We studied and conceptually analyzed a retrospective case series of patients with airway compression due to an anterior vertebral body protrusion. The goal was to describe the pathology, methods of management, and a new concept for quantifying deformity. Case reports have been published on this pathology, but there has been no case series to date. In this study 18 patients with ages ranging from 7.3 to 18.0 years had thoracic lordoscoliosis due to a variety of etiologies; most ( n = 10) had a neuromuscular disorder. Following treatment, which most commonly was anterior subtotal subperiosteal vertebral body resection followed by posterior instrumentation and arthrodesis, atelectasia disappeared and any abnormal blood gases normalized; however, the effect on vital capacity was variable. Based on computed tomographic studies, the concept of the deformity as an endothoracic vertebral hump was developed and quantified. Study of this series of patients with compression of the airway due to vertebral body protrusion into the thorax provided the opportunity to describe treatment, define a new concept (the spinal penetration index), and make general recommendations about the management of both the endothoracic hump and the exothoracic rib hump.