Reading Pelvis X-rays
Ring vs acetabulum — which series, and which lines must be smooth.
Aug 31, 2026 · 3 refs
At a glance
The AP pelvis is the trauma workhorse. Inlet/outlet are for the ring. Judet views (iliac and obturator obliques) are for the acetabulum. Mixing those series is how people miss an open book or an anterior-column break.
Technique pointers
AP pelvis lines
- Anterior and posterior walls
- Iliopectineal (anterior column) and ilioischial (posterior column)
- Teardrop, Shenton as a cue
- Symphysis, SI joints, both obturator rings
Which extra films
- Inlet / outlet → pelvic ring (AP translation, vertical shear)
- Judet → acetabulum (iliac oblique: anterior wall + posterior column; obturator oblique: posterior wall + anterior column)
A CT does not replace the flat-plate AP in a trauma bay — the gantry can close an open book.
Decision-making
Unstable ring injuries are a binder and resuscitation problem before they are a reconstruction problem. Acetabular wall/column breaks are a different consult. Name the series you used and the line that is broken.
High-yield / exam
- AP pelvis in every trauma activation
- Inlet/outlet for ring; Judet for acetabulum
- Know the six lines on the AP
- CT complements, it does not replace, the flat plate
Questions
Ortho Skills (Real Life) and Boards items for this topic are coming.
Your pearl
One line you’d tell a junior at 2am.
References
- 01
Pelvic fractures: value of plain radiography in early assessment and management
1986 · Clinical Orthopaedics and Related Research · review
Plain films still set the acute ring plan.
- 02
Pelvic ring injuries — evaluation and acute management
2015 · Journal of the American Academy of Orthopaedic Surgeons · review
AP pelvis first; special views match ring vs acetabulum.
- 03
OTA teaching on pelvic ring stability and acute hemorrhage control
2019 · Orthopaedic Trauma Association · guideline
Flat-plate AP for open-book screening; binder when the ring is open.
From the Journal
Films and cases live in the long-form. This Topic is the system.
Related