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Henry Gray (1825–1861).  Anatomy of the Human Body.  1918.
 

Peculiarities.—The testis, developed in the lumbar region, may be arrested or delayed in its transit to the scrotum (cryptorchism). It may be retained in the abdomen; or it may be arrested at the abdominal inguinal ring, or in the inguinal canal; or it may just pass out of the subcutaneous inguinal ring without finding its way to the bottom of the scrotum. When retained in the abdomen it gives rise to no symptoms, other than the absence of the testis from the scrotum; but when it is retained in the inguinal canal it is subjected to pressure and may become inflamed and painful. The retained testis is probably functionally useless; so that a man in whom both testes are retained (anorchism) is sterile, though he may not be impotent. The absence of one testis is termed monorchism. When a testis is retained in the inguinal canal it is often complicated with a congenital hernia, the funicular process of the peritoneum not being obliterated. In addition to the cases above described, where there is some arrest in the descent of the testis, this organ may descend through the inguinal canal, but may miss the scrotum and assume some abnormal position. The most common form is where the testis, emerging at the subcutaneous inguinal ring, slips down between the scrotum and thigh and comes to rest in the perineum. This is known as perineal ectopia testis. With each variety of abnormality in the position of the testis, it is very common to find concurrently a congenital hernia, or, if a hernia be not actually present, the funicular process is usually patent, and almost invariably so if the testis is in the inguinal canal.
  The testis, finally reaching the scrotum, may occupy an abnormal position in it. It may be inverted, so that its posterior or attached border is directed forward and the tunica vaginalis is situated behind.
  Fluid collections of a serous character are very frequently found in the scrotum. To these the term hydrocele is applied. The most common form is the ordinary vaginal hydrocele, in which the fluid is contained in the sac of the tunica vaginalis, which is separated, in its normal condition, from the peritoneal cavity by the whole extent of the inguinal canal. In another form, the congenital hydrocele, the fluid is in the sac of the tunica vaginalis, but this cavity communicates with the general peritoneal cavity, its tubular process remaining pervious. A third variety known as an infantile hydrocele, occurs in those cases where the tubular process becomes obliterated only at its upper part, at or near the abdominal inguinal ring. It resembles the vaginal hydrocele, except as regards its shape, the collection of fluid extending up the cord into the inguinal canal. Fourthly, the funicular process may become obliterated both at the abdominal inguinal ring and above the epididymis, leaving a central unobliterated portion, which may become distended with fluid, giving rise to a condition known as the encysted hydrocele of the cord.
 
3c. 2. The Ductus Deferens
 
  
(Vas Deferens; Seminal Duct)


The ductus deferens, the excretory duct of the testis, is the continuation of the canal of the epididymis. Commencing at the lower part of the tail of the epididymis it is at first very tortuous, but gradually becoming less twisted it ascends along the posterior border of the testis and medial side of the epididymis, and, as a constituent of the spermatic cord, traverses the inguinal canal to the abdominal inguinal ring. Here it separates from the other structures of the cord. curves around the lateral side of the inferior epigastric artery, and ascends for about 2.5 cm. in front of the external iliac artery. It is next directed backward and slightly downward, and, crossing the external iliac vessels obliquely, enters the pelvic cavity, where it lies between the peritoneal membrane and the lateral wall of the pelvis, and descends on the medial side of the obliterated umbilical artery and the obturator nerve and vessels. It then crosses in front of the ureter, and, reaching the medial side of this tube, bends to form an acute angle, and runs medialward and slightly forward between the fundus of the bladder and the upper end of the seminal vesicle. Reaching the medial side of the seminal vesicle, it is directed downward and medialward in contact with it, gradually approaching the opposite ductus. Here it lies between the fundus of the bladder and the rectum, where it is enclosed, together with the seminal vesicle, in a sheath derived from the rectovesical portion of the fascia endopelvina. Lastly, it is directed downward to the base of the prostate, where it becomes greatly narrowed, and is joined at an acute angle by the duct of the seminal vesicle to form the ejaculatory duct, which traverses the prostate behind its middle lobe and opens into the prostatic portion of the urethra, close to the orifice of the prostatic utricle. The ductus deferens presents a hard and cord-like sensation to the fingers, and is of cylindrical form; its

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