| Abduction |
Movement away from the midline. |
| Acetabulum |
Hip socket formed by the ilium, ischium, and pubis. |
| Acromion |
Bony projection of the scapula forming the top of the shoulder. |
| Adduction |
Movement toward the midline. |
| Amphiarthrodial Joint |
Slightly movable joint, such as the sacroiliac joint. |
| Artifact |
Unwanted image feature that can obscure anatomy or mimic pathology. |
| Axial |
Beam angled along the long axis of the body or part. |
| Bankart Lesion |
Injury to the anterior glenoid labrum due to dislocation. |
| Beam Filtration |
Removes low-energy photons to improve image quality and reduce patient dose. |
| Ball-and-Socket Joint |
Synovial joint allowing movement in all directions (e.g., shoulder, hip). |
| Calibration Marker |
Used to scale measurements accurately in digital imaging. |
| Carina |
Ridge at the tracheal bifurcation; used to verify ET tube placement. |
| Cephalad |
Beam angled toward the head. |
| Closed Joint Space |
Suggests poor positioning or incorrect beam angle. |
| Collimation |
Restricts the x-ray beam to the area of interest. |
| Condyle |
Rounded articular surface at the end of a bone (e.g., femoral condyle). |
| Contrast |
Difference in density between adjacent areas on a radiograph. |
| Coracoid Process |
Hook-like projection from the scapula; anterior shoulder landmark. |
| Costophrenic Angle |
Angle between diaphragm and rib cage; blunting may indicate effusion. |
| Cross-Table |
Horizontal beam projection used in trauma when the patient cannot be moved. |
| Decubitus |
Patient lying down with a horizontal beam; used to detect air-fluid levels. |
| Diarthrodial Joint |
Freely movable synovial joint. |
| Dorsiflexion |
Flexing the foot upward toward the shin. |
| Epicondyle |
Projection above a condyle; used for rotation checks in positioning. |
| Exposure Index (EI) |
Numeric value indicating receptor exposure level. |
| Fat Pad |
Radiolucent area that can indicate joint effusion. |
| Flexion |
Bending a joint to decrease the angle. |
| Foreshortening |
Distortion that makes anatomy appear shorter than it is. |
| Gliding Joint |
Synovial joint allowing sliding movement (e.g., AC joint). |
| Grid |
Device that reduces scatter radiation and improves contrast. |
| Hill-Sachs Lesion |
Compression fracture of the humeral head from dislocation. |
| Hinge Joint |
Synovial joint allowing flexion and extension (e.g., elbow, knee). |
| Impingement |
Compression of soft tissue structures, often in the shoulder. |
| Intercondylar Fossa |
Depression between femoral condyles; seen in tunnel views. |
| Joint Mice |
Loose bodies within a joint space. |
| Jugular Notch |
Superior border of the manubrium; landmark for chest centering. |
| Lateral |
Image taken from the side; used to show depth and displacement. |
| Manubrium |
Upper portion of the sternum. |
| Malleolus |
Bony prominence on each side of the ankle (medial/lateral). |
| Magnification Marker |
Reference object used to calibrate size in orthopedic imaging. |
| Mediastinum |
Central thoracic compartment containing heart, trachea, and vessels. |
| Mortise |
Ankle joint space formed by tibia, fibula, and talus. |
| Motion Blur |
Loss of image sharpness due to patient movement. |
| Neutral |
Anatomical position without rotation or flexion. |
| Noise |
Random variation in image brightness or density that can obscure detail. |
| Oblique |
Body or part is rotated to visualize anatomy not seen in AP or lateral views. |
| Open Joint Space |
Indicates proper positioning and beam alignment. |
| Pars Interarticularis |
Part of vertebra between superior and inferior articular processes. |
| Patellar Apex/Base |
Inferior (apex) and superior (base) portions of the patella. |
| Phototime |
Automatic exposure control based on image brightness. |
| Pivot Joint |
Synovial joint allowing rotation (e.g., radioulnar joints). |
| Plantar Flexion |
Pointing the foot downward. |
| Recumbent |
General term for lying down (supine, prone, or lateral). |
| Receptor |
The device that captures the x-ray image, such as a digital detector or film. |
| Resolution |
The ability of an imaging system to distinguish small details. |
| Rotation |
Misalignment of anatomy due to improper positioning. |
| Saddle Joint |
Synovial joint allowing flexion, extension, abduction, and adduction (e.g., thumb CMC). |
| Scatter Radiation |
Radiation that has changed direction after interacting with matter. |
| Signal-to-Noise Ratio (SNR) |
A measure of image clarity; higher SNR means better image quality. |
| Sinus Tarsi |
Depression on the lateral foot between talus and calcaneus. |
| Stitching |
Combining multiple images into one long-length view. |
| Superimposition |
Overlapping of anatomical structures on an image. |
| Supine |
Patient lying on their back, facing upward. |
| Tangential |
Beam skims a surface to profile a structure. |
| Trabecular Detail |
Fine internal bone pattern visible on radiographs. |
| Tuberosity |
Large rounded projection for muscle attachment (e.g., tibial tuberosity). |
| Valsalva Maneuver |
Forced exhalation against a closed airway; used in GI/GU studies. |
| Weight-Bearing |
Imaging performed while the patient is standing to assess joint alignment under load. |
| Zygapophyseal Joint |
Facet joint between vertebrae; seen in oblique spine views. |
