Lecture Notes: Anatomy of the Cervical Plexus

Introduction

• Cervical Plexus: Network of nerves from the spinal cord between the 1st and 4th cervical vertebrae.
  • Functions: Relays sensory information and sends motor signals.
  • Unique Interaction: Interacts with cranial nerves.

Structure of Cervical Plexus

• Ventral Rami: Focus on ventral (anterior) rami of spinal nerves.
• Naming System: Spinal root is named after the vertebra it is superior to.
  • Example: C1 root is superior to vertebra C1.

Orientation and Anatomy

• Location: Deep to the sternocleidomastoid muscle.
• Bony Structure: Base of skull, cervical vertebrae C1-C4, with C5 leading to brachial plexus.
• Diagram: Cervical plexus shown in green.

Major Components and Chunks

• The Trimmings: Motor nerves innervating smaller neck muscles.

  • Muscles: Longus capitis, Longus colli, Scalene, Levator scapulae.

• Hypoglossal and Handle

  • Hypoglossal Nerve (CN 12): Controls tongue movement.
  • Ansa Cervicalis: Loop from C1-C3, interacts with hypoglossal nerve.
  • Innervation: Infrahyoid muscles (omohyoid, sternothyroid, sternohyoid).

• Big Muscle Chunk

  • Sternocleidomastoid and Trapezius: Innervation from C1-C4.
  • Phrenic Nerve: From C3-C5, innervates diaphragm and thoracic cavity structures.

• Sensory Nerves

  • Lesser Occipital, Great Auricular, Transverse Cervical, Supraclavicular: Sensory nerve branches off C2, C3, C4.
  • Mnemonic: OATS for sensory nerves.

Summary and Mnemonics

• Trimmings: Smaller motor nerves.
• Hypoglossal and Handle: Hypoglossal nerve and ansa cervicalis.
• Big Muscle: Innervation of larger muscles and phrenic nerve.
• Sensory Nerves: OATS mnemonic for sensory branches.

Additional Details

• Sympathetic Connections: Each spinal root has a connection to the sympathetic nervous system.

Resources and Sponsor

• Kenhub: Recommended resource for anatomy learning, detailed illustrations, and custom quizzes.
• Sponsorship Mention: Offers discount subscription and refund policy.

This concludes the summary of the cervical plexus lecture. For hands-on practice, explore resources like Kenhub for detailed anatomical illustrations and quizzes.