Which of the following muscles is noted for its potential involvement in post-op space infections?

The mylohyoid muscle is significant in the context of post-operative space infections due to its anatomical location and the role it plays in forming the floor of the mouth. This muscle creates a barrier separating the submandibular and sublingual spaces, which are critical areas involved in dental, surgical, and infectious conditions of the mouth and neck.

Infections can originate in the oral cavity, particularly after procedures like tooth extractions or surgeries involving the mandibular region. If bacteria are introduced into the submandibular space, the mylohyoid can act as a pathway for the spread of infection to deeper structures, such as the sublingual space and even further into the neck. Therefore, its involvement in the potential development of post-operative infections makes it a crucial muscle to consider in clinical scenarios surrounding oral and maxillofacial surgery.

Considering the other muscles listed, the frontalis is primarily involved in facial expression and is located in the forehead region, distanced from the oral cavity; the sternocleidomastoid is involved in neck movement and doesn't directly relate to the oral regions; the digastric muscle, while associated with the jaw and floor of the mouth, doesn’t have the same critical implication for the spread of infections