A list of normal radiological reference values is as follows:

• adrenal gland: <1 cm thick, 4-6 cm length
• abdominal aorta: <3 cm diameter
• appendix: on CT <6 mm calibre
• atlantodental distance
  • adults: <3 mm
  • children: <5 mm
• azygos vein: on erect chest x-ray <10 mm diameter
• bladder wall: <3 mm (well-distended state)
• Boehler angle: 20-40^o
• calcaneal pitch: <20^o
• capitolunate angle: <30^o
• carinal angle: <60-70^o
• colon:
  • lumen: <5 cm
  • wall: <3 mm
• common bile duct
  • <7 mm and add 1 mm for each decade over age of 60 years
  • up to 10 mm postcholecystectomy
• diaphragm (right dome is usually higher than left)
  • difference between right and left: <3 cm
• endometrial thickness
  • premenopausal: 3-15 mm
  • postmenopausal: <6 mm
• oesophagus wall: <3 mm (with distended lumen)
• gallbladder wall: <3 mm (well-distended)
• heart (cardiothoracic ratio): <0.55
• hepatic vein: 5.6 to 6.2 mm
• inferior vena cava: 12 to 17 mm
  • dilated when >17-25 mm
• internal carotid artery:
  • peak systolic velocity (PSV): <125 cm/s
  • end-diastolic velocity (EDV): <40 cm/s
• kidneys : 8-10 cm x 4-6 cm
• liver span: <15 cm
• lymph nodes (all measurements are of short axis)
  • mediastinal: <10 mm
  • retrocrural: <6 mm
  • hepatogastric ligament: < 8 mm
  • porta hepatis: <6 mm
  • coeliac and mesenteric (preaortic), pancreaticoduodenal, perisplenic, mesenteric, retroperitoneal: <10 mm in short axis
  • pelvic: < 15 mm
• ovarian follicle: <2.5-3 cm
• ovaries: volume
  • premenopausal: <10 mL
  • postmenopausal: <8 mL
• paraspinal lines:
  • left: <10 mm wide
  • right: <3 mm wide
• paratracheal stripe: <5 mm
• pancreatic duct
  • head: 3.5 mm
  • body: 2.5 mm
  • tail: 1.5 mm
• pituitary gland - maximal height (see Elster's rule)
  • children <12 years: 6 mm
  • puberty: 10 mm
  • young adult
    • male: 8 mm
    • female: 9 mm
    • pregnancy: 12 mm
  • adult >50 years: gradual decrease in size
• portal vein: <13 mm diameter
• prevertebral soft tissue thickness (lateral c-spine x-ray):
  • 7 mm at C2
  • 2 cm at C7
  • easiest way to remember is "7 at 2 and 2 at 7" 
• prostate volume: <25-30 mL
• pulmonary artery
  • descending branch of right pulmonary artery:
    • <16 mm (males)
    • <15 mm (females)
  • main pulmonary artery: <29 mm
• rectum: wall thickness <5 mm
• renal arteries: PSV 60-100 cm/sec
• scapholunate angle: 30-60^o
• small bowel
  • lumen: <3 cm
  • wall: <3 mm
• spleen: <12 cm (maximal dimension: any orientation)
• splenic vein: <10 mm diameter
• testis
  • vein: <2 mm diameter
  • size: <5 x 3 x 3 cm (volume: 12.5-19 mL)
• thyroid: <2 cm anteroposterior dimension
• trachea
  • chest x-ray:
    • <25 mm (males)
    • <21 mm (females)
• ureter: 30-34 cm long, 2-8 mm diameter
• uterus
  • prepubescent: length ≤3 cm, diameter ~1 cm
  • nulliparous: length ≤8 cm, diameter ~8 cm
  • multiparous: length ≤9.5 cm, diameter ~5.5 cm
  • postmenopausal: length ≤6 cm, diameter ~2 cm
• uterine cervix: diameter <3 cm

See also

• sonographic values in obstetrics and gynaecology