Renal anatomy

Question 1

What is the inguinal canal?

Answer 1

An oblique passageway through the muscles of the anterior abdominal wall, lying superiorly to the medial half of the inguinal ligament
It passes through each layer of the abdominal wall extending from the deep inguinal ring (an aperture in the transversalis fascia) to the superficial inguinal ring (an aperture in the external oblique aponeurosis)

Question 2

What are the borders of the inguinal canal?

Answer 2

Anterior- external oblique aponeurosis
Antero-laterally- internal oblique aponeurosis
Posterior- Transversalis fascia
Postero-medially- medial fibres of the aponeurosis of the internal oblique and transversus abdominis (form the conjoint tendon)
Roof- Transversalis fascia and arching fibres of the internal oblique and transversus abdominis
Floor- Inguinal ligament (lower border of the external oblique aponeurosis)

Question 3

What are the contents of the inguinal canal in females?

Answer 3

Round ligament of the uterus
Ilioinguinal nerve
Genital branch of the genitofemoral nerve

Question 4

What are the contents of the inguinal canal in males?

Answer 4

All the contents of the inguinal canal are within the spermatic cord EXCEPT the ilioinguinal nerve.
There are 2 nerves: genitofemoral nerve and sympathetic nerve fibres
There are 3 arteries: testicular artery, cremasteric artery and artery to the vas deferens
There are 3 fascial layers: External spermatic fascia (derived from external oblique aponeurosis), cremaster muscle and fascia (internal oblique), internal spermatic fascia (transversalis fascia)
There are 4 structures: pampiniform venous plexus, lymphatics, vas deferens, processus vaginalis (superior to testis)

Question 5

What is a hernia?

Answer 5

An abnormal protrusion of tissues or organs from one region into another due to muscle weakness or incised muscles during surgery

Question 6

What is an inguinal hernia? Usually which organs are involved?

Answer 6

When there is a protrusion of abdominal contents (usually the greater omentum and loops of small intestine) through the anterior abdominal wall into the inguinal canal.

Question 7

What is the difference between a direct and indirect inguinal hernia?

Answer 7

Indirect → When intra-abdominal contents are forced through the deep inguinal ring and into the canal. They may even be forced through the superficial inguinal ring and possibly extend into the scrotum or labia majora.
Direct → When intra-abdominal contents are forced through the posterior wall of the inguinal canal (through the relatively weak transversalis fascia) and directly through the superficial inguinal ring.
Herniated tissue can strangulate and become ischemic. It can lead to scrotal swellings
Indirect → can become irreducible and are more common than direct hernias
Direct → are often easier to reduce and are less common than indirect hernias

Question 8

What forms the scrotal septum?

Answer 8

Superficial fascia

Take note: each half of the scrotum contains a testis, epididymis and lower part of the spermatic cord.

Question 9

What are the testes covered by?

Answer 9

Three layers of fascia, (external spermatic fascia, cremaster muscle and fascia, and internal spermatic fascia)
They are also partially surrounded by a sac derived from the peritoneum called the tunica vaginalis.

Question 10

What is the epididymis?

Answer 10

A coiled tube lying along the posterior border of each testis. It has an expanded head superiorly, a body and a pointed tail lying in the lower pole of the testis.

Question 11

Where is spermatozoa formed and stored?

Answer 11

They are formed in the testis and stored in the epididymis.

Question 12

What is the function of the vas deferens?

Answer 12

It is a muscular tube that travels from the epididymis, through the spermatic cord to just posterior of the bladder (urethra) and it transports mature sperm to prepare for ejaculation

Question 13

What is the blood supply and drainage of the testes?

Answer 13

The testes is supplies by the testicular arteries which are a direct branch from the abdominal artery
The venous blood from the testes and epididymis enters the pampniform venous plexus which forms the testicular vein. The right testicular vein drains into IVC and the left testicular vein drains into the left renal vein.

Question 14

What are the erectile tissues of the penis? What are they enclosed by?

Answer 14

2 corpora cavernosa (dorsally, top of penis)
1 corpus spongiosum (ventrally, bottom of penis)
They are enclosed within the deep fascia of the penis (buck’s fascia)

Question 15

What is the end of the penis called? And what is it an expansion of?

Answer 15

The glans, an expansion of the corpus spongiosum.

Question 16

What does the penile urethra carry, where does it lie and where does it open?

Answer 16

It carries urine and semen
It lies in the corpus spongiosum and it open via the external urethral meatus towards the end of the penis

Question 17

What is the arterial supply of the penis?

Answer 17

It is supplied by the penile arteries which branches of the internal pudendal arteries which branch of from the internal iliac arteries (branches of the abdominal aorta)

Question 18

What is the nerve supply of the penis? (sympathetic and parasympathetic)

Answer 18

Supplied by nerves from S2 - S4 (pudendal nerve)
General sensation and sympathetic innervation is carried by the dorsal nerve a branch of the pudendal nerve
Parasympathetic nerve fibres (which cause erection by dilating the arteries of the corpora) arise from the peri-prostatic nerve plexus

Question 19

What happens during penile erection? What is the main role of the corpus spongiosum?

Answer 19

The corpora cavernosa are primarily responsible for the increase in size and rigidity of the penis during an erection.
During sexual arousal, arterial blood flow into the corpora cavernosa increases (so the corpora become engorged with blood)
(corpus spongiosum also becomes engorged with blood but not to same extent)
The corpus spongiosum main role is to prevent the urethra from being compressed, which would prevent ejaculation.