The picture on the right shows the sonographic image of the posterior femoral cutaneous nerve at the level of the gluteal crease with a curved array probe

Place the patient in the lateral decubitus position

Place the probe (linear or curved array) in the gluteal crease, depending on the amount of adipose tissue in the gluteal crease

Identify the biceps femoris and the posterior femoral cutaneous nerve between the biceps femoris and the fascia lata (see next page)

Insert the needle in-plane from the lateral end of the probe and advance the needle tip to the target nerve

Inject 5 mL local anaesthetic perineurally

At this level the posterior femoral cutaneous nerve can be blocked selectively and typically includes the perineal branches and the inferior cluneal branches

The posterior femoral cutaneous nerve innervates the postero-lateral part of the perineum and the adjacent part of thigh

The posterior femoral cutaneous nerve runs deep to the fascia lata during most of its trajectory from the gluteal crease to the popliteal fossa

The posterior femoral cutaneous nerve supply the following cutaneous branches:

– the skin of the posterior thigh from the gluteal sulcus to the popliteal fossa

– inferior cluneal nerves to the skin of the gluteal sulcus

– perineal branches to the posterior part of the perineal region and adjacent thigh

The posterior femoral cutaneous nerve (PFCN) runs underneath the fascia lata most of its trajectory from the gluteal crease to the popliteal fossa with its branches piercing the fascia lata in order to innervate the skin of the posterior thigh, the gluteal crease and the perineum

The PFCN runs across the long head of the biceps femoris in an infero-medial direction between the fascia lata and the muscle fascia

Campos NA, Chiles JH, Plunkett AR: Ultrasound-guided cryoablation of genitofemoral nerve for chronic inguinal pain. Pain Physician 12: 997-1000 (2009)

The femoral branch of the genitofemoral nerve runs immediately lateral to the femoral artery just below the inguinal ligament

Indications for blockade of the posterior femoral cutaneous nerve:

– anaesthesia of the skin of the posterior thigh including the popliteal fossa

– anaesthesia of the skin of and surrounding the gluteal sulcus

– anaesthesia of the skin of the posterior part of the perineum and adjacent thigh

The posterior femoral cutaneous nerve (PFCN) exits the pelvis together with the sciatic and pudendal nerves through the greater sciatic foramen underneath the piriformis muscle. The PFCN and the sciatic nerves run laterally covered by the gluteus maximus, and the pudendal nerve deviates infero-medially into Alcocks canal.

At the inferior margin of the gluteus maximus the inferior cluneal nerves branch off the PFCN. The perineal branches branch off the PFCN below the ischial tuberosity. Hereafter, the PFCN runs superficial to the tendon of the long head of the biceps femoris, while the sciatic nerve dives deep to the biceps femoris. In the trajectory down to the popliteal fossa, the PFCN is sandwiched between the hamstrings – mainly the long head of the biceps femoris – and the fascia lata with its branches piercing the fascia lata to innervate the skin of the posterior thigh.

In the picture on the right the PFCN is depicted with magenta and its perineal branches with cyan colour. Long head of biceps femoris (green asterix), semitendinosus (red asterix), semimembranosus (blue asterix).