Cervical Plexus

Question 1

The Cervical Plexus is in the Posterior Triangle within the Prevertebral Fascia.

Which nerve roots is it made up of?

Answer 1

Anterior Rami of C1-C4

Question 2

What is the Ansa Cervicalis?

What does it contribute to?

Answer 2

A loop of purely motor branches formed by nerve roots C1-C3

Innervates Infrahyoid muscles

Question 3

How is the Ansa Cervicalis related to the Carotid Sheath?

Answer 3

Lies anterior to OR in the Carotid Sheath

Question 4

Which of the nerve roots of the Cervical Plexus does not have a sensory function?

Answer 4

C1 (Purely Motor)

Question 5

Other than Ansa Cervicalis, name a motor component of the Cervical Plexus

Describe this structure’s path

Answer 5

Phrenic nerve (C3, C4, C5)

After arising from plexus, this nerve travels down surface of Anterior Scalene and enters Thorax, then descends to Diaphragm

Question 6

Which parts of the body are supplied by Sensory branches of the Cervical Plexus?

Answer 6

• Skin of neck
• Part of Scalp and Ear
• Superior thorax

Question 7

Describe the relationship of the sensory branches of the Cervical Plexus to the SCM muscle

Answer 7

• Initially deep to SCM
• Converge and emerge at Midpoint of Posterior Border of SCM

This point is known as the Nerve Point of the Neck (Erb’s Point)

Question 8

Name the 4 Sensory branches of the Cervical Plexus

Answer 8

• Greater Auricular nerve
• Transverse Cervical nerve
• Lesser Occipital nerve
• Supraclavicular nerves

Question 9

The Greater Auricular and Transverse Cervical nerves are both formed by fibres from C2 and C3 roots.

Compare their area of innervation

Answer 9

Greater Auricular;
- External ear and skin over Parotid gland

Transverse Cervical;
- Anterolateral neck and Upper Sternum

Question 10

Compare the Lesser Occipital and Supraclavicular nerves in fibres they’re formed from and the skin they innervate

Answer 10

Lesser Occipital nerve;

• From C2, sometimes with contribution from C3
• Postero-superior scalp

Supraclavicular nerve;

• Group of nerves formed from C3 and C4
• Skin overlying Supraclavicular Fossa, Upper thorax and Sternoclavicular joint

Question 11

What is the Clinical Significance of the Nerve Point of the Neck (Erb’s Point)?

Answer 11

Can be used for nerve blocks to provide regional anaesthesia

(Not performed on those with Cardiac or Respiratory disease, as Phrenic nerve affected)