The superficial, or external inguinal ring is an opening of the external oblique aponeurosis, located about 1.25cm above the pubic tubercle. It's lined by superomedial and inferolateral crural fibers.
The deep inguinal ring is a U-shaped condensation of the fascia transversalis, located 1.25cm above the mid-inguinal point (midpoint of a line joining the ASIS to the pubic symphysis)
The boundaries of inguinal canal :
a) Anterior : External oblique aponeurosis and cojoined msucles laterally (1/3)
b) Posterior : Fascia transversalis and conjoined tendon medially (2/3)
c) Floor : Inguinal ligament
d) Roof : Internal oblique and Transversus abdominis muscles (the conjoined muscles)
In males, the spermatic cord, genital branch of genitofemoral nerve, and ilioinguinal nerve traverses through the canal
In females, it's replaced by the round ligament of uterus.
Remember the contents of spermatic cord :
2 nerves : genital branch of genitofemoral nerve + ilioinguinal nerve
2 vessels : cremesteric artery, testicular artery
2 structures : pampiniform venous plexus, lymphatics
Noticed that the inferior epigastric artery lies medial to the internal inguinal ring. The triangular area bounded medially by the lateral border of rectus abdominis, laterally by inferior epigastric artery and inferiorly by the inguinal ligament is known as the Hesselbach's triangle.
In case of indirect inguinal hernia, the abdominal contents enters through the deep inguinal ring, traverses through the canal, and exits through the superficial inguinal ring.
In case of direct inguinal hernia, it protrudes directly through the Hesselbach's triangle without entering the deep inguinal ring.
Anatomy of the Femoral canal
The femoral canal overlies the medialmost compartment of the femoral sheath, extending from the femoral ring above to the saphenous opening below.
It's about 1.25cm in length and width, and contains cloquet's node, lymphatic vessels and fat.
The above is closed by septum crurale, whilst below is by the cribiform fascia.
The boundaries of femoral ring :
Anterior : Inguinal ligament
Posterior : Pubic bone, Pectineal fascia, iliopectineal ligament
Medial : Lacunar ligament
Lateral : Septum that divides it from the femoral vein
A hernia is defined as an abnormal protrusion of a viscus (or part of it) through an abdominal opening of the wall of it's containing cavity.
Before discussing about inguinal hernia, there's some basic concepts must be understood first.
Composition of hernia :
1) The sac
2) The coverings of sac
3) The contents of sac
Possible contents of the sac :
Omentum -> Omentocele
Intestines -> Enterocele
Ovary without fallopian tubes
Part of the bladder
Circumferential part of an intestine (Ritcher's Hernia)
Meckel's diverticulum (Littre's Henia)
5 clinical types of Hernia :
1) Reducible hernia
It means the hernia can be reduced, either spontaneously when the patient lies down supine, or manually.
For enterocele, the initial part of reduction is difficult. A gurgling sound is usually heard.
For omentocele, the initial part of reduction is easy, but the terminal part is difficult.
2) Irreducible hernia
Usually occurs due to adhesion occurs in between the neck of the sac and contents or even when there's overcrowding of contents.
Other than the irreducibility, there's no other abnormalities.
There's a risk of strangulation at any time.
3) Obstructed hernia
It means the intestinal loop within the hernial sac is obstructed.
Presents with cardinal features of intestinal obstruction.
Eventually progresses towards strangulation.
4) Strangulated hernia
In this case, not only there's bowel obstruction, but with ischaemia of the contents within the sac.
Gangrene of the contents usually occurs 5-6 hours after the onset.
There are 2 types of inguinal hernia :
1) Direct inguinal hernia
It's an accquired hernia.
Almost always seen in elderly, or individuals with the nature of occupation is lifting heavy weights (manual labourers).
Previous apendicectomy, which involves an accidental removal of the ilioinguinal nerve predisposes to direct inguinal hernia, since it weakens the abdominal wall.
The size of hernia is usually small, and rarely descends down to the scrotum.
Since the neck of the hernia is wide, direct inguinal hernia rarely strangulates.
2) Indirect inguinal hernia
Types of indirect inguinal hernia :
1) Bubonocele - The extent of protrusion of the viscus is within the canal
2) Funicular - The processus vaginalis obliterates just above the epididymis. Hence, the hernia is separately palpable from the testis (above it)
3) Complete - extending from the deep inguinal ring, through the canal, exits the superficial ring and down to the scrotum.
Differential diagnosis of inguinal hernia :
a) In males :
1) Vaginal hydrocele
2) Femoral hernia
3) Encysted hydrocele of the cord
4) Lipoma of the cord
5) Undescended testis within the canal
b) In females
1) Femoral hernia
2) Hydrocele of the canal of nuck
The incidence of femoral hernia is more common in females (Female:Male ratio=2:1). The major problem regarding femoral hernia the risk of strangulation is high.
This is mainly due to the narrow neck of the hernia sac and rigidity of the femoral ring.
Hence, once femoral hernia is clinically identified, operation must be done as soon as possible.
Differential diagnosis of femoral hernia :
1) Inguinal hernia
2) Saphena Varix
3) Enlarged cloquet's node
4) Femoral aneurysm
5) Psoas abscess
History taking in a case of Hernia
1) Firstly, the typical questions for lump
When do you noticed it?
How do you noticed it?
Is there any other lumps in the body?
How does this lump disturbs you? (Associated symptoms)
Any change in the size of the lump since you noticed it?
What is the initial size?
What is the current size?
What do you think is the cause?
2) Questions specific for hernia
Is the swelling reducible?
(If not reducible, ask for previous h/o of reducibility)
When you cough/exerts, does it increase in size?
Any dragging pain, sensation of heaviness?
What's your occupation?
Is there any history of chronically raised intra-abdominal pressure?
(eg, chronic cough, vomiting, abdominal distension, constipation, micturition)
Is there any history of : (Strangulation)
Colicky abdominal pain?
Is there previous history of abdominal surgery?
Do you smoke? (Increases risk)
*Always bear in mind that hernia in elderly might be a sign of malignancy
Examination of hernia
1) Positioning of patient and exposure
Examine the patient while he/she is standing.
Exposure - umbilicus to the knee
Note, is it right/left sided or bilateral?
Is it confined to the groin, or it extends down to the scrotum?
What's the shape?
Measure the size of the swelling.
Over the skin of the swelling, is there signs of inflammation?
Ask the patient to look up the ceiling and cough. Does it the swelling expands?
Check whether there's any rise of temperature
Try getting above the swelling, using your index finger and thumb. If possible, then, most likely it's a pure scrotal lump, otherwise, it's an inguino-scrotal swelling.
Comment on the surface, and note if there's any tenderness.
Is the testis separately palpable from the swelling?
Is the skin over the swelling pinchable?
Now, stand beside the patient.
Place your right hand over the patient's back, with your left hand approximately parallel to the inguinal ligament, place it over the swelling.
Now ask the patient to cough.
Note any increased tension of the contents and any expansile cough impulse.
Now, ask the patient to lie down in supine position.
If the swelling does not reduce spontaneously, ask if he/she can reduce it him/herself.
If not possible, then, manually reduce it yourself.
Note the position of pubic tubercle.
While patient in standing position, gently press over the swelling, and then it's lower part.
Then, gently lift the swelling upwards, and towards the superficial ring.
If the swelling reduces at a point medial and above to the pubic tubercle, it's an inguinal hernia.
If the swelling reduces at a point lateral and below to the pubic tubercle, it's femoral hernia.
Then, try sliding your hand laterally and upwards, towards the deep ring.
Can the swelling be controlled by pressure over the deep ring?
Now, remove your hand from the area of swelling.
For direct hernia, it projects directly forwards.
For indirect hernia, it runs obliquely through the canal, then only protrudes out.
4) Deep ring occlusion test
After complete reduction of hernia, place your thumb over the deep ring.
Ask the patient to cough.
If the swelling doesn't reappears -> Indirect inguinal hernia
If the swelling appears medial to your thumb -> Direct inguinal hernia
Any bowel sounds?
6) Examine the abdomen for any signs of raised intra-abdominal pressure
6) Examine the abdomen for any signs of raised intra-abdominal pressure