Root of Neck

Root of Neck: Detailed Study Notes

Identify and list the boundaries of the root of the neck.
Identify and list the three divisions and branches of the right and left subclavian artery.
Discuss the location and importance of the cervical sympathetic chain.
Discuss the general location of the cervical nodes and the locations they drain.
Discuss the location and importance of the thoracic duct.

General Description:
- The root of the neck is the area superior to the superior thoracic aperture and axillary inlets.
- It contains structures passing between the neck, thorax, and upper limb.
Specific Boundaries:
- Anterior: Manubrium of sternum
- Lateral: Rib 1
- Posterior: T1 vertebrae

Description:
- The cervical pleura, also known as the cupula, represents the apex of the pleural cavity.
- It extends above the manubrium of sternum and rib 1.

Origin:
- Branches from the brachiocephalic trunk.
Pathway:
- Arches superiorly and laterally over the apex of the pleural cavity.
- Passes over rib 1 to become the axillary artery.

Origin:
- A direct branch of the arch of the aorta.
Pathway:
- Ascends and arches laterally, located between the anterior and middle scalene muscles.
- Passes over rib 1 to become the axillary artery.

The subclavian artery is divided into three parts by the anterior scalene muscle:
1. From the aortic arch to anterior scalene muscle
2. Located posterior to anterior scalene muscle
3. Positioned lateral to the anterior scalene muscle, before it reaches the lateral border of rib 1.

General Information:
- All branches will arise from the first portion of the artery except for the costocervical trunk on the right subclavian artery.
Main Branches:
- Vertebral Artery
- Thyrocervical Trunk
- Internal Thoracic Artery
- Costocervical Trunk
- Brachiocephalic Trunk

Costocervical trunk originates on:
- The second portion of the subclavian artery, while the majority of branches arise from the first portion.
Thyrocervical Trunk Components:
- Inferior Thyroid Artery
- Transverse Cervical Artery
- Suprascapular Artery

Description:
- The first branch of the subclavian artery.
- Located medial to the anterior scalene muscle.
Pathway:
- Ascends and enters the transverse foramina of the cervical vertebrae (from C6 to C1).
- Crosses the posterior arch of C1 and passes through the foramen magnum to enter the cranial fossa.

Position:
- The second branch of the subclavian artery, located medial to the anterior scalene muscle.
Branches of Thyrocervical Trunk:
1. Inferior Thyroid Artery
2. Transverse Cervical Artery
3. Suprascapular Artery.

Description:
- A continuation of the thyrocervical trunk.
- Supplies the posterior aspect of the thyroid gland.
Main Branches include:
a. Ascending Cervical Artery:
- Branch of inferior thyroid artery that supplies:
  - Prevertebral muscles via muscular branches.
  - Spinal cord via spinal branches.
b. Inferior Laryngeal Artery:
- Supplies the lower larynx.
c. Pharyngeal Branches:
- Supply the lower pharynx.

Description:
- Passes laterally, located anterior to the anterior scalene muscle.
- Crosses the base of the posterior triangle of the neck, passing deep to the trapezius muscle.

Right Costocervical Trunk:
- Arises from the second part of the subclavian artery.
Left Costocervical Trunk:
- Arises from the first part of the subclavian artery.
Two Terminal Branches of Costocervical Trunk:
1. Deep Cervical Artery:
- Ascends in the back of the neck and anastomoses with the occipital artery.
1. Supreme Intercostal Artery:
- Descends anterior to rib 1 and divides to form posterior intercostal arteries, supplying the first two intercostal spaces.

Origin:
- Begins at the lateral margin of rib 1 as a continuation of the axillary vein.
Pathway:
- Passes anterior to the anterior scalene muscles.
- Joins with the internal jugular vein to form the brachiocephalic veins.
- The external jugular vein acts as the only tributary of the subclavian vein.

Phrenic Nerve:
- Mixed nerve (motor and sensory).
- Arises from the anterior rami of C3 – C5 of the cervical plexus.
- Located anterior to the origin of the brachial plexus in the neck.
Pathway of Phrenic Nerve:
- Found pinned to the anterior scalene muscle via transverse cervical and suprascapular arteries.
- Travels between the subclavian artery and vein to enter the thorax.
Vagus Nerve (including Recurrent Laryngeal Nerves):
- As right and left vagus nerves enter the thorax, their pathway is:
- Anterior to the subclavian artery
- Posterior to the subclavian vein.

Location:
- Found posterior to common carotid artery and internal carotid artery.
- Anterior to longus colli and longus capitis muscles.
Notable Structure:
- The inferior/stellate cervical ganglion is found at the root of the neck.

Description:
- Form a ring around the head.
- Drain the respective scalp, face, and neck areas.
- Distributed throughout arteries of their respective location.
Associated Arteries and Nodes:
- Occipital Artery: drains occipital node.
- Superficial Temporal Artery/Transverse Facial Artery: drains pre-auricular/parotid nodes.
- Facial Artery: drains submental and submandibular nodes.

Description:
- Forms a chain along the internal jugular vein.
- Divided into superior and inferior deep cervical nodes.
- Receives all lymphatic drainage from head and neck.
Drainage:
- Empties into the thoracic duct or right lymphatic duct.

Description:
- Major lymphatic channel of the body.
Pathway:
- Begins in the abdomen.
- Enters the root of the neck to the left of the esophagus.
- Continues laterally, going posterior to the carotid sheath.
- Terminates between the left internal jugular and subclavian veins.