Lecture Notes: Triangles of the Neck

Introduction

• Presenter: Dr. Morton, noted anatomist
• Importance of triangles in anatomy:
  • Facilitates descriptions of neck anatomy
  • Aids in identifying structures

The Concept of Triangles

• Triangles help in identifying smaller landmarks within the neck, similar to using major geographical landmarks on a map.
• Example: Using the digastric muscle and mandible to identify the facial artery in the submandibular triangle.

The Neck Triangles

• Main Triangles:
  • Posterior Triangle
  • Anterior Triangle

Posterior Triangle

Borders:

• Sternocleidomastoid (SCM)
• Trapezius (traps)
• Clavicle

Roof and Floor:

• Roof: Deep investing fascia
• Floor: Prevertebral fascia

Contents:

• Cutaneous nerves from the cervical plexus (Herb's point)
• External jugular vein
• Superficial cervical nodes
• Muscles (e.g., omohyoid)

Subdivisions:

• Occipital Triangle: Contains occipital artery
• Supraclavicular Triangle: Contains suprascapular artery and transverse scapular artery

Important Structures in Floor:

• Spinal accessory nerve (Cranial Nerve XI)
• Transverse cervical artery
• Subclavian artery and vein
• Brachial plexus (C5-T1)

Anterior Triangle

Borders:

• Sternocleidomastoid (SCM)
• Mandible
• Anterior midline of the neck

Subdivisions:

1. Submandibular Triangle:

   • Bordered by anterior and posterior bellies of digastric muscle and mandible
   • Contents: Submandibular salivary gland, facial artery and vein, submandibular lymph nodes

2. Submental Triangle:

   • Bordered by mandible, anterior belly of digastric, and hyoid bone
   • Contents: Submental lymph nodes, tributaries of anterior jugular veins

3. Carotid Triangle:

   • Bordered by posterior belly of digastric, superior belly of omohyoid, and SCM
   • Contents: Internal jugular vein, carotid arteries, vagus nerve, deep cervical lymph nodes, hypoglossal nerve (CN XII), ansa cervicalis

4. Muscular Triangle:

   • Bordered by omohyoid, sternohyoid, and SCM
   • Contents: Thyroid and parathyroid glands

Summary

• Understanding the anatomy of the neck through these triangles aids in clinical practice and anatomical studies.