A hernia is an abnormal protrusion of an anatomical structure through a normal opening (hiatus hernia), defect (herniated disk) or weakness (direct inguinal hernia). It is suspected that there is an underlying change in the collagenous tissues.
Herniae are often precipitated by raised pressure within the cavity.
Herniae may be classified according to the type of tissue involved (e.g. neural, muscular, visceral), but are more often classified according to the region involved (e.g. abdominal, diaphragmatic, tentorial).
A hernia may be complicated. Although complications can theoretically occur in any hernia, in practice they apply to external abdominal herniae (e.g. strangulation).
External abdominal herniae consist of a sac with inner contents and outer coverings. The nature of these three components will vary with the site and type of the hernia. The edge of the defect (through which the hernia moves) is the ring. The relationship between the hernial components forms the clinical features seen.
Most herniae occur in the inguinoscrotal region. There is a broad range of lesions possible here that can be confused with a hernia, so a skilled assessment technique is required.
Inspection is carried out first, followed by palpation. An important difference with a hernia is that the examination is performed standing, then lying (sitting up may reveal divarication), followed by standing again. Knowledge of landmarks (bony and soft tissue) is required. Reducibility is carefully assessed in all positions.
A finger may be invaginated into the upper scrotal skin towards the superficial inguinal ring. When the patient is asked to cough, the direction of hernial descent is ascertained.
Even with a full assessment, it can be difficult to correctly diagnose a hernia except at operation.
It is vital at the time of examination to be fully aware of any sign of irreducibility of the hernia (as this is a warning of potential strangulation).
The clinical features discovered are compared to those of common herniae found here - indirect inguinal, direct inguinal and femoral.
A general patient assessment is also required. Notes should be contemporaneous, specific, clearly written and readily available.
External Abdominal Hernia