The painless lump

The lump in the groin may have been a chance finding by the patient and may not be associated with symptoms. Each of the conditions listed in Box 21.1 may present as a painless lump. Indeed, pain does not occur with a saphena varix, lipoma of the cord, encysted hydrocoele of the cord, hydrocoele of the canal of Nuck, or testicular maldescent. Hernias, inguinal lymphadenopathy and femoral aneurysms may or may not be associated with pain. Historically, the development of a hernia may have been preceded by groin pain after a heavy lift or ‘strain’. However, many hernias appear without any such antecedent history.

The painful lump

Hernias can be associated with several types of pain.

First, there may be a dull ache in the groin experienced when the hernia is filled with intraabdominal contents, such as bowel or omentum. This ache is relieved by spontaneous reduction of the hernia, such as often occurs when the patient lies down. In these patients, the ache is typically worse at the end of a long, physically active day when the intraabdominal contents have filled and distended the hernial sac.

Secondly, there is the pain secondary to venous congestion of the intraabdominal contents of the hernial sac, caused by the constrictive effect of the neck of the hernia on venous outflow of the contents. This is a more severe, constant pain that may increase in intensity should venous congestion progress to arterial insufficiency (strangulation). In this circumstance, the hernia will not be reducible and will be locally tender to palpation. These symptoms and signs are related to inflammation in the tissues around the hernial sac.

Incarceration of the contents of a hernia within a hernial sac may be associated with intestinal obstruction, which is more commonly small bowel than large bowel. Small bowel obstruction is associated with central abdominal colicky pain, vomiting, abdominal distension and constipation (Ch 4).

A painful enlarged lymph node is always inflamed. An inflamed lymph node is associated with a constant ache without abdominal symptoms. Not uncommonly, the cause of the inflamed lymph node, such as an infected ulcer or boil on the foot, will also be a source of pain.

A femoral artery aneurysm, or pseudoaneurysm, is rarely painful. This is because the rate of expansion of the aneurysm is usually slow. Rapid expansion is more common with a pseudoaneurysm than a true aneurysm, and can be associated with a dull ache. A false aneurysm is secondary to puncture or rupture of the artery, as can occur after angiography or penetrating trauma. If the puncture site does not close or seal, there is a communication between the lumen of the artery and the haematoma outside the artery. A true aneurysm is surrounded by attenuated arterial wall, while a false aneurysm is surrounded by a fibrous capsule.

Reducibility

There are three causes of a reducible lump: an inguinal hernia (most common); a femoral hernia; and a saphena varix (least common). A saphena varix is always reducible as it always disappears when the patient lies down. An inguinal hernia is commonly reducible, while a femoral hernia is less often reducible because the neck is usually narrow and rigid.

An incarcerated hernia is where the contents of a hernial sac are irreducible. This may lead to intestinal obstruction or even strangulation of the hernial contents (as above).

Anatomical localisation of the lump

The initial step in the physical examination is to stand the patient to define whether the lump is in the inguinal or femoral region, whether or not there is a cough impulse and also observe if there is bilateral swelling. The two regions are separated by the inguinal ligament, which stretches between the anterior superior iliac spine laterally and the pubic tubercle medially. Both of these bony prominences are readily palpable.

The other useful landmark to determine the precise position of lumps in the femoral region is the femoral artery, located just below the midinguinal point and identifiable by its pulsatile nature. The midinguinal point is situated midway between the anterior superior iliac spine and the pubic symphysis.

Figure 21.1 details the various groin lumps above and below the inguinal ligament.

Figure 21.1 Groin lumps below and above the inguinal ligament.

Lumps in the inguinal region (above inguinal ligament)

Inguinal hernias

Inguinal hernias exit from the abdominal cavity and then pass along the inguinal canal together with the spermatic cord in the male. The inguinal canal passes medially from the deep inguinal ring, the surface marking of which is the midinguinal point (see above) to the superficial inguinal ring, which is just above and medial to the pubic tubercle (Fig 21.2).

Figure 21.2 Anatomy of the inguinal region and important landmarks.

From Browne NL. An introduction to the symptoms and signs of surgical disease. 3rd edn. New York: Oxford University Press; 1977.

It is imperative to examine the patient complaining of a lump in the groin while the patient is standing because a hernia may be apparent only in this position. Having examined in the standing position, have the patient lie down and determine if the hernia is reducible—coughing should also cause it to return. By placing the fingers along the line of the inguinal canal and asking the patient to cough, a cough impulse may be elicited; this is a pathognomonic sign of an inguinal hernia. This sign refers to the sudden expansion of a bulge beneath the examining fingers, which occurs when the increase of intraabdominal pressure blows some of the intraabdominal contents out into the hernial sac. If the examiner believes that the sign has been elicited, then it is worth trying to elicit the sign on the contralateral side for two reasons. First, inguinal hernias are not uncommonly bilateral. Secondly, the cough impulse of a hernia can be confused with a normal anterior movement of the whole of the lower anterior abdominal wall anteriorly with coughing. This anterior movement is not expansile.