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RAD141-Chap 1b
RAD141-Chap 1B - Positioning Terminology
Question | Answer |
---|---|
What does radiographic positioning refer to? | the study of patient positioning to radiographically demonstrate or visualize specific body parts on image receptors (IRs) |
What is a radiograph? | a film or other base material containing a processed image of an anatomic part of a patient as produced by action of x-rays on an IR |
What is the difference between a radiograph and an x-ray film? | x-ray film refers just to the physical piece of material on which a radiographic image is exposed; radiograph includes the film and the image |
What are radiographic images? | a representation of the patient's anatomic structures, obtained and viewed as hardcopy (radiographs) or as digital images (soft-copy) |
What are the 5 general functions of a radiographic exam? | 1) positioning of the body part & CR alignment; 2) selection of radiation protection measures; 3) selection of exposure factors on the control panel; 4) patient instructions relating to respiration & initiation of the exposure; 5) processing of the IR |
What are the 4 common planes used in radiography? | sagittal (left/right parts), coronal (anterior & posterior parts), horizontial (axial) (any transverse plane passing at right angles to the longitudinal plane), oblique (either longitudinal or transverse, not parallel to sagittal, coronal, or horizontal |
What are sections? What are the 2 main types of sections? | "cuts" or "slice" images of body parts; longitudinal sections (lengthwise) in the sagittal, coronal, or oblique planes; transverse or axial sections (cross-sections) -> at right angles along any point of the longitudinal axis |
What are the 3 common orientations or views used in CT and MRI images? | sagittal, coronal and axial |
What are the 2 planes of the skull? | base plane (aka anthropologic plane or Frankfort horizontal plane) and the occlusal plane |
How is the base plane of the skull formed? | it is a precise transverse plane formed by connecting the lines from the infraorbital margins (inferior edge of bony orbits) to superior margins of the external auditory meatus (EAM) |
How is the anthropologic plane used? | in orthodontics and cranial topography to measure and locate specific cranial points or structures |
How is the occlusal plane formed? | it is a horizontal plane formed by the biting surfaces of the upper and lower teeth w/jaws closed; used as a reference plane of the head for dental & skull radiography |
What is a projection? | a positioning term that describes the direction or path of the CR of the x-ray beam as it passes thru the patient, projecting an image onto the IR |
Describe the CR position in a true posteroanterior projection | In a true PA, the CR is perpendicular to the coronal body plane and parallel to the sagittal plane (unless some qualifying oblique or rotational term is used to indicate otherwise) |
What is an AP oblique projection? | an AP projection of the upper or lower limb that is obliqued or rotated; it is not a true AP and must also include a qualifying term indicating which way it is rotated (such as medial or lateral rotation) |
What are mediolateral and lateromedial projections? | lateral projections described by the path of the CR; determining the medial and lateral sides is based on the patient in the anatomic position |
What are the 8 most commonly used general body positions in radiography? | supine, prone, erect (standing or sitting), recumbent, Trendelenberg, Fowler's position, Sim's position, and Lithotomy position |
What are the 3 recumbent positions? | dorsal recumbent, ventral recumbent, and lateral recumbent (right or left lateral) |
What is the Trendelenburg position? | a recumbent position with the whole body tilted so that the head is lower than the feet |
What is Fowler's position? | a recumbent position with the body tilted so that the head is higher than the feet |
What is Sim's position? | a recumbent oblique position w/patient lying on the left anterior side, right knee and thigh flexed, and with the left arm extended down behind the back |
What is the lihtotomy position? | a recumbent (supine) position with knees and hip flexed and thighgs abducted and rotated externally, supported by ankle supports |
Besides body position, how else is the term position used in radiography? | it can also refer to a specific body position described by the body part closest to the IR (obliques and laterals) or by the surface on which the patient is lying (decubitus) |
What is the lateral position? | side view; specific lateral positions described by the part closest to the IR, or that body part from which the CR exits; a true lateral must be perpendicular to a true AP or PA projection, otherwise, it's an oblique position |
What is an oblique position? | an angled position in which neither the sagittal nor the coronal body plane is perpendicular to the IR; described by the part closest to the IR |
What are the 4 oblique positions? | left and right posterior obliue (LPR, RPO); right and left anterior oblique (RAO, LAO) |
How are obliques of upper and lower limbs further qualified? | ther are correctly described as AP or PA obliques, but use either medial or lateral rotation as a qualifier |
What is a decubitus position? Why are they important? | lying down; lie on a horizontal surface; important for detect air-fluid levels or free air in a body cavity |
How should the x-ray beam be positioned with a decubitus position? | the x-ray beam is always horizontal |
What are the 4 decubitus positions? | right or left lateral, dorsal, ventral |
How should right or left lateral decubitus positions be qualified? | with AP or PA projection |
What is an axial projection? | describes any angle of the CR more than 10 deg along the long axis of the body |
What are examples of inferosuperior projections? Superoinferior projections? | inferosuperior => shoulder and hip; superoinferior -> special nasal bones projection |
What is a tangential projection? What are some examples? | describes a projection that merely skims a body part to project that part into profile and away from other body structures; ex: zygomatic arch projection, trauma skull projection (for demonstrating depressed skull fracture), special projection of patella |
What is an AP axial projection - lordotic projection? | a specific AP chest projection for demonstrating the apices of the lungs; aka apical lordotic projection; the long axis is angle rather than the CR |
What is a transthoracic lateral projection? | a lateral projection through the thorax; requires a qualifiying positioning term (right or left lateral position) to indicate which shoulder |
What are dosoplantar & plantodorsal projections? | dorsoplantar (DP) -> AP projection of the foot; axial plantodorsal (PD) is PA projection of the foot and is angled |
What are parietoacanthial and acanthioparietal projections? | parietoacanthial -> the CR enters at the cranial parietal bone & exits at the acanthion (junction of nose & upper lip); opposite is acanthioparietal; aka PA Waters and AP reverse Waters methods (for visualizing facial bones) |
What are the submentovertex (SMV) and verticosubmental (VSM) projections? | submentovertex -> for the skull & mandible; CR enters below the chin (mentum) & exits at the vertex (top of skull); verticosubmental projection, less common -> CR enters at top of skull and exits from the mandible |
What are the 3 terms describing curvature of the spine? | lordosis -> "swayback"; kyphosis -> "humpback"; scoliosis -> lateral curvature of the spine |
What is hyperextension? What is abnormal hyperextension? | extending a joint beyond the straight or neutral position; abnormal hyperextension for elbows or knees is extension beyond the neutral position -> not a natural movement for these joints and results in injury or trauma |
What is flexion, extension, and hyperextension of the spine? | flexion is bending forward; extension is returning to the straight (neutral) position; hyperextension is a backward bending |
What is normal hyperextension of the wrist? | normal hyperextension of the wrist is when the wrist is extended beyond the neutral position (aka dorsiflexion) -> used for viewing the carpal canal or carpal tunnel view of the carpals |
What is acute flexion of the wrist? | a full flexion of the wrist; required for a special tangential projection for a carpal bridge view of the posterior aspect of the wrist |
What terms are used to describe "lateral flexion" of the wrist? | ulnar and radial deviation of the wrist; deviation means "to turn aside" |
What is eversion and inversion? | eversion => outward stress movement of the foot @ the ankle; inversion -> inward stress movement of the foot, as applied to the foot, WITHOUT ROTATION of the leg |
What do the terms valgus and varus describe? | valgus -> bending of the part outward (away from) the midline -> eversion stress of the ankle; varus ("knock kneed"), bending of a part inward, toward the midline -> inversion stress of the ankle |
What are medial and lateral rotation? | medial rotation is a rotation or turning of a body part, moving the anterior aspect of the part towrd the inside (or median) plane; lateral rotation is a rotation of an anterior body part toward the outside (away from the median plane) |
What is protraction and retraction? | protraction is a movement forward from a normal position; retraction is a movement backward, or the condition of being drawn back; ex: protraction is moving the jaw or shoulders forward; retraction is the opposite |
What is elevation and depression? | elevation is a lifting, raising, or moving of a part superiorly; depression is a letting down, lowering, or moving of a part inferiorly; ex: raising shoulders is elevation; depressing the shoulders is lowering them |
What is rotation vs. tilt? | rotation is to turn or rotate a body part on its axis; tilt is a slanting or tilting movement with respect to the long axis |