10. The Cervical Plexus Flashcards Preview

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Flashcards in 10. The Cervical Plexus Deck (6)
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1
Q

Where is the cervical plexus located

A

Network of nerve fibres located:

  • in posterior triangle of neck
  • within prevertebral layer of cervical fascia
  • superficial to scalenus medius and levator scapulae
  • deep to SCM
2
Q

Which spinal cord segments form the cervical plexus

A

Anterior rami C1-C4

3
Q

Which structures do the sensory branches of cervical plexus provide cutaneous innervation to

A
  1. Posterior scalp: lesser occipital n. (C2-3)
  2. External ear + mastoid process: greater auricular n. (C2-3)
  3. Anterior neck: transverse cervical nn. (C2-C3)
  4. Supraclavicular fossa: supraclavicular nn. (C3-4)
4
Q

What is Erb’s point and what is its clinical relevance

A
  • Area of skin (middle of posterior border of SCM) where sensory nerves of cervical plexus emerge.
  • Utilised clinically when performing cervical plexus nerve block - provides regional anaesthesia for surgery in neck region, e.g. Thyroidectomy, cervical lymph node excision
5
Q

Which structures do the motor branches of the cervical plexus innervate

A
  1. Infrahyoids (depress hyoid bone for swallowing and speech): several branches from C1-C3 form a loop - ansa cervicalis - giving off 4 motor branches to these muscles
  2. trapezius and SCM: accessory n. (C3-4)
  3. Diaphragm: phrenic n. (C3-5)
6
Q

Which clinical signs would suggest accessory n palsy?

A
  • wasting of shoulder muscles
  • winging of scapula
  • weakened shoulder abduction and external rotation