Lecture on the Cervical Plexus

Introduction

• Cervical Plexus Overview:
  • Supplies structures of the head, neck, and certain muscles
  • Series of lectures on different plexuses: cervical, brachial, lumbar, sacral

Anatomy of the Spinal Cord

• Spinal Cord Structure:
  • Anterior view: cerebellum, medulla, pons
  • Anterior gray horn: rootlets form spinal nerves
  • Spinal nerves are paired (left and right)
• Spinal Segments:
  • Cervical Segments: 8 pairs of spinal nerves
  • Thoracic Segments: 12 pairs of spinal nerves
  • Lumbar Segments: 5 pairs of spinal nerves
  • Sacral Segments: 5 pairs of spinal nerves
  • Coccygeal Segment: 1 nerv
• spinal nerves run from intervertebral foramen except c1 which is between occipital condyles and atlas

Plexus Details

• C1 to C5 and Contributions:
  • C1: Superior root of ansa cervicalis, other branche (with hg) to geniohyoid and thyrohyoid
  • Hypoglossal Nerve (CN XII): Runs with C1, supplying tongue muscles(styloglosis,hyoglosis,genoglosis,intrinsic muscles)
  • Vagus Nerve (CN X): Communication with C1 and C2
  • Muscles Involved: Rectus capitis anterior and lateralis, longus capitis
• Roots Interaction and Muscles:
  • C2 and C3: Greater auricular and transverse cervical nerves
  • Lesser Occipital Nerve: Primarily from C2
  • Ansa Cervicalis Formation(superior and inferior : Supplies omohyoid, sternothyroid, steinohyoid,omhyoid(inferior belly)
  • C2 ,c3 ,c4,c5separately has branches to longus coli, longus capitus
  • C3,c4 separately also branches to scalens and levator scapula
  • C3,c4 come together and form supraclavicular nerve(cutaneous branch)

Phrenic Nerve

• C3, C4, C5 Contribution: Essential for diaphragm function
• Clinical Importance: Lesions can cause respiratory failure

Accessory Nerve and Related Fibers

• Spinal Accessory Nerve (CN XI):
  • Fibers from C1-C5(lateral funiculus ), runs through foramen magnum,as spinalaccessory nerve,gains fibres from cranial accessory nerve,run throgh the jugular foramen, most fibres will go with vagus nerves
  • Rest moves as spinal accessory nerve and Supplies sternocleidomastoid(c2,c3) and trapezius muscles(c2,c4)
  • Clinical relevance: posterior triangle of the neck

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Conclusion

• Cervical Plexus Importance:
  • Detailed anatomy and nerve supply
  • Essential for head and neck functions
  • Clinical significance in diagnosing and treating conditions related to nerve damage