Anatomy of the extrinsic nerve supply of the oesophagus in oesophageal atresia of the common type.
Cadaver dissections of the oesophagus were carried out to evaluate its extrinsic nerve supply in oesophageal atresia (OA) with distal tracheo-oesophageal fistula. In OA the atresia occurs at an anatomic watershed in the oesophagus. Proximal to the atresia, the oesophageal wall contains striated muscle. There is a known change in the type of muscle that forms the oesophagus as it descends through the chest. As a continuation of the pharynx, its wall is made up entirely of striated muscle, which is gradually replaced by smooth muscle. What percentage of the wall proximal to an atresia is normally striated is not known. Distal to the atresia the oesophagus is a smooth-muscle tube that receives its extrinsic motor nerve supply from the vagal nerves. These specific nerve fibres have their central origin in the dorsal nucleus of the vagus and are part of the autonomic nervous system. They appear to reach the oesophagus with its blood supply in an ordered but random manner. As the autonomic nervous system does not supply striated muscles, fibres of the vagal nerves that supply the proximal pouch must be somatic nerves. This is confirmed, as this portion of the oesophagus is shown to be supplied by the recurrent laryngeal nerves, which contain fibres that have their origin in the nucleus ambiguous. These nerves are bilateral and reach the oesophageal wall in a segmental fashion; this supply is continuous with that of the pharynx. As the oesophagus proximal to an atresia anatomically belongs to the pharynx, it is called the pharyngeal oesophagus. For a similar reason, the distal segment is named the gastric oesophagus. This anatomy is of practical importance to the surgeon.
Division of Paediatric Surgery, 154/28 JHB Hospital, P. Bag X39, 2000, Johannesburg, South Africa.
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Davies