Читать книгу The Esophagus - Группа авторов - Страница 158

In the four‐week embryo, paired grooves of ectodermal origin – the branchial clefts – appear on the sides of the neck. Four outpouchings of endodermal origin – the branchial pouches – grow to meet the branchial clefts [40]. The second branchial cleft forms the middle ear, eustachian tube, and floor of the tonsillar fossa. The third and fourth branchial pouches form the piriform sinuses. Persistence of branchial clefts or pouches may lead to the development of sinus tracks (that end blindly beneath the skin), fistulae (that extend to the skin), or cysts. Branchial pouch sinus tracks arise from the tonsillar fossa (second pouch) (Figure 6.19), the upper anterolateral piriform fossa (third pouch), or the lower anterolateral piriform sinus (fourth pouch).

Figure 6.14 Extrinsic impressions during passage of bolus through the pharyngoesophageal segment. A smooth‐surface hemispheric impression represents incomplete opening of the cricopharyngeus (white arrow). Osteophytes impress the proximal cervical esophagus (arrowhead). Also note redundant post‐cricoid mucosa (open arrow) opposite the cricopharyngeal bar.

Source: Reproduced from Rubesin SE. Oral and pharyngeal dysphagia. Gastroenterol Clin North Am1995; 24:331–352, with permission.