Thorax and Abdomen
Soft Tissue Neck
Anatomy
Students should be able to identify the following structures on radiographic images:
pharynx, nasopharynx, orophaynx, laryngopharyns, larnyx, epiglottis, trachea, hyoid bone
Routine Projections (ARRT Required)
AP Upper Airway
CR Location & Positioning
- SID: 72 inches (to minimize magnification)
- Patient position: Upright preferred, facing the tube, MSP perpendicular to IR
- Adjustments: Arms at sides; shoulders depressed; chin elevated slightly
- CR: Perpendicular to IR at level of C4 (midway between laryngeal prominence and jugular notch); top of IR at EAM
- Pt. Instructions: Take a deep breath in and hold it (full inspiration fills airway with air)
- Exposure: On full inspiration
Evaluation Criteria
- Coverage (what anatomy must be included and how you verify it’s complete): Air-filled trachea and larynx from nasopharynx through proximal trachea included
- Rotation checks (how symmetry or alignment tells you if positioning is correct): Sternoclavicular joints equidistant from spine (no rotation)
- Motion checks (how sharpness confirms patient cooperation/exposure timing): Sharp soft tissue and bony margins (no swallowing motion)
- Technique checks (what contrast, density, soft tissue visibility, and artifacts to look for): Air column visible through larynx and trachea without over-penetration of cervical spine
- Clinical aim (what contrast, density, soft tissue visibility, and artifacts to look for): Demonstrate airway patency and identify narrowing, obstruction, or foreign body
Lateral Upper Airway
CR Location & Positioning
- SID: 72 inches
- Patient position: Upright preferred, left lateral position, MCP perpendicular to IR
- Adjustments: Shoulders depressed and pulled back; chin elevated slightly to avoid mandible superimposition
- CR: Perpendicular to IR at level of C4; top of IR at EAM
- Pt. Instructions: Quiet inspiration or slow, gentle breathing (especially if epiglottitis suspected)
- Exposure: During inspiration
Evaluation Criteria
- Coverage: Air-filled upper airway from nasopharynx through proximal trachea
- Rotation checks: Cervical vertebrae in true lateral alignment
- Motion checks: Clear, sharp soft tissue outlines without blur
- Technique checks: Mandible and hyoid bone not obscuring airway; tracheal air column visible
- Clinical aim: Demonstrate the epiglottis, larynx, and upper trachea for airway pathology evaluation
Supplemental Projections
Cross-Table Lateral (Trauma or Critical Airway Assessment)
CR Location & Positioning
- SID: 72 inches
- Patient position: Supine or seated if unable to stand; IR placed vertically beside neck
- Adjustments: Do not move neck if trauma suspected; align CR perpendicular to IR at C4
- Pt. Instructions: Quiet breathing if possible; do not disturb patient airway
- Exposure: On inspiration
Evaluation Criteria
- Coverage: Nasopharynx through proximal trachea
- Rotation checks: Posterior cervical spine superimposed
- Motion checks: Air column margins distinct; no swallowing or breathing blur
- Clinical aim: Assess airway patency and epiglottic contour without repositioning unstable patients
Hows & Whys of Soft Tissue Neck Radiography
Anatomy
- How does the air column assist visualization of soft tissue structures?
The air naturally provides negative contrast, outlining the pharynx, larynx, and trachea against soft tissue. - How do the larynx and trachea differ anatomically?
The larynx houses the vocal cords and epiglottis (C3–C6); the trachea begins inferiorly at C6 and extends to the bronchi at T5. - How does the hyoid bone function in airway imaging?
It acts as a landmark at the level of C3–C4 and should not obscure the laryngeal airway if properly positioned.
Positioning
- Why are upright positions preferred for soft tissue neck studies?
Upright positioning prevents airway collapse, reduces aspiration risk, and improves visualization of the air column. - Why is the lateral projection essential for suspected epiglottitis?
The lateral view best demonstrates the swollen epiglottis (“thumb sign”), allowing immediate diagnosis. - Why elevate the chin slightly on both projections?
To prevent superimposition of the mandible over the upper airway. - Why should breathing be quiet or gentle during lateral imaging?
Strained breathing can distort airway size and appearance. - Why is full inspiration required for AP projection?
It expands the tracheal air column, improving visualization of the larynx and subglottic region.
Technique & Image Evaluation
- How do you confirm no rotation on the AP?
Sternoclavicular joints are equidistant from the spine; clavicles symmetrical. - How do you check for motion?
Soft tissue outlines (pharynx, trachea) remain distinct, with no blur from swallowing or respiration. - How do you know exposure factors are correct?
Airway structures visible without overexposure; cervical vertebrae visible but not dominant. - How do you adjust exposure for radiolucent foreign bodies?
Slightly increase mAs to enhance soft tissue contrast and visualize airway shape changes.
Clinical Applications
- Why must technologists exercise caution with suspected epiglottitis?
Epiglottitis can progress rapidly to complete obstruction; patient should remain upright and not be distressed. - Why are both AP and lateral projections required for foreign body localization?
Two orthogonal views allow triangulation of the object’s position within the airway. - Why should technologists avoid supine positioning for airway obstruction?
Supine posture can worsen obstruction by allowing the tongue or epiglottis to fall backward. - Why are soft tissue neck exams critical in pediatrics?
Children are more susceptible to airway narrowing from inflammation or swelling due to smaller airway diameters.
