Anatomy: The Abdomen II - Inguial Region

anterior superior iliac spine <—> pubic tubercle

it is a region where structures exit and enter the abdominal cavity

the pathways of exit and entrance are potential sites of herniation.

75% - 90%

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 testis

anterior superior iliac spine to the pubic tubercle

a bilaminar anterior (flexor) retinaculum

-spans the subinguinal space

- flexors of the hip and the neurovascular structures serving much of the lower limb pass through the space

external oblique

the pubic tubercle

• superior pubic ramus lateral to the tubercle

• arching lacunar ligament

Pectineal ligament (of Cooper)

These fibers form the reflected inguinal ligament

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

inguinal ligament and iliopubic tract

• area of innate weakness

groin hernias

• direct & indirect inguinal + femoral hernias

• oblique passage

• approx. 4 cm long

• directed inferolaterally through inferior anterolateral abdominal wall

• parallel + superior to medial half of inguinal ligament

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)

in the extraperitoneal connective tissue in the superior lumbar region of the posterior abdominal wall

• male gubernaculum

• future site of the deep ring of the inguinal canal

• 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) 12th week of development

2) by 28 weeks (7th month)

3A) during the 28th week; 3B) takes 3 days

around month 9

(approx. 4 weeks after passing through the inguinal canal)

- musculofascial extensions of the anterolateral abdominal wall

- internal and external spermatic fasciae + cremaster muscle

"tunica vaginalis testis"

• testis + epididymis

(usually obliterates by the 6th month of fetal development)

superior lumbar region of the posterior abdominal wall

• migrate to the lateral wall of the pelvis

protrudes into the developing labium majus

ovary and primordial uterus is connected to the developing labium majus

ovarian ligament (b/t ovary + uterus)

round ligament of uterus (b/t uterus and labium majus)

* (image is premature)

subcutaneous tissue of the labium majus

• females = marrower canals

• infants = shorter canals

almost directly anterior to the deep inguinal rings

"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 openi

innermost covering (internal fascia) of structures that traverse the canal

superficial (external) inguinal ring

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

• 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).

collapsed anteroposteriorly against the structures it conveys

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.

because of the oblique path of 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)

• 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

it makes the roof of the canal descend, constricting the canal

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

• 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

- 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

weakness of anterior abdominal wall in inguinal triangle

owing to:

• distended superficial ring

• narrow inguinal falx

• attenuation of aponeurosis in males >40 yrs

patency of processus vaginalis (complete or at least superior part) in younger persons

• majority of which are males -

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.

1. peritoneum + transversalis fascia

(lies outside inner 1 or 2 fascial coverings)

2. 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)

1. peritoneum of persistant processus vaginalis + all 3 fascial coverings of cord/round ligament

2. 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)