Positioning & Rotation
This projection of the chest should show equal distance from the medial clavicles to the spine.
PA Chest
Explanation:
Equal distance from the medial clavicles to the spine checks for chest rotation.
This controls the quantity of x-ray photons.
mAs (milliampere-seconds)
Explanation:
mAs mainly controls photon quantity, receptor exposure, and image noise.
On a PA chest, this structure should be centered and not cut off inferiorly.
Costophrenic Angles
Explanation:
PA chest must include apices through costophrenic angles.
The petrous ridges are part of this bone.
Temporal Bone
Explanation:
The petrous ridges/pyramids are dense portions of the temporal bones.
This fracture occurs at the distal radius with posterior displacement.
Colles Fracture
Explanation:
Distal radius fracture with posterior/dorsal displacement. Dinner-fork deformity.
On a lateral knee, the femoral condyles should be mostly this.
Superimposed
Explanation:
A true lateral knee should show the femoral condyles nearly superimposed.
Increasing this improves beam penetration and image receptor exposure.
kVp (Kilovoltage Peak)
Explanation:
kVp controls beam energy/penetration and affects contrast.
If the the top of the lungs are clipped on a chest x-ray, the technologist failed to include this anatomy.
Lung Apices
Explanation:
Clipping apices means the top of the lungs was not included.
The olecranon process belongs to this bone.
Ulna
Explanation:
The olecranon is the proximal posterior projection of the ulna.
This condition causes increased lung radiolucency and flattened diaphragms.
Emphysema/COPD
Explanation:
Hyperinflation, increased radiolucency, and flattened diaphragms.
For an AP oblique cervical spine, this set of foramina is demonstrated.
Foramina farther from the IR
Explanation:
AP oblique cervical spine demonstrates the opposite-side intervertebral foramina.
The 15% rule says increasing kVp by 15% has roughly the same exposure effect as doing this to mAs.
Doubling mAs
Explanation:
A 15% increase in kVp is roughly equivalent to doubling mAs in receptor exposure.
A lateral wrist should show superimposition of these three structures.
Distal radius, distal ulna, and proximal metacarpals/carpals.
Explanation:
A true lateral wrist should show superimposition of the distal radius/ulna region and metacarpals. The pisiform should project over the scaphoid/triquetrum area depending on exact positioning.
The intervertebral foramina are best seen on this routine projection of the lumbar spine.
Lateral Lumbar Spine
Explanation:
Lumbar intervertebral foramina are demonstrated on lateral views.
In additive pathology, the part generally appears more this on the image.
Radiopaque/White
Explanation:
Additive pathology adds density, so it tends to look whiter.
On oblique spine imaging, the side closest to the IR is generally the side being demonstrated for this region of the spine.
Lumbar Spine
Explanation:
Lumbar obliques usually demonstrate the zygapophyseal joints closest to the IR.
Think: Downside = Lumbar.
A grid is mainly used to reduce this type of radiation.
Scatter Radiation
Explanation:
Grids absorb scatter before it reaches the IR.
If a lateral elbow is over-rotated, these structures will not be properly superimposed.
Humeral Epicondyles
Explanation:
A true lateral elbow should show superimposed epicondyles.
The zygapophyseal joints are formed by these parts of adjacent vertebrae.
Superior and Inferior Articular Processes
Explanation:
Zygapophyseal joints are facet joints between articular processes.
A fat pad sign at the elbow may indicate an occult fracture of this bone.
Radial Head
Explanation:
Elbow fat pad sign often suggests occult radial head fracture in adults.
The side of interest is usually placed closest to the IR primarily to reduce this.
Magnification
Explanation:
The side of interest goes closest to the IR to reduce OID and magnification.
Increasing SID while keeping technique unchanged will cause receptor exposure to do this.
Decrease
Explanation:
Increasing SID lowers intensity/receptor exposure due to the inverse square law.
If the sternoclavicular joints are not symmetric on a PA chest, this most likely indicates this positioning error.
Rotation
Explanation:
Asymmetric SC joints on a PA chest usually mean patient rotation.
The pars interarticularis is located between these two vertebral processes.
Superior and Inferior Articular Processes
Explanation:
The pars interarticularis is between the superior and inferior articular processes. Classic “Scotty dog collar” region.
This type of fracture is incomplete and commonly seen in pediatric patients.
Greenstick
Explanation:
Incomplete fracture, common in children because their bones are more flexible.