8 – Sonoanatomy of the posterior cutaneous nerve – with colour coding

In a non-obese patient the posterior femoral cutaneous nerve (PFCN) can be visualized with a linear probe. It has a spindle shaped cross-sectional profile and is sandwiched between the deep fascia and the long head of the biceps femoris

The epidermis is a narrow hyperechoic layer

The dermis has a superficial hypoechoic and heterogenous layer and a deep hyperechoic and homogenous layer

The superficial fascia is the subcutaneous layer which attaches the skin to the underlying deep fascia. It is a fibroareolar layer composed of hypoechoic fatty tissue with intermingled hyperechoic linear bands which are fibrous septae

The deep fascia is a hyperechoic dense fibrous sheath that envelopes muscles and gives off intermuscular compartmental septae that attaches to the periosteum