Reproductive ultrasonography in males: Normal studies (Proceedings)


Reproductive ultrasonography in males: Normal studies (Proceedings)

Apr 01, 2009

Generally, coping with disorders in small animal reproduction, is a rewarding subspecialty in veterinary medicine. Clients owning pets with urogenital problems are usually very motivated to achieve resolution. Although demanding of the clinician's time and expertise, the breeder client tends to be very loyal and compliant. A good reproductive practice generates its own referrals, and usually is quite busy. Obstetrics and pediatrics are undeniably rewarding parts of the specialty for veterinarians and their staff. Reproductive practice incorporates the interesting fields of physiology, endocrinology, embryology, genetics, metabolism, nutrition, pediatric and maternal critical care, anesthesia, pharmacology and anatomy. The field is uniquely requires expertise in medicine, ultrasonography and surgery.

Diagnostic ultrasonography has become an important component of small animal theriogenology since its introduction to practice in 1978. The use of ultrasound as a tool in canine and feline reproduction has expanded from its initial role in early pregnancy diagnosis to its current use in the approach to clinical reproduction (obstetrics, infertility, urogenital disorders and pediatrics). The availability of ultrasonography in veterinary practice increased as reasonably priced, better quality diagnostic ultrasound equipment became commercially available to veterinarians. Ultrasonography has become a standard of practice in many communities, with diagnostic ultrasound available at primary private practices, via readily accessible referral centers or from mobile specialty practices. Veterinary school curricula and continuing education courses now commonly include ultrasonography, providing students and graduates with the training to perform and interpret diagnostic ultrasound. Recent developments in scanhead technology have allowed improved visualization of reproductive anatomy.

Normal Male Reproductive Tract: Dog and Tom


The male canine reproductive tract consists of the male genital organs including the scrotum, the two testes (normally located within the scrotum), the epididymides, the deferent ducts (leading from the epididymis to the urethra), the spermatic cords, the prostate, the penis and the urethra. The scrotum is a pouch divided by a thin wall into two cavities, each of which is occupied by a testicle, an epididymis, and the tail end of the spermatic cord. The skin of the scrotum is covered with fine hairs. The dartos of the scrotum is a layer of tissue that lies just under the skin and is made up of muscle and other tissue. Under the dartos is connective tissue lining the scrotum. Each testicle is oval in shape and thicker centrally. The testicles contain seminiferous tubules. The epididymis is comparatively large in the dog and consists of an elongated structure composed of a long convoluted or twisted tube. It begins at the cranial aspect of the testicle and is positioned along the edge. The deferent ducts are thin muscular tubes that are made up of three layers. The prostate gland surrounds the neck of the bladder, as well as the distal ductus deferens. A thin wall divides the gland into two equal-sized smooth, firm lobes. The prostate has multiple openings into the urethra. The penis is a highly vascularized structure. It is composed of several parts, including the root, body and distal portion or glans penis. The root and body are made up of a vascular expansile tissue, the glans, and the os penis. During copulation, the glans penis swells permitting the copulatory lock. The penis also surrounds the termination of the urethra and is important in directing the stream of urine to the outside of the body. The prepuce is the tubular sheet of skin that covers the free part of the non-erect penis.

The reproductive tract of the tom cat consists of the penis, the scrotum, two testicles, the prostate gland, two bulbourethral glands (Cowper's glands), the epididymis, the ductus deferens (also called the vas deferens), the spermatic cords, and the urethra.

The penis is located within the prepuce. When the penis is not erect it is completely enclosed within the prepuce, which is visible on the caudal aspect of the body between the two pelvic limbs. The penis is covered by a protective sheath called the prepuce. The tip of the penis is called the glans, and it is covered with 120 to 150 penile spines that are directed caudally, away from the end of the glans. These penile spines start to appear at about 12 weeks of age and are fully developed at puberty. They are absent in neutered male cats, disappearing by six weeks after castration. The penis is a highly vascularized structure. It surrounds the termination of the urethra and is important in directing the stream of urine to the outside of the body.