MCQs in ANATOMY: THYROID GLAND

In this post, I have posted 15 MCQs related to anatomy of thyroid gland.The keys to these question will be posted separately with explanation for some.

1. Knowledge of location of the thyroid gland is important to perform the physical examination. It is located anteriorly at the lower part of neck in relation to trachea and lies deep to the anterior triangle neck muscles.

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


2. The thyroid consists of two lobes connected by a narrow isthmus which is related to tracheal ring. 

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


3. Thyroid is covered with the fibrous true capsule which sends septa inward and divide the organs into lobules. External to the fibrous capsule, it is covered by loose connective tissue sheath (false capsule) which is derived from one of the layers of cervical fascia. 

Which layer of cervical fascia forms the false capsule of thyroid gland?
a)             Investing layer
b)            Pretracheal layer
c)             Prevertebral layer


4. Thyroid gland is located deep in the anterior neck triangle. 

It lies deep to which muscles?
a)             Digastric muscles
b)            Omohyoid muscles
c)             Sternothyroid and Sternohyoid
d)            Thyrohyoid and myelohyoid


5. The development of thyroid gland is marked by a depression called foramen cecum in the floor of the primitive pharynx. The foramen caecum gives rise to a diverticulum which later elongates and descends anterior to the hyoid bone and thyroid cartilage to assume the adult position. 

What is this diverticulum called?
a)             Hyoglossal duct
b)            Laryngeal diverticulum
c)             Respiratory diverticulum
d)            Thyroglossal duct


6. Thyroid gland is highly vascular and is supplied by branches of a pair of superior and inferior thyroid arteries which lie between the fibrous and loose connective tissue layers. 

Which artery generally gives rise to the superior thyroid artery?
           a)    External carotid artery
           b)   Internal carotid artery  
           c)    Brachiocephalic trunk
           d)   Thyrocervical trunk


7. Which artery generally gives rise to inferior thyroid artery?
           a)    External carotid artery
           b)   Internal carotid artery
           c)    Brachiocephalic trunk
           d)   Thyrocervical trunk


8. Thyroid ima artery is present in approximately 10% people and generally arises from brachiocephalic trunk (or also from other vessels like arch of aorta, common carotid, subclavian and internal thoracic arteries). This artery runs in the midline anterior to the trachea and ascend upward towards the gland.

Which part of the gland is supplied by this artery?
          a)    Apex
          b)   Base
          c)    Isthmus
         d)   Lateral surfaces


9. Thyroid gland is drained by three pairs of veins, superior, middle and inferior thyroid veins which arise from thyroid venous plexus. The middle thyroid vein has no corresponding artery and accompanies inferior thyroid artery whereas the inferior thyroid veins runs independently.

Where does the superior thyroid vein drain?
a)             Brachiocephalic vein
b)            External jugular vein
c)             Internal Jugular vein
d)            Subclavian vein


10. Where does the middle thyroid vein drain?
a)             Brachiocephalic vein
b)            External jugular vein
c)             Internal Jugular vein
d)            Subclavian vein


11. Where does the inferior thyroid artery drain?
a)             Brachiocephalic vein
b)            External jugular vein
c)             Internal Jugular vein
d)            Subclavian vein


12. Superior thyroid artery descends to the superior pole (or apex) of the thyroid gland. In its initial course, the artery accompanies a nerve which when approaching the apex passes deep to the gland.

Which is this nerve related with the superior thyroid artery?
a)             External laryngeal nerve
b)            Internal laryngeal nerve
c)             Recurrent laryngeal nerve
d)            Superior laryngeal nerve


13. Given this close relationship of superior thyroid artery with external laryngeal nerve at its initial course (as mentioned above in question# 12), where do you like to ligate the artery during the surgical removal of thyroid gland (thyroidectomy)?
a)             Away from the apex
b)            Close to the apex
c)             It does not matter


14. Inferior thyroid artery after arising from the thyrocervical trunk runs above and medially towards the inferior pole (or base) of the thyroid gland. Near the base of the gland, the artery is closely related with a nerve.

Which is this nerve related with the inferior thyroid artery close to the base?
a)             External laryngeal nerve
b)            Internal laryngeal nerve
c)             Recurrent laryngeal nerve
d)            Superior laryngeal nerve


15. Given this close relationship of inferior thyroid artery with the nerve (as mentioned in question # 14), where do you like to ligate the artery during the surgical removal of thyroid gland (thyroidectomy)?
a)             Away from the apex
b)            Close to the apex
c)             It does not matter