الفهرس 
Anatomy of male reproductive systemOnly 14 pages are availabe for public view
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Abstract
Until recently, the clinical evaluation of male infertility was limited by the inability to
visualize directly and non-invasively the distal parts of tl1e vas deferens, seminal vesicles,
ejaculatory duct, and prostate. Vasography was regarded as the best method for imaging these
structures for many years. It is an invasive technique, however, and can cause iatrogenic scarring
and occlusion of the vas deferens. Currently, CT and operative vasography have been alomost totally
replaced by TRUS, which provides superior visualization and identification of the many varieties of
anomalies of he distal reproductive system (Kuligowska & Oliver; 1998).
The use of ultrasound in the evaluation of male infertility offers valuable information to the
urologist There are a number of diseases of the prostate that affect fertility, including
congenital abnormalities and prostatitis. Endorectal sonography is an inexpensive and less
invasive examination capable of detecting these abnormalities. Patients with low ejaculate volume
and azoospermia can gain the most information from an endorectal ultrasound examination without
having to go through more costly and invasive tests (Thomas & Keener,· 1997).
The most important segment of an ultrasound examination of the infertile male is the
evaluation of the seminal vesicles and the ampullae of the vasa deferentia.
The examiner must demonstrate that both seminal vesicles and ampullae are present and free of
abnormalities. Absence of the vas deferens and ampulla is one of the most common causes of
obstructive azoospermia.
Absence of a seminal vesicle may result in low ejaculate volume, although spermatozoa would still
be present within the ejaculate. It is important for the sonographer to remember that if a seminal
vesicle or vas deferens is absent or hypoplastic, a congenital defect must be suspected and the
kidneys should be evaluated for any further abnormalities (Thomas & Keener; 1997).
The other concern is the size of these structures. Unless the seminal vesicles are grossly
enlarged, it is difficult to say that these structures are abnormal in size because of the wide
range of reported normal measurements. Also, because seminal vesicles store secretions used in
ejaculation, they may be enlarged due to sexual abstinence or age. If however, the seminal vesicles
appear grossly enlarged and the above conditions do not apply, a distal obstruction of the
ejaculatory duct must be suspected. It is important to role out cystic structures or calculi that
may be obstructing these ducts. A Mullerian duct cyst may cause an obstruction by externally
compressing the ejaculatory ducts. Ejaculatory duct diverticula may also be seen caused by a distal
obstruction of the ejaculatory duct by a stone or other lesion. These lesions become significant in
the presence of fertility Issues such as low ejaculate volume and
azoospermia. Prostatitis plays a direct role in infertility. It has been shown to have direct
effects on the motility and number of sperms present in the ejaculate. The prostate should appear
homogenous and free from focal areas of abscess, calcifications and hyperemia, all of which have
been seen in patients with prostatitis. All of the above ultrasound findings independently do not
indicate infertility. Within the appropriate clinical setting, however, these ultrasound findings
aid in the diagnosis of lesions that may cause infertility (Thomas & Keener; 1997).
To define the causes of azoospermia, it is helpful to sub-classify patients into those with a
low-volume ejaculate (less than 1 ml) or a normal-volume ejaculate (above lml). Low-volume
ejaculates may result from stenosis, obstruction or anomalies of distal sperm transporting system.
Conditions that produce low-volume ejaculate with azoospermia or oligospermia include agenesis of
the vas deferens or seminal vesicles, inflammatory strictures or obstruction of the vas deferens
and seminal vesicles, ejaculatory duct obstruction, and urethral strictures. Low-volume ejaculate
also can be caused by retrograde ejaculation. Retrograde ejaculation secondary to neurologic
conditions such as spinal cord injury, multiple sclerosis, and diabetes mellitus or after
prostatectomy. Normal-volume ejaculate with azoospermia or oligospermia is caused by testicular
or other scrotal abnormalities [Fig. 46] (Kuligowska & Oliver; 1998).