Scoliosis are "captured", meaning that they are held fast between the ilium bones of the pelvis. Compared to humans, Old World monkeys have far larger erector spinae muscles, which are the muscles which hold the spine steady. These factors make the lumbar spine of most primates less flexible and far less likely to deviate than those of humans. While this may explicitly relate only to lumbar scolioses, it is possible that small imbalances in the lumbar spine could precipitate thoracic problems as well. Scoliosis may be a byproduct of strong selection for bipedalism. For a bipedal stance, a highly mobile, elongated
Body without organs But every actual body also has a virtual dimension: a vast reservoir of potential traits, connections, affects, movements, etc. This collection of potentials is what Deleuze calls the BwO. The full body without organs is "schizophrenia as a clinical entity" ("Anti-Oedipus," p. 310). This drop in intensity is a means of blocking all investments of reality: "the unproductive, the sterile, the unengendered, the unconsumable" ("Anti-Oedipus," p. 9). Unlike other social machines such as the Body of the Earth, the Body of the Despot or the Body of Capital, the full body without organs cannot inscribe other bodies. The body without