Which muscles are typically overstretched in a patient with hyperkyphosis of the thoracic spine?

In cases of hyperkyphosis of the thoracic spine, the characteristic excessive forward curvature leads to certain muscle groups being overstretched due to the altered posture. The erector spinae group, which consists of the iliocostalis, longissimus, and spinalis muscles, is primarily responsible for extending the spine and maintaining an upright posture. When the thoracic spine is excessively curved, these muscles are put in a lengthened position, leading to a state of overstretch. This overstretching can result in discomfort and muscular imbalance, as these muscles are no longer able to effectively stabilize the spine.

In contrast, the other muscle groups identified are either not directly affected by hyperkyphosis in the same way or may actually be in a shortened position due to the forward leaning posture. For instance, muscles such as the rectus abdominis and external obliques are more likely to be lengthened as a consequence of the anterior pelvic tilt that often accompanies hyperkyphosis, but they are not primarily responsible for thoracic spine extension. The latissimus dorsi can play a role in shoulder movement and back extension but is not directly associated as being overstretched in hyperkyphosis.

Overall, the erector spina