Ulnar Nerve - Volar Approach

Modern Study Review (AI-Generated)

High-Yield Summary

The volar approach to the ulnar nerve is primarily indicated for decompression at the wrist, including Guyon’s canal syndrome and distal ulnar nerve pathologies. It provides direct access to the ulnar nerve and artery on the volar distal forearm and wrist. Although there is no true internervous plane, careful dissection along the radial border of the flexor carpi ulnaris (FCU) tendon allows safe exposure. While minimally invasive and endoscopic techniques are emerging, the open volar approach remains the gold standard for comprehensive decompression.

Applied Anatomy & Intervals

Internervous Interval

No true internervous plane; dissection proceeds along the radial border of the FCU tendon.

Anatomic Landmarks

Radial border of the hypothenar eminence
Volar wrist crease (incision crosses wrist joint obliquely at ~60°)
Volar aspect of distal forearm proximal to wrist crease

Patient Positioning & Setup

Table Type

Standard operating table with tourniquet capability

Patient Position

Supine with the arm abducted on an arm board

Specialized Equipment

Pneumatic tourniquet on the upper arm
Magnification loupes recommended
Optional: Hand table or arm support for stability
C-arm rarely needed unless combined with other procedures

Surgical Technique (The “Vital Steps”)

Incision & Superficial Dissection

Curved incision following the radial border of the hypothenar eminence
Cross the wrist joint obliquely at approximately 60° angle
Extend proximally onto the volar distal forearm as needed

Deep Dissection & Exposure

Identify the FCU tendon
Incise fascia over the FCU tendon on its radial border carefully
Retract FCU tendon ulnarly to expose the ulnar neurovascular bundle
Trace the ulnar nerve and artery distally toward the wrist
Incise the volar carpal ligament to decompress Guyon’s canal

The “Danger Zone”

Structure	Risk Description	Protection Strategy
Ulnar nerve	Vulnerable when incising fascia on radial border of FCU and volar carpal ligament	Use meticulous sharp dissection; identify nerve before cutting fascia; gentle retraction
Ulnar artery	Lies adjacent to nerve; risk of injury during deep dissection	Visualize and protect artery during exposure
Superficial branches of ulnar nerve	Risk of injury during distal dissection	Preserve branches by careful dissection and minimal traction

Post-Operative Pearl

Early gentle mobilization of the wrist and fingers is encouraged to prevent stiffness. Avoid aggressive wrist flexion or ulnar deviation for 2-3 weeks to protect the decompressed nerve and soft tissues.

Classic Clinical Notes