ABSTRACT
The ejaculatory ducts develop from the distal-most vas (the Wolffian duct system). The seminal vesicles develop as a blind diverticulum at the most terminal end of the vas (16). The ejaculatory ducts are a direct continuation of the seminal vesicles and, anatomically, begin after the ampulla of the vas joins the seminal vesicle duct on its medial aspect at an acute angle (Fig. 1) (6,17,18). The ducts are approximately 1 to 2 cm long
and enter the prostate obliquely and posteriorly at its base, course medially and anteriorly through the prostatic glandular tissue, and enter the prostatic urethra at the verumontanum (6,9,17,18). Between the two ejaculatory ducts at the verumontanum sits the prostatic utricle-a Mullerian tubercle remnant of endodermal origin (18). The ejaculatory ducts open, in the majority of cases, anterolateral to the orifice of the utricle (18). In most men, the utricle is less than 6 mm in size but can exceed 10 mm in up to 10% of men (19). The utricle does not communicate with any other structures (6,17,18,20). Injection of methyl methacrylate into the vas deferens of intact autopsy prostate/seminal vesicles/vasa specimens reveals the ejaculatory ducts exiting close to one another at the verumontanum, with a small utricle lying between them. No methyl methacrylate can be seen exiting the utricle (Fig. 2) (21). In sagittal sections, the ejaculatory duct forms an almost straight course from the prostatic base to the verumontanum (Fig. 3). The close relationship of the ejaculatory ducts to the utricle can be seen in the transverse section at the verumontanum of a radical retropubic prostatectomy specimen (Fig. 4) (21). The anatomic structures of the ejaculatory ductal system and their relationships can also be demonstrated using rectal coil magnetic resonance imaging (MRI) (5,22). In sagittal images, the relationships between the bladder, bladder neck, seminal vesicles, prostate, and ejaculatory ducts are demonstrated. In addition, this patient has a midline cyst that divides the ejaculatory ducts laterally (Fig. 5). Also note that the distal ejaculatory duct and cyst are distal and inferior to the bladder neck. Each duct is surrounded by circular lamellar tissue and, in turn, both ducts are surrounded by a communal muscular envelope (17,23). The existence of a sphincter spermaticus has been confirmed, but its role in the pathophysiology of partial or functional ejaculatory duct obstruction remains poorly understood (4,7). The ejaculatory ducts are lined by a yellow pigmented cuboidal to pseudostratified columnar epithelium (Fig. 6) (17,23). (For further details on male anatomy, please refer to Chapter 2.)
† ETIOLOGIES OF OBSTRUCTION
Ejaculatory duct obstruction can be either congenital or acquired (9,11). Congenital causes include congenital atresia or stenosis of the ejaculatory ducts, and utricular, Mullerian, and Wolffian duct cysts. Acquired causes may be secondary to trauma, either iatrogenic or otherwise, or may have infectious or inflammatory etiologies (9,11). Calculus formation secondary to infection may also cause obstruction (4). Cyst formation from prior instrumentation or infection may also occur (20). Many times, patients with ejaculatory duct obstruction have no significant antecedent history (6). Several authors have found that patients with congenital or noninfectious causes of ejaculatory duct obstruction do better after treatment than those with infectious causes (9,11). Other authors, however, have not been able to support this (6,24,25).
