The Abdomen II - Inguial Region Flashcards
The inguinal region (groin), extends between…
anterior superior iliac spine <—> pubic tubercle
The inguinal region is important anatomically because…
it is a region where structures exit and enter the abdominal cavity
The inguinal region is important clinically because…
the pathways of exit and entrance are potential sites of herniation.
inguinal hernias account for _________% of all abdominal hernias?
75% - 90%
Which gender statistically experiences more inguinal hernias?
What is the percentage and why do this occur?
occur in both sexes, but **more commonly in males **
- approximately 86%
because the spermatic cord passes through the inguinal canal; it is bigger than the round ligament in female therfore, the canal is larger making it weaker.
The inferior migration of which male structre (originally formed in the abdomen) accounts for many of the structural features of the inguinal canal?
the testis
The inguinal ligament (and iliopubic tract) extends from …….
anterior superior iliac spine to the pubic tubercle
The inguinal ligament is a ______________ of the hip joint?
a bilaminar anterior (flexor) retinaculum
What does the a bilaminar anterior (flexor) retinaculum (inguinal ligament) span, and which structure pass through this space?
-spans the subinguinal space
- flexors of the hip and the neurovascular structures serving much of the lower limb pass through the space
The inguinal ligament is a dense band constituting the inferiormost part of the aponeurosis of which anterior abdominal muscle?
external oblique
Most of the fibers of the inguinal ligament’s medial end insert into….?
the pubic tubercle
Some of the deeper fibers of the inguinal ligament pass posteriorly to attach to the ___________?
These fibers form the _______________, which forms the medial boundary of the subinguinal space.
- superior pubic ramus lateral to the tubercle
- arching lacunar ligament
The most lateral fibers of the inguinal ligament continue to run along the pecten pubis, forming the ____________?
Pectineal ligament (of Cooper)
Some of the more superior fibers of the inguinal ligament fan upward, crossing the linea alba + blending with the lower fibers of the contralateral external oblique aponeurosis. These form what ligament?
These fibers form the reflected inguinal ligament
Iliopubic tract
thickened inferior margin of the transversalis fascia
- appears as a fibrous band running parallel and deep to the inguinal ligament
- reinforces the posterior wall + floor of the inguinal canal; bridges the structures traversing the subinguinal space
The myopectineal orifice is a region of the groin spanned by what two structures?
Is it considered to be strong or weak?
inguinal ligament and iliopubic tract
- area of innate weakness
The myopectineal oriface is the site of what common type of injury?
What 2 types of this injury are frequently seen here?
groin hernias
- direct & indirect inguinal + femoral hernias
Describe the inguinal canal in adults
- oblique passage
- approx. 4 cm long
- directed inferolaterally through inferior anterolateral abdominal wall
- parallel + superior to medial half of inguinal ligament
What is the main structure passing through the inguinal canal in males?
What is the main structure in females?
males = spermatic cord
females = roung ligament
- functionally + deveopmentally disctint structures occuring in the same location
- also contains blood and lymphatic vessels and the ilioinguinal nerves (both sexes)
Where do the testes develop?
in the extraperitoneal connective tissue in the superior lumbar region of the posterior abdominal wall
What is the fibrous cord connecting the primordial testis to the anterolateral abdominal wall?
This is the future site of what?
- male gubernaculum
- future site of the deep ring of the inguinal canal
What is the processus vaginalis?
- A peritoneal diverticulum traversing the developing inguinal canal
- carries muscular + fascial layers of the anterolateral abdominal wall before it as it enters the primordial scrotum
1. The testis is in the pelvis by what week of development?
2. Testis lies close to the developing deep inguinal ring by what week?
3A. Testis begins to pass through the inguinal canal during what week?
3B. This process takes approx. how many days?
1) 12th week of development
2) by 28 weeks (7th month)
3A) during the 28th week; 3B) takes 3 days
At what time does the testis enter the scrotum?
around month 9
(approx. 4 weeks after passing through the inguinal canal)
As the testis, its duct (the ductus deferens), and its vessels and nerves descend, they are ensheathed by ____________________?
These account for the presence of their derivatives in the adult scrotum: the_____________ and _____________?
- musculofascial extensions of the anterolateral abdominal wall
- internal and external spermatic fasciae + cremaster muscle
The stalk of the processus vaginalis normally degenerates; however, its distal saccular part forms the ______________, the serous sheath of what 2 structures?
“tunica vaginalis testis”
- testis + epididymis
(usually obliterates by the 6th month of fetal development)
The ovaries develop in the what part of the body?
Where do they migrate to?
superior lumbar region of the posterior abdominal wall
- migrate to the lateral wall of the pelvis
As in the male, the processus vaginalis of the peritoneum traverses the transversalis fascia at the site of the deep inguinal ring, forming the inguinal canal as in females.
What structure does it protrude into?
protrudes into the developing labium majus
What structures are connected by the female gubernaculum?
ovary and primordial uterus is connected to the developing labium majus
After birth, the female gubernaculum is represented by what structure?
(2 different names in 2 different areas)
ovarian ligament (b/t ovary + uterus)
round ligament of uterus (b/t uterus and labium majus)
* (image is premature)
Because of the attachment of the ovarian ligaments to the uterus, the ovaries do not descend to the inguinal region; however, the round ligament passes through the inguinal canal and attaches to the ________________?
subcutaneous tissue of the labium majus
The inguinal canals in females are wider/narrower than those in males?
The canals in infants of both sexes are shorter/longer and much less oblique than in adults?
- females = marrower canals
- infants = shorter canals
Where do superficial inguinal rings in infants lie?
almost directly anterior to the deep inguinal rings
What is the internal entrance to the inguinal canal called?
Where is it located?
“deep (internal) inguinal ring”
located:
- superior to the middle of the inguinal ligament
- lateral to the inferior epigastric artery
*it is the beginning of an ivagination in the transversalis fascia = forms an opening*
The transversalis fascia itself continues into the inguinal canal, forming_____________?
innermost covering (internal fascia) of structures that traverse the canal
What is the inferior opening of the inguinal canal called?
superficial (external) inguinal ring
What are crura?
Where do the lateral crus and medial crus attach to?
parts of the external oblique aponeurosis that lie lateral and medial to, and form the margins of, the superficial ring
lateral crus = pubic tuberacle
medial crus = pubic crest
intercrural fibers
- superficial layer of investing (deep) fascia
- overlying the external oblique muscle and aponeurosis (perpendicular)
- pass from one crus to the other (across the superolateral part of the ring)
- help prevent the crura from spreading apart (i.e., they keep the split in the aponeurosis from expanding).
Between its 2 openings, the inguinal canal has two walls (anterior and posterior), as well as a roof and floor.
What is its normal position?
collapsed anteroposteriorly against the structures it conveys
What are the boundaries of the following inguinal canal regions?
- anterior wall
- posterior wall
- superior wall (roof)
- inferior wall (floor)
1. Anterior wall: aponeuroses of the external oblique and internal oblique muscles.
2. Posterior wall: aponeurosis of the transverse abdominal muscle and transversalis fascia.
3. Superior wall (roof): arching fibers of the internal oblique and transverse muscles.
4. Inferior wall (floor): inguinal and lacunar ligaments.
Why don’t the deep and superficial inguinal rings in the adult overlap?
because of the oblique path of the inguinal canal
What effect does intra-abdominal pressure have on the inguinal canal?
- it acts on the inguinal canal, forcing the posterior wall of the canal against the anterior wall and strengthening this wall
- decreasing the likelihood of herniation
(until the pressures overcome the resistant effect of this mechanism)
What effect does contraction of the external oblique have on the inguinal canal?
- it approximates the anterior wall of the canal to the posterior wall
- also increases tension on the medial and lateral crura, resisting enlargement (dilation) of the superficial inguinal ring
When the muscles forming the lateral part of the arches of the internal oblique and transverse abdominal muscles contract, what effect does it have on the inguinal canal?
it makes the roof of the canal descend, constricting the canal
Inguinal Hernias
protrusion of parietal peritoneum and viscera, such as the small intestine, through a normal/abnormal opening from the cavity in which they belong
- Most hernias are reducible (thru appropriate manipulation)
- Between 80% and 90% of abdominal hernias are in the inguinal region
- 2 main types = **direct + indirect inguinal **hernias
- More than 2/3 are indirect hernias
**Indirect inguinal hernia **
- passes through the deep inguinal ring, inguinal canal, and superficial inguinal ring and descends into the scrotum
- lies lateral to the inferior epigastric vessels
- more common than direct inguinal hernia
- found more commonly on the right side in men
**Direct inguinal hernia **
- occurs directly through a weakened area of the abdominal wall muscles (posterior wall of the inguinal canal), lateral to the edge of the conjoint tendon (falx inguinalis), in the inguinal triangle
- rarely descends into the scrotum
- lies medial to the inferior epigastric vessels
- protrudes forward to (rarely through) the superficial inguinal ring
- acquired (develops after birth) and has a sac formed by the peritoneum and occasionally the transversalis fascia
Predisposing factors for direct (aquired) hernias
weakness of anterior abdominal wall in inguinal triangle
owing to:
- distended superficial ring
- narrow inguinal falx
- attenuation of aponeurosis in males >40 yrs
Predisposing factors for indirect (congenital) hernias
patency of processus vaginalis (complete or at least superior part) in younger persons
- majority of which are males -
FACT CARD:
The peritoneal part of the hernial sac of an indirect inguinal hernia is formed by the persisting processus vaginalis.
FACT CARD:
If the entire stalk of the processus vaginalis persists, the hernia extends into the scrotum superior to the testis, forming a complete indirect inguinal hernia.
Direct (aquired) Hernia:
- What structures exit the abdominal cavity?
- How dies it exit the abdominal cavity?
- peritoneum + transversalis fascia
(lies outside inner 1 or 2 fascial coverings)
- passes thru/around inguinal canal (usually onlu traversing medial 1/3 of canal) external + parallel to remnant of process vaginalis.
EXITS THRU: superficial ring, lateral to cord.
(rarely enters scrotum)
Indirect (congenital) Hernia:
- What structures exit the abdominal cavity?
- How dies it exit the abdominal cavity?
- peritoneum of persistant processus vaginalis + all 3 fascial coverings of cord/round ligament
- Traverses inguinal canal (entire length is size is sufficient) within processus vaginalis
EXITS THRU: superficial ring inside cord
(commonly passing in to scrotum/labium majus)
