A Cadaveric Study of the Posterior Interosseous Nerve and Its Branches at the Level of the Distal Radius

Abstract

Posterior interosseous nerve (PIN) damage has been cited as a cause of wrist pain syndrome after distal radius fractures. The goal of this cadaveric study was to examine this hypothesis by looking for branches between the PIN and the periosteum of the distal radius. Methods: The PIN was dissected in 10 adult specimens (8 fresh and 2 embalmed) under Â2.5 magnification. All of the dissections started from the last motor branch of the PIN, innervating the extensor indicis proprius, and proceeded from proximal to distal. Results: The PIN was divided into 3 terminal segments in the dorsal wrist joint (proximal, middle, and distal segments). We were able to observe that branches to the distal radial periosteum were constant and emerged from the middle segment where the nerve is enclosed in a sturdy fibro-fatty sheath adhered to the dorsal periosteum of the distal radius. No collateral bundle was identified in the proximal segment. In the distal segment, every specimen had branches to the radiocarpal joint; 9 of 10 had a midcarpal innervation. Terminal branches to the carpometacarpal joints were identified in 2 cadaveric wrists. Conclusions: The radial periosteum PIN branches consistently identified in these specimens may contribute to dorsal wrist pain seen at the time of late follow-up in patients after distal radius fractures. Clinical relevance: The benefit of PIN denervation as an adjuvant procedure should be evaluated further in the surgical management of wrist injuries.

Posterior Interosseous Nerve Graft: Utilizing External Landmarks and Anthropometric Ratios to Predict Available Length for Digital Nerve Reconstruction in a Cadaveric Study

“…In Plastic Surgery 30 (2) cadaveric studies, Waters and Schwartz described the diameter of the PIN to range from 1 to 5 mm, 17 while Gregory et al found the range to be 0.6 to 1.1 mm. 25 Similarly, a study using ultrasound on live patients demonstrated the diameter of the PIN to range from 1.02 + 0.22 mm. 27 These widths are similar to our mean diameter of 1.1 mm.…”

“…20 In contrast, several other studies found much shorter lengths of harvestable PIN. Among these, Reissis et al and Gregory et al reported mean available lengths of 3.7 cm 24 and 2.7 cm, 25 while both Jariwala et al and Das et al found mean lengths of 4.69 cm 22 and 4.71 cm. 23 A more moderate mean length of 6.2 cm was found by Elgafy and colleagues.…”

“…12,17,18 The reported length of this sensory portion has been highly variable across several studies. 17,18,[20][21][22][23][24][25] There exists no literature demonstrating an anatomical relationship between patient anthropometry and sensory PIN length. An accurate assessment of this length could provide useful information regarding digital nerve reconstruction.…”