Straight back syndrome

The whole spine T2 sagittal image shows straightening of the normal kyphotic angulation of the dorsal spine. Reduced antero-posterior dimension of the thorax is also noted. Features are favoring Straight Back Syndrome. (The patient had come for symptoms of low backache with radiation to right leg). 

The above image shows T2 weighted MRI of the dorsal spine. Image on the left shows a yellow line drawn along the anterior surface of D4 to D12 vertebral bodies. In straight back syndrome the distance between the yellow line and anterior surface of midportion of the D8 vertebral body should be < 1.2 cm. (This is the Davies modification (1980) of the DeLeon (1956) criteria, and is actually mentioned in the lateral chest x-ray, and not in MRI). In the above image this distance measured only ~2mm. 

The right side images shows AP dimension of thorax from the posterior surface of the sternum to the anterior surface of the D8 vertebral body, which should be < 10-11 cm. Here it measured exactly 10 cm.

Straight back syndrome is considered as a benign skeletal abnormality of the thorax, narrowed AP dimension of the thoracic cavity, resulting in cardiovascular and bronchial compression, but with most of the patients being asymptomatic. If symptomatic, patients usually present with symptoms of chest pain and palpitations, mimicking a primary cardiac condition. An ejection systolic murmur may be heard in the pulmonary area on auscultation. 

Mitral Valve prolapse (MVP) may be seen as an association in up to two third of patients. Prominence of the pulmonary arteries, deviation of the heart to left and cardiomegaly are also described in association.

References: 

1. Davies, M. K., Mackintosh, P., Cayton, R. M., Page, A. J., Shiu, M. F., & Littler, W. A. (1980). The straight back syndrome. The Quarterly journal of medicine, 49(196), 443–460.

2. Gold PM, Albright B, Anani S, Toner H. Straight Back Syndrome: positive response to spinal manipulation and adjunctive therapy - A case report. J Can Chiropr Assoc. 2013;57(2):143-149.