Thyroid and parthyroid gland Flashcards
from the Latin guttur, throat), defined as an enlargement of the thyroid
Goiter
thyroid gland was not documented until the
Renaissance period
Hieronymus FabriciusabAquapendente recognized that goiters arose from the thyroid gland
1619
1656 -(Greek thyreoeides, shield-shaped) The term thyroid gland attributed to
Thomas wharton
classified thyroid as a ductless gland
1776 -Albrecht von Haller
first accounts of thyroid surgery for the treatment of goiters by Roger Frugardi
1170
Most notable thyroid surgeon
Emil Theodor Kocher (1841–1917) and •C.A. Theodor Billroth(1829–1894
Nobel Prize for medicine in recognition •”for his works on the physiology, pathology, and surgery of the thyroid gland
Emil theodore kocher
thyroid gland, an outpouchingof the primitive foregut
3rd week of gestation
Thyroid gland originates at the base of the tongue at the _____________
Foramen cecum
During its descent, the anlageremains connected to the foramen cecumvia an epithelial-lined tube known as the
Thyroglossal duct
The epithelial cells making up the anlagegive rise to the
Thyroid follicular cell
Endoderm cells in the floor of the ___________anlage thicken to form the ____________anlagethat descends in the neck anterior to structures that form the hyoid ____________
Pharyngeal
Medial thyroid
Hyoid bone and larynx
paired lateral anlagesoriginate from the _________________ and fuse with the median anlageat approximately the ___________________
Fourth branchial pouch
Fifth week of gestation
Origin of lateral anlages
Neuroectodermal
Parafollicular or c cells
Calcitonin
Location of c cells
superoposterior region of the gland
Neuroectodermal
Provide the calcitonin from c cells
Ultimobrachial bodies
Thyroid follicles are initially apparent by
8 weeks
colloid formation begins by the
Eleventh week of gestation
most commonly encountered congenital cervical anomalies
Thyroglossal duct cyst
___________ of gestation, the thyroglossalduct lumen starts to obliterate, duct disappears by the ___________
Fifth week
Eight week
failure of the median thyroid anlageto descend normally •may be the only thyroid tissue present
Lingual thyroid
Normal thyroid tissue may be found anywhere
Ectopic thyroid
Thyroid tissue situated lateral to the
Carotid sheath and jugular vein
Ectopic thyroid previuosly termed
lateral aberrant thyroid
Blood supply of thyroid gland
Superior thyroid artery
Origin of right superior thyroid artery
External carotid artery
Common carotid artery
Brachiocephalic trunk
Arch of aorta
Origin of left superior thyroid artery
External carotid artery
Left common carotid artery
Arch of aorta
Drainage of superior thyroid vein
Internal jugular vein
Brachiocephalic vein
Superior vena cava
Middle thyroid artery
Internal jugular vein
Inferior vena cava
Brachiocephalic vein
Largest of all endocrine gland
Thyroid gland
Each lobe [5cm] extends to level of
6th tracheal cartilage
Thyroid anatomy
Consists of Right and Left lobes •Each lateral lobe has a superior pole and an inferior pole •approximately 20 g •Larger in women •Enlarges during pregnancy •May enlarge slightly during menstruation
Thyroid is posterior toe the
Strap muscle
thyroid lobes located adjacent to the
Thyroid cartilage
located just inferior to the cricoidcartilage
Isthmus
Ascends from isthmus usually from left side towards the hyoid bone
Pyramidal lobe
Pyramidal lobe May be attached to hyoid bone by fibrous band, ______________
Levator glandulaethyroidae
Pyramidal lobe Derived from inferior end of embryonic __________________
Thyroglossalduct
in disorders resulting in thyroid hypertrophy the pyramidal lobe usually is
Enlarge and palpable
Superiorly thyroid lobes extend to the
Midthyroid cartilage
Thyroid gland lie adjacent to the
Carotid artery
Thyroid land laterally to the
SCM
Strap muscles of thyroid
Sternohyoid •Sternothyroid •superior belly of the omohyoid
Thyroid strap muscles located anteriorlyand are innervated by the ansa cervicalis(ansahypoglossi
Ansa cervicalis or ansa hypoglossi
The thyroid gland is enveloped by a
Loosely connecting fascia
derived from deep cervical fascia •attached to cricoidand thyroid cartilages
Pretracheal fascia
Thus, moves up and down with larynx during swallowing
Petracheal fascia
The true capsule of the thyroid is a thin, densely adherent fibrous layer that sends out septa that invaginateinto the gland, forming
Pseudolobules
cricoidcartilage and upper tracheal rings
Posterior suspensory or berrys ligaments
arise from the ipsilateralexternal carotid arteries (ECA)and divide into anterior and posterior branches at the apices of the thyroid lobes
Superiorthyroid arteries
1stanterior branch of ECA •Descends the lateral part of the neck under the superior belly of______________and _______________
Omohyoid
Sternothyroid
Superior thyroid arteries Above the level of the superior pole, accompanied by the ______________ of the _________________
External laryngeal branch
Superior laryngeal nerve
arise from the thyrocervicaltrunk shortly after their origin from the subclavianarteries
Inferior thyroid arteries
INFERIOR THYROID ARTERIES •Ascends vertically for a short distance posterior to the carotid sheath •turning medially, forming an arching loop and entering the tracheoesophagealgroove
Tracheoespphagealgrooe
INFERIOR THYROID ARTERY •crosses the
Recurrent laryngeal nerve
arises directly from the aorta or innominate •1 to 4% of individuals •enter the isthmus or replace a missing inferior thyroid artery
Thyroidea IMA artery
three sets of thyroid drainage
Superior, middle and inferior thyroid vein
The SUPERIOR THYROID VEINS run with the superior thyroid arteries
Bilaterally
Middle thyroid vein
Least consistent
The superior and middle veins drain directly into
Internal jugular vein
Parasymphatetic fiber
Vagus nerve
Sympathetic fiber
superior, middle, inferior sympathetic ganglia of the sympathetic trunk
1849
Sir Richard Owen
first accurate description of the normal parathyroid gland after autopsy examination of an
Indian rhinoceros
a medical student in Uppsala, Sweden. •1stgross and microscopic description of human parathyroids •although their function was not known
1879 inar sandstrom
Glands be named
glandulaeparathyroideae
association of Hyperparathyroidand the bone disease osteitisfibrosa cysticawas recognized
1903 •Friedrich Daniel von Recklinghausen
1925 •first successful parathyroidectomywas performed in by
Felix Mandl
Approximately 1% of normal upper glands may be found in the
paraesophagealor retroesophagealspace
As the embryo matures, the thymus and inferior parathyroidsmigrate together caudally in the
Neck
The frequency of intrathyroidalglands is about
2%
The superior glands usually are dorsal to the
RLN at the level of the cricoidcartilage
inferior parathyroid glands are located ventral to the
RLN
Parathyroid color depends on
cellularity, fat content, and vascularity
503 cadaver subjects•84% had 4 parathyroid•13% had supernumerary•3% had Less than 4
Akerstrom
428 cadaver subjects•–•6.7% had supernumerary
Gilmour
posterior aspect of the superior pole of the lateral lobes of the thyroid gland and close to the recurrent laryngeal nerve (constant location
Superior pair of PTG
posterior aspect of the inferior pole of the lateral lobes of the thyroid gland
Inferior pair of PTG
PTG derive their blood supply from the
Inferior thyroid artery
SUPERIOR THYROID ARTERY supply at least _____ of upper glands
20%
The parathyroid glands drain ipsilaterallyby the
Superior thyroid veins. •middle thyroid veins. •inferior thyroid veins
Pathologic enlargements of the inferior PTG may extend to the
Trachea and esophagus
PTG
Maintain serum calcium and phosphorus levels
The left recurrent laryngeal nerve loops around what structure before it ascends back to towards the thyroid area
Aortic arch
What is the main arterial supply of superior parathyroid gland
Inferior thyroid artery
How many percent of individuals has ThyroidiaIma
1-4%
What is the first anterior branch of the External Carotid Artery that supplies the thyroid and parathyroid
Superior thyroid artery
in 1903 he was the first person to associate hyperparathyroidand osteitisfibrosiacystic, a disease also associated wit his name. Who is this fellow
von Recklinghausen, Friedrich Daniel
Fourth branchial pouch
Superior parathyroid gland
Thyroid gland
Thrid branchial pouch
Inferior parathyroid gland
Thymus
Super parthyroid
More consistent
80%
Level of cricoid cartilage
Inferior parathyroid gland
Inferior thyroid artery and RLN cross
Inferior gland
15% of thymus
Inferior gland
Longer migratory path
Undescended inferior and undescended thymus
Skull base
Mandible
Superior to the upper parathyroid glands
Newborn parathyroid
Gray, semitransparent
Adult parathyroid
Golden yellow to light brown
Normal parathyroid gland
Ovoid Loose tissue or fat 7mm 40-59mg Secrete PTH