TBL15 - Inguinal Region of the Abdominal Wall

Question 1

Locate the pubic tubercle of the pubis. What does the dense inferiormost part of the external oblique aponeurosis form?

Answer 1

The dense inferiormost part of the external oblique aponeurosis forms the inguinal ligament that extends from the ASIS to the pubic tubercle

Question 2

Where is the inguinal canal located in relation to the inguinal ligament? Where is the superficial inguinal ring located in relation to the pubic tubercle?

Answer 2

1) The inguinal canal is just superior and parallel to the medial half of the inguinal ligament
2) The superficial inguinal ring is superolateral to the pubic tubercle

Question 3

Where is the deep inguinal ring located in relation to the inguinal ligament? In relation to the inferior epigastric artery?

Answer 3

1) The deep inguinal ring is just superior to the midpoint of the inguinal ligament
2) The deep ring is positioned lateral to the inferior epigastric artery

Question 4

What occupies the inguinal canal in males? What occupies the inguinal canal in females?

Answer 4

1) In males, the main occupant of the inguinal canal is the spermatic cord
2) The round ligament of the uterus occupies the inguinal canal in females

Question 5

What traverses the deep inguinal ring to enter the inguinal canal in the male? Where do they exit?

Answer 5

1) The testis and attached spermatic cord traverse the deep inguinal ring to enter the inguinal canal
2) The attached structures exit the canal via the superficial inguinal ring

Question 6

Why does palpation of an impulse at the superficial inguinal ring and a mass at the deep inguinal ring define an indirect inguinal hernia? How is a direct inguinal hernia detected by palpation?

Answer 6

1) With the palmar surface of the finger against the anterior abdominal wall, the deep inguinal ring may be felt as a skin depression superior to the inguinal ligament, 2–4 cm superolateral to the pubic tubercle. Detection of an impulse at the superficial ring and a mass at the site of the deep ring suggests an indirect hernia
2) Palpation of a direct inguinal hernia is performed by placing the palmar surface of the index and/or middle finger over the inguinal triangle and asking the person to cough or bear down (strain). If a hernia is present, a forceful impulse is felt against the pad of the finger. The finger can also be placed in the superficial inguinal ring; if a direct hernia is present, a sudden impulse is felt medial to the finger when the person coughs or bears down

Question 7

Where does an undescended testis commonly lie and what is its clinical risk? How can an undescended testis be distinguished from an inguinal hernia in infants?

Answer 7

1) If a testis has not descended or is not retractable (capable of being drawn down), the condition is cryptorchidism
2) The undescended testis usually lies somewhere
along the normal path of its prenatal descent, commonly
in the inguinal canal
3) The importance of cryptorchidism is a greatly increased risk for developing malignancy in the undescended testis, particularly problematic because it is not palpable and is not usually detected until cancer has progressed
4) Undescended testis are not palpable while inguinal hernias are palpable

Question 8

What forms the anterior wall of the inguinal canal? What forms the posterior wall of the inguinal canal?

Answer 8

1) The anterior wall of the inguinal canal is formed by the external oblique aponeurosis
2) The posterior wall is formed by the conjoint tendon i.e., merged aponeuroses of the internal oblique and transverse abdominis muscles

Question 9

Locate the deep inguinal ring. What does the testis create in the parietal peritoneum and what does it do?

Answer 9

The testis creates a diverticulum in the parietal peritoneum called the processus vaginalis that pushes the muscular and fascial layers of the anterolateral wall ahead of it into the inguinal canal

Question 10

What surrounds the processus vaginalis? What do the internal oblique muscle and aponeurosis form? What is formed by the aponeurosis of the external oblique muscle?

Answer 10

1) The processus vaginalis is immediately surrounded by the internal spermatic fascia, which is formed by the transversalis fascia
2) The internal oblique muscle and aponeurosis form the cremaster muscle and cremasteric fascia that surround the internal spermatic fascia
3) The external spermatic fascia surrounding the cremaster and cremasteric fascia is formed by the aponeurosis of the external oblique muscle

Question 11

What does the stalk part of the processus vaginalis normally do? What does the distal saccular part form?

Answer 11

1) The stalk part of the processus vaginalis normally collapses around the spermatic cord
2) Its distal saccular part forms the tunica vaginalis that closely adheres to the testis and epididymis (to be studied later)

Question 12

How is a persistent processus vaginalis related to a hydrocele of the testis and how does a hydrocele of the spermatic cord differ from a hydrocele of the testis?

Answer 12

1) A hydrocele is the presence of excess fluid in a persistent processus vaginalis
2) A hydrocele of the testis is confined to the scrotum and distends the tunica vaginalis
3) A hydrocele of the spermatic cord is confined to the spermatic cord and distends the persistent part of the stalk of the processus vaginalis
4) A congenital hydrocele of the cord and testis may communicate with the peritoneal cavity

Question 13

What does the genital branch of the genitofemoral nerve do? What does the ilioinguinal nerve do? What do these nerves constitute?

Answer 13

1) The genital branch of the genitofemoral nerve provides somatic motor fibers to the cremaster muscle
2) The ilioinguinal nerve provides somatic sensory fibers to the skin of the superomedial thigh
3) The nerves constitute the motor and sensory components of the cremasteric reflex

Question 14

How is the cremasteric reflex tested?

Answer 14

1) Contraction of the cremaster muscle is elicited by
lightly stroking the skin on the medial aspect of the
superior part of the thigh with an applicator stick or tongue depressor
2) The rapid elevation of the testis on the same side is the cremasteric reflex

Question 15

What does the spermatic cord contain? What does the pampiniform plexus do?

Answer 15

1) The spermatic cord contains the ductus (aka vas) deferens, testicular artery, and pampiniform venous plexus
2) The pampiniform plexus cools blood in the testicular artery to maintain the testis a few degrees below body temperature thereby insuring normal spermatozoa production

Question 16

What does the pampiniform plexus converge superiorly as?

Answer 16

The pampiniform plexus converges superiorly as the testicular vein

Question 17

What is the mucosa of the vas deferens surrounded by? What does sympathetic-mediated contraction of the muscle along the ductus deferens do?

Answer 17

1) The mucosa of the vas deferens is surrounded by circular bundles of smooth muscle
2) Sympathetic-mediated contraction of the muscle propels spermatozoa along the ductus deferens during ejaculation

Question 18

What is a hematocele of the testis?

Answer 18

A hematocele of the testis is a collection of blood in the tunica vaginalis that results, for example, from rupture of branches of the testicular artery by trauma to the testis

Question 19

Why is torsion of the spermatic cord a surgical emergency?

Answer 19

1) Torsion of the spermatic cord is a surgical emergency because necrosis (pathologic death) of the testis may occur
2) The torsion (twisting) obstructs the venous drainage, with resultant edema and hemorrhage and subsequent arterial obstruction

Question 20

Why does a palpable varicocele seem to disappear when the patient lies down?

Answer 20

The enlargement usually disappears when the person lies down, particularly if the scrotum is elevated while supine, allowing gravity to empty the veins

Question 21

Where does the round ligament of the uterus extend from and to?

Answer 21

The round ligament of the uterus extends from the lateral uterine wall through the inguinal canal into the subcutaneous tissue of the labia majora (to be studied later)

Question 22

What is the fate of the processus vaginalis and round ligament in females? What is a result of this?

Answer 22

1) The processus vaginalis and round ligament degenerate

2) Thus, the inguinal canal is typically less clinically relevant in females

Question 23

How is the round ligament related to metastasis of uterine cancer?

Answer 23

1) Some lymphatic vessels follow the course of the round ligament through the inguinal canal
2) Thus, while occurring less often, metastatic uterine cancer cells (especially from tumors adjacent to the proximal attachment of the round ligament) can spread from the uterus to the labium majus, and from there to the superficial inguinal nodes, which receive lymph from the skin of the perineum (including the labia)