Questions and Answers
Which of the following is true about the 1st intercostal nerve?
What distinguishes the 2nd intercostal nerve's lateral cutaneous branch?
What is the function of the superior part of the 1st thoracic (T1) spinal nerve?
What happens to the 7th–11th intercostal nerves after they give rise to lateral cutaneous branches?
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Where do the 1st and 2nd intercostal nerves course?
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What is the primary communication feature of the intercostobrachial nerve?
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Study Notes
Spinal Nerve Anatomy
- The anterior ramus of the 1st thoracic (T1) spinal nerve bifurcates into a large superior and a small inferior part.
- The superior part integrates with the brachial plexus, vital for upper limb innervation.
- The inferior part becomes the 1st intercostal nerve.
Atypical Features of Intercostal Nerves
- 1st and 2nd intercostal nerves run along the internal surface of the 1st and 2nd ribs, differing from typical pathways through costal grooves.
- The 1st intercostal nerve typically lacks an anterior cutaneous branch and may not have a lateral cutaneous branch.
- When present, the lateral cutaneous branch of the 1st intercostal nerve innervates the axilla skin and may connect with the intercostobrachial nerve or the medial cutaneous nerve of the arm.
Intercostobrachial Nerve
- The 2nd intercostal nerve provides a significant lateral cutaneous branch, called the intercostobrachial nerve.
- The intercostobrachial nerve exits from the 2nd intercostal space at the midaxillary line (MAL) and travels into the axilla and arm.
- It typically innervates the floor of the axilla and collaborates with the medial cutaneous nerve of the arm.
Thoraco-Abdominal Nerves
- The 7th to 11th intercostal nerves, after branching laterally, extend across the costal margin to supply abdominal skin and muscles, transitioning from intercostal to thoraco-abdominal nerves.
- Anterior cutaneous branches of these nerves penetrate the rectus sheath, indicating their role in abdominal wall innervation.
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Description
Test your knowledge on the anatomy of the thoracic spinal nerves, focusing specifically on the 1st thoracic (T1) spinal nerve and its divisions into the intercostal nerves. This quiz covers atypical features and the connections of these nerves to the brachial plexus and upper limb. Perfect for students of anatomy and physiology.