Rectus sheath hematoma

A rectus sheath hematoma is an accumulation of blood in the sheath of the rectus abdominis muscle. It causes a painful abdominal mass. The hematoma may be caused by either rupture of one of the epigastric arteries or by a muscular tear. Causes of this include anticoagulation, coughing, pregnancy, abdominal surgery and trauma. Most hematomas resolve without treatment, but they may take several months to resolve.

A rectus sheath hematoma can develop following an intramuscular (IM) injection with an antithrombotic agent such as enoxaparin.