Anatomy - Lec.13

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Inguinal Region and HerniaSuha Aqaileh

Mohammad Al-Haidari

Tuesday, 27/9/2011

Anatomy

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Anatomy Lecture 13

Tuesday, 27-9-2011

Done by: Suha Aqaileh

Inguinal Region and Hernia

Today well cover what might happen in the abdominal muscles abnormally and

leads to what is called herniation of certain internal viscera.

Hernia: a protrusion of viscera through a weak point in a muscle.

These are common sites for herniation:

1- Abdominal wall and umbilicus region2- Inguinal region

1- Abdominal wall and umbilicus region:One of the common herniations is linked to the abdominal wall, but why?

Because theres no bone support (as rib cage for example) and all the coverings are soft

tissue, skin and muscles although we have tendinous intersections which protect the

central median muscle in the middle, but this intersection will be terminated at the level

of umbilicus, so anything below the level of umbilicus is mainly a muscle and theres no

protection for it. Also the umbilicus (which is lying in the midline between the two recti

muscles in linea alba) itself is a weak point because its the site ofumbilical cord; it used

to be an opening/connection between the fetus and the maternal side and it should be

obliterated, but it remains a weak point.

So umbilicus is a weak region; for that, when new born children cry, a bulge will

usually be seen at the region of umbilicus. This is a common problem which should


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subside within few months or a year, so this is what we call umbilical hernia (common in

children) - see the figure below.

In adult, if theres a diversion of the rectus muscle -see the figure below- (usually

in the region of linea alba) from one another, itll make a weak point and this usually

happens in people who have an increase in the intra-abdominal pressure.

What might increase intra abdominal pressure?

- Pregnancy

- Chronic cough

- Tumor, masses

- Pressure during constipation


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This problem (diversion of recti) is common in multipara women (women who gave

birth for several children); they will have weakness and laxity in this region and a part of

internal viscera might bulge outside because of this weakness.

2- Inguinal region:The commonest hernia is in the region of the lower abdomen (at the junction of the

lower limbs with the abdomen) which is called the groin or the inguinal region, why do

we call it inguinal region?

Because theres a very important tough strong ligament attached in that region

between two bony projections: a lateral one (anterior superior iliac spine) and a medial

one (the pubic tubercle).

There are three muscles at the lateral aspect of the abdominal; all of them

approach the midline and meet the straight tough muscle in the middle (the rectus).

These 3 muscles are very thin, membranous in shape, they have muscular fleshy part

laterally and when they approach anteriorly to the rectus, they become aponeurotic


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fibers; so you can see the aponeurosis of these muscle anteriorly while laterally the

fleshy part.

We can identify them by examining the fleshy part; actually they are

continuation of the same muscles of the thoracic wall. In the thorax, there are internal

and external intercostals while in the abdomen we have internal and external oblique;

they are the same muscles; they have the same direction -downward, forward for the

external and backward, upward for the internal-. So actually in the thoracic region, ribs

cut these intercostal muscles, so what we see in adult are just small spaces between the

ribs, for that we call them intercostals, but in the abdomen, theres no interruption;

theres a continuation, a flat large muscle (internal and external oblique), the 3rd

one

whichs the deepest one is the transversalis muscle and of course -as other abdominal

wall muscles- when it approaches anteriorly, it loses the fleshy part and becomes the

transversalis fascia.

So, all abdominal wall muscles terminate at the inguinal ligament. The most

superficial muscle (the external oblique) attaches itself to the ligament (inguinal

ligament) and twists around it, so actually it makes a sort of gutter or canal.


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The weakness which might happen at this region may lead later on to a

protrusion of a viscus which we call hernia because its a soft abdominal muscular region

and pressure is present.

In this region, we have many modifications between males and females because

here is the region of the central portion; the perineum where the genital organs are

present, so in addition to these (factors make this region weak), the genital organs in

this region lead to weakness. So being very close to the perineum -the site of the genital

organs especially in male gonads (testis)- adds more weakness to this region.

How can we explain this weakness?

Gonads are abdominal organs (they are not pelvic or perineal organs as they aresupplied (testicular or ovarian arteries) by the abdominal aorta). Gonads originally (in

the fetus before birth) were in the posterior abdominal wall when they start to mature

and descend (whether they are ovaries or testis) to their final destination.

The male gonads require temperature whichs lower than body temperature ,

while the female gonads require the same as body temperature for them to function

normally. So how can the male gonads achieve lower temperature than the body? They

should leave the body to certain specialized sac which is present outside the body

(which is called the scrotum).

In the female its the same journey, but the gonads (ovaries in this case) should

be arrested somewhere and not allowed to leave the body, so it will stay in the body to

be subjected to body temperature to function normally at puberty.

So both gonads will start their descending from the abdomen to their final

destination during early life but one of them (testis) should have a special sac outside

the body to achieve lower temperature.


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(The figure below maybe isnt clear as the doctor showed but it might help.)

In the region of the perineum, as soon as gonads start to descend, it will start to

prepare the sac for their reception in both sexes, so a bulge will appear in the

perineal region. In males, a continuous descend will pull the testis in this sac until it will

be housed in the scrotum, while in females the same sac is present but when it reaches

a side where its going to leave the body theres another organ (the uterus), which has

two extensions, having a sort of motile distal end which will hold it so the embryo

uterine tube will hold the ovaries and itll remain pelvic, but in the male theres nothing

to hold the testis and no need for holding them, so they will continue their descend until

they reach the scrotum with specialized skin and sweat glands to keep the temperature

lower than body temperature.

Q: Are the testis and ovaries mature at this stage?

No, they are still immature. The maturity will start at the age of puberty but medically

you can examine them and decide if these gonads are ovaries or testis.


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The male gonads are going to cross the pubic body from above and leave the

body until it reaches the final destination, while in females gonads it wont be allowed

to reach there because it will be held by uterine tubes of the uterus.

The point of the passage of the male gonad into the scrotum is the inguinal

canal; it actually passes through this canal whichs formed by ligaments and the folding

of lateral muscles of the abdomen.

Females have the same structure (sac) in the same region but they are actually

smaller in size because theres no complete descend of the gonads and the sac which

was prepared for the gonads didnt receive them, so itll remain a bulge without an

organ (this bulge is called labia majora which has the same origin as the scrotum).

So in the passage of the females gonads -which is prevented by uterine tubes-

whats remaining is just the track with ligament in it holding the ovaries and of course

the side ligament which goes in the same direction! We call it the round ligament of the

uterus.

So in the case of males, we can see testis with its following tube, while in females

we cant see ovaries; we only see a remnant of the round ligament of the uterus and

adipose tissue, so the whole sac is closed (by adipose tissue and ligament); theres no

organ, theres no cavity. So, its very rare to have bulging of viscera in females because

the opening is very small (so less weakness) compared to males.

The whole abdominal region is covered by muscles that are covered by specific

fascia. Now when fascia reaches the groin, it actually ends there, so theres a complete

separation between the abdominal wall and the thigh wall (for example, if one has a car

accident and ruptured his bladder, urine will spread through the abdomen alone and it

wont descend to the lower limbs because of the fascia).

Fascia of abdomen is 2 types: fatty and membranous; it covers the whole area

and reflects to the perineum.


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The membranous one we call it the Scarpas fascia, while the fatty one we

called it the Campers fascia. By looking at the sagittal section, we can see how the

fascia of the abdomen is separated from that of the lower limb; you see the whole fascia

will surround the genital organ and the sac prepared for gonads until they reach in

urogenital triangle and they will end there in central adhesion - we call it the perineal

body. So this fascia prevents the whole abdominal content from descending down in the

thigh region; thats why ruptured bladder will spread the urine inside the abdomen but

it wont reach down the lower limb.

So again remember the fascia with its 2 layers which covers the abdomen and

surrounds the genital organ and sac until it reaches the end at perineal bodyposteriorly.

Q: the two layers of the fascia will end at the perineal body or just one?

Both of them will terminate there.


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If we come to the inguinal region, the 3 muscles which we numerated (external

oblique, internal oblique, and transversalis) reach the inguinal ligament region. 2 of

them have deficiency or an opening within their structure. Now, when a gonad is

approaching this region and wants to descend, it should first meet the transversalis, so

the first weakness (which we call the deep inguinal opening/ring) presents in

transversalis fascia. If the structure passing through this canal -which is made by

ligaments and is directed toward midline-, it should leave it through another triangular

opening externally through external oblique aponeurosis (called the superficial inguinal

ring).

In children, these openings are situated one against the other. When the child

grows, stretch and elongation of the ligament will take place and the two openings will

appear at a different position making a sort of canal which actually houses the tubeconnected to the testis in males or houses the round ligament in females


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So this canal was one opposite to the other in new born, but then with growth it

elongates, actually in adults its about 4-5 cm of course oblique in direction and in the

direction of the inguinal ligament (between anterior superior iliac spine and pubic

tubercle). Both sexes have the same canal, the same rings, the same direction, but the

contents are different.

If rings (superficial and deep) are opposite to each other in children, we dont

expect that increased intra abdominal pressure will create a problem; thats why its

very rare to see herniation in children in this region. You will see herniation in adults and

itll increase with age because of laxity which might take place on the abdominal wall

and increase intra-abdominal pressure.

Q: Isnt it weaker when the two openings are opposite to each other in children than in

adult?

Yes weaker, but in children the viscera are very small compared to the adult (about

meters in length), so there isn't much pressure in children and if theres a pressure the

hernia will be in the umbilicus children.

Q: Theres no opening in the internal oblique muscle fascia, so how can the viscera pass

through it?

It will push the fascia with it, you will see that it pushes the transversalis fascia and takes

it with it as covering, whatever surrounds it will push it also and take it as covering and

when it approaches the superficial ring it emerges with the covering and goes down into

its terminal destination.


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You know that the superior epigastric artery is a branch of the internal thoracic

artery (internal thoracic artery will branch at the level of 7th

intercostals space into

musculophrenic and superior epigastric) and the inferior epigastric artery is a branch of

the external iliac artery. Actually, the inferior epigastric artery is a land mark in surgery

because the ring lateral to it is the deep inguinal ring and the ring medial to it is the

superficial inguinal ring. (See the figure below)

If you look at a section of the

inguinal canal in male, you can see the deep

and superficial inguinal rings. The whole

structure of the testis; its covering and the

tube/duct (vas deferens: which transmitswhat is produced in testis) should always

remain in this region from testis down to the

seminal vesicle behind the urinary bladder,

so its always present there in the inguinal

canal with nerves, vessels and certain

venous plexus.

If the intra-pressure increases for

any reason, it has 2 chances to push certain

viscera against a weakness (see the figure

on the next page):

# If it passes through deep inguinal ring, it s

going to run/pass obliquely until it reaches

(if the pressure continues) the scrotum and

we can see hernia filling the whole scrotum;

this is called oblique/indirect hernia.

# If the pressure is on this direction -more

medially-, itll push against the superficial

ring and if pressure continues, itll create

another bulge and travel into the scrotum;

this is called direct hernia.


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In hernia sac, what passes is actually a viscus; usually a loop of intestine, the

apex or the major part is what goes first and the rest will follow. The problem in

herniation is when these rings constrict and prevent these loops from going back; this

might lead to strangulation, this is a medical emergency, so you have to push the hernia

and suture the area to obstruct the enlargement. So what passes is actually loops of

intestine into the scrotum and it might be direct or indirect.

Femoral hernia

Inguinal hernia especially the indirect is more common in males and very rare in

females because there's no canal structure. But theres another type of hernia in which

the females will have more weakness than males; this called the femoral hernia.


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This is the inguinal region and the inguinal canal behind it, and passing from the

pelvis to the recti is a fascial canal called the femoral canal which surrounds 3

structures: the artery laterally, the vein medially, and adipose tissue in the most medial

part; this is what we call femoral canal and this is wider in females because the pelvis

itself structurally is wider in females. So, the femoral canal is another weak point which

presents in both sexes but with old age and increasing pressure the females has more

chance to develop herniation in this region than the inguinal one.

Sorry for any mistakes .

Good luck

Anatomy - Lec.13

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