Novel Branching Pattern of the Common Fibular Nerve: Emergence of the Superficial Fibular Nerve Within the Anterior Crural Compartment.

Distal to its origination from the sciatic nerve, the common fibular (peroneal) nerve divides into the superficial and deep fibular (peroneal) nerves. Whereas the deep fibular nerve continues its course into the anterior compartment, the superficial fibular nerve (SFN) usually arises near the fibular neck and projects distally within the lateral crural compartment before entering the superficial fascia proximal to the ankle. In this report, we describe a unilateral case where the SFN arises within the anterior crural compartment and remains there for the remainder of its course deep to the deep fascia of the leg. Surgeons should be aware of anomalies such as this, for example, when performing fasciotomies to avoid inadvertently damaging an anomalously placed SFN.

The fibularis digiti quinti tendon: A cadaveric study with anthropological and clinical considerations.

In addition to the fibularis longus and brevis muscles, a number of anomalous muscles or tendons can arise from the lateral compartment of the leg. The authors describe a bilateral and robust fibularis digiti quinti (FDQ) tendon present in the foot of a 99-year-old female cadaver, present the incidence of this tendon in a cohort of 26 cadavers dissected by podiatric-medical students for a lower-extremity anatomy course, and discuss the anthropological and clinical significance of the findings. In these specimen, the FDQ tendon arose from the fibularis brevis tendon proximal to the lateral malleolus, but did not separate completely from the fibularis brevis tendon until passing through the inferior fibular retinaculum. On the lateral dorsum of the foot, the FDQ passed through a third fibular retinaculum formed by the fibularis tertius tendon, and inserted onto the extensor sling of the fifth digit. This case specimen is designated as an example of the fully present category. Of the 52 limbs dissected, 17 limbs (33%) showed a fully present FDQ, while 20 limbs (38%) exhibited an FDQ in a rudimentary form. Thus, 71% of the limbs showed some presence of the FDQ. Because human bipedality requires less dexterity than that of nonhuman primates in the routine use of their hindlimbs, the authors interpret the high variability of the FDQ, including its absence in many feet, as a relaxation of natural selection maintaining this trait since the divergence of humans from African apes.