Impact of Median Nerve Injury on the Brachial Artery
Median nerve injury does not directly affect the brachial artery's vascular function, but complications from brachial artery injuries can cause median nerve compression and dysfunction.
Anatomical Relationship Between Median Nerve and Brachial Artery
The median nerve and brachial artery have an intimate anatomical relationship in the upper arm:
- The brachial artery is the main arterial supply to the arm, continuing from the axillary artery and terminating at the cubital fossa by dividing into the radial and ulnar arteries 1
- The median nerve typically runs alongside the brachial artery in the medial aspect of the arm
- Both structures travel through the same neurovascular bundle in the arm
Effects of Median Nerve Injury on Brachial Artery
A median nerve injury by itself does not directly impact brachial artery function for the following reasons:
- The median nerve is primarily sensory and motor in function, not vasomotor
- Brachial artery blood flow and vasodilation capabilities remain intact with median nerve injury
- Flow-mediated dilation (FMD) of the brachial artery, which depends on endothelial function and nitric oxide synthesis, is not affected by median nerve damage 2
Reverse Scenario: Brachial Artery Injuries Affecting the Median Nerve
While median nerve injury doesn't affect the brachial artery, the reverse scenario is well-documented:
- Brachial artery injuries can lead to pseudoaneurysm formation that may compress the median nerve 3
- Hematoma formation from brachial artery injury can cause median nerve compression, as documented in a case where cardiac catheterization led to complete median nerve palsy 4
- In a study of 124 surgically managed brachial artery injuries, 62.1% had associated peripheral nerve lesions, demonstrating the frequent co-occurrence of neurovascular injuries 5
Clinical Implications
When evaluating a patient with median nerve injury:
- No specific vascular assessment is needed for the brachial artery based solely on median nerve injury
- Standard neurovascular examination should include assessment of distal pulses, capillary refill, and motor/sensory function
- If brachial artery injury is suspected (from trauma that caused the nerve injury), CTA is the preferred examination for evaluation of suspected arterial injury 2
Important Distinctions from Lower Extremity Injuries
Upper extremity neurovascular injuries have different clinical implications than lower extremity injuries:
- Predictors of amputation differ between upper and lower extremity vascular injuries
- Even with significant nerve deficits, limb salvage is often successful in brachial artery injuries 6
- Delayed presentation, nerve deficits, and diminished capillary refill are less predictive of amputation in brachial artery injuries compared to lower extremity injuries 6
In summary, median nerve injury itself does not compromise brachial artery function, but clinicians should be vigilant about potential brachial artery injuries that may accompany median nerve trauma, as these can lead to further neurological complications.