Brachial Plexus
Description
Names
- Brachial Plexus
General
- Network of nerves that gives rise to all motor/ sensory nerves of the upper extremity
- Arises from the anterior rami of spinal nerves C5 to T1
- Undergoes several splits and mergers until giving rise to the terminal branches
- It also gives rise to multiple pre-terminal or supraclavicular branches
Gross Anatomy
- Roots of the brachial plexus are formed from anterior rami of spinal nerves C5 to T1
- They immediately merge to form trunks, which subsequently split into divisions
- The divisions then merge into the cords of the brachial plexus
Roots
- Anterior branches of C5 to T1 spinal nerves emerge from the spinal cord
- Shortly after, the 5 nerve roots merge to form the superior, medial, inferior trunks
- Three supraclavicular branches also arise here:
Trunks
- Superior trunk: C5, C6
- Middle trunk: root of C7 only
- Inferior trunk: C8, T1
- These trunks travel between the anterior scalene and middle scalene, behind the subclavian artery
- They then cross over the apex of the lung, first rib coursing towards the clavicle
- Superior trunk gives rise two more supraclavicular branches
Divisions
- As they reach the posterior aspect of the middle third of the clavicle
- Each trunk divides into an anterior and posterior division (6 divisions total)
- Continue to pass behind the clavicle to enter the axillary region
Cords
- Formed by the 3 anterior and posterior divisions, merge in a specific way
- Lateral cord: anterior division of superior trunk + anterior division middle trunk
- Medial cord: continuation of anterior division of inferior trunk
- Posterior cord: posterior division of all 3 trunks
- Named after their relationship to the axillary artery
- Additional preterminal branches
- Lateral: lateral pectoral nerve
- Posterior: subscapular nerves, thoracodorsal nerve
- Medial Cord: medial pectoral nerve, medial cutaneous nerve of forearm, medial cutaneous nerve of arm
- Cords terminate a the level of the inferior margin of pectoralis minor, become terminal branches
- Lateral: musculocutaneous nerve, lateral root of median nerve
- Posterior: radial nerve, axillary nerve
- Medial: ulnar nerve, medial root of median nerve
Supraclavicular Branches
Branches of the Lateral Cord
- Lateral Pectoral Nerve
- Lateral root of Median Nerve
- Musculocutaneous Nerve
Branches of Medial Cord
- Medial Pectoral Nerve
- Medial Brachial Cutaneous Nerve
- Medial Antebrachial Cutaneous Nerve
- Medial root of Median Nerve
- Ulnar Nerve
Branches of Posterior Cord
Clinical Significance
- Brachial Neuritis
- Brachial neuralgia
- Brachial plexus neuritis
- Hereditary brachial plexus neuropathy
- Neuralgic amyotrophy
- Shoulder girdle neuropathy
See Also
References
- ↑ Grahn-Shahar, Petra. "Improving Shoulder Function in Brachial Plexus Birth Injury." (2021).
- ↑ Nikkhah, Dariush, and Sohail Akhtar. "Brachial Plexus Palsy." Diagnostic Clusters in Shoulder Conditions (2017): 213-220.
- ↑ Image courtesy of orthoinfo.aaos.org/
- ↑ Sumarwoto, Tito, et al. "Brachial plexus injury: recent diagnosis and management." Open Access Macedonian Journal of Medical Sciences 9.F (2021): 13-24.
- ↑ Baskaran, A. "167 Ultrasound guided costoclavicular brachial plexus block for proximal humerus fracture with pneumothorax in an elderly patient–A case report." Regional Anesthesia and Pain Medicine 70.Suppl 1 (2021): A87-A88.