Rib fractures (RF) represent the most common bone fracture after blunt trauma, occurring in 10–20% of all trauma patients and leading to concomitant injuries of the inner organs in severe cases. However, a standardized classification system for serial rib fractures (SRF) does still not exist. Basic knowledge about the facture pattern of SRF would help to predict organ damage, support forensic medical examinations, and provide data for in vitro and in silico studies regarding the thoracic stability. The purpose of our study was therefore to identify specific SRF patterns after blunt chest trauma.

All SRF cases (≥3 subsequent RF) between mid-2008 and end of 2015 were extracted from the CT database of our University Hospital (n=383). Fractures were assigned to anterior, antero-lateral, lateral, postero-lateral, and posterior location within the transverse plane (36° each) using an angular measuring technique (reliability ±2°). Rib level, fracture type (transverse, oblique, multifragment, infracted), as well as degree of dislocation (none, </≥ rib width) were recorded and each related to the cause of accident.

In total, 3747 RF were identified (9.7 per patient, ranging from 3 (n=25) to 33 (n=1)). On average, most RF occurred in crush/burying injuries (15.9, n=13) and pedestrian accidents (12.2, n=14), least in car/truck accidents (8.8, n=76). Altogether, RF gradually increased from rib 1 (n=140) towards rib 5 (n=517) and then decreased towards rib 12 (n=49), showing a bell-shaped distribution. More RF were detected on the left thorax (n=2027) than on the right (n=1720). Overall, most RF were found in the lateral (33%) and postero-lateral (29%) segment. Posterior RF mostly occurred in the lower thorax (63%), whereas anterior (100%), antero-lateral (87%), and lateral (63%) RF mostly appeared in the upper thorax. RF were distributed symmetrically to the sagittal plane, showing a hotspot (up to 98 RF) at rib levels 4 to 7 in the lateral segment and rib level 5 in the antero-lateral segment. In the car/truck accident group, 47% of all RF were in the lateral segment, in case of frontal collision (n=24) even 60%. Fall injuries (n=141) entailed mostly postero-lateral RF (35%). In case of falls >3 m (n=45), 48% more RF were detected on the left thorax compared to the right. CPR related SRF (n=33) showed a distinct fracture pattern, since 70% of all RF were located antero-laterally. Infractions were the most observed fracture type (44%), followed by oblique (25%) and transverse (18%) fractures, while 46% of all RF were dislocated (15% ≥ rib width).

SRF show distinct fracture patterns depending on the cause of accident. Additional data should be collected to confirm our results and to establish a SRF classification system.