Medial Antebrachial Cutaneous Nerve
The medial antebrachial cutaneous nerve (MACN) lies along the basilic vein distally in the arm.
Anatomical Relationship
The medial antebrachial cutaneous nerve consistently runs adjacent to the basilic vein in the upper arm and forearm 1. This close anatomical relationship has important clinical implications:
- The MACN is directly adjacent to the basilic vein at the midarm level, where it can be reliably identified using high-resolution ultrasound 2
- In the upper arm, the medial cutaneous nerves of the forearm lie next to the basilic vein, making this nerve vulnerable during vascular access procedures 1
- Filaments of the MACN typically traverse the anterior aspect of the basilic vein, creating risk during surgical manipulation of this vessel 3
Clinical Significance for Vascular Access
This anatomical proximity creates specific risks during basilic vein procedures:
- During second-stage basilic vein transposition for arteriovenous fistula creation, the MACN must be carefully managed to avoid nerve injury 3
- The nerve can be injured during venipuncture or catheter placement in the basilic vein, particularly in the upper arm where the relationship is most intimate 2
- Ultrasound-guided procedures should specifically identify the MACN adjacent to the basilic vein before needle insertion to minimize nerve injury risk 2
Surgical Considerations
When operating on the basilic vein:
- Axial splitting of the MACN can facilitate basilic vein elevation without requiring vein division and reanastomosis, reducing operative complexity 3
- The nerve perineurium can be incised longitudinally with intrafascicular division to allow the vein to be elevated between divided nerve fibers 3
- This technique results in minimal sensory deficit, with only isolated cases of localized hypoesthesia reported 3
Common Pitfall
The most critical error is failing to recognize the MACN's location before basilic vein cannulation or surgery, which can result in painful dysesthesias and chronic neuropathic pain in the medial forearm distribution 2, 3.