Fascicular analysis at perineurial level of the branching pattern of the human common peroneal nerve

Abstract

The macroscopic branching pattern of the peripheral nerves is usually provided by the epineurial connective tissue, whereas the removal of the epineurium discloses component fascicles covered by a perineurial sheath comprising a fine network with a peculiar branching pattern. In order to compare both patterns, the common peroneal nerve (PC) was dissected minutely in 10 human legs. At the epineurial level the branching pattern into tributary bundles was variable in respect to both the origin of the superficial peroneal nerve and that of the muscular branches (Rr. m. peroneus longus, RPL) to the peroneus longus. At the perineurial level the fascicles formed intricate tiny plexuses without a discrete branching pattern, but as a whole consisted of a regular arrangement divided into four crural streams for the deep peroneal (PP), the accessory deep peroneal (PPA) and two dorsal cutaneous nerves. The RPL fascicles were derived substantially from the PPA stream. The findings on the fascicular branching pattern in the present study show that the PC consists of two muscular and two sensory streams that were ensheathed by the epineurium to form the PP containing a single muscular stream, and the superficial peroneal nerve with the three remaining streams. Thus the extensor and peroneal muscles of the leg have their own nerve supply from the PP and PPA, respectively. The branching pattern of the fascicles of muscular branches at the perineurial level may be a useful estimator of muscle grouping, for which the branching pattern at the epineurial level is hardly of any use due to its variability.

Size and separability of the calcaneal and the medial and lateral plantar nerves in the distal tibial nerve

“…In general there was a high variability in the separability of the TN, also at the fascicular level, which agrees with the finding of significant fascicular branching patterns of peripheral nerves by Kudoh and Sakai (2007).…”

“…In this work we examine the dimensions and the separability of the CB, LPN and MPN, and the location of the bifurcation point of the TN and the branching point of the CB. The examination is based on cross-sections of the studied nerves allowing for the study of the fascicular branching pattern at the perineural level, the importance of which was recently emphasised by Kudoh and Sakai (2007).…”

Fascicular involvement in common fibular neuropathy: Evaluation with ultrasound

“…To differentiate from usual common fibular neuropathy, the nerve had to be only partially involved on ultrasound, because increase in nerve size can be due to total nerve enlargement or only enlargement of a part of the nerve. Precise localization of the enlarged fascicle(s) in the internal structure of the nerve was also recorded (anterior component: fascicles localized in the anterior half of the nerve, presumed to be the deep fibular nerve; posterior component: fascicles that run in the posterior half of the nerve, presumed to be the superficial fibular nerve). We used the term “single fascicular involvement” for involvement of a single “function‐related area” corresponding to the deep fibular component (anterior fascicles) or to the superficial fibular component (posterior fascicles).…”

“…Therefore, fascicles of the deep branch of the CF nerve may be more vulnerable to injury than those of the superficial fibular branch . The clinical and electrodiagnostic findings in CF neuropathy resemble the anatomical structure of the CF nerve, indeed fibers for the deep fibular nerve and the superficial fibular nerve are bounded in separate fascicles along the course of the nerve . Topographical separation of the deep and superficial fibers could explain the clinical picture.…”

The nerves to the plantaris muscle and a bipennate part of the soleus muscle

“…In the forearm, Homma (1980) and Yamada (1986) classified the muscle groups based on the branching patterns of the median nerve, with Yamada proposing a new interpretation of the formation of the forearm flexor muscles. In the leg, Kudoh and Sakai (2007) studied the branching pattern of the common peroneal nerve. They clarified the branching pattern by removing the epineurium with teasing examination.…”