Lateral pectoral nerve
|Nerve: Lateral pectoral nerve|
Nerves of the left upper extremity. (Lateral anterior thoracic visible in upper right.)
|Latin||n. pectoralis lateralis|
Although this nerve is described as mostly motor, it also has been considered to transport proprioceptive and nociceptive fibers. It arises from the anterior portion of the upper and middle trunk or from the lateral cord of the brachial plexus, unlike the medial pectoral nerve, which arises from the lower trunk. It either splits into four to seven other branches that pierce the clavipectoral fascia to innervate the pectoralis major, or innervates the superior portion of the pectoralis major. The medial and lateral pectoral nerves form a connection, or loop, around the axillary artery, called the ansa pectoralis. The lateral pectoral nerve has been described as double, while the medial pectoral nerve has been described as single.
The lateral pectoral nerve is important in breast augmentation and mastectomies. With this nerve innervating the pectoralis major muscle, surgeons block both pectoral nerves. In breast implants, when the implant is inserted by the subpectoral route, more pain is expected. An ultrasound guided approach can selectively block the pectoral nerves. The surgeon makes three different injections, one to block the medial pectoral nerve, the second to block the perforating branches of the medial pectoral nerve, and the third to block the lateral pectoral nerve. It is easier to apply than other approaches because it relies on the ultrasound to locate the pectoralis major and minor muscles and the presumed course of the pectoral nerves.
Neuromuscular blockade of the lateral pectoral nerve is also needed in cases such as shoulder dislocation and other orthopedic procedures. Spasms of the pectoralis major and severe pain occur which may be reduced by neuromuscular blockade. They will decrease the muscle tone, but can help to obtain better cosmetic results during breast augmentation or mastectomies. “The skin projection point of neurovascular bundle (NVB) represents the denervation point (DP).” The NVB may be the guide for local anesthetic applications for pectoral muscle denervation. “Routine botulinum toxin infiltration of the chest wall musculature at the time of mastectomy and immediate reconstruction…would paralyze the muscles and reduce the postoperative pain caused by muscle spasm.” 
- Porzionato, Macchi; Stecco (2012). "Surgical Anatomy of the Pectoral Nerves and the Pectoral Musculature". Clinical Anatomy 25: 559–575. doi:10.1002/ca.21301.
- Desroches, Jean; Grabs (2013). "). "Selective Ultrasound Guided Pectoral Nerve Targeting in Breast Augmentation: How to Spare the Brachial Plexus Cords?"". Clinical Anatomy 26: 49–55. doi:10.1002/ca.22117.
- Titiz, Izzet; Ozel, Ozel, Toros, Marur, Yildirim, Erdogdu, Kara (19 August 2010). "Denervation Point for Neuromuscular Blockade on Lateral Pectoral Nerves: A Cadaver Study.". Surgical & Radiologic Anatomy 33.2: 105–108. doi:10.1007/s00276-010-0712-7.
- Anatomy photo:05:st-0506 at the SUNY Downstate Medical Center
- EatonHand ner-014
- Lateral+pectoral+nerve at eMedicine Dictionary
- Photo at mun.ca
- MedEd at Loyola grossanatomy/dissector/labs/ue/pect_scap/p2_1.html
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