Expansion
Above the arcuate line it is contained; below it, blood can spread freely
Expansion
Bleeding comes from the inferior epigastric vessels or from tearing of the rectus muscle itself, typically after violent coughing, straining or minor trauma, and especially in patients on anticoagulants.
The behaviour depends on the level:
- Above the arcuate line - the intact posterior sheath contains the blood, so the haematoma is limited, firm and localised
- Below the arcuate line - there is no posterior sheath, only transversalis fascia, so blood spreads freely into the preperitoneal space and can be large enough to cause haemodynamic compromise
Clinically it mimics an acute abdomen. Fothergill’s sign distinguishes it: asking the patient to tense the abdominal wall by lifting the head keeps the mass palpable, whereas an intra-abdominal mass becomes impalpable. The mass also does not cross the midline, being confined by the linea alba.
Most are managed conservatively with reversal of anticoagulation.