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The ureters are 1.5–6 mm (0.06–0.24 in) in diameter [1] and surrounded by a layer of smooth muscle for 1–2 cm (0.4–0.8 in) near their ends just before they enter the bladder. [ 2 ] The ureters enter the bladder from its back surface, traveling 1.5–2 cm (0.6–0.8 in) before opening into the bladder at an angle on its outer back ...
The French scale measures and is proportional to the outer diameter of a catheter, with 1 French (Fr) defined as 1 ⁄ 3 millimeter, making the relationship: 1 mm = 3 Fr. Thus, the outer diameter of a catheter in millimeters can be calculated by dividing the French size by 3. [ 2 ]
In the human female, the urethra is about 4 cm long, [10] [12] having 6 mm diameter, [12] and exits the body between the clitoris and the vaginal opening, extending from the internal to the external urethral orifice. The meatus is located below the clitoris.
Rigid cystoscopy can be performed under the same conditions, but is generally carried out under general anesthesia, particularly in male subjects, due to the pain caused by the probe. The sizes of the sheath of the rigid cystoscope are 17 French gauge (5.7 mm diameter), 19 Fr gauge (6.3 mm diameter), and 22 Fr gauge (7.3 mm diameter).
Alternatively, the size of a 10 Fr catheter might be expressed as 10 Ch (Charriere units – named after a 19th century French scientific instrument maker, Joseph-Frédéric-Benoît Charrière). The most common sizes are 10 Fr to 28 Fr. 1 Fr is equivalent to 0.33 mm = .013" = 1/77" of diameter.
In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. [ 1 ] [ 2 ] In humans, the bladder is a distensible organ that sits on the pelvic floor . The typical adult human bladder will hold between 300 and 500 ml (10 and 17 fl oz ) before the urge to empty occurs, but can hold considerably more.
The size of the renal pelvis plays a major role in the grading of hydronephrosis. Normally, the anteroposterior diameter of the renal pelvis is less than 4 mm in fetuses up to 32 weeks of gestational age and 7 mm afterwards. [2] In adults, 13% of the normal population have a transverse pelvic diameter of over 10 mm. [3]
This means an anteroposterior diameter of less than 4 mm in fetuses up to 32 weeks of gestational age and 7 mm afterwards. [18] In adults, cutoff values for renal pelvic dilation have been defined differently by different sources, with anteroposterior diameters ranging between 10 and 20 mm. [ 19 ] About 13% of normal healthy adults have a ...