From the Guidelines
The brachial plexus is a complex network of nerves formed from the C5-T1 ventral rami, supplying motor and sensory innervation to the upper limb, and its injuries can result in significant morbidity and impact on quality of life. The brachial plexus begins as five nerve roots that merge to form three trunks (upper, middle, and lower), which then divide into anterior and posterior divisions 1. These divisions regroup to form three cords (lateral, posterior, and medial) named according to their relationship to the axillary artery. From these cords emerge the major terminal branches: musculocutaneous, axillary, radial, median, and ulnar nerves. Each nerve innervates specific muscles and provides sensation to distinct areas of the upper limb.
- The musculocutaneous nerve supplies the anterior arm muscles
- The axillary nerve innervates the deltoid and teres minor
- The radial nerve controls the posterior compartment muscles
- The median nerve supplies most anterior forearm muscles and thumb muscles
- The ulnar nerve innervates the intrinsic hand muscles. Brachial plexus injuries can occur from trauma, compression, or inflammation, resulting in weakness, numbness, or pain in the affected areas, and are classified by location (pre-ganglionic or post-ganglionic) and mechanism (traction, compression, or laceration) 1. Understanding this complex neural network is crucial for diagnosing and treating upper limb neurological conditions, and early diagnosis and treatment can significantly improve outcomes and reduce morbidity 1.
From the Research
Brachial Plexus Structure and Function
- The brachial plexus is a complex network of nerves that supplies motor, sensory, and sympathetic fibers to the upper extremity 2.
- It is formed by the union of the ventral primary rami of the spinal nerves, C5-C8 & T1, also known as the "roots" of the brachial plexus 3, 2.
- The brachial plexus functions to provide sensation and motor innervation to the skin and muscles of the chest and upper limb 3.
Brachial Plexus Injuries
- Brachial plexus injuries occur relatively frequently and are due mainly to traumatic accidents that lead to traction or compression of the nerve roots 3.
- Traumatic brachial plexus injuries are devastating life-altering events, with pervasive detrimental effects on a patient's physical, psychosocial, mental, and financial well-being 4.
- Injuries to the brachial plexus can be classified into adult versus obstetric brachial plexus injury, with different treatment options and outcomes 3.
Diagnosis and Treatment of Brachial Plexus Injuries
- The diagnosis of brachial plexus injuries includes a detailed history, comprehensive physical examination, and critical review of imaging and electrodiagnostic studies 4.
- Surgical reconstruction depends on the timing of presentation and specific injury pattern, with a range of techniques available including neurolysis, nerve grafting, nerve transfers, free functional muscle transfers, tendon transfers, and joint arthrodesis 4.
- A multidisciplinary team approach is necessary for the successful management of patients with brachial plexus injuries, including peripheral nerve surgeons, neurology, hand therapy, physical therapy, pain management, social work, and mental health 4.
Management of Neuropathic Pain
- Neuropathic pain following traumatic brachial plexus injury can be managed with neurolysis and oral gabapentin, with significant reduction in pain scores and improvement in quality of life 5, 6.
- Gabapentin has been shown to be an effective adjunct to intraoperative and postoperative pain management in patients undergoing surgery for brachial plexus injury 5.