KUB

X-Ray

Seen in ~70–80%

Normal Value

Loss of outline may suggest obscuration by bowel gas, fat loss, or pathology.

9–12 cm (right slightly lower than left)

Normal Value

Not directly measured on plain film; better on USG. Large kidney = hydronephrosis, tumor; small = CKD.

Parallel to psoas margin

Normal Value

Malrotation suggested if deviated.

Normally not seen

Normal Value

Seen if calcified stones or gas (emphysematous ureter).

Absent

Normal Value

Abnormal: emphysematous cystitis, bladder stones.

Phleboliths (round with central lucency)

Normal Value

Must be differentiated from ureteric calculi.

Renal stones, ureteric stones, bladder stones

Normal Value

Radiopaque calculi: calcium oxalate, phosphate, struvite. Radiolucent: uric acid, cystine (not visible).

Stomach + scattered bowel gas

Normal Value

Diffuse gaseous distension obscuring renal shadows may indicate ileus or obstruction.

Measurement	Normal Value	Comments
Renal Outline Visibility	Seen in ~70–80%	Loss of outline may suggest obscuration by bowel gas, fat loss, or pathology.
Renal Length (approx, adult)	9–12 cm (right slightly lower than left)	Not directly measured on plain film; better on USG. Large kidney = hydronephrosis, tumor; small = CKD.
Renal Axis	Parallel to psoas margin	Malrotation suggested if deviated.
Ureter Visibility	Normally not seen	Seen if calcified stones or gas (emphysematous ureter).
Bladder Gas / Calcifications	Absent	Abnormal: emphysematous cystitis, bladder stones.
Physiological Calcifications	Phleboliths (round with central lucency)	Must be differentiated from ureteric calculi.
Pathological Calcifications	Renal stones, ureteric stones, bladder stones	Radiopaque calculi: calcium oxalate, phosphate, struvite. Radiolucent: uric acid, cystine (not visible).
Bowel Gas Pattern (KUB context)	Stomach + scattered bowel gas	Diffuse gaseous distension obscuring renal shadows may indicate ileus or obstruction.