Dissection 6-the Root Of The Neck

Question 1

Thyroid Gland

Answer 1

Located at vertebral levels C5-T1

-laterally the thyroid gland is in contact with the carotid sheath

Question 2

Right and Left lobes of the Thyroid Gland

Answer 2

-connected by the isthmus of the thyroid gland which crosses the anterior surface of tracheal rings 2 and 3

Question 3

Superior Thyroid artery

Answer 3

Enters the superior end of the lobe of the thyroid gland

-a branch of the external carotid artery

Question 4

Superior and Middle thyroid Veins

Answer 4

Tributaries to the internal jugular vein
-the inferior thyroid veins descend into the thorax on the anterior surface of the trachea. They drain into the right and left brachiocephalic veins

Question 5

Thyroidea Ima Artery

Answer 5

Clinical variant
(2-12% of the population)
-it enters the thyroid gland from inferiorly, near the midline

Question 6

Recurrent Laryngeal Nerve

Answer 6

-passes immediately posterior to the lobe of the thyroid gland in the groove between the trachea and the esophagus

Question 7

Parathyroid Glands

Answer 7

• on the posterior part of the lobes of the thyroid gland
• may be darker in color
• usually 2 on each side but vary from 1-3

Question 8

In the Clinic: Recurrent Laryngeal Nerve

Answer 8

If a recurrent laryngeal nerve is injured by a thyroid tumor or during a thyroidectomy, paralysis of the laryngeal muscles will occur on the affected side. Results in hoarseness of the voice

Question 9

In the Clinic: Parathyroid Glands

Answer 9

• play an important role in the regulation of calcium metabolism.
• during thyroidectomy, these small endocrine glands are in danger of being damaged or removed. To maintain proper serum calcium levels, at least one parathyroid gland must be retained during surgery

Question 10

External Jugular Vein and Subclavian Vein

Answer 10

The external jugular vein is the only tributary of the subclavian vein

Question 11

Subclavian Vein

Answer 11

Lies anterior to the anterior scalene muscle

Question 12

Internal Jugular vein and Subclavian Vein

Answer 12

Join together to form the bachiocephalic vein

Question 13

Thoracic Duct

Answer 13

-formed in the abdomen by the union of smaller lymphatic ducts, notably the cisterna chyli and ascends through the posterior mediastinum to join the venous systems in the root of the neck at the junction of the left subclavian vein and left internal jugular vein

Question 14

Right lymphatic duct

Answer 14

On the right side of the neck, several small lymphatic vessels joint with lymph vessels form the rights upper limb and right side of the thorax to form the right lymphatic duct
-drains into the junction of the right subclavian vein and right internal jugular vein

Question 15

Subclavian Artery

Answer 15

Right subclavian artery is a branch of the brachiocephalic trunk
Left subclavian artery is a branch of the aortic arch
-lies between the anterior scalene and middle scalene muscles together with the supraclavicular part of the brachial plexus

Question 16

Parts of the Subclavian Artery

Answer 16

First part: from its origin to the media border of the anterior scalene muscle
2nd part: posterior to the anterior scalene muscle
3rd: between the lateral border of the anterior scalene muscle and the lateral border of the first rib

Question 17

Branches of the subclavian artery (1st part)

Answer 17

• Internal thoracic artery: arises from the anteroinferior surface of the subclavian artery and passes inferiorly to supply the anterior thoracic wall
• Thyrocervical trunk: arises from the anterosuperior surface of the subclavian artery. This has 3 branches as well
• Vertebral Artery: courses superiorly between the anterior scales muscle and the longus Colli muscle. It passes superiorly into the transverse foramen of the vertebra C6

Question 18

Thyrocervical Trunk (branches)

Answer 18

• transverse cervical artery: crosses the root of the neck superior to the clavicle and deep to the omohyoid muscle. It supplies the trapezius muscle. (Superficial branch enters the anterior border of the trapezius muscle. The deep branch runs along the rhomboid muscles and is called the dorsal scapular artery. The dorsal scapular artery can also arise as a separate artery from the subclavian artery (usually the 3rd part)
• suprascapular artery: passes laterally and posteriorly to the region of the suprascapular notch. It passes superior to the transverse scapular ligament and supplies the supraspinatus and infraspinatus muscles
• inferior thyroid artery: passes medially toward the thyroid gland. Passes posterior to the cervical sympathetic trunk. The ascending cervical artery is a branch of the inferior thyroid artery

Question 19

Branches of the 2nd part of the subclavian artery

Answer 19

Costocervical trunk

-divides into deep cervical artery and supreme intercostal (artery gives rise to posterior intercostal arteries 1 and 2)

Question 20

3rd part of the Subclavian Artery (branches)

Answer 20

Dorsal Scapular Artery

• passes between the superior and middle trunks of the supraclavicular part of the brachial plexus to supply the muscles of the scapular region
• in about 30% of cases, this artery arises from the transverse cervical artery instead of the subclavian

Question 21

Right Vagus Nerve

Answer 21

• passes anterior to the subclavian artery

- gives off right recurrent laryngeal nerve

Question 22

Left Vagus Nerve

Answer 22

• passes on the left side of the aortic arch

- gives off the left recurrent laryngerla nerve

Question 23

Phrenic Nerve

Answer 23

-passes vertically down the anterior surface of the anterior scalene muscle, Posterior to the transverse cervical and suprascapular arteries

Question 24

Interscalene Triangle

Answer 24

Where the anterior and middle scalene muscles attach to the first rib
-adjacent borders of the anterior and middle scalene muscles and first rib

Question 25

In the Clinic: Scalene Triangle

Answer 25

Becomes significant when anatomical variations (additional muscular slips, an accessory cervical rib, or exostosis on the first rib) narrow the interval. As a result, the subclavian artery and/or roots of the brachial plexus may become compressed, resulting in ischemia and/or nerve dysfunction in the upper limb