From the Guidelines
The phrenic nerve innervates the central portion of the diaphragmatic parietal pleura, specifically the part that covers the inferior surface of the diaphragm. This innervation pattern is clinically significant because pain originating from this region is often referred to the ipsilateral shoulder due to the shared C3-C5 nerve root origins of the phrenic nerve. The phrenic nerve provides both motor innervation to the diaphragm and sensory innervation to this specific part of the parietal pleura. The remaining portions of the parietal pleura have different innervation: the costal pleura is supplied by intercostal nerves, the mediastinal pleura by the phrenic and vagus nerves, and the cervical pleura by branches from the brachial plexus. Understanding this innervation pattern helps explain why diaphragmatic irritation (such as from subphrenic abscesses or hepatic disorders) can present with referred shoulder pain, which is an important diagnostic consideration in clinical practice, as noted in guidelines for treating thymic epithelial tumors 1. Key points to consider in the context of phrenic nerve innervation include:
- The importance of preserving phrenic nerve function to avoid severe respiratory morbidity, as bilateral phrenic nerve resection is contraindicated 1
- The role of the phrenic nerve in referred pain patterns, particularly shoulder pain, which can be a presenting symptom of diaphragmatic irritation or other conditions affecting the central portion of the diaphragmatic parietal pleura.
From the Research
Parietal Pleura Innervation
- The phrenic nerve is responsible for innervating the mediastinal and diaphragmatic portions of the parietal pleura 2.
- However, the specific part of the parietal pleura innervated by the phrenic nerve is not explicitly stated in the provided studies.
- The phrenic nerve contains primarily efferent phrenic axons and afferent axons from diaphragm sensory receptors, but is also a conduit for autonomic fibers 2.
- The studies provided focus on the phrenic nerve's role in respiratory function, diaphragmatic paralysis, and nerve transfer procedures, but do not specifically address the innervation of the parietal pleura 3, 4, 5.
- One study is unrelated to the topic as it discusses boar spermadhesins and their role in fertilization 6.