Which nerve is responsible for the motor innervation of the diaphragm?
Solution
Correct Answer: Option A
- The nerve responsible for the motor innervation of the diaphragm is the Phrenic nerve.
- This nerve originates from the cervical spinal cord, specifically from the C3, C4, and C5 nerve roots.
- It plays a crucial role in breathing by providing the main motor supply to the diaphragm, which is the primary muscle involved in respiration.
Here are the key points to understand:
- Phrenic nerve: Arises from cervical spinal nerves C3, C4, and C5 (commonly remembered by the phrase "C3, 4, and 5 keep the diaphragm alive").
- Motor innervation: The phrenic nerve provides the sole motor control to the diaphragm, enabling contraction and relaxation necessary for breathing.
- Vagus nerve: Primarily supplies parasympathetic innervation to thoracic and abdominal organs but does not innervate the diaphragm motor function.
- Intercostal nerves: Supply the intercostal muscles, which assist in inspiration but do not control the diaphragm.
- Accessory nerve: Innervates the sternocleidomastoid and trapezius muscles and does not contribute to diaphragmatic motor function.
In summary, the phrenic nerve is essential for the motor activity of the diaphragm, and damage to this nerve can result in diaphragmatic paralysis and respiratory difficulties.
Reference: Gray's Anatomy, 41st Edition, Thorax, Chapter 8, Page 850
- This nerve originates from the cervical spinal cord, specifically from the C3, C4, and C5 nerve roots.
- It plays a crucial role in breathing by providing the main motor supply to the diaphragm, which is the primary muscle involved in respiration.
Here are the key points to understand:
- Phrenic nerve: Arises from cervical spinal nerves C3, C4, and C5 (commonly remembered by the phrase "C3, 4, and 5 keep the diaphragm alive").
- Motor innervation: The phrenic nerve provides the sole motor control to the diaphragm, enabling contraction and relaxation necessary for breathing.
- Vagus nerve: Primarily supplies parasympathetic innervation to thoracic and abdominal organs but does not innervate the diaphragm motor function.
- Intercostal nerves: Supply the intercostal muscles, which assist in inspiration but do not control the diaphragm.
- Accessory nerve: Innervates the sternocleidomastoid and trapezius muscles and does not contribute to diaphragmatic motor function.
In summary, the phrenic nerve is essential for the motor activity of the diaphragm, and damage to this nerve can result in diaphragmatic paralysis and respiratory difficulties.
Reference: Gray's Anatomy, 41st Edition, Thorax, Chapter 8, Page 850
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