Neural Perforasomes of the Upper Extremity.

BACKGROUND: In the setting of the rapid advancement of integumentary vascular knowledge, we hypothesized that the extrinsic blood supply to the major peripheral nerves of the upper extremity could be categorized into discrete neural "perforasomes".

METHODS: Total limb perfusion of the arterial system was performed with gelatin-red lead oxide in cadaveric upper limbs. The perforating vessels to the radial, median and ulnar nerves were identified, confirmed with fluoroscopy and dissected. Distances to major anatomic landmarks of the upper extremity were measured. Additional cadaveric limbs' nerves were dissected and source arteries were selectively cannulated and injected to assess specific contribution to extrinsic nerve perfusion. The perfusion of each nerve was then calculated among all specimens.

RESULTS: The radial, median and ulnar nerve perforators were mapped. The corresponding neural perforasomes were mapped. The distal portions of the superficial radial nerve (SRN) and the posterior interosseous nerve (PIN) demonstrated a lack of staining. Similarly, at the carpal tunnel and at the proximal 25% of the median nerve (corresponding to the pronator teres), the nerve lacked vascular staining. At Guyon's canal and the flexor carpi ulnaris (FCU) the ulnar nerve demonstrated a lack of vascular staining.

CONCLUSIONS: Peripheral nerves can be divided into neural perforasomes with limited overlap. The extrinsic perfusion of peripheral nerves is highly segmental. Absent staining within the nerves correspond to common sites of compression: carpal tunnel and pronator teres for the median nerve, supinator for the PIN, and Guyon's canal and the FCU for the ulnar nerve.