel to the inferior endplate of the seventh cervica body, the other through the midpoints of the anterior and posterior tubercles of the atlas
- Construct perpendiculars and measure the angle. Normally 35º-45º ( average 40º)
- Lack of lordosis may idicate trauma, muscle spasm, or DJD; 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
- 6mm at C2 (retropharyngeal interspace/RPI)
-20mm at C6 (retrotracheal interspace/RTI)
-Increased w/ any ST mass (hematoma, abscess, tumor)
Functional Evaluation for Instability
- Lateral cervical in neutral, flexion and extension
- Template is drawn over cervical vertebral bodies and SPs in neutral
- >/= 4mm translation at posterior body margin line suggest instability
- Sagittal rotation assessd by Henderson-Dorman or Penning method
