Peroneal nerve branching suggests compression palsy in the deformities of Charcot-Marie Tooth disease.

Altered expression of the PMP-22 protein may be implicated in Charcot-Marie-Tooth disease and the much rarer disease, hereditary liability to pressure palsy. An element of chronic pressure palsy may explain the unique distribution of motor imbalance in patients with Charcot-Marie-Tooth disease. If this is the case, innervation of the lateral leg motor units should show sufficient anatomic segregation to explain the variable disease patterns. Twelve fresh cadaver specimens were dissected to examine the innervation of the anterior and lateral compartment muscles from the peroneal nerve. Nine specimens had a branch to the peroneus longus at or proximal to nerve passage of the posterior fibular neck. The first branch to the peroneus longus was 2.1 +/- 6.7 mm proximal, and the first branch to the peroneus brevis was 110.9 +/- 19 mm distal. The nerve to the tibialis anterior originated within 5 mm of the reference point and wrapped transversely along the fibular neck for 17.2 +/- 1.4 mm. These discrete pathways to the individual motor units in the anterolateral leg were consistent with the possible implication of chronic pressure palsy in the patterns of atrophy in Charcot-Marie-Tooth disease.