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Congenital Disorders of the Neck
Published in Raymond W Clarke, Diseases of the Ear, Nose & Throat in Children, 2023
The development of the head and neck in the embryo is complex, and it is no surprise that congenital anomalies in this region are fairly commonplace. Disorders in infants and children that present with a neck mass are very different from those that occur in adults and require a different approach to investigation and management. Congenital disorders include developmental cysts, vascular anomalies and abnormalities of the embryonic pharyngeal arches. Not all of these are immediately apparent at birth; they may present when the child is a little older.
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Published in Samar Razaq, Difficult Cases in Primary Care, 2021
Abnormal development of the third and fourth pharyngeal arches during embryonic development results in DiGeorge’s syndrome. The majority of cases are caused by chromosomal deletion at 22q11, although other chromosomal abnormalities have also been implicated. It results in immunodeficiency (due to inadequate thymic development), congenital heart defects, hypocalcaemia (due to underactive parathyroids) and abnormal facies. An extra copy of chromosome 18 results in Edwards’s syndrome, in which there may be a wide variety of congenital defects and mental retardation. Trisomy 21 is commonly known as Down’s syndrome.
De Fabrica Humani Corporis—Fascia as the Fabric of the Body
Published in David Lesondak, Angeli Maun Akey, Fascia, Function, and Medical Applications, 2020
Blood vessels, often as neurovascular bundles, play a role in the shaping of the body. In the development of the embryo, strands of connective tissue surrounding a vascular structure may function as a restraining structure, providing resistance and biomechanical constraint to growth with flexure, or “flexion growth”, if you will, as consequence. This may be observed in developing limbs or in the formation of pharyngeal arches.13 The widespread presence of capillaries throughout the body also reinforces the idea of fascia in a broader sense as the matrix in which all organs are woven and embedded. Blood and fascia take the shape of the body, one might say, and literally create the web in which everything is both connected and separated.
The carotid body and associated tumors: updated review with clinical/surgical significance
Published in British Journal of Neurosurgery, 2019
Nasir Butt, Woong Kee Baek, Stefan Lachkar, Joe Iwanaga, Asma Mian, Christa Blaak, Sameer Shah, Christoph Griessenauer, R. Shane Tubbs, Marios Loukas
Each carotid body has a fibrous capsule and is lobulated by a septum. Within each lobule are collections of type I or chief cells, which are enveloped by type II or sustentacular cells. Between the type II cells and endothelium are non-myelinated nerve fibers, neurolemmocytes, fibrocytes, and collagen fibers.11 Chief cells of the carotid body are also known as amine precursor uptake and decarboxylation (APUD) cells and are components of the neuroendocrine system. These groups of cells are associated with the sympathetic nervous system and can take up amine precursors, while sustentacular cells of the carotid body are associated with the parasympathetic nervous system and have chemoreceptor activity. The carotid body itself is an embryological derivative of the third pharyngeal arch.4 During the embryogenesis, neuroblasts migrate along the glossopharyngeal nerve to form the carotid body.4
Anatomical structure, and expression of CCL4 and CCL13-like during the development of maxillary barbel in Paramisgurnus dabryanus
Published in Organogenesis, 2019
Kianann Tan, Ruijing Geng, Zhiqiang Wang, Han Liu, Weimin Wang
Through light microscopy (Fig. 4) and scanning electron microscopy (Fig. 5), we observed that a pair of maxillary barbels developed first, followed by the development of a pair of mandibular barbels. The maxillary barbels were first visible at 24 hpf as lateral protrusions on the head located posteriorly to the eye and anteriorly to the midbrain-hindbrain boundary. Maxillary and mandibular barbel protrusions at the first pharyngeal arch became apparent at 24 hpf. Maxillary barbel buds were positioned on the above processes. Throughout the embryonic development, maxillary barbels migrated anteriorly together with the mouth, but retained their position at the margin of the upper jaw. Once their position was fixed, maxillary barbels underwent elongation process starting from 56 hpf. Through the scanning electron microscopy observation, scattered taste buds could be seen on the surface of barbels.
Hypoparathyroidism concomitant with macrothrombocytopenia in an elderly woman with 22q11.2 deletion syndrome
Published in Platelets, 2018
Hsiu-Chien Yang, Shih-Hua Lin, Yi-Ying Wu, Chih-Chien Sung
Numerous candidate genes have been linked to the different phenotype of 22q11.2DS. In 1999, TBX-1, a member of the T-box transcription factor family, was identified as one of the most vital gene controlling pharyngeal arch development. Therefore, haploinsufficiency in TBX1 compromises facial structure, parathyroid, and thymus development (1,3,7). In two studies, parathyroid hypoplasia associated with hypocalcaemia was found in approximately 50% of 22q11.2DS cases, typically in pediatric patients (1,3). However, 22q11.2DS may remain undiagnosed in adults because they may lack severe phenotypic features (8,9). A late-onset symptomatic hypocalcemia can be caused by increased calcium requirements with inadequate parathyroid hormone secretion (during adolescence, pregnancy, infection, or surgery) (10–12). Alternatively, the aging process and chronic kidney disease could aggravate hypocalcemia symptoms because of vitamin D deficiency. In this case, hypocalcemia symptoms exacerbated by chronic kidney disease and aging might be presented in the elderly life without cardiovascular abnormalities.