| branchial clefts | A bilateral series of slitlike openings into the pharynx through which water is drawn by aquatic animals; in the walls of the cleft's are the vascular gill filaments that take up oxygen from the water passing through the cleft's; sometimes loosely applied to the branchial ectodermal grooves of mammalian embryos, which are imperforate, rudimentary homologues of complete gill clefts. Synonym: gill clefts. (05 Mar 2000) |
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| branchial cyst | Also called a branchial cleft cyst, this is a cavity that is a remnant from embryologic development present at birth in one side of the neck just in front of the large angulated muscle on either side (the sternocleidomastoid muscle). The cyst may not be recognised until adolescence as it enlarges its oval shape. It may develop a sinus or drainage pathway to the surface of the skin from which mucus can be expressed. Total surgical excision is the treatment of choice. Recurrence is not expected. (12 Dec 1998) |
| branchial efferent column | A column of gray matter in the brainstem of the embryo, represented in the adult by the nucleus ambiguus and the motor nuclei of the trigeminal and facial nerves. (05 Mar 2000) |
| branchial fissure | A persistent branchial cleft. (05 Mar 2000) |
| branchial fistula | A congenital fistula in the neck resulting from incomplete closure of a branchial cleft. (05 Mar 2000) |
| branchial groove | An external embryonic groove between contiguous branchial arches. See: branchial clefts. (05 Mar 2000) |
| branchial mesoderm | Mesoderm surrounding the primitive stomodeum and pharynx; it develops into the pharyngeal arches. (05 Mar 2000) |
| branchial pouches | pharyngeal pouches |
| branchial region | Region containing paired arched columns that bear gills in lower aquatic vertebrates and appear in the embryos of higher vertebrates in comparable form. In higher vertebrates the arches are subsequently modified into structures of the neck and ear. (12 Dec 1998) |