**2. Sensory innervation of the hip joint**

The hip joint is a typical ball-and-socket joint formed by an articulation between the head of the femur and the acetabulum surrounded by a cartilaginous labrum. The entire joint is enveloped by a joint capsule and additionally stabilised by ischiofemoral, iliofemoral and pubofemoral ligament, together with various muscles that either originate in, insert or just pass by this area [3]. Innervation of the hip joint derives from

**Figure 1.** *Sensory innervation of the hip joint.*

both lumbar (L1–L4) and sacral (L4–S4) plexuses and the variety of their muscular branches 4. The location of the origin from the main trunk of the nerves providing articular branches to the hip capsule appears to be variable and has only been recorded for the obturator and femoral nerves. There is though substantial discrepancy between studies. According to the studies, most frequent nerve to innervate the hip capsule is the nerve to quadratus femoris muscle followed by the obturator and then the femoral nerve. In general, the course of hip capsule articular branches follows the path of the vessels, but differences in innervation of the hip capsule appear to be present between individuals [4, 5]. Sensory innervation of the hip joint is shown in **Figure 1**.
