s of about 25% of the glandular prostate and includes the area around the urethra and ejaculatory ducts. Moreover, the transition zone extends along the lateral aspects of the proximal urethra and consists of between 5 and 10% of the prostate's glandular tissue (5:274). Lastly, approximately 70% of the glandular prostate makes up the lateral and posterior lobes.
In young boys, the organ is relatively undeveloped. At puberty though, in response to androgens, its size increases significantly (2:42). By about the fourth decade, most men develop multiple calcifications with concomitant benign prostatic hyperplasia. Such findings are generally called "common" rather than "normal." The term "abnormal" is generally reserved for such things as cancer, cysts, and conglomerates of calcifications.
These anatomic structures are perhaps best visualized by transrectal ultrasonography in both the transverse and longitudinal planes. Ultrasound technologies were first evaluated for medical purposes following World War I. Then, in 1940, a definitive summary of their use, "Ultrasound in Medicine," was published by Gohr and Wedekind. These authors predicted that the "evaluation of organ pathology would be a valuable addition to roentgen diagnosis (1:1)." During the years following World War II, ultrasound was extensively investigated in both Japan and the United States for use in medical diagnosis (i.e., the detection of solid bodies such as brain tumors). It wasn't until the late 1960s and early 1970s, however, that the techniques were applied to the genitourinary system. Watanabe and his associates (1968) used transrectal ultrasound to evaluate the prostate. Since that initial study, ultrasound prostate imaging methods--as well as transperineal and transrectal biopsy guidance by ultrasound--have evolved rapidly. Current ultrasound techniques produce objective reproducible estimates of prostatic size and echo pattern. S...