In patients with grade 4 scoliosis, the symptoms are due to the fact that the spine is not only curved, but also twisted. Why the chest loses symmetry and deforms, which leads to a mixture of thoracic organs.
So, scoliosis of the 4th degree of the thoracic region or thoracic scoliosis, in which an arc of curvature is formed by several vertebrae of the thoracic region - in the interval between the third and ninth, is manifested by deformation of the chest, distortion of the suprascapular region, bulging of the scapula, formation of a costal hump (front or back), pain in the back and shortness of breath.
Just below the middle of the thoracic spine, a second curvature in the opposite direction can form, and then a thoracolumbar (thoracolumbar) S-shaped scoliosis of the 4th degree is determined. With it, due to the torsion of the vertebral bodies, the chest and pelvis unfold in different planes - with a skew of the pelvic region (skewness), different lengths of the lower limbs and lameness when walking.
Lumbar or lumbar scoliosis of the 4th degree in 75% of cases is accompanied by spinal pain associated with pelvic distortion and protrusion of the upper edge of the ilium, degenerative changes in the facet joints and displaced intervertebral discs, as well as overload of the paravertebral muscles that resist progressive deformation.
Scoliosis of the lumbosacral spine of the 4th degree develops in rare cases, since all five vertebrae of the sacral region gradually grow together at the age of 18-25 years, forming a solid bone - the sacrum (sacrum). But if a lateral curvature of this localization occurs, then its symptoms are similar to lumbar scoliosis.
Pregnancy and scoliosis grade 4
Scoliosis of such a high degree, experts attribute to factors that increase the risk of disorders during pregnancy - both for the woman and for the unborn child.
Firstly, as the gestation period increases, the load on the spine increases, especially in the lumbar region (where hyperlordosis is formed), and pain will increase significantly in a pregnant woman with grade 4 lumbar scoliosis. 
Secondly, the uterus grows with an increase in the height of its bottom, and with thoracic or thoracolumbar scoliosis of the 4th degree, this will lead to serious problems associated with displacement of the uterus, since the chest is deformed, the internal organs are displaced, and the pelvic part is asymmetric. Therefore, there is placental insufficiency , and violations of the mechanisms of uteroplacental circulation. In addition, a decrease in lung volume with such a disease of the spine is fraught with insufficient oxygen supply to the fetus, that is, perinatal hypoxia.
Pregnancy with scoliosis of 3 and 4 degrees can be interrupted at any time due to placental abruption (even when it is located normally); in some women with such a diagnosis, the progression of scoliosis of the spine is noted both during childbearing and after birth.
Natural childbirth with scoliosis of the 4th degree of the thoracic spine is possible if the patient underwent surgical treatment of scoliosis several years before. But even in such cases, according to some reports, almost half of the women undergo a caesarean section.