"Thyroid The thyroid gland, or simply the thyroid, is an endocrine gland in the neck, consisting of two lobes connected by an . It is found at the front of the neck, below the Adam's apple. The thyroid gland secretes thyroid hormones, which primarily influence the metabolic rate and protein synthesis. The hormones also have many other effects including those on development. The thyroid hormones triiodothyronine (T) and thyroxine (T) are created from iodine and tyrosine. The thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis. Hormonal output from the thyroid is regulated by thyroid-stimulating hormone"
"orthographic revision of what was previously known in the Nomina Anatomica as ""foramen thyreoideum"", an inconstantly present opening in the lamina of the thyroid cartilage. Thyroid cartilage The thyroid cartilage is the largest of the nine cartilages that make up the ""laryngeal skeleton"", the cartilage structure in and around the trachea that contains the larynx. It does not completely encircle the larynx; only the cricoid cartilage does. The thyroid cartilage is a hyaline cartilage structure that sits in front of the larynx and above the thyroid gland. The cartilage is composed of two halves, which meet in the middle at"
"at the bottom of the cartilage is called the inferior thyroid notch. The two halves of the cartilage that make out the outer surfaces extend obliquely to cover the sides of the trachea. The posterior edge of each half articulates with the cricoid cartilage inferiorly at a joint called the cricothyroid joint. The most posterior part of the cartilage also has two projections upwards and downwards. The upper projection is called the ""superior horn"" (), and the lower is called the ""inferior horn"". The superior horn is long and narrow, backward, and medialward, and ends in a conical extremity, which"
"""thyroid cartilage"" is derived from the Latin expression ""cartilago thyreoides"". The latter is a translation of Ancient Greek χόνδρος θυρεοειδής, attested in the writings of the Greek physician Galen. The Latin word ""cartilago"", as well as the Ancient Greek word χόνδρος, both mean ""cartilage"", while the ancient Greek word θυρεοειδής means ""shield-like"" or ""shield-shaped"". The latter compound is composed of Ancient Greek θυρεός, ""shield"" and εἶδος, ""form""/""shape"". The Greeks used εἶδος in compounds to indicate a resemblance with the first part of the word. The ancient Greek word θυρεός can be found in the ""Odyssey"" of Homer, and represented a"
"the rings of cartilage around the trachea (which are not continuous – rather they are C-shaped with a gap posteriorly). The cricoid is joined to the first tracheal ring by the cricotracheal ligament, and this can be felt as a more yielding area between the firm thyroid cartilage and firmer cricoid. It is also anatomically related to the thyroid gland; although the thyroid isthmus is inferior to it, the two lobes of the thyroid extend superiorly on each side of the cricoid as far as the thyroid cartilage above it. The posterior part of the cricoid is slightly broader than"
"cartilage. In 16th-century Italian anatomist Realdo Colombo's ""De re anatomica"", besides the aforementioned incorrect ""petalis cartilago"", correct forms like ""scutalis cartilago"" and ""scutiformis cartilago"" can be found, as the ""scutum"" is the real Roman pendant of the Greek θυρεός. The latter Latin expression can be found in its English form in medical dictionaries as ""scutiform cartilage"", while the name of the shield itself, i.e. ""scutum"", is still being mentioned as a synonym for the thyroid cartilage. In the various editions of the official Latin nomenclature (""Nomina Anatomica"", in 1998 rebaptized as ""Terminologia Anatomica""), three different spellings can be found, i.e."
"gives attachment to the lateral thyrohyoid ligament. The ""inferior horn"" is short and thick; it is directed downward, with a slight inclination forward and medialward, and presents, on the medial side of its tip, a small oval articular facet for articulation with the side of the cricoid cartilage. The entire superior edge of the thyroid cartilage is attached to the hyoid bone by the thyrohyoid membrane. The thyroid cartilage is found between the levels of the C4 to C5 vertebrae. The ""oblique line"" is a line on the thyroid cartilage. It marks the upper lateral borders of the thyroid gland."
"was formerly known as vocal fold mass. Thyroid Cartilage Control: This figure demonstrates control of the position or ""tilt"" of the thyroid cartilage through engagement or disengagement of the cricothyroid muscle. The speaker or singer can tilt the thyroid cartilage by adopting the posture of crying or sobbing, or making a soft whimpering noise, like a small dog whining. In Estill Voice training, it is proposed that the position of the thyroid cartilage influences not only pitch but also the quality and intensity of the sound produced. Cricoid Cartilage Control: This figure demonstrates control of the position of the cricoid"
"Cartilage Cartilage is a resilient and smooth elastic tissue, a rubber-like padding that covers and protects the ends of long bones at the joints, and is a structural component of the rib cage, the ear, the nose, the bronchial tubes, the intervertebral discs, and many other body components. It is not as hard and rigid as bone, but it is much stiffer and much less flexible than muscle.The matrix of cartilage is made up of chondrin. Because of its rigidity, cartilage often serves the purpose of holding tubes open in the body. Examples include the rings of the trachea, such"
"of goitre. In 1500 polymath Leonardo da Vinci provides the first illustration of the thyroid. In 1543 Anatomist Andreas Vesalius gave the first anatomic description and illustration of the gland. In 1656 the thyroid received its name, by the anatomist Thomas Wharton. The gland was named thyroid, meaning shield, as its shape resembled the shields commonly used in Ancient Greece. The English name ""thyroid gland"" is derived from the medical Latin used by Wharton – ""glandula thyreoidea"". ""Glandula"" means ""gland"" in Latin, and ""thyreoidea"" can be traced back to the Ancient Greek word θυρεοειδής, meaning ""shield-like""/""shield-shaped"". French chemist Bernard Courtois"
"of the x-ray. Cartilaginous fish (chondrichthyes) like sharks, rays and skates have a skeleton composed entirely of cartilage. Cartilage tissue can also be found among some arthropods such as horseshoe crabs, some mollusks such as marine snails and cephalopods, and some annelids like sabellid polychaetes. Arthropods The most studied cartilage in arthropods is the ""Limulus polyphemus"" branchial cartilage. It is a vesicular cell-rich cartilage due to the large, spherical and vacuolated chondrocytes with no homologies in other arthropods. Other type of cartilage found in ""Limulus polyphemus"" is the endosternite cartilage, a fibrous-hyaline cartilage with chondrocytes of typical morphology in a"
"English but earlier works preferred the etymologically correct ""thyreoid cartilage"". The official Latin veterinary nomenclature, ""Nomina Anatomica Veterinaria"" has the form ""cartilago thyroidea"", in common with the human Nomina Anatomica/Terminologia Anatomica, but allows (in contrast to the latter) ""cartilago thyreoidea"" as an alternative spelling. An unfortunate mishap is the resemblance between Latin thyroidea and English thyroid on the one side and Ancient Greek θυροειδής on the other side, as the latter does not mean ""shield-like"", but actually means ""like a door"", derived from θύρα, door. Θυροειδής is however used in anatomic nomenclature in the expression θυροειδές τρῆμα (τρῆμα = hole,"
"the thyroid and cricoid cartilages. In a healthy person the gland is not visible yet is palpable as a soft mass. Examination of the thyroid gland includes the search for abnormal masses and the assessment of overall thyroid size. The character of the thyroid, swellings, nodules, and their consistency may all be able to be felt. If a goitre is present, an examiner may also feel down the neck consider tapping the upper part of the chest to check for extension. Further tests may include raising the arms (Pemberton's sign), listening to the gland with a stethoscope for bruits, testing"
"Two muscles originate along the line, the thyrohyoid muscle and inferior pharyngeal constrictor. The sternothyroid inserts along the line. Movement of the cartilage at this joint produces a change in tension at the vocal folds, which in turn produces variation in voice. The thyroid cartilage forms the bulk of the front wall of the larynx. It protects the vocal folds (""vocal cords""), which are located directly behind it. When the angle of the thyroid cartilage changes relative to the cricoid cartilage, this changes the pitch of voice. The cartilage also serves as an attachment for several muscles. The English term"
"Cricoid cartilage The cricoid cartilage , or simply cricoid (from the Greek ""krikoeides"" meaning ""ring-shaped"") or cricoid ring, is the only complete ring of cartilage around the trachea. It forms the back part of the voice box and functions as an attachment site for muscles, cartilages, and ligaments involved in opening and closing the airway and in producing speech. The cricoid cartilage sits just inferior to the thyroid cartilage in the neck, at the level of the C6 vertebra, and is joined to it medially by the median cricothyroid ligament and postero-laterally by the cricothyroid joints. Inferior to it are"
"Hyaline cartilage Hyaline cartilage is the glass-like (hyaline) but translucent cartilage found on many joint surfaces. It is also most commonly found in the ribs, nose, larynx, and trachea. Hyaline cartilage is pearl-grey in color, with a firm consistency and has a considerable amount of collagen. It contains no nerves or blood vessels, and its structure is relatively simple. Hyaline cartilage is covered externally by a fibrous membrane known as the perichondrium or, when it's along articulating surfaces, the synovial membrane. This membrane contains vessels that provide the cartilage with nutrition through diffusion. Hyaline cartilage matrix is primarily made of"
"as the cricoid cartilage and carina. Cartilage is composed of specialized cells called chondrocytes that produce a large amount of collagenous extracellular matrix, abundant ground substance that is rich in proteoglycan and elastin fibers. Cartilage is classified in three types, ""elastic cartilage"", ""hyaline cartilage"" and ""fibrocartilage"", which differ in relative amounts of collagen and proteoglycan. Cartilage does not contain blood vessels (it is avascular) or nerves (it is aneural). Nutrition is supplied to the chondrocytes by diffusion. The compression of the articular cartilage or flexion of the elastic cartilage generates fluid flow, which assists diffusion of nutrients to the chondrocytes."
"called colloid, containing thyroglobulin, a precursor to other thyroid hormones, which are manufactured within the colloid. The thyroid hormones increase the rate of cellular metabolism, and include thyroxine (T4) and triiodothyronine (T3). Secretion is stimulated by the hormone TSH, secreted by the anterior pituitary. When thyroid levels are high, there is negative feedback that decreases the amount of TSH secreted. Most T4 is converted to T3 (a more active form) in the target tissues. Calcitonin, produced by the parafollicular cells of the thyroid gland in response to rising blood calcium levels, depresses blood calcium levels by inhibiting bone matrix resorption"
"thyroid cancer. HBME-1 staining may be useful for differentiating papillary carcinomas from follicular carcinomas; in papillary lesions it tends to be positive. Reduced expression of ATP5E is significantly associated with the diagnosis of papillary thyroid cancer and may serve as an early tumor marker of the disease. Papillary thyroid cancer gets its name from the papillae among its cells, visible on microscopy. Features include: Several variants are recognized, although classical papillary thyroid carcinoma is the most frequent; microscopic, follicular variant, diffuse sclerosing variant, tall cell variant, columnar cell variant, hobnail variant, among others. The encapsulated follicular variant, specifically when noninvasive,"
"levator muscle of thyroid gland, connecting the isthmus to the body of the hyoid bone, and the presence of the small thyroid ima artery. At the microscopic level, there are three primary features of the thyroid—follicles, follicular cells, and parafollicular cells, first discovered by Geoffery Websterson in 1664. Thyroid follicles are small spherical groupings of cells 0.02–0.9mm in diameter that play the main role in thyroid function. They consist of a rim that has a rich blood supply, nerve and lymphatic presence, that surrounds a core of colloid that consists mostly of thyroid hormone precursor proteins called thyroglobulin, an iodinated"
"Superior thyroid artery The superior thyroid artery arises from the external carotid artery just below the level of the greater cornu of the hyoid bone and ends in the thyroid gland. From its origin under the anterior border of the sternocleidomastoid the superior thyroid artery runs upward and forward for a short distance in the carotid triangle, where it is covered by the skin, platysma, and fascia; it then arches downward beneath the omohyoid, sternohyoid, and sternothyroid muscles. To its medial side are the inferior pharyngeal constrictor muscle and the external branch of the superior laryngeal nerve. It distributes twigs"
"cricoid cartilage is easily felt, while between this and the suprasternal notch, the trachea and the isthmus of the thyroid gland may be made out. At the side, the outline of the sternomastoid muscle is the most striking mark; it divides the anterior triangle of the neck from the posterior. The upper part of the former contains the submaxillary gland also known as the submandibular glands, which lies just below the posterior half of the body of the jaw. The line of the common and the external carotid arteries may be marked by joining the sterno-clavicular articulation to the angle"
"vascular, encapsulated structure made up of right and left lobes, which are connected at the midline by the isthmus. Each lobe is about 2 cm thick, 3 cm wide, and 5 cm long. The thyroid apex is located superiorly at the level of the mid-thyroid cartilage. The inferior margin of the gland is at the level of the fifth or sixth tracheal ring. The thyroid gland is encapsulated by the middle layer of deep cervical fascia and is part of the visceral space in the infrahyoid neck. It wraps around the trachea and is separated from the oesophagus by the"
"excision of the lower pole of the thyroid gland. The injection of dye into the inferior thyroid artery can be used as an alternate method in identification the recurrent laryngeal nerve. Inferior thyroid artery The inferior thyroid artery is an artery in the neck. It arises from the thyrocervical trunk and passes upward, in front of the vertebral artery and longus colli muscle. It then turns medially behind the carotid sheath and its contents, and also behind the sympathetic trunk, the middle cervical ganglion resting upon the vessel. Reaching the lower border of the thyroid gland it divides into two"
"Arytenoid cartilage The arytenoid () cartilages are a pair of small three-sided pyramids which form part of the larynx, to which the vocal folds (vocal cords) are attached. These allow and aid in the vocal cords' movement. Each is pyramidal or ladle-shaped in form (arytenoid comes from Greek ""arytaina"" meaning ladle + ""eidos"", meaning form), and has three surfaces, a base, and an apex. The posterior surface is a triangular, smooth, concave, and gives attachment to the arytenoid muscle and transversus. The antero-lateral surface is somewhat convex and rough. On it, near the apex of the cartilage, is a rounded"
"most common application of synthetic cartilage. Cartilage is an avascular, aneural and alymphatic tissue within the body. The extracellular matrix (ECM) of collagen is what gives it its high strength. The figure below shows the components of the ECM. There are three structural zones in articular cartilage including a superficial tangential zone, a middle transitional zone and a deep zone. In the tangential zone, collagen fibers are aligned parallel to the surface and become gradually randomly aligned while moving into the deep zone. Collagen fibers in the superficial zone are aligned parallel to the surface in order to restrict shear"
"the inferior part of the pharynx (hypopharynx) with the trachea. The laryngeal skeleton consists of six cartilages: three single (epiglottic, thyroid and cricoid) and three paired (arytenoid, corniculate, and cuneiform). The hyoid bone is not part of the larynx, though the larynx is suspended from the hyoid. The larynx extends vertically from the tip of the epiglottis to the inferior border of the cricoid cartilage. Its interior can be divided in supraglottis, glottis and subglottis. There are six cartilages, three unpaired and three paired, that support the mammalian larynx and form its skeleton. Unpaired cartilages: Paired cartilages: The muscles of"
"classification is proposed by Pelizzo et al. Zuckerkandl's tubercle (thyroid gland) Zuckerkandl's tubercle is a pyramidal extension of the thyroid gland, present at the most posterior side of each lobe. Emil Zuckerkandl described it in 1902 as the ""processus posterior glandulae thyreoideae"". Although the structure is named after Zuckerkandl, it was discovered first by Otto Madelung in 1867 as the ""posterior horn of the thyroid"". The structure is important in thyroid surgery as it is closely related to the recurrent laryngeal nerve, the inferior thyroid artery, Berry's ligament and the parathyroid glands. The structure is subject to an important amount"
"and was the most practical approach found in one study. Thyroid-associated ophthalmopathy (TAO), or thyroid eye disease (TED), is the most common extrathyroidal manifestation of Grave's disease. It is a form of idiopathic lymphocytic orbital inflammation, and although its pathogenesis is not completely understood, autoimmune activation of orbital fibroblasts, which in TAO express the TSH receptor, is thought to play a central role. Hypertrophy of the extraocular muscles, adipogenesis, and deposition of nonsulfated glycoaminoglycans and hyaluronate, causes expansion of the orbital fat and muscle compartments, which within the confines of the bony orbit may lead to dysthyroid optic neuropathy, increased"
"Zuckerkandl's tubercle (thyroid gland) Zuckerkandl's tubercle is a pyramidal extension of the thyroid gland, present at the most posterior side of each lobe. Emil Zuckerkandl described it in 1902 as the ""processus posterior glandulae thyreoideae"". Although the structure is named after Zuckerkandl, it was discovered first by Otto Madelung in 1867 as the ""posterior horn of the thyroid"". The structure is important in thyroid surgery as it is closely related to the recurrent laryngeal nerve, the inferior thyroid artery, Berry's ligament and the parathyroid glands. The structure is subject to an important amount of anatomic variation, and therefore a size"
"Cartilage will wear over the years. Cartilage has a very limited capacity for self-restoration. The newly formed tissue will generally consist of a large part of fibrous cartilage of lesser quality than the original hyaline cartilage. As a result, new cracks and tears will form in the cartilage over time. The articular disks of the knee-joint are called menisci because they only partly divide the joint space. These two disks, the medial meniscus and the lateral meniscus, consist of connective tissue with extensive collagen fibers containing cartilage-like cells. Strong fibers run along the menisci from one attachment to the other,"
"can often be seen as secondary lymphoid follicles (germinal centers, not to be confused with the normally present colloid-filled follicles that constitute the thyroid). Atrophy of the colloid bodies is lined by Hürthle cells, cells with intensely eosinophilic, granular cytoplasm, a metaplasia from the normal cuboidal cells that constitute the lining of the thyroid follicles. Severe thyroid atrophy presents often with denser fibrotic bands of collagen that remains within the confines of the thyroid capsule. Diagnosis is usually made by detecting elevated levels of anti-thyroid peroxidase antibodies (TPOAb) in the serum, but seronegative (without circulating autoantibodies) thyroiditis is also possible."
"level of the cricoid cartilage; the anterior jugular vein crosses the artery just above the clavicle, but is separated from it by the sternohyoid and sternothyroid. Behind, the artery is separated from the transverse processes of the cervical vertebrae by the longus colli and longus capitis muscles, the sympathetic trunk being interposed between it and the muscles. The inferior thyroid artery crosses behind the lower part of the vessel. Medially, it is in relation with the esophagus, trachea, and thyroid gland (which overlaps it), the inferior thyroid artery and recurrent laryngeal nerve being interposed; higher up, with the larynx and"