You are here: >home >outlines >measurements     Thursday, 07-27-2017


Warning!

Please note that in addition to points made in Disclaimer for this website, the following applies to this page. The accuracy of the measurements mentioned on this page can not be guaranteed. Medicine and health care remain arts in addition to sciences. No person or machine with a ruler or other measuring device can substitute for judgement of physician or other health care professional in real world encounters.


Head | Neck | Chest | Abdomen | Pelvis | Male | Female | Pregnancy | LN | MSK
  1. Head
    • Infundibulum thickness (Barkovich, 2005)
      • 2.6 mm
    • Pituitary height in puberty (Barkovich, 2005)
      • Female 10 mm
      • Male 7-8 mm
    • Inner Ear (Neurographics, 2013, 3(3), 144-154)
      • IAC stenosis < 2mm
      • Large vestibular aqueduct > 1.5 mm at its midpoint
  2. Neck
    1. C-spine
      1. Anterior atlanto dental interval:
        1. < 8yrs: 4.5 mm
        2. Adults: 2.5 mm and non change on flex/ext
      2. Spinal stenosis <13mm or Spinal Canal/Vertebral Body <80%
      3. Atlantoccipital Dissociation
        1. BDI and BAI (normal 12 mm)
        2. Power's Ratio (< 1)
        3. Wackenheim's clivus line
      1. Basilar Invagination Lines
        1. McCrae's line
        2. McGregor's line
        3. Chamberlain's line
        4. Ranawat's lines
    2. Thyroid lobes:  4 - 6 x 2 x 2 cm
    3. Thyroid isthmus => 0.4 - 0.6 cm
    4. Carotids
      1. Velocity
        Ratio
        %Stenosis
        >125 cm/s
        2
        >50%
        >230 cm/s 4
        >70%
      2. Use ratios when CCA velocity is < 50 cm/sec or > 100 cm/sec
      3. Bisferiences Waveform
        1. AR
        2. Severe HOCM
      4. Notch in systole in vertebral artery
        1. Presteal waveform
  3. Chest
    1. Trachea
      1. Narrowing of coronal diameter to coronal/sagittal ration of < 0.6 = saber sheath trachea
      2. Right paratracheal stripe should be less than 4 mm.
      3. Tracheoesophageal stripe should be less than 5 mm.
    2. Aorta
      1. Ascending => 4 cm
    3. Pulmonary artery
      1. Main >2.9 cm => pulmonary hypertension
      2. Proximal interlobar pulmonary artery > 16 mm => pulmonary hypertension
    4. Pulmonary Neoplasms
      1. Nodule < 3cm
      2. Masses > 3cm
  4. Abdomen
    1. Liver => 16 cm
      1. CBD => 0.6 cm at porta hepatis, 1.0 cm distal
      2. GBW => < 0.3
      3. TIPS
        1. Normal velocities range from 100-200 cm/sec
        2. Change of more than 50 cm/sec is abnormal
        3. Stenosis  > 200 cm/sec
        4. MPV < 30 cm/sec indicates possible shunt malfunction
    2. Ascites fluid
      1. Serous ascites => -10 to +10 HU
      2. Exudative ascites => +15 HU
      3. Acute blood => + 45 HU
    3. Spleen => 12(13) x 7(6) x 5 cm
    4. Pancreas
      1. Head => < 3 cm
      2. Body => < 2.5 cm
      3. Tail => < 2.0 cm
      4. Duct => < 0.3 cm
    5. Kidneys => 9.5 -12 F; 10-12.5 M
    6. Adrenals => 0.5 - 0.7 cm thick; 3 cm length each limb
    7. Stomach
      1. Folds
        1. 1 cm at the fundus
        2. 5 mm at the antrum
      2. 2 cm at GE junction
      3. Pyloric stenosis
        1. Muscle wall < 0.3 cm (or 0.35)
        2. Pyloric length < 1.7 cm (or 1.2-1.5)
    8. Bowel wall
      1. Distended 0.1 - 0.2 cm
      2. Collapsed 0.3 - 0.4 cm
      3. Jejunal folds: 2.5 mm
    9. Vessels
      1. Celiac stenosis
        1. PSV > 200 cm/sec
        2. EDV > 55 cm/sec
      2. SMA stenosis
        1. PSV > 275 cm/sec (normal < 180 cm/sec)
        2. EDV > 45 cm/sec
      3. Renal artery
        1. Flow reducing stenosis (>60%)
          1. Renal/aortic ratio > 3.5
          2. PSV > 180 cm/sec
        2. < 60% stenosis
          1. Renal/aortic ratio <3.5
          2. PSV > 180 cm/sec
  5. Pelvis
    1. Appendix
      1. 0.7 cm diameter on US
    2. Presacral space => 1.5 cm
  6. Male
    1. Prostate
    2. Testis =>
      1. 5 x 3 x 2.5 cm (16-20 cc)
      2. Harris (V=H x W x L x 0.52)
      3. < 11 yo => 2 cm3
      4. Prepubertal => 2-10 cm3
      5. Adults => 10-14 cm3
    3. Veins => < 0.3 cm
    4. Penis
      1. Systolic velocities > 35 cm/sec considered normal; < 25 cm/sec abnormal after papaverine or prostaglandin E injection.
  7. Female
    1. Uterus => 8 x 5 x 4 cm
      1. EM
        1. Premenopausal
          1. Proliferative 0.4 - 0.8 cm
          2. Secretory 0.8 - 0.14 cm
        2. Postmenopausal
          1. Asymptomatic < 0.8 cm
          2. Symptomatic < 0.4 cm
          3. Not on HRT
            1. 0.4 cm
          4. On HRT
            1. Biopsy if more than 0.8 cm
    2. Ovaries (Volume = L x W x H x 0.52)
      1. Premenarachal => 2-6 ml
      2. Menstruating => 8-18 ml
      3. Postmenopausal => 6-8 ml
    3. Ovarian cysts
      1. <2.5 cm => no follow up
      2. 2.5-5 cm => follow up
      3. >5cm => surgery
    4. Pregnancy
      1. EM thickness
        1. EM > 8 mm in 97% of nl IUPs
        2. Average EM is 6 mm in early ectopic
      2. bHCG
        1. HCG levels in ectopic pregnancy are highly variable
        2. Single bHCG 3000 mIU/ml or more - viable IUP possible, but unlikely. Follow up bHCG and US prior to rx for ectopic
      3. Gestational age
        1. SOGC Clinical Guidelines 2014
          1. CRL up to 84 mm
          2. BPD > 84mm
          3. Combination is better in second and third trimesters
        2. Gestational sac with double rings = 5 weeks
        3. Gestational sac + yolk sac =  5.5 weeks
        4. Gestational sac + heartbeat = 6 weeks
      4. MSD (See below new 2012 SRU Consensus Conference numbers)
        1. Must be seen (transvaginal/transabdominal):
          1. 10 mm/20 mm => yolk sac
          2. 18 mm/25 mm => fetal pole
          3. 5 mm fetal pole => must see heart beat
        2. Should be seen
          1. 8 mm => yolk sac should be seen
          2. 16 mm => embryo should be seen
      5. Yolk sac <6 mm
      6. CRL
        1. 5 mm => heartbeat should be seen
      7. Lower limits of normal embryonic HR
        1. 5 to 6 weeks
          1. 90
        2. 8 weeks
          1. 120
      8. Signs diagnostic of pregnancy failure (2012 SRU Consensus Conference)
        1. CRL 7 mm or more and no HR
        2. MSD 25 mm or more and no embryo
        3. No embryo with HR 2 weeks or more after a scan that demonstrated GS without YOS
        4. No embryo with HR 11 days or more after a scan that demonstrated GS with YOS
      9. Findings suspicious for pregnancy failure (2012 SRU Consensus Conference)
        1. CRL less than 7 mm and no fetal HR
        2. MSD 16-24 mm and no embryo
        3. No embryo with HR 7-13 days after a scan that showed GS without YOS
        4. No embryo with HR 7-10 days after a scan that showed GS with YOS
        5. No embryo 6 weeks or more after LMP
        6. No visible embryo in visible amnion adjacent to YOS
        7. YOS more than 7 mm
        8. Small GS compared to CRL (<5mm difference between GS and CRL)
      10. Placenta previa
        1. Distance from placental edge to os should be 2 cm
      11. Placental thickness < 5 cm (2-4 cm)
      12. Umbilical cord thickness < or = 2cm
      13. Cervical incompetence
        1. Normal length = 4cm
        2. Incompetent cervix < or = 2.5 cm
      14. Fetal measurements
        1. Atrium of the lateral ventricle => 10 mm
        2. Cisterna magna => 2-10 mm
        3. Nuchal fold (15 - 21 weeks) => abnormal if more than 6 mm
        4. Nuchal translucency (11 - 14 weeks) => abnormal if more than 3 mm
  8. Lymph nodes
    1. Mediastinum
      1. Short axis 10 mm
        1. Prevascular lymph nodes 6 mm
    2. Abdomen
      1. 10-15 mm
        1. Retrocrural space 6 mm
        2. Retroperitoneum 10 mm
        3. Pelvis 13 mm
    3. Long-axis/short-axis ratio < 1.5 suspicious for malignancy
    4. Mesenteric lymph nodes => <3-4 mm in diameter
  9. MSK
    1. Osteochondroma
      1. Cartilagenous cup is suspicious for malignant transformation if more >1.5 cm
    2. Foot
      1. Hallux valgus >11*
      2. Boehler's angle of calcaneus => 28-40 degrees
      3. Talocalcaneal angle
        1. AP 15*-40*
          1. Hindfoot varus < 15*
          2. Hindfoot valgus > 40*
        2. Lateral (Kite angle)
          1. Line bisectging talus and line along the base of the calcaneus
          2. Normal 25* - 45* (50* in newborns)
          3. Hindfoot varus < 25*
          4. Hindfoot valgus >45*
  10. Dialysis grafts
    1. PSV ratio of 2.0-2.99 => 50-74% stenosis
    2. PSV ratio => 3.0 => 75% stenosis