NBME Free 120 Branch of the thyrocervical trunk (NBME Answers)

Retired NBME Free 120 Answers

free120/Block 2/Question#24 (reveal difficulty score)
A 33-year-old man undergoes a radical ...
Branch of the thyrocervical trunk 🔍 / 📺 / 🌳 / 📖
tags:

+5 upvote downvote
submitted by ivypoison(6)

get full access to all content ⋅ pick a username

Why high PTH 200pg/ml (normal <60)? it should be primary hypoparathyroidism!

get full access to all content ⋅ pick a username

amm13e i think with no proper Blood supply, the PTH cant sample the Ca2+ levels in the blood, making the gland secrete more PTH +7

castlblack secrete pth into where? the lost blood supply it doesn't have? Also, there are no parathyroid glands because the dude had a thyroidectomy! +2

alimd @castlblack maybe they left it hanging of the fucking veins))) +2

+3 upvote downvote
submitted by ∗bwdc(697)

get full access to all content ⋅ pick a username

This question is asking for the vascular supply of the parathyroid glands. That would be the inferior thyroid arteries, which arise from the thyrocervical trunk.

get full access to all content ⋅ pick a username

focus Diagram: https://www.sciencedirect.com/topics/medicine-and-dentistry/inferior-thyroid-artery +1

weenathon I originally chose vein because I was thinking maybe the hormone release couldn't be carried to the body anymore, but looking back the working of "moderate hemorrhaging" and vessels requiring ligation is what implies it's an artery. Just throwing that out there in case you thought like I did. +6

cheesetouch if you were clueless like me (well I knew artery but..), picking one with 'thyro' in the name when discussing a thyroid surgery is a good guess :) +10

cbreland I'm really out here picking one of the answers with vein +2

cheesetouch Anatomy image: https://image.slidesharecdn.com/thyroidgland-150501155351-conversion-gate01/95/thyroid-gland-14-638.jpg?cb=1430513690 FA18 p 338 relates to thyroidectomy +1

+3 upvote downvote
submitted by ∗t123(32)

get full access to all content ⋅ pick a username

PMID 8165531

Both superior thyroid (ext carotid) and inferior thyroid (thyrocervical) supply the parathryoids. Bad q...

get full access to all content ⋅ pick a username

tekkenman101 Main supply to parathyroids is inferior, so no. +1

mistermbg "The thyroid gland and the parathyroid glands share the same blood supply. The inferior thyroid arteries supply the parathyroid glands via its branches (supplying both the inferior and superior parathyroids in most cases). Collaterals via the superior thyroid artery, thyroid ima artery, laryngeal, tracheal, and esophageal arteries. Parathyroid veins drain into the thyroid vein plexus." https://www.ncbi.nlm.nih.gov/books/NBK537203/#:~:text=Blood%20Supply%20and%20Lymphatics,-The%20thyroid%20gland&text=The%20inferior%20thyroid%20arteries%20supply,%2C%20tracheal%2C%20and%20esophageal%20arteries. the MAIN SUPPLY IS FROM THE INFERIOR THYROID ARTERIES. the little bit of blood received from the collateral keeps them alive but now they sense low ca2+ --->>> so release tons of PTH... if the superior was knocked out = not a big deal --> not main supply to the glands. +2

burak everyone keeps saying it is sensing low ca level so secreting more pth. But Ca is already low so it is not sensing anything wrongly. Or I am just blind i dont know. +1

+1 upvote downvote
submitted by ∗niboonsh(409)

get full access to all content ⋅ pick a username

external carotid branch supplies the superior parathyroid glands as well........?

get full access to all content ⋅ pick a username

yng Yes the superior part supplied by superior thyroid gland which is a branch of external carotid branch. +1

llamastep1 No they do not, parathyroids are supplied by the inferior thyroid arteries. https://teachmeanatomy.info/neck/viscera/parathyroid-glands/ +15

suckitnbme Superior thyroid artery does supply some blood to the parathyroids through anastomoses but the main vascular supply is from the inferior thyroid artery. +2

okokok1 https://www.earthslab.com/wp-content/uploads/2017/07/070417_1014_Parathyroid1-1.jpg this shows a great visual of how inferior thyroid artery does most of the supplying. +1

+1 upvote downvote
submitted by ∗jbrito718(48)

get full access to all content ⋅ pick a username

the MAIN SUPPLY IS FROM THE INFERIOR THYROID ARTERIES. the little bit of blood received from the collateral (superior thyroid from external carotid) keeps them alive but now they sense low ca2+ --->>> so release tons of PTH... if the superior was knocked out = not a big deal --> not main supply to the glands.

** I copied @mistermbg explanation because he explains it really well!

get full access to all content ⋅ pick a username

Must-See Comments from free120

sugaplum on It is a polymorphism
bwdc on Elaboration of proteases and urease with ...
bwdc on Hypercoagulability from advanced malignancy
bwdc on Ribosomal assembly
bwdc on Aspiration
bwdc on Amygdala
imnotarobotbut on von Willebrand disease
bwdc on Trinucleotide repeat expansion
bwdc on Mediation of cell entry via a fusion protein
bwdc on Metabolism
bwdc on Basement membrane
melchior on Aspiration
hungrybox on Immune complex deposition in tissues
aejinkim on Decreased activity in the enzyme that ...