Black and blue mark on my husbands right side of his lower abdomen he doesn't recall getting a. bruise and this never happens has had lower back pain?

Consider eval: Hi, thanks for reaching out. Even with people the "bruise easily" we expect most bruising to occur in the arms/legs because in the even of trauma, we try to protect our core body from injury. Spontaneous bruising in the core/abdomen can potentially be worrisome. If it is fairly large and he has back pain, I would try to get examined by a doctor or at least speak with one soon in more detail.