Glossary — S

A saline implant is a breast implant made of a silicone outer shell filled with sterile saltwater (saline solution). They are used in breast reconstruction following mastectomy and in cosmetic breast augmentation. Saline implants can be filled to a specific volume during surgery, and if they rupture, the saline is safely absorbed by the body.

A salpingo-oophorectomy is surgery to remove one or both ovaries along with the fallopian tube on the same side. When both sides are removed, it is called a bilateral salpingo-oophorectomy (BSO). The procedure may be performed to treat ovarian cancer or cysts, endometriosis, or as a preventive measure in women with high-risk BRCA gene mutations.

Medical screening refers to tests or exams given to people who have no symptoms, with the goal of detecting disease — or conditions that could lead to disease — at the earliest possible stage, when treatment is most effective. Common examples include mammograms for breast cancer, Pap smears for cervical cancer, and bone density scans for osteoporosis.

The sentinel lymph node is the first lymph node — or small group of nodes — that drains fluid from the area of a tumor. If cancer is going to spread through the lymphatic system, it would most likely appear here first. Surgeons sample this node to determine whether the cancer has begun to travel, using the result to guide further treatment decisions.

A silicone implant is a breast prosthesis made of a silicone outer shell filled with silicone gel. They are used in breast reconstruction after mastectomy and in cosmetic augmentation. Silicone gel implants are generally considered to feel more similar to natural breast tissue than saline implants, though they require periodic MRI monitoring to check for silent rupture.

A sonogram is the picture produced when high-frequency sound waves are directed into the body and their echoes are converted into an image by a computer. The terms sonogram and ultrasound are commonly used interchangeably. Sonograms are widely used in breast imaging, obstetrics, abdominal assessment, and many other diagnostic settings.

Staging is the process of determining how large a cancer is and whether it has spread to nearby lymph nodes or other parts of the body. The result — typically expressed as stage I through IV — tells your care team how advanced the cancer is, which directly guides treatment planning and helps predict how the disease is likely to behave.

Stenosis refers to the narrowing of a blood vessel, heart valve, or other hollow structure in the body. When a vessel narrows, blood flow through it becomes restricted, which can reduce the supply of oxygen and nutrients to downstream tissues. Stenosis in arteries supplying the heart or brain is a common contributor to heart attack and stroke.

Stereotactic biopsy is a minimally invasive procedure that uses two angled mammogram X-ray images to calculate the exact three-dimensional location of a suspicious area — such as microcalcifications — in the breast. A needle is then guided to that precise point to remove tissue samples for pathology review, avoiding the need for open surgery.

A stress fracture is a small crack or severe bruising within a bone caused by repetitive activity or force over time. Unlike a traumatic fracture from a single impact, stress fractures develop gradually when muscles become fatigued and can no longer absorb shock, transferring that stress directly to the bone.

A stroke occurs when the blood supply to part of the brain is suddenly interrupted — either by a blockage (ischemic stroke) or by a burst blood vessel (hemorrhagic stroke). Without oxygen-rich blood, brain cells begin to die within minutes, making stroke a medical emergency requiring immediate treatment.