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Background: The risk of injuring recurrent laryngeal nerves which can result in voice or swallowing problems can be a major complication during thyroid surgeries. Intraoperative injury to RLN can be an issue and can have a detrimental impact on patients’ quality of life. The incidence of injury to recurrent laryngeal nerve worldwide ranges from 0.5 to 20%. To prevent such surgical complications of thyroid, a detailed anatomy of inferior vascular pedicle (inferior thyroid artery) and its relation to adjacent recurrent laryngeal nerve is required. Aim: The aim of the study was, To find out the variable anatomical relationship between inferior thyroid artery and recurrent laryngeal nerve at the base of lateral lobes of thyroid gland. Materials and methods: This descriptive study was conducted for a period of 72 months at the Department of Anatomy, Government Medical College, Omandurar Government Estate, Chennai-2, between January 2015 – January 2021 by dissection method in 60 adult (54 male and 6 female) cadavers (60 – right & 60 – left sides). Results: Results were noted, tabulated and interpreted. It was found that the recurrent laryngeal nerve at the base of thyroid gland which was predominantly posterior on both sides (R-78.33%, L- 100%) to inferior thyroid artery and in 21.66% anterior to ITA on right. Conclusion: The recurrent laryngeal nerve may lie anterior or posterior to inferior thyroid artery. In the present study, the recurrent laryngeal nerve was posterior most commonly on both sides to inferior thyroid artery. On the right, the second common presentation was the recurrent laryngeal nerve lying anterior to inferior thyroid artery.
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Introduction: Terminal branches of inferior thyroid artery (ITA) supplies thyroid and parathyroids. Recurrentlaryngeal nerve (RLN) is related to ITA at lower pole of thyroid and RLN may lie either posterior, anterior orintermingled with terminal branches of ITA. RLN is a vulnerable structure that gets damaged during thyroidsurgeries.Aim: Present study aims to determine variation in relationship between ITA and RLN, entering pattern of ITA intothyroid and number of terminal branches of ITA in Sri Lankan population.Materials and methods: A total of 312 sides (Male:204, Female:108) of thyroid together with intact neurovascularstructures were selected for study of relationship, entrance pattern and number of terminal branches of ITA. TheRLN may lie either posterior (Type A) or anterior (Type B) to ITA or its branches. Sometimes RLN may interminglewith terminal branches of ITA (Type C).Results: A total sample of 65.2% in male (M) and 60.9% in female (F) were Type A, samples of 10.35%(M) and22.22%(F) were Type B and 24.5%(M) and 17.59%(F) were type C. Type A was more predominant in left side of bothgenders and in the right side there are 50% of chances for Type A in both genders. Comparatively Type B was morein female and Type C was more in male. A total of 63.7%(M) and 69.44%(F) ITA entered into middle 1/3rd, 36.27%(M)and 30.55%(F) into lower 1/3rd of the thyroid lobe and entering pattern was more or less similar in both genders.ITA commonly entered thyroid just above junction of middle and lower third of thyroid lobe. ITA divided into twobranches in 52.45%9(M) and 56.48%(F), three in 44.6%(M) and 41.66%(F) and four in 2.94%(M) and 1.85%(F) ofstudied samples.Conclusions: Knowledge of anatomical variation of ITA and RLN is mandatory to avoid injury to RLN in thyroidsurgeries. Understanding the entrance pattern and terminal branches of ITA are essential for thyroid andparathyroid surgeries
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Background: There are reports regarding the origin of the inferior thyroid artery from the vertebral artery and internal thoracic artery. The absence of inferior thyroid artery has been reported in studies, but most of these studies have reported the unilateral absence of inferior thyroid artery. Objective: The objective of the study was to identify and variations in origin (especially presence or absence of artery) and branches of inferior thyroid artery. Materials and Methods: A total of 96 cadavers were dissected and observed for origin and branching pattern of inferior thyroid artery. Results: Inferior thyroid artery originated from thyrocervical trunk in 94 cadavers, in one cadaver there are bilateral absence of inferior thyroid artery and in one case unilateral absence of Rt. inferior thyroid artery. Multiple variations of relations of recurrent laryngeal nerve and inferior thyroid artery are found. Conclusion: Knowledge of arterial variation is extremely important while carrying out surgical procedures in the neck region. During operations of the thyroid gland, surgeries of neck region, carotid angiographies any misinterpretation can lead to life-threatening complications. This study is not only focusing on the presence of different branching pattern but also the absence of major arteries. Studies like these can help surgeons to look closely for variations in both cases either presence or absence of main arteries.
ABSTRACT
Parathyroid glands always remain at risk of damage during the thyroid surgery as they lie in close proximity to the thyroid gland. Parathyroid glands are small endocrine glands that produce parathyroid hormone. The major function of parathyroid hormone is to maintain the level of calcium and phosphate within a narrow range in the body. Aim of the present study was to locate and identify the parathyroid glands during thyroid surgery and to observe their relationship with the surgical landmarks. The present study was a prospective study conducted in the department of otorhinolaryngology and HNS in SMGSH, GMC, Jammu for a time period of 1 year from Nov.2015 to Oct. 2016. 40 patients undergoing thyroid surgery were included in the study. Meticulous technique was employed during dissection and parathyroid glands were identified in the surgical field. Location of the each parathyroid gland was determined in relation to a nearby surgical landmark. The study included 12 right (R) and 8 left (L) hemithyroidectomies, 10 sub- total thyroidectomies and 1 total thyroidectomy. An average of 1.2 parathyroid glands were identified in hemithyroidectomies and 2.4 was the average number of parathyroid glands identified in subtotal and total thyroidectomies. Location of parathyroid glands was observed in relation to cricothyroid (CT) joint, recurrent laryngeal nerve (RLN), inferior thyroid artery (ITA) and tubercle of Zukerkandl for superior parathyroid glands, and in relation to RLN, RLN & ITA junction, tubercle of Zukerdandl & lower pole for inferior parathyroid glands. In this study RLN was the most frequent landmark for identification of superior parathyroid gland while the inferior parathyroid glands were frequently seen related to the lower pole of the thyroid gland.
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Introduction: The Thyroid gland is a highly vascular gland placed anteriorly in the neck, extending from the level of fifth cervical vertebra to first thoracic vertebra.The lobes of gland are conical. Their apices diverge laterally to the oblique line on the lamina of thyroid cartilage, and their bases are at the level of 4th or 5th tracheal ring. The relationship of the superior thyroid artery to the external laryngeal nerve is important to the surgeon during thyroid surgery.The artery and nerve are close to each other higher up but diverge near the gland. Thus in order to avoid injury to the external laryngeal nerve, the superior thyroid artery is ligated as near to the gland as possible. Subjects and Methods: This study was conducted on 50 cadavers of known age and sex in the dissection laboratory, department of anatomy. The cadavers were embalmed through carotid arterial perfusion or femoral arterial perfusion. Results: The site of the origin of the superior thyroid artery (STA) was evaluated as it arose from external carotid artery in 66% cases, from carotid bifurcation in 33% cases and from common carotid artery in 1% cases.The site of the origin of the superior thyroid artery (STA) was evaluated as it arose from external carotid artery in 66% cases, from carotid bifurcation in 33% cases and from common carotid artery in 1% cases.The evaluation of distance from upper pole of the thyroid gland to the level where External superior laryngeal nerve turns medially from Superior thyroid artery was found More than 1 cm in 73% cases & Less than 1 cm in 27% cases. Conclusion: The relationship of superior thyroid artery to external superior laryngeal nerve is very important for surgeons during thyroid surgeries to avoid injuries to above nerves while ligating STA.
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Introduction: The arteries and nerves related to the thyroid gland are very important as they are the potentialsource of bleeding and palsy during thyroidectomies and other head and neck surgeries. Thus a thoroughknowledge of relation between them is a prerequisite for the surgeons and other interventionists.Materials and Methods: The study was done in the Department of Anatomy, Government Medical College, Patiala,Punjab among 30 adult human cadavers from May 2015 to Nov 2015. The origin, course, terminal branches andthe relation of superior and inferior thyroid arteries to external and recurrent laryngeal nerves respectively werenoted and the results were evaluated. The complete pattern of morphology of the thyroid gland in relation to thearterial and nerve supply was labelled as standard or variant. Bilateral symmetry of pattern was noted anddetails of the variations were enumerated. A detailed inference was obtained in the light of present observationsand the findings of earlier workers.Results: In 29 cases we found the superior and inferior thyroid arteries were originating from the externalcarotid artery and thyrocervical trunk respectively while in 1 case there was thyroidea ima artery originatingfrom right common carotid artery with absent right inferior thyroid artery. The external and recurrent laryngealnerves were related to superior and inferior thyroid arteries as described by most of the standard textbooks butthe detail percentages of the relationship is given below.Conclusion: The study is an attempt to establish a relation between the variations that we generally encounter inthyroid glands related to its arteries and nerves. Proper identification of thyroid gland vessels is very importantin order to avoid major complications during and after neck surgeries. Thyroid anatomy and its associatedanatomical variations are very essential to know for Endocrinologist and Surgeons, so that these anomalies arenot overlooked while arriving at a diagnosis
ABSTRACT
Background: Thyroid gland is one of the vital organs in neck region. It is highly vascularized and variations of the thyroid arteries are frequent and have been well documented in literature. This fact increases the significance of being cautious about thyroid gland while performing surgery in neck region. Objective: To study the morphological anatomy of Inferior thyroid artery and to report the origin of the Inferior thyroid artery, to measure the length of the Inferior thyroid artery from its origin to its entry into the gland, to measure the distance from the midline of the neck to the entry of the Inferior thyroid artery into the thyroid gland and to trace its branches. Method: A total of fifty human cadavers were dissected at anatomy department dissection hall of MGM Medical College, Navi Mumbai, Maharashtra and the measurements were taken as per objective of the study. Results: Inferior thyroid artery originated from the thyrocervical trunk in all cases on the left side. On right side in 48 out of 50 cadavers, it originated from thyrocervical trunk (96%) and in rest two cases it originated from the subclavian artery (4%). Statistically significant variation (p<0.001) of mean length of inferior thyroid artery between the right and left side of cadaver was found, indicating mean length was more on left side. Statistically significant variation (p<0.001) of mean distance from midline to entry of inferior thyroid artery into gland between the right and left side of cadaver was found signifying mean distance from midline was more on the right when compared to the left side. Conclusions: Variations of inferior thyroid arteries are well documented in literature. To keep morbidity to minimum, surgeons should have extensive knowledge of the topographic anatomy and its variations.
ABSTRACT
Thyroid gland is an important endocrine organ. Its hormone thyroxine is essential for life. The structure and function of thyroid gland were discovered during 17th to 20th centuries. Thyroid surgery is being done since early 19th century, perfected by Theodre Kocher in early 20th century . Thyroid is the first endocrine gland to develop in embryo and is endodermal origin. The surgically important anatomical relations of thyroid are recurrent laryngeal nerve, parathyroid glands and external laryngeal nerve with variations. Thyroid gland secrets thyroxine hormone which contains Iodine. Thyroxine has effects on all organs of body and its secretion is regulated by Pituitary. Present article throws light on some historical aspects, embryology, anatomy and physiology of thyroid gland based on relevant articles and textbooks.
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OBJECTIVE: To determine the role of peak systolic velocity, end-diastolic velocity and resistance indices of both the right and left inferior thyroid arteries measured by color-flow Doppler ultrasonography for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy. METHODS: The right and left inferior thyroid artery-peak systolic velocity, end-diastolic velocity and resistance indices of 96 patients with thyrotoxicosis (41 with gestational transient thyrotoxicosis, 31 age-matched pregnant patients with Graves' disease and 24 age- and sex-matched non-pregnant patients with Graves' disease) and 25 ageand sex-matched healthy euthyroid subjects were assessed with color-flow Doppler ultrasonography. RESULTS: The right and left inferior thyroid artery-peak systolic and end-diastolic velocities in patients with gestational transient thyrotoxicosis were found to be significantly lower than those of pregnant patients with Graves' disease and higher than those of healthy euthyroid subjects. However, the right and left inferior thyroid artery peak systolic and end-diastolic velocities in pregnant patients with Graves' disease were significantly lower than those of non-pregnant patients with Graves' disease. The right and left inferior thyroid artery peak systolic and end-diastolic velocities were positively correlated with TSH-receptor antibody levels. We found an overlap between the inferior thyroid artery-blood flow velocities in a considerable number of patients with gestational transient thyrotoxicosis and pregnant patients with Graves' disease. CONCLUSIONS: This study suggests that the measurement of inferior thyroid artery-blood flow velocities with colorflow Doppler ultrasonography does not have sufficient sensitivity and specificity to be recommended as an initial diagnostic test for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy.