Why is a SOMI not effective in controlling cervical extension?

The effectiveness of a SOMI (Sterno-Occipital-Mandibular Immobilizer) in controlling cervical extension is influenced by its design and anatomical positioning. The key reason why the SOMI may not be effective in controlling cervical extension is that the occipital pad pivots in the sagittal plane. This means that while it can provide some support and stability, the components of the SOMI do not offer the necessary rigidity or fixed positioning required to effectively restrict movement in the extension direction of the cervical spine.

In this regard, even though the design might be intended for immobilization, the architecture and flexibility of the device allow for some movement, particularly extension. The soft tissue support and pivoting nature of the occipital pad fail to prevent backward bending of the cervical vertebrae, which is essential when immobilizing for certain conditions or post-surgical recovery.

The other factors related to the design may contribute to its limitations, but the primary issue lies in the pivotal action of the occipital pad and the insufficiency of overall rigidity to maintain a strict immobilization of the neck in that particular direction. This underscores the importance of device design in orthotic and prosthetic applications where ensuring firm control over specific regions of movement is critical for