Human leg lumbar plexus. It supplies motor innervation to iliopsoas, pectineus, sartorius, and quadriceps; and sensory branches to the anterior thigh, medial lower leg, and posterior foot. The nerves of the sacral plexus pass behind the hip joint to innervate the posterior part of the thigh, most of the lower leg, and the foot. The superior (L4-S1) and inferior gluteal nerves (L5-S2) innervate the gluteus muscles and the tensor fasciae latae. The posterior femoral cutaneous nerve (S1-S3) contributes sensory branches to the skin on the posterior thigh. The sciatic nerve (L4-S3), the largest and longest nerve in the human body, leaves the
Composition of the human body viewed on an atomic and molecular scale as shown in this article. The estimated gross molecular contents of a typical 20-micrometre human cell is as follows: Body composition can also be expressed in terms of various types of material, such as: There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal