Anatomical variations of thyroid glands in northeastern-Thai embalmed cadavers / Variaciones anatómicas de la glándula tiroides en cadáveres embalsamados del noreste de Tailandia

SUMMARY: This study aimed to investigate the variation patterns of thyroid glands in embalmed cadavers donated for anatomical studying and research in the northeastern part of Thailand. The crossed-sectional descriptive study was applied to systemically observe the thyroid gland in abnormality of 45 embalmed cadavers. The study was conducted in the Anatomy Laboratory of College of Medicine and Public Health, Ubon Ratchathani University. The indications of thyroid gland abnormalities were recorded by photographs before classification of data used further in a descriptive analysis using SPSS. The results showed that 8 of the 45 cadavers (17.8 %) were observed with thyroid gland abnormality (4 males; 8.9 % and 4 females; 8.9 %). Such variations could be classified into 3 types; pyramidal lobe (8.8 %), levator glandulae thyroideae (2.2 %) and the co-existing of levator glandulae thyroideae (8.8 %), respectively. The thyroid gland abnormality observed in this study was mainly related to many previous reports. Besides the number of thyroid variations are a crucial indication of thyroid gland abnormality recurring, these gland abnormalities are susceptible to the operation of radiology physicians in thyroidectomy and tracheostomy.

RESUMEN: El objetivo de este estudio fue investigar los patrones de variación de la glándula tiroides en cadáveres embalsamados donados para estudios e investigaciones anatómicas en el noreste de Tailandia. El estudio transversal descriptivo se aplicó para observar sistémicamente la glándula tiroides en caso de anomalía en 45 cadáveres embalsamados. El estudio se realizó en el Laboratorio de Anatomía de la Facultad de Medicina y Salud Pública de la Universidad de Ubon Ratchathani. Las anomalías de la glándula tiroides se registraron mediante fotografías antes de la clasificación de los datos y se utilizaron en un análisis descriptivo con SPSS. Los resultados mostraron que en 8 de los 45 cadáveres (17,8 %) se observaron anomalías de la glándula tiroides (4 hombres; 8,9 % y 4 mujeres; 8,9 %). Tales variaciones podrían ser clasificadas en 3 tipos: lóbulo piramidal (8,8 %), músculo elevador de la glándula tiroides (2,2 %) y la coexistencia del músculo elevador de la glándula tiroides (8,8 %), respectivamente. La anomalía de la glándula tiroides observada en este estudio se relacionó principalmente con informes anteriores. Además, la cantidad de variaciones tiroideas es una indicación crucial de la anomalía de la glándula tiroides que se repite, esta anomalía de la glándula es susceptible a las intervenciones de los médicos radiólogos en la tiroidectomía y la traqueotomía.

Agenesis Of Isthmus Of Thyroid Gland – A Rare Case Report In An Adult Male Cadaver

Introduction: The thyroid gland is a highly vascular endocrine gland. The congenital anomalies of thyroid glandincludes thyroglossal cyst, ectopic thyroid tissue and rarely agenesis of one of the lobes or isthmus of thyroidgland. One such rare finding observed in the present study which is highly relevant both to the non – operativeclinician and in operative surgery.Materials and Methods: During routine dissection on an adult male cadaver in the department of anatomy,Ponnaiyah Ramajayam Institute of medical sciences, Chennai, we report agenesis of isthmus of thyroid gland.Results and Discussion: The lobes of the thyroid gland appear to be normal in size, shape and position. Anotherimportant rare finding was the presence of levator glandulae thyroideae which arises from the left lobe to thehyoid bone. Agenesis of isthmus and presence of levator glandulae thyroideae from the left lobe might occur dueto high separation of thyroglossal duct.Conclusion: The knowledge of normal anatomy and its variation of this vital endocrine gland is highly essentialfor physicians and surgeons for the repair of any thyroid ailment and also during tracheostomy

Agenesis of Isthmus of thyroid gland with presence of pyramidal lobe and levator glandulae thyroideae.

A wide range of morphological and developmental variations of thyroid gland like hypoplasia, ectopic thyroid tissue, hemiagenesis or agenesis of thyroid gland has been reported. Out of these agenesis of the thyroid isthmus is a very rare congenital anomaly. Thyroid isthmus agenesis does not manifest clinical symptoms, and it can be confused with other thyroid pathologies. Also the presence of levator glandulae thyroideae and its anatomical variations gain importance in the pathologies which are related to thyroid gland and their treatment modalities. We hereby, report the absence of isthmus and presence of levator glandulae thyroideae and pyramidal lobe in a middle aged male cadaver. The present case report is an attempt to highlight the implications of variation of thyroid gland from diagnostic, phylogenetic and functional perspectives.

Variation of the Infrahyoid Muscle: Duplicated Omohyoid and Appearance of the Levator Glandulae Thyroideae Muscles

The embryologic origin of the omohyoid muscle is different from that of the other neck muscles. A number of variations such as the absence of muscle, variable sites of origin and insertion, and multiple bellies have been reported. However, variations in the inferior belly of the omohyoid muscle are rare. There have been no reports of the combined occurrence of the omohyoid muscle variation with the appearance of the levator glandulase thyroideae muscle. Routine dissection of a 51-year-old female cadaver revealed a duplicated omohyoid muscle and the appearance of the levator glandulae thyroideae muscle. In this case, the two inferior bellies of the omohyoid muscle were found to originate inferiorly from the superior border of the scapula. One of the inferior bellies generally continued to the superior belly with the tendinous intersection. The other inferior belly continued into the sternohyoid muscle without the tendinous intersection. In this case, the levator glandulae thyroideae muscle appeared on the left side, which attached from the upper border of the thyroid gland to the inferior border of the thyroid cartilage. These variations are significant for clinicians during endoscopic diagnosis and surgery because of the arterial and nervous damage due to iatrogenic injuries. The embryologic origins of the omohyoid and levator glandulae thyroideae muscles may be similar based on the descriptions in the relevant literature.