Injury patterns to other body regions and load vectors in nearside impact occupants with and without shoulder injuries.

CIREN and NASS-CDS databases were used to analyze nearside impact injuries. Front seat occupants with and without shoulder injuries were examined on an individual basis in both databases. All vehicles were from model year 2000 or newer. Variables such as the type of collision, change in velocity, principal direction force, demographics, injuries scored by the MAIS and ISS metrics, and injuries to the head, thorax, abdomen and pelvis were included. Shoulder injuries included fractures to the humerus, scapula and clavicle, and associated joint traumas. The median changes in velocities for occupants with and without shoulder injuries were 36 and 32 km/h in CIREN and 29 and 32 km/h in NASS databases. Approximately two-thirds of all cases occurred below 40 km/h. In both databases, the clavicle, scapula and humerus fractures, and AC joint dislocations were found, and the scapula fracture was associated with the clavicle, AC joint, acromion and humerus injuries in few occupants. The clavicle fracture was associated with AC joint and humerus injuries only in the NASS database. Thorax, abdomen and pelvic injuries and skull fractures increased with the presence of shoulder injuries in both databases, albeit not at the same rate. Anterior oblique loading was more frequent than pure lateral loading in both databases suggesting the importance of the oblique vector in side impact trauma. These findings underscore a need for detailed examinations of shoulder load-sharing using biomechanical studies to better understand its role in side impact traumas, shoulder biofidelity and injury assessments in dummies.