Hernias Flashcards
Describe the inguinal region
It is the Junction between the anterior abdominal wall and the thigh
This area is between the ASIS and the pubic tubercle
The anterior abdominal wall is weakened in the inguinal region
It is clinically important because it is a potential site where most of the abdominal hernias occur.
It is anatomically important because structures exit and enter the abdominal cavity (e.g. spermatic cord, round ligament, vessels
What causes the inherent weakness in the abdominal wall in the groin
Caused by changes that occur in the development of the gonads.
Before the descent of the testes and the ovaries from their original position high in the anterior abdominal wall, a peritoneal outpouching (the processus vaginalis) forms, protruding through layers of the anterior abdominal wall
What do the testes and ovaries gain coverings from
Transversalis fascia (deepest) Second covering is from the internal oblique muscle ( a covering from the transversus is not acquired as the processus vaginalis passes under the arching fibres of the abdominal wall muscle) Its most superficial covering is the aponeurosis of the external oblique.
What forms as a result of the processus vaginalis
It is transformed into a tubular structure with multiple coverings from the layers of the anterior abdominal wall- forming the basic structure of the inguinal canal.
Summarise the inguinal canal
Inguinal canal – The testis and spermatic cord descend from the abdomen into the scrotum via the developing inguinal canal. in the female the uterine round ligament descends through the developing inguinal canal. (testicular descent starts after 7th wk of IUL and enter the inguinal canal around 28 wks of IUL and enters the scrotum by 32-36 wks of IUL.)
Summarise the femoral canal
Another canal below the inguinal ligament through which femoral artery and vein pass
What are these canals vulnerable to
These two canals remain vulnerable throughout life for potential herniation of the abdominal viscera to occur.
Define hernia
A hernia* is a condition in which part or whole of an organ or tissue abnormally protrude through the wall of the structure containing the organ or tissue.
Outline the anatomy of a hernia
Weakness/defect/hole on the wall through which the hernia protrudes
Hernial Sac – e.g. peritoneum with neck, body and fundus
Contents of the hernial sac - e.g. bowel, bladder
Hernial coverings - skin
Summarise the clinical features of hernias
A lump or protrusion in the groin
Appears intermittently or present all the time
Painless/painful and uncomfortable
Hernia may be reducible or irreducible
May be strangulated with tissue death- and associated with vomiting, constipation, intestinal obstruction – this is an emergency situation
List some facts about hernias in the groin
In both sexes most of the groin lumps or swellings are hernias
Inguinal hernias > femoral
Accounts for 10% of surgical outpatient referrals
Inguinal hernias accounts for 7% of surgical outpatient consultations
Accounts for 12% of operating theatre time
Inguinal hernia is 8 times greater in males than in females
Femoral hernias are rare in males -accounts for 2.5% of the groin swellings
Femoral hernias are higher in women and increases with age and number of pregnancies
List the different types of hernias
Inguinal Hernia
Indirect inguinal hernia
Direct inguinal hernia
Femoral Hernia
Describe the structure of the inguinal canal
Slit-like passageway that extends in a downwards and medial direction (oblique) just above and parallel to the lower half of the inguinal ligament
Present in both males and females, 4 cm long in adults
It begins as the deep inguinal ring and ends at the superficial inguinal ring.
What are the contents of the inguinal canal
In males- Contents: spermatic cord & ilioinguinal nerve
In females- Contents: round ligament & ilioinguinal nerve
Also genital branch of the genitofemoral nerve is present in both sexes
Describe the deep inguinal ring
Beginning of inguinal canal and formed halfway between the ASIS and pubic symphysis
It is just above the inguinal ligament and immediately lateral to the inferior epigastric vessels
Beginning of the tubular evagination of the transversalis fascia that forms one of the coverings (internal spermatic fascia) of the spermatic cord or round ligament
Describe the superficial inguinal ring
Superior to pubic tubercle
Triangular opening in the aponeurosis of the external oblique, with its apex pointing superolaterally and its base formed by the pubic crest.
The two remaining sides of the triangle, the medial and lateral crus are attached to the pubic symphysis and the pubic tubercle respectively. At the apex, the two crura are held together by crossing (intercrural) fibres which prevent further widening of the superficial ring.
What is the superficial inguinal ring formed by
It is the beginning of the tubular evagination of the aponeurosis of the external oblique onto the structures transversing the inguinal canal and emerging from the superficial inguinal ring
The continuation of tissue on the spermatic cord is the external spermatic fascia
What are the locations of each of the rings
Deep ring is about 1.5 cm above the midpoint of inguinal ligament
Superficial ring immediately above and medial to pubic tubercle
Describe the anterior wall of the inguinal canal
Formed along its entire length by the aponeurosis of the external oblique
Reinforced laterally by the lower fibres of the internal oblique that originate from the lateral 2/3rds of the inguinal ligament.
This adds an additional covering over the deep inguinal ring, which is a potential point of weakness
Because of this covering it contributes a layer- cremasteric fascia containing the cremasteric muscle to the coverings of the structures passing through the canal.
Describe the posterior wall of the inguinal canal
Formed along its length by transversalis fascia
Reinforced along its medial one-third by the conjoint tendon (combined insertion of the transversus abdominis and internal oblique muscles into the pubic crest and pectineal line)
Position of the conjoint tendon posterior to the superficial ring provides additional support to a point of weakness.
Describe the roof of the inguinal canal
Formed by the arching fibres of the transversus abdominis and internal oblique muscles
they pass from the lateral point of origin from the inguinal ligament to their common medial attachment as the conjoint tendon
Describe the floor of the inguinal canal
Formed by the medial one-half of the inguinal ligament
This rolled under, free margin of the lowest part of the aponeurosis of the external oblique forms a gutter or trough on which the contents are positioned
The lacunar ligament reinforces most of the medial part of the gutter.
Describe the conjoint tendon
lowest fibres of the internal oblique aponeurosis and similar fibres of the transversus abdominis aponeurosis join to form the conjoint tendon. Conjoint tendon is attached medially to linea alba.
Describe the key difference between direct and indirect inguinal hernias
A direct hernial defect tends to go through Hesselbach’s Triangle (inguinal traingle) which is always MEDIAL to the inferior epigastric vessels- through deep inguinal ring
An Indirect hernial defect is always the internal ring which is always LATERAL to the inferior epigastric vessels- through posterior wall of canal
Summarise direct inguinal hernias
Older age group
Acquired defect in posterior wall of the inguinal canal
Associated with chronic straining
Associated with weak musculature
The hernia’s path is straight through the posterior wall of the inguinal canal
Defect is in the posterior wall of the inguinal canal medial to the Inferior epigastric vessels
What are the boundaries of Hesselbach’s triangle
Laterally by the inferior epigastric artery
Medially by the rectus abdominis muscle
Inferiorly by the inguinal ligament
Describe the other features of direct inguinal hernias
Acquired as it develops when abdominal musculature has been weakened- commonly seen in mature men
Internally, a thickening of the transversalis fascia follows the course of the inguinal ligament
This type does not traverse the entire length of the inguinal canal but may exit through the superficial inguinal ring- when this occurs the peritoneal sac acquires a layer of external spermatic fascia and can extend, like an indirect hernia into the scrotum.
Summarise indirect inguinal hernias
Most common type
Tend to be in younger adults and children
The hernia takes an indirect path through the abdominal wall
The defect is a dilated deep ring
The hernia enters the deep ring then passes through the inguinal canal, external inguinal ring and into the scrotum
Describe the features of indirect inguinal hernias
More common in men
Part or all of the embryonic processus vaginalis remains open or patent- it is therefore congenital
Extent of excursion down the canal depends on the amount of processus vaginalis that remains patent.
If all of it is patent- the peritoneal sac may traverse the entire length, exit the superficial ring and continue into the scrotum in men or the labia majus in women
In this case, the protruding peritoneal sac acquires the same three coverings associated with the spermatic cord in men or the round ligament of the uterus in women.
Summarise femoral hernias
Hernia through the femoral canal
Not as common as inguinal hernias
Commoner in elderly and females
Have a high incidence of obstruction and strangulation
What are the borders of the femoral canal
Superior – Inguinal ligament
Inferior – Pectineus fascia
Medial – Lacunar ligament
Lateral – Femoral vein
How do femoral hernias appear on examination
Femoral hernias tend to be irreducible, and hot and painful if they are strangulated
They can be distinguished from inguinal hernias because they appear below and lateral to the pubic tubercle
Inguinal hernias are above and medial to the pubic tubercle
Describe the femoral canal
Lies along the femoral sheath and contains the femoral artery, vein and lymphatics
The neck is extremely narrow and is prone to trapping bowel within the sac- so making this type of hernia irreducible and susceptible to bowel strangulation.
As women have wider pelvises, more likely to occur in women.
What can the extensions of the fibres of the medial end of the inguinal ligament form
Lacunar ligament- crescent shaped extension of fibres at the medial end of the inguinal ligament that pass backwards and attach to the pectin pubis on the superior ramus of the pubic bone
Additional fibres extend from the lacunar ligament along the pecten pubis of the pelvic brim to form the pectineal (Cooper’s ligament)
