Thyroid and Parathyroid

what leads to thyroid glands movement up and down during swallowing

Fixation of the gland to the larynx and the trachea: leads to its movement up and down during swallowing

enlargement of thyroid causes: When thyroid gland enlarges it cannot move superiorly because of

Goiter causes: dyspnea, fainting attacks (rel. to blood supply), dysphagia, hoarseness of voice(laryngeal n) cannot move superiorly because of the superior attachments of the sternothyroid and sternohyoid muscles& pretracheal fascia

3- Thyroide ima: og: course: supply:

10% of people o Origin: Brachiocephalic trunk or the arch of the aorta o Course: ascends on anterior surface of trachea o Supply: Isthmus

Blood supply of the Thyroid ARTERIES

ARTERIRES 1- Superior thyroid artery 2- Inferior Thyroid artery 3- Thyroidea ima (not needed is a var)

Two inferior parathyroid glands: position

• close to inferior poles of the thyroid gland • Sometimes found some distance caudal to the thyroid gland in assoc with inferior thyroid veins, or in superior mediastinum in the thorax

1- Superior thyroid artery og: accompanied by which nerve? supplies:

Origin: Branch of External carotid ART. • Accompanied by external laryngeal nerve but diverges from it near the Upper pole • supply upper 2 3rds of lobe and upper ½ of isthmus *ligate close to gland

2- Inferior Thyroid artery og: accompanied by which nerve? supplies:

Origin: Branch of Thyrocervical trunk, originates from (first part of Subclavian artery) • Accompanied by recurrent laryngeal nerve (very close at lower pole) • supply lower 1 3rd of lobe& lower ½ of isthmus *ligate away from gland

Relations of the Lobes Anterolaterally (lateral surface):

Skin, fascia& (4 muscles cover the Lateral (superficial) surface of Thyroid lobe) 1- Sternothyroid 2- Sternohyoid 3- Superior belly of the omohyoid 4- The anterior border of the sternocleidomastoid

name this structure: dense condensation of pre-trachea that attaches the thyroid gland to trachea what is its importance?

Suspensory ligament (Berry's ligament) importance: close relationship to recurrent laryngeal nerve

2. What is the vertebral level that the thyroid gland is situated in the neck? a) C5, C6 and C7 b) C5, C6, C7 and T1 c) C6, C7 and T1 d) C6, C7, T1 and T2,

b) C5, C6, C7 and T1

5. recurrent laryngeal nerve is in close association with ? a- superior thyroid artery b- inferior thyroid artery c- middle thyroid vein d- superior thyroid vein

b- inferior thyroid artery

4. Thyroid gland lies deep to which muscles? a) Digastric muscles b) Inferior belly of omohyoid muscle c) Sternothyroid and Sternohyoid d) Thyrohyoid and myelohyoid

c) Sternothyroid and Sternohyoid

3. Which tracheal rings are generally related to isthmus? a) 1 st and 2 nd b) 1 st 2 nd and 3 rd c) 2 nd and 3 rd d) 2 nd , 3 rd and 4 th,

d) 2 nd , 3 rd and 4 th

sometimes found embedded within the capsule or the thyroid substance itself • more constant in position • lie at the level of the middle of the posterior border of the thyroid gland is describing the sup or inf parathyroid glands?

- Two superior parathyroid glands: • more constant in position • lie at the level of the middle of the posterior border of the thyroid gland (1 cm superior to the point of entry of the inferior thyroid arteries)

Thyroidectomy (total or partial) which structures can be damaged during this process?

-posterior part of the thyroid gland is left undisturbed so that the parathyroid glands(resp for Ca levels -tetany-) are not damaged -recurrent laryngeal nerve (Hoarseness of voice) -external laryngeal nerve (loss of strength of voice -carotid sheath

Relations of the Lobes Posterolaterally (Posterior surface):

1- Carotid sheath (CCA, IJV, CN X) 2- Superior and Inferior Parathyroid glands 3- Anastomosis bet superior and inferior thyroid arteries

Lymph Drainage of the Thyroid

1- Nodes beside Trachea (Paratracheal nodes), and also, prelaryngeal, pretracheal LN. 2- Deep cervical nodes: along IJV related to carcinomas

which muscles have to be retracted during thyroidectomy(muscles that cover lat surface of thyroid)?

1- Sternothyroid 2- Sternohyoid 3- Superior belly of the omohyoid 4- The anterior border of the sternocleidomastoid

thyroid gland Surrounded by:

1- True Capsule innner(fibrous capsule) 2- Fascial sheath outer(False capsule): derived from Pretracheal fascia fixes gland to the larynx and the trachea.

Relations of the Lobes Anterior border: Posterior border (thick and rounded):

Anterior border (Thin): anterior branch of superior thyroid artery Posterior border (thick and rounded): • Inferior thyroid artery (anastomoses with superior thyroid artery) • parathyroid glands

Blood supply of the PARATHYROID GLANDS

Arterial supply: Inferior Thyroid arteries Venous drainage: Into superior, middle, and inferior Thyroid veins

Relations of the Lobes Medially (Medial surface):

Below: 1 - Trachea 2 - Esophagus 3 - Recurrent laryngeal nerve: In the groove between Esophagus and Trachea Above: 1 - larynx (Thyroid, Cricoid cartilages) 2- Pharynx - (Inferior constrictor) 3 - Cricothyroid ms. & External laryngeal nerve supplying it ( 2 tubes(pharynx & larynx), 2 cartilages(thyroid & cricoid), 2 muscles(inf constrictor & cricothyroid m.), 2 nerves(ext laryngeal & recurrent laryngeal n.))

location of thyroid gland

Lies anterior below and lateral to Thyroid cartilage • Opp C 5 th , 6 th , 7 th & T1 Vertebrae

1. regarding thyroid gland which of the followings is not true a. Is supplied by the branch of external carotid artery b. Moves with deglutition because its connected to the hyoid bone c. The lateral lobes pass superior to the oblique line of thyroid cartilage d. It is located anteriorly in the upper neck

d. It is located anteriorly in the upper neck d. It is located anteriorly in the LOWER neck

Blood supply of the Thyroid VEINS

drain the thyroid gland and arise from venous plexus deep to capsule 1- Sup thyroid vein (commence at lobes) • Drains into IJV 2 - Middle thyroid vein (commence at lobes) • Drains into IJV 3 - Inf. thyroid veins (arise from isthmus) Drain into the right and left brachiocephalic veins (Mainly left)

PARATHYROID location

external to the thyroid capsule but inside its sheath (closely related to the posterior border) of each lobe

sup thyroid artery ligated... inf thyroid artery ligated .............

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surfaces and borders of thyroid

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levator glandulae thyroideae: is a remnant of

levator glandulae thyroideae: is a remnant of the Thyroglossal duct of the foetus

isthmus of thyroid in front of..

midline in front of the 2 nd , 3 rd, and 4 th, tracheal rings

small part of the gland projects upward from the isthmus is called? attached to hyoid bone by....

pyramidal lobe levator glandulae thyroideae: A fibrous or muscular band

which nerve if damaged during thyroidectomy leads to hoarseness of voice ?

recurrent laryngeal nerve (damaged larynx) close relation w berrys ligament

Relations of the Isthmus

❑ Ant: 1- Sternothyroids 2- Sternohyoids 3- Anterior jugular veins 4- Skin and Pretracheal fascia ❑ Post: -2 nd , 3 rd, and 4 th, Tracheal rings ❑ Upper border: 1- Pyramidal Lobe 2- Anastomosis bet terminal branches of Sup and inf thyroid arteries ❑ Lower border: Beginning of inferior thyroid veins Thyroide ima Artery(ima is a var)

apex of thyroid reaches... base ........reaches.....,

❑Apex: oblique line on the lamina of the thyroid cartilage ❑Base: at the level of 4 th, or 5 th, tracheal ring