A characteristic of Morgagni hernia is that it

A. arises through the central tendon of the diaphragm.
B. has an ill-defined hernia sac.
C. is the most common congenital diaphragmatic hernia.
D. is usually asymptomatic.
E. usually requires repair in childhood.

Answer D

Morgagni's hernia is a retrosternal anterior diaphragmatic hernia which arises through the xiphoid and costochondral attachments. This hernia represents 3% of all congenital diaphragmatic effects. It is more common on the right because the left side is protected by the pericardium. Morgagni's hernia usually remains asymptomatic and is found on routine chest films and mistaken for a mediastinal mass. The well-formed hernia sac usually contains omentum of the transverse colon. Symptoms of bowel obstruction usually occur after age 40 in symptomatic patients. The general consensus is that Morgagni's hernia should be repaired at the time of diagnosis. Surgical repair is best performed via subcostal transperitoneal incision. Laparoscopic repair of this defect has also been reported.

Fell SC. Surgical anatomy of the diaphragm and phrenic nerve. Chest Surg Clin N Amer 1998;8:281-94.
In this article, the anatomy of the diaphragm and phrenic nerves is discussed, together with related surgical implications. Since the major cause of phrenic nerve injury is surgery, usually for congenital or acquired heart disease, incisions in the diaphragm that do not injure major branches of the phrenic nerve are also discussed. Diaphragmatic plication is usually required in infants less than 3 months of age, and older children may be managed by ventilatory support if electrophysiologic studies document the possibility of return of nerve function. In adults with normal pulmonary function, unilateral diaphragmatic paralysis is usually asymptomatic. 

Berardi RS, Tenquist J, Sauter D, et al. An update on the surgical aspects of Morgagni hernia. Surg Rounds 1997;20:370-6.
Morgagni's hernias may be a cause of serious complications, necessitating emergency surgery. The majority of patients presented in this study were asymptomatic. The transabdominal approach is the route of choice for repair of these hernias, and the results have been good to excellent. The general consensus is that Morgagni's hernias should be repaired at the time of diagnosis.

Kuster GR, et al. Diaphragmatic hernia through the foramen of Morgagni: Laparoscopic repair case report. J Laparoendosc Surg 1992;2:93.
Laparoscopic repair of a diaphragmatic hernia through the foramen of Morgagni in a 67-year-old woman with symptoms of partial colon obstruction is described. The patient had a prompt and complete recovery with no evidence of recurrence one year after surgery. The technique, which incorporates the rectus abdominal fascia in the repair, may be suitable for other laparoscopic surgical procedures.