Branchial

BRANCHIAL (from Greek branchia- gills and genos- origin), arising from gills, gill clefts. The term Branchial is accepted to denote various congenital developmental defects or acquired diseases if they are connected by their origin to the gill apparatus. In the early embryonic period, between the gill arches, four parallel grooves from the endoderm are formed on the lateral wall of the pharynx, and opposite them, on the outer surface of the head and neck, four grooves from the ectoderm (so-called internal and external gill grooves, pouches). These gill grooves, or pouches, deepening, turn into fairly deep passages, or slits, but in the future all disappear except the upper one, which goes to form the Eustachian tube, middle ear, and external auditory canal. Sometimes it may happen that a part of any of the three lower gill slits does not undergo normal regression and is preserved in the extrauterine period. Under such conditions this remnant of the external or internal gill groove can become a source of pathological formations, which are called Branchial. These include Branchial fistulas (sinuses) and cysts of the neck, finally, Branchial cancers.

A. Abrikosov. V. neck fistula (gill fistula, congenital neck fistula, fistula colli congenita), represents a product of improper development and involution of the gill slits (see Gills), when their complete closure is not observed and narrow fistulous passages remain. Branchial fistulas may have only an internal, or only an external opening, or both. From the opening of a Branchial fistula usually a serous-mucous fluid is secreted. The external opening, often barely noticeable, lies usually in the space between the hyoid bone and the sternocleidomastoid muscle, at the inner edge of the latter and more often near the sternoclavicular joint (lateral Branchial fistula); less often Branchial fistulas lie medially or parasternally and, most often, below the hyoid bone. According to the opinion of some authors, the origin of medial neck fistulas from gill slits is not proven; Bramann (Bramann) points out the significance here of the ductus thyreoglossus; indeed, sometimes it is possible to prove the communication of the fistula with the foramen coecum of the tongue. The lumen of the fistula is usually narrow, the length is short, in the depth of the fistula go, most often, several parallel passages (up to 20). If the opening of the Branchial fistula is located high, the fistula goes in the direction of the greater horn of the hyoid bone, between the carotid arteries, to the tonsillar region, where the opening of internal Branchial fistulas is often located, or so-called complete Branchial fistulas, i.e. opening both into the pharynx and onto the neck. For one or another characteristic of a Branchial fistula (lateral, medial) it is important to trace all its direction; sometimes a fistula arises not where it should be; for example, a medial Branchial fistula, in case of suppuration and secondary perforation, can give a lateral opening on the neck. The structure of the walls of a Branchial fistula is different; its internal endodermal parts are lined with a multilayered ciliated or flat non-keratinized epithelium, under which a plate of lymphoid tissue with admixture of mucous (sometimes salivary) glands and smooth muscle is located. The ectodermal part of a Branchial fistula has the usual structure of skin. Branchial fistulas can be primary, i.e. exist from the very beginning as such, or secondary, developing from Branchial cysts. Venglovsky pointed out the close relation of the Branchial fistula to the third gill slit (namely to the ductus thymopharyngeus); Kostanecki and Hammar (Kostanecki, Hammar) advanced the significance of the second gill slit (ductus ectobranchialis II).