Other apes have a shorter and less mobile lower spine than humans. Some of the lumbar vertebrae in Pan 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, 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 lower spine is very beneficial. For instance, the human spine takes on an S-shaped curve with lumbar lordosis, which allows for better balance and support of an upright trunk. Selection for bipedality was likely strong enough to justify the maintenance of such a disorder. Bipedality is hypothesized to have emerged for a variety of different reasons, many of which would have certainly conferred fitness advantages. It may increase viewing distance, which can be beneficial in hunting and foraging as well as protection from predators or other humans; it makes long-distance travel more efficient for foraging or hunting; and it facilitates terrestrial feeding from grasses, trees, and bushes.
Braces are sometimes prescribed for adults to relieve pain related to scoliosis. Bracing involves fitting the person with a device that covers the torso; in some cases, it extends to the neck (example being the Milwaukee Brace). The most commonly used brace is a TLSO, such as a Boston brace, a corset-like an appliance that fits from armpits to hips and is custom-made from fiberglass or plastic. It is typically recommended to be worn 22–23 hours a day, and applies pressure on the curves in the spine. The effectiveness of the brace depends on not only brace design and orthotist skill, but also peoples compliance and amount of wear per day. An alternative form of brace is a nighttime only brace, that are worn only at night whilst the child sleeps, which overcorrect the deformity. Whilst nighttime braces are more convenient for children and families, it is unknown if the effectiveness of the brace is as good as conventional braces, therefore the UK government have funded a large clinical trial to resolve this uncertainty; called the BASIS study. The BASIS study is ongoing throughout the UK in all of the leading UK childrens hospitals that treat scoliosis, with families encouraged to take part. Indications for bracing: people who are still growing who present with Cobb angles less than 20° should be closely monitored.