Dissection 6-the Root Of The Neck Flashcards
Thyroid Gland
Located at vertebral levels C5-T1
-laterally the thyroid gland is in contact with the carotid sheath
Right and Left lobes of the Thyroid Gland
-connected by the isthmus of the thyroid gland which crosses the anterior surface of tracheal rings 2 and 3
Superior Thyroid artery
Enters the superior end of the lobe of the thyroid gland
-a branch of the external carotid artery
Superior and Middle thyroid Veins
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
Thyroidea Ima Artery
Clinical variant
(2-12% of the population)
-it enters the thyroid gland from inferiorly, near the midline
Recurrent Laryngeal Nerve
-passes immediately posterior to the lobe of the thyroid gland in the groove between the trachea and the esophagus
Parathyroid Glands
- 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
In the Clinic: Recurrent Laryngeal Nerve
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
In the Clinic: Parathyroid Glands
- 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
External Jugular Vein and Subclavian Vein
The external jugular vein is the only tributary of the subclavian vein
Subclavian Vein
Lies anterior to the anterior scalene muscle
Internal Jugular vein and Subclavian Vein
Join together to form the bachiocephalic vein
Thoracic Duct
-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
Right lymphatic duct
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
Subclavian Artery
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
Parts of the Subclavian Artery
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
Branches of the subclavian artery (1st part)
- 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
Thyrocervical Trunk (branches)
- 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
Branches of the 2nd part of the subclavian artery
Costocervical trunk
-divides into deep cervical artery and supreme intercostal (artery gives rise to posterior intercostal arteries 1 and 2)
3rd part of the Subclavian Artery (branches)
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
Right Vagus Nerve
- passes anterior to the subclavian artery
- gives off right recurrent laryngeal nerve
Left Vagus Nerve
- passes on the left side of the aortic arch
- gives off the left recurrent laryngerla nerve
Phrenic Nerve
-passes vertically down the anterior surface of the anterior scalene muscle, Posterior to the transverse cervical and suprascapular arteries
Interscalene Triangle
Where the anterior and middle scalene muscles attach to the first rib
-adjacent borders of the anterior and middle scalene muscles and first rib
In the Clinic: Scalene Triangle
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
