The slide is of blood supply and nerve supply of the Thyroid gland. It can be used by MBBS Anatomy students.

1. THYROID GLAND : BLOOD SUPPLY ,
NERVE SUPPLY AND APPLIED
NAME – PRAVIN PANDEY
ROLL NO. – 68
BATCH – 2021-22

2. CONTENTS
 ARTERIAL SUPPLY
 VENOUS DRAINAGE
 NERVE SUPPLY
 APPLIED

3. ARTERIAL SUPPLY
 Gland is highly vascular
 Supplied by following arteries:
 1. SUPERIOR THYROID ARTERY
 2. INFERIOR THYROID ARTERY
 3. THYROIDEA IMA ARTERY
 4. ACCESSORY THYROID ARTERY

5. 1. SUPERIOR THYROID ARTERY
 Branch of EXTERNAL CAROTID ARTERY.
 Runs downward and forward in company with external laryngeal
nerve, leaves near upper pole.
 At apex – divides into Anterior and Posterior branches.


6. ANTERIOR BRANCH : Descends along anterior
border of lobe.
: Continues along the upper
border of isthmus.
: Anastomose with its fellows
of opposite side.

7.  POSTERIOR BRANCH : Descends along posterior
 border of lobe.
 : Anastomose with ascending
 branch of inferior thyroid
 artery.
 SUPERIOR THYROID
 ARTERY supplies: Upper one-third of lobe.
 : Upper half of isthmus.

8. 2.INFERIOR THYROID ARTERY
 Branch of thyrocervical trunk from the first part
of subclavian artery.
 Runs upward along medial border of scalenus
anterior.
 Related to RECURRENT LARYNGEAL NERVE.
 This nerve presents variable relationship with
artery .

9. VARIABLE RELATIONSHIP OF ARTERY WITH NERVE

10.  Inferior Thyroid Artery gives 4 or 5 branches.
 One ascending branch anastomoses with posterior
branch of Superior Thyroid Artery.
 Supplies : Lower two-third of lobe.
 : Lower half of isthmus.

11.  3. THYROIDEA IMA ARTERY ( 30% cases)
 Branch of brachiocephalic trunk or,
 May arise directly from arch of aorta.
 Enters isthmus from below.
 4. ACCESSORY THYROID ARTERIES
 Arise from tracheal or oesophageal arteries.

12. VENOUS DRAINAGE
 Venous blood from gland is drained by 3 set of veins :
 1. SUPERIOR THYROID VEIN
 2. MIDDLE THYROID VEIN
 3. INFERIOR THYROID VEIN.
 4. THYROID VEIN (OF KOCHER) (present sometime).

14.  1. SUPERIOR THYROID VEIN : Emerge at upper pole.
 : Runs upward and laterally.
 : Drain into Internal Jugular Vein.
 2. MIDDLE THYROID VEIN : Short and wide
 : Emerge at middle of lobe.
 : Drain into Internal Jugular Vein.

15.  3. INFERIOR THYROID VEIN : Emerge at lower border of isthmus.
 : Form plexus in front of trachea.
 : Drain into Left Brachiocephalic Vein.
 4.THYROID VEIN ( OF KOCHER) : Emerge between middle and
Inferior thyroid veins.
: Drain into Internal Jugular Vein.

16. NERVE SUPPLY
 Supplied by both sympathetic and parasympathetic nerve fibres.
 1. PARASYMPATHETIC SUPPLY : from VAGUS and
RECURRENT LARYNGEAL NERVES.
 2. SYMPATHETIC SUPPLY : from SUPERIOR , MIDDLE and
 INFERIOR CERVICAL sympathetic ganglion.
 (Mainly from MIDDLE one.)

17. CLINICAL CORRELATION
 1. THYROIDECTOMY :Removal of gland with true capsule.
 2. SUBTOTAL THYROIDECTOMY : Posterior parts of both
 lobes are left behind.
 Done to avoid : - Risk of removal of parathyroid glands.
 - Postoperative myxoedema due to thyroid
 hormone deficiency.

18.  3. LIGATION OF THYROID ARTERIES DURING
 THYROIDECTOMY.
 AT APEX : Superior thyroid artery ligated CLOSE to the apex.
 Of thyroid lobe to avoid injury to external laryngeal nerve.
 AT BASE : Inferior thyroid artery ligated away from the base.
 To avoid injury to recurrent laryngeal nerve.

20. BIBLIOGRAPHY
 Textbook of Anatomy – Vishram singh (3rd edition).
 Gray’s Anatomy