In this paper, a new computer-assisted ultrasound probe placement system is introduced to guide paramedics and first responders to conduct abdominal ultrasound imaging for diagnosing trauma patients in emergency situations where specialists are not present. Recently, tele-Sonography has been employed to supervise paramedics by remote experts to perform ultrasound scan for triaging, although its utility is limited by unavailability of fast internet connectivity in remote regions. In the proposed solution of this paper, a paramedic is first instructed to place the ultrasound probe on an initial placement for imaging an organ of interest. Then, a 3D ultrasound image is acquired and processed to determine the organ's shape misalignment with respect to a reference alignment. Afterward, the organ's shape misalignment is used to estimate the probe misalignment, and then, a probe placement command is generated to guide the paramedic. This process iterates until a correct organ's view of interest is obtained. As the advantage of the proposed solution over the existing technique, the proposed solution does not require a fast internet connectivity and a dedicated remote specialist to conduct ultrasound imaging by a paramedic. The utility of the proposed solution is evaluated for a case study on the right upper quadrant (RUQ) view, which has a paramount importance in triaging trauma patients. Accuracy and robustness of the proposed solution is verified using actual and simulated 3D ultrasound images of the RUQ view.