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Fertilization and normal embryonic and early fetal development
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Asim Kurjak, Ritsuko K. Pooh, Aida Salihagic-Kadic, Iva Lausin, Lara Spalldi-Barisic
During the 5th week, limb buds elongate and their distal ends become paddle shaped. The second pharyngeal arch overgrows the third and fourth arches and forms an ectodermal depression known as the cervical sinus. Ultra-sonography reveals some primitive spontaneous movements of the embryo, such as twitching of the trunk, in the 7th week.
Surgical Anatomy of the Neck
Published in John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford, Head & Neck Surgery Plastic Surgery, 2018
Laura Warner, Christopher Jennings, John C. Watkinson
Branchial cysts typically arise from the second branchial cleft, which grows caudally, eventually obliterating the third and fourth clefts in normal development. This creates a potential space known as the cervical sinus, hypothesized to be a site of trapped epithelium which develops into a branchial cleft cyst. Branchial cysts are often asymptomatic and go unnoticed until they enlarge secondary to upper respiratory tract infection. A popular alternative theory for branchial cyst development is cystic degeneration within a lymph node, hypothesized because lymphoid tissue, as well as epithelium, is found within the walls of brachial cysts.6
Cysts of the jaws, face and neck
Published in John Dudley Langdon, Mohan Francis Patel, Robert Andrew Ord, Peter Brennan, Operative Oral and Maxillofacial Surgery, 2017
Several cysts occur in the soft tissues of the face and neck. Developmental cysts of the neck are rare malformations that develop along embryonic fusion lines or from other embryonic remnants. Four pharyngeal clefts separating the branchial arches are noted in the 5-week-old embryo. The dorsal aspect of the first cleft penetrates the underlying mesoderm and results in the development of the external auditory meatus. Active proliferation of the mesodermal tissue of the second arch causes it to overlap the third and fourth arches. The second, third and fourth clefts temporarily form an ectoderm-lined sinus, the cervical sinus. Branchial cleft anomalies are believed to develop as a result of incomplete obliteration of the cervical sinus or from epithelial rests of the branchial clefts. These abnormalities include cysts, sinuses and fistulae. They typically occur in the lateral neck region, anterior border of the sternocleidomastoid muscle, or in the vicinity of the parotid gland and external ear.
Ecotoxicological effects of bisphenol A and nonylphenol on the freshwater cladocerans Ceriodaphnia silvestrii and Daphnia similis
Published in Drug and Chemical Toxicology, 2018
Mariângela Spadoto, Ana Paula Erbetta Sueitt, Carlos Alexandre Galinaro, Tiago da Silva Pinto, Caroline Moço Erba Pompei, Clarice Maria Rispoli Botta, Eny Maria Vieira
Another Daphnidae that has been proposed as a test organism for monitoring aquatic environments is Ceriodaphnia silvestrii (Fonseca and Rocha 2004, ABNT 2005). Ceriodaphnia silvestrii is a neotropical specie, very common in Brazilian freshwaters. This species can be rapidly diagnosed among other Ceriodaphnia species by the presence of an accentuated cervical sinus, large eye almost filling the whole anterior portion of the head, 9–12 anal spines, and a claw with a pectin (Fonseca and Rocha 2004).