Lymphatic Levels in the Neck

Lymphatic Levels in the Neck

🩺 Introduction

Today we're diving into an important topic for every medical student and clinician: Lymphatic Levels in the Neck.

Why is this important? Understanding the lymphatic system of the neck is crucial for diagnosing various conditions, especially malignancies. Knowing these levels also plays a key role in viva exams and both undergraduate and postgraduate exams.

💉 Lymphatics of the Neck: Superficial vs Deep

The lymphatic system of the neck can be divided into two major components: superficial and deep systems.

• Superficial Lymphatics: These drain the skin and then perforate the deep cervical fascia, eventually draining into the deep system.

Why does malignancy involving superficial lymphatics need skin resection very commonly?

• Deep Lymphatics: These are closely associated with fascial condensations, vessels, nerves, and muscles in the neck.

Today, we’ll focus on these deep lymphatic levels, as they are the primary ones associated with draining the head and neck structures.

🔬 Overview of Deep Lymphatic System

According to the AAOHNS, the deep lymphatic system is divided into 7 levels.

Let’s take a look at each level and its corresponding anatomical boundaries and functions.

1️⃣ Level 1: Submental and Submandibular Regions

1a. Submental Lymph Nodes

• Location: Midline zone forming the submental triangle.

What are the boundaries of Submental Triangle?

• Boundaries:

  • Anterior belly of the digastric muscle
  • Hyoid bone
  • Midline of the neck

• Structures Drained:

  • Anterior floor of mouth
  • Lower lip
  • Ventral aspect of the tongue

1b. Submandibular Lymph Nodes

• Location: Submandibular triangle.

What are the boundaries of Submandibular Triangle?

• Boundaries:

  • Anterior belly of digastric
  • Posterior belly of digastric
  • Lower border of the mandible

• Structures Drained:

  • Lateral aspect of the tongue
  • Rest of the floor of mouth
  • Buccal cavity

2️⃣ Level 2: Upper Jugular Chain

• Location: Extends from the skull base to the inferior border of the hyoid bone.

• Structures Drained:

  • Oral cavity
  • Nasopharynx
  • Hypopharynx
  • Larynx
  • Parotid glands
  • First echelon lymph nodes of the oropharynx

Level 2a and 2b

• 2a: Caudal to the spinal accessory nerve.
• 2b: Cranial to the spinal accessory nerve.

What is Suarez Triangle?

3️⃣ Level 3: Middle Jugular Chain

• Location: Extends from the inferior border of the hyoid bone to the inferior border of the cricoid.

• Structures Drained:

  • Lower oropharynx
  • Hypopharynx
  • Larynx

4️⃣ Level 4: Lower Jugular Chain

• Location: Extends from the inferior border of the cricoid to the level of the clavicle.

• Structures Drained:

  • Hypopharynx
  • Larynx

What are Virchow’s Nodes?

5️⃣ Level 5: Posterior Triangle

• Location: Bounded by the sternocleidomastoid and trapezius muscles.

• Structure Drained: Drains lymph from other nodal areas.

Level 5a and 5b

• 5a: Above an imaginary horizontal line at the level of the cricoid.
• 5b: Below this line, related to the transverse cervical artery and supraclavicular lymph nodes.

6️⃣ Level 6: Central Compartment

• Location: Between the two common carotid arteries, extending from the hyoid bone to the innominate artery.

• Structures Drained:

  • Paratracheal, perithyroid, and precricoid lymph nodes
  • Delphian (Precricoid) Lymph Nodes

What is the complication that develops post operatively after removing Level 6 Nodes as a part of Total Thyroidectomy or Total Laryngectomy?

7️⃣ Level 7: Superior Mediastinal Nodes

• Location: Lymph nodes in the superior mediastinum.

• Structures Drained:

  • Thyroid
  • Subglottis
  • Trachea
  • Cervical esophagus

• Clinical Importance: Lymph nodes here can drain thymic remnants.

📝 Summary

The lymphatic levels in the neck are critical for understanding the drainage patterns of various head and neck structures.

This knowledge is essential for diagnosing head and neck malignancies and for performing surgical procedures like neck dissections.

Here's a quick rundown:

• Level 1: Submental and submandibular nodes.
• Level 2: Upper jugular chain (subdivided into 2a and 2b).
• Level 3: Middle jugular chain.
• Level 4: Lower jugular chain and Virchow’s nodes.
• Level 5: Posterior triangle, subdivided into 5a and 5b.
• Level 6: Central compartment, including Delphian nodes.
• Level 7: Superior mediastinal nodes.

Understanding these levels is crucial for both clinicians and surgeons in diagnosing conditions and performing treatments.