Hernias and other groin problems
Introduction
The anatomy of the groin provides a good starting point for understanding surgical problems in this area and is explained in Figure 32.1.
Fig. 32.1 Structure of the inguinal and femoral canals
(a) The entire groin area. The surface marking of the femoral pulse is shown, midway between the pubic symphysis and the anterior superior iliac spine; the deep ring lies 2.5 cm above it. (b) Structure of the femoral canal—the abdominal opening seen from below. (c) Structure of the inguinal canal. The inguinal canal displayed by incising the anterior wall (external oblique aponeurosis) as in the first stage of open repair; the spermatic cord has been removed for clarity
Lumps in the groin
• Examine the patient both standing and lying
• Examine for the presence of a cough impulse and test the reducibility of the lump
• Demonstrate the relationship of the origin of the lump to the inguinal ligament and the pubic tubercle
Position for examination
The patient must first be examined whilst standing, which increases intra-abdominal pressure, making any hernia more visible. Ask the patient to cough while palpating the lump: intra-abdominal pressure is thus transmitted through the abdominal wall and an expansile cough impulse is felt in a hernia. Small inguinal hernias may reduce on lying down, and a scrotal varicocoele (see Ch. 33) will empty.
Consistency and reducibility
Hernias are usually soft and ‘squishy’ but the most reliable diagnostic sign is if the lump reduces when the patient lies flat or can be reduced by gentle manipulation by patient or clinician. Most inguinal hernias are at least partly reducible, although longstanding hernias gradually become irreducible because of adhesions within the sac. These are said to be incarcerated, i.e. chronically irreducible. In contrast, femoral hernias are nearly always irreducible and have no cough impulse as the femoral canal is so narrow (see Table 32.1).
Table 32.1
Summary of groin lumps and swellings and their clinical features
Disorder | Anatomical/developmental basis | Clinical features |
a. Inguinal hernia Direct |
Simple bulging of abdominal contents resulting from inadequate support by weak or ruptured posterior wall of inguinal canal (transversalis fascia) | Discomfort; lump usually disappears on lying down; risk of incarceration if large but low risk of strangulation |
Indirect | Passage of abdominal contents, often including bowel, through inguinal canal towards scrotum or labium majus | Potential for incarceration and strangulation; much more common in men |
b. Femoral hernia | Abdominal contents, often including bowel, migrate into femoral canal | Rarely has a cough impulse; rarely reducible; high rate of strangulation; more common in women |
c. Inguinal lymphadenopathy | Inguinal nodes drain lower limb, abdominal wall below umbilicus, anal canal, scrotal skin, penis (but not testes, which drain to para-aortic and para-iliac nodes) | Enlarged nodes indicate infection, lymphoma or metastases from primary lesion in drainage area |
d. Saphena varix | Dilatation of long saphenous vein superficial to deep fascia before it enters the femoral vein | Can be mistaken for femoral hernia but empties on pressure and disappears on lying down, unlike femoral hernia; varicose veins present in the leg |
e. Femoral artery aneurysm | Dilatation of common femoral artery just below inguinal ligament | Found in patients over 65 years, mostly male; classic clinical sign is expansile pulsation; could be mistaken for femoral hernia |
f. Psoas abscess | Classically, a tuberculous abscess of lumbar vertebra tracking down inside sheath of psoas muscle; occasionally a pyogenic abscess originating within the abdomen presents via the same route | TB presents as swelling or ‘cold abscess’ below inguinal ligament; rare nowadays but may be confused with lymph nodes; pyogenic abscess typically ‘hot’; rarely may be due to abscess from renal stones |
Relationship to the inguinal ligament
The site of the lump in relation to the inguinal ligament needs to be identified. The ligament is not visible but stretches between two palpable bony prominences, the anterior superior iliac spine laterally and the pubic tubercle medially (see Fig. 32.1a). The pubic tubercle is higher than might be imagined from the skin contour, lying 2–3 cm above the groin crease. The iliac spine is easy to locate but the pubic tubercle can be difficult, especially in obese patients. It is best found by palpating along the upper border of the pubic symphysis, outwards from the midline (care is needed in the male as the spermatic cord can be tender where it crosses the pubic tubercle).
As shown in Figure 32.2, inguinal hernias always originate above the inguinal ligament, whereas femoral hernias, saphena varices and femoral artery aneurysms always arise below it. Enlarged inguinal lymph nodes are usually situated below the inguinal ligament.
Fig. 32.2 Significance of the relationship of groin lumps to the inguinal ligament
A, B and C are stages in the enlargement of an indirect inguinal hernia. Note that the neck is above the inguinal ligament. A direct inguinal hernia enlarges forwards in position A, but occasionally extends into the scrotum
Direct and indirect inguinal hernias (Fig. 32.3)
Distinguishing between direct and indirect inguinal hernias may be clinically difficult but it is a useful exercise in eliciting clinical signs and frequently comes up in student examinations! By definition, an indirect inguinal hernia is one in which the hernial sac lies within the spermatic cord, leaving the abdomen via the deep (internal) inguinal ring to pass along the inguinal canal, exiting through the superficial (external) ring. Thus, if the hernia can be completely reduced, finger pressure over the deep ring will prevent it reappearing on coughing (the deep ring is midway between the pubic symphysis and the pubic tubercle, 2.5 cm above the femoral pulse; see Fig. 32.1a). In contrast, a direct inguinal hernia leaves the abdomen through a weakness or split in the transversalis fascia, the posterior wall of the inguinal canal, emerging directly through the superficial ring and cannot be controlled by digital pressure over the deep ring. In practice, this test is often unreliable. The patient’s age is perhaps the most useful indicator of the likely type of inguinal hernia, with indirect hernias most frequent under the age of 50 and direct hernias more common after that age.
Fig. 32.3 Direct and indirect inguinal hernias
A direct inguinal hernia bulges medially to the inferior epigastric artery and is not usually attached to the spermatic cord. An indirect inguinal hernia leaves the deep inguinal ring lateral to the artery and lies within the cremaster muscle covering the cord
Inguinal hernia
As shown in Figure 32.4, inguinal hernias in males are by far the most common type of groin hernia. Inguinal hernias occur eight times more often in males because of the abdominal wall deficiency caused by testicular descent. Femoral hernias are rare in males, comprising only 2.5% of groin hernias. Even in females, inguinal hernias are the most frequent (twice as common as femorals). Femoral hernias are twice as common in females as in males.