INGUINAL CANAL n n Is an oblique passage
INGUINAL CANAL n n Is an oblique passage through the lower part of the anterior abdominal wall and is present in both sexes. It allows structures to pass to and from the testis to the abdomen in males. In females it permits the passage of the round ligament of the uterus from the uterus to the labium majus. In addition, it transmits the ilioinguinal nerve in both sexes.
INGUINAL CANAL
INGUINAL CANAL n n The canal is about (4 cm) long in the adult and extends from the deep inguinal ring downward and medially to the superficial inguinal ring. It lies parallel to and immediately above the inguinal ligament. In the newborn child, the deep ring lies almost directly posterior to the superficial ring so that the canal is considerably shorter at this age. Later, as the result of growth, the deep ring moves laterally.
INGUINAL CANAL n n n The deep inguinal ring, an oval opening in the fascia transversalis, lies about (1. 3 cm) above the inguinal ligament midway between the anterior superior iliac spine and the symphysis pubis. Related to it medially are the inferior epigastric vessels, which pass upward from the external iliac vessels. The margins of the ring give attachment to the internal spermatic fascia (or the internal covering of the round ligament of the uterus).
Walls of the lnguinal Canal Anterior wall of the canal n n n Is formed along its entire length by the aponeurosis of the external oblique muscle. It is reinforced in its lateral third by the origin of the internal oblique from the inguinal ligament. This wall is therefore strongest where it lies opposite the weakest part of the posterior wall, namely, the deep inguinal ring.
Walls of the lnguinal Canal Posterior wall of the canal n n n Is formed along its entire length by the fascia transversalis. It is reinforced in its medial third by the conjoint tendon. This wall is therefore strongest where it lies opposite the weakest part of the anterior wall, namely, the superficial inguinal ring.
Walls of the lnguinal Canal Inferior wall of the canal (floor) n Is formed by the inguinal ligament and, at its medial end, the lacunar ligament.
Walls of the lnguinal Canal Superior wall of the canal (roof) n Is formed by the arching lowest fibers of the internal oblique and transversus abdominis muscles.
Functions of the lnguinal Canal n In the male, the inguinal canal allows structures of the spermatic cord to pass to and from the testis to the abdomen. ¨ (Normal spermatogenesis takes place only if the testis leaves the abdominal cavity to enter a cooler environment in the scrotum. ) n In the female, the smaller canal permits the passage of the round ligament of the uterus from the uterus to the labium majus. n In both sexes, the canal also transmits the ilioinguinal nerve.
Mechanics of the Inguinal Canal The presence of the inguinal canal in the lower part of the anterior abdominal wall in both sexes constitutes a potential weakness. It is interesting to consider how the design of this canal attempts to lessen this weakness.
Mechanics of the Inguinal Canal n n Except in the newborn infant, the canal is an oblique passage with the weakest areas, namely, the superficial and deep rings, lying some distance apart. The anterior wall of the canal is reinforced by the fibers of the internal oblique muscle immediately in front of the deep ring.
Mechanics of the Inguinal Canal n n n The posterior wall of the canal is reinforced by the strong conjoint tendon immediately behind the superficial ring. On coughing and straining, as in micturition, defecation, and parturition, the arching lowest fibers of the internal oblique and transversus abdominis muscles contract, flattening out the arched roof so that it is lowered toward the floor. The roof may actually compress the contents of the canal against the floor so that the canal is virtually closed.
Mechanics of the Inguinal Canal n n When great straining efforts may be necessary, as in defecation and parturition, the person naturally tends to assume the squatting position: the hip joints are flexed, and the anterior surfaces of the thighs are brought up against the anterior abdominal wall. By this means, the lower part of the anterior abdominal wall is protected by the thighs.
Spermatic Cord n n n The spermatic cord is a collection of structures that pass through the inguinal canal to and from the testis. It is covered with three concentric layers of fascia derived from the layers of the anterior abdominal wall. It begins at the deep inguinal ring lateral to the inferior epigastric artery and ends at the testis.
Coverings of the spermatic cord
Structures of the Spermatic Cord n Ø Ø Ø Ø Ø The structures are as follows: vas deferens, testicular artery, testicular veins (pampiniform plexus), testicular lymph vessels, autonomic nerves, remains of processus vaginalis, cremasteric artery, artery of the vas deferens, genital branch of the genitofemoral nerve.
Spermatic Cord Vas Deferens n n The vas deferens is a cordlike structure that can be palpated between finger and thumb in the upper part of the scrotum. It is a thick-walled muscular duct that transports spermatozoa from the epididymis to the urethra.
Spermatic Cord Testicular Artery n A branch of the abdominal aorta (L 2). n It is long and slender and descends on the posterior abdominal wall. n It traverses the inguinal canal and supplies the testis and the epididymis.
Spermatic Cord Testicular Veins n n n An extensive venous plexus (pampiniform plexus), leaves the posterior border of the testis. As the plexus ascends, it becomes reduced in size so that at about the level of the deep inguinal ring, a single testicular vein is formed. This runs upon the posterior abdominal wall and drains into the left renal vein on the left side and into the inferior vena cava on the right side.
Spermatic Cord Lymph Vessels n The testicular lymph vessels ascend through the inguinal canal and pass up over the posterior abdominal wall to reach the lumbar (para-aortic) lymph nodes on the side of the aorta at the level of (L 1). n This because the gonads had migrated from high up.
Spermatic Cord Autonomic Nerves n Sympathetic fibers run with the testicular artery from the renal or aortic sympathetic plexuses. n Afferent sensory nerves accompany the efferent sympathetic fibers.
Spermatic Cord Other Structures n n Remnants of Processus Vaginalis. Cremasteric artery (a branch of the inferior epigastric artery) supplies the cremasteric fascia. Artery to the vas deferens (a branch of the inferior vesical artery). The genital branch of the genitofemoral nerve, which supplies the cremaster muscle.
Coverings of the Spermatic Cord External spermatic fascia Cremasteric fascia Internal spermatic fascia
Coverings of the Spermatic Cord n n n External spermatic fascia aponeurosis Cremasteric fascia Internal spermatic fascia the external oblique the internal oblique muscle the fascia transversalis
Development of the Inguinal Canal n n n A peritoneal diverticulum called the processus vaginalis is formed. It passes through the layers of the lower part of the anterior abdominal wall. It acquires a tubular covering from each layer.
Development of the Inguinal Canal n n A band of mesenchyme, extending from the lower pole of the developing gonad through the inguinal canal to the labioscrotal swelling, has condensed to form the gubernaculum. This band guides the descent of the developing gonad.
Development of the Inguinal Canal
Development of the Inguinal Canal n n n The testis descends through the pelvis and inguinal canal during the seventh and eighth months of fetal life. The normal stimulus for the descent of the testis is testosterone, which is secreted by the fetal testes. The testis follows the gubernaculum and descends behind the peritoneum on the posterior abdominal wall. The testis then passes behind the processus vaginalis and pulls down its duct, blood vessels, nerves, and lymph vessels. The testis takes up its final position in the developing scrotum by the end of the eighth month.
Development of the Inguinal Canal
Development of the Inguinal Canal
Development of the Inguinal Canal
Development of the Inguinal Canal n Because the testis and its accompanying vessels, ducts, and so on follow the course previously taken by the processus vaginalis, they acquire the same three coverings as they pass down the inguinal canal.
Development of the Inguinal Canal n n Regarding females, the round ligament of the uterus is the part of the gubernaculum extending from uterus to the labium majus. The inguinal canal in female transmits the round ligament of the uterus, lymph vessels and the ilioinguinal nerve.
VASECTOMY l l Bilateral vasectomy is a simple operation performed to produce infertility. Under local anesthesia, a small incision is made in the upper part of the scrotal wall, and the vas deferens is divided between ligatures. Spermatozoa may be present in the first few post operative ejaculations, but that is simply an emptying process. Now only the secretions of the seminal vesicles and prostate constitute the seminal fluid, which can be ejaculated as before.
Scrotum n n n 1. 2. The scrotum can be considered as an out- pouching of the lower part of the anterior abdominal wall. It contains the testes, the epididymis, and the lower ends of the spermatic cords. The wall of the scrotum has the following layers: Skin, Superficial fascia; Ø Ø 3. 4. 5. 6. dartos muscle (fatty layer), Colles fascia (membranous layer), External spermatic fascia (external oblique), Cremasteric fascia (internal oblique), Internal spermatic fascia (fascia transversalis), Tunica vaginalis.
Scrotum n n n The skin of the scrotum is thin, wrinkled, and pigmented and forms a single pouch. The dartos muscle is innervated by sympathetic nerve fibers and is responsible for the wrinkling of the skin. A slightly raised ridge in the midline indicates the line of fusion of the two lateral labioscrotal swellings. Both layers of superficial fascia contribute to the median partition that crosses the scrotum and separates the testes from each other. In the female, the swellings remain separate and form the labia majora.
Scrotum n The spermatic fasciae lie beneath the superficial fascia and are derived from the three layers of the anterior abdominal wall on each side.
Scrotum n n n The cremaster muscle can be made to contract by stroking the skin on the medial aspect of the thigh. This is called the cremasteric reflex. The afferent fibers of this reflex arc travel in the femoral branch of the genitofemoral nerve (L 1 and 2), and the efferent motor nerve fibers travel in the genital branch of the genitofemoral nerve. The function of the cremaster muscle is to raise the testis and the scrotum upward for warmth and for protection against injury for testicular temperature and fertility.
Scrotum n n n The tunica vaginalis lies within the spermatic fasciae and covers the anterior, medial, and lateral surfaces of each testis. It is the lower expanded part of the processus vaginalis; normally, just before birth, it becomes shut off from the upper part of the processus and the peritoneal cavity. The tunica vaginalis is thus a closed sac, invaginated from behind by the testis.
Scrotum n Lymph drainage from the skin and fascia. including the tunica vaginalis, drains into the superficial inguinal lymph nodes.
Testis The testis is a firm, mobile organ lying within the scrotum. n The left testis usually lies at a lower level than the right. n The upper pole of the gland is tilted slightly forward. n
Testis n n Each testis is surrounded by a tough fibrous capsule, the tunica albuginea. Extending from the inner surface of the capsule is a series of fibrous septa that divide the interior of the organ into lobules.
Testis n n n Lying within each lobule are one to three coiled seminiferous tubules. The tubules open into a network of channels called the rete testis. Small efferent ductules connect the rete testis to the upper end of the epididymis.
Testis n n n Normal spermatogenesis can occur only if the testes are at a temperature lower than that of the abdominal cavity. When they are located in the scrotum, they are at a temperature about 3°C lower than the abdominal temperature. The control of testicular temperature in the scrotum is not fully understood, but the surface area of the scrotal skin can be changed reflexly by the contraction of the dartos and cremaster muscles.
Testis n n It is now recognized that the testicular veins in the spermatic cord that form the pampiniform plexus—together with the branches of the testicular arteries, which lie close to the veins— probably assist in stabilizing the temperature of the testes by a countercurrent heat exchange mechanism. By this means, the hot blood arriving in the artery from the abdomen loses heat to the blood ascending to the abdomen within the veins.
Epididymis n n The epididymis is a firm structure lying posterior to the testis, with the vas deferens lying on its medial side. It has an expanded upper end, the head, a body, and a pointed tail inferiorly.
Epididymis n n n Laterally, a distinct groove lies between the testis and the epididymis, which is lined with the inner visceral layer of the tunica vaginalis and is called the sinus of the epididymis. The epididymis is a much coiled tube nearly (6 m) long, embedded in connective tissue. The tube emerges from the tail of the epididymis as the vas deferens, which enters the spermatic cord.
Function of the Epididymis The long length of the duct of the epididymis provides storage space for the spermatozoa and allows them to mature. n A main function of the epididymis is the absorption of fluid. n Another function may be the addition of substances to the seminal fluid to nourish the maturing sperm. n
Varicocele l l l A varicocele is a condition in which the veins of the pampiniform plexus are elongated and dilated. It is a common disorder in adolescents and young adults, with most occurring on the left side. This is thought to be because the right testicular vein joins the low-pressure inferior vena cava, whereas the left vein joins the left renal vein, in which the venous pressure is higher. Rarely, malignant disease of the left kidney extends along the renal vein and blocks the exit of the testicular vein. A rapidly developing left-sided variocele should therefore always lead one to examine the left kidney.
Varicocele
Malignant Tumor of the Testis l l A malignant tumor of the testis spreads upward via the lymph vessels to the lumbar (para-aortic) lymph nodes at the level of the L 1 vertebra. It is only later, when the tumor spreads locally to involve the tissues and skin of the scrotum, that the superficial inguinal lymph nodes are involved.
Malignant Tumor of the Testis Clinical Focus 5 -15, Netter’s Clinical Anatomy, 3 rd Ed Clinical Anatomy, Abdominal Wall 61
Torsion of the Testis l l Torsion of the testes is a rotation of the testis around the spermatic cord within the scrotum. It is often associated with an excessively large tunica vaginalis. Torsion commonly occurs in active young men and children and is accompanied by severe pain. If not treated quickly, the testicular artery may be occluded, followed by necrosis of the testis.
Torsion of the Testis
Processus Vaginalis Normally, the upper part becomes obliterated just before birth and the lower part remains as the tunica vaginalis. It may become very much narrowed, but its lumen remains in communication with the abdominal cavity. l Peritoneal fluid accumulates in it, forming a congenital hydrocele. l l. The upper and lower ends of the processus may become obliterated, leaving a small intermediate cystic area referred to as an encysted hydrocele of the cord. It may persist partially or in its entirety as a preformed hernial sac for an indirect inguinal hernia.
Processus Vaginalis l l The tunica vaginalis is closely related to the front and sides of the testis. So, inflammation of the testis can cause an accumulation of fluid within the tunica vaginalis. This is referred to simply as a hydrocele. Most hydroceles are idiopathic.
Processus Vaginalis l l l 1. 2. 3. 4. 5. 6. 7. Tapping a hydrocele is a procedure to remove excess fluid from the tunica vaginalis. A fine trocar and cannula are inserted through the scrotal skin. The following anatomic structures are traversed: skin, dartos muscle, membranous layer of fascia (Colles’ fascia), external spermatic fascia, cremasteric fascia, internal spermatic fascia, parietal layer of the tunica vaginalis.
Processus Vaginalis
Congenital Anomalies of the Testis 1. Anterior inversion, in which the epididymis lies anteriorly and the testis and the tunica vaginalis lie posteriorly. 2. Polar inversion, in which the vertical position of the testis is reversed and the head of epididymis can be felt below the testis.
Congenital Anomalies of the Testis 3. Imperfect descent (cryptorchidism); Incomplete descent, in which the testis, although traveling down its normal path, fails reach the floor of the scrotum, It may be found within the abdomen, within the inguinal canal, the superficial inguinal ring, or high up in the scrotum.
CONGENITAL ANOMALIES OF THE TESTIS 4. Maldescent, in which the testis travels down an abnormal path and fails to reach the scrotum. It may be found in the superficial fascia of the anterior abdominal wall above the inguinal ligament, in front of the pubis, in the perineum, or in the thigh.
Congenital Anomalies of the Testis l l It is necessary for the testes to leave the abdominal cavity because the temperature there retards the normal process of spermatogenesis. If an incompletely descended testis is brought down into the scrotum by surgery before puberty, it will develop and function normally.
Congenital Anomalies of the Testis l l A maldescended testis, although often developing normally, is susceptible to traumatic injury and, for this reason, should be placed in the scrotum. Many authorities believe that the incidence of tumor formation is greater in testes that have not descended into the scrotum.
Congenital Anomalies of the Testis l The appendix of the testis and the appendix of the epididymis are embryologic remnants found at the upper poles of these organs that may become cystic.
LABIA MAJORA n n The labia majora are prominent, hair-bearing folds of skin formed by the enlargement of the genital swellings in the fetus. (In the male, the genital swellings fuse in the midline to form the scrotum). Within the labia are a large amount of adipose tissue and the terminal strands of the round Iigaments of the uterus.
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