Sacrum
/ˈseɪkrəm/
A triangular bone in the lower back formed from fused vertebrae and situated between the two hipbones.
Sagittal
/ˈsædʒɪtəl/
A plane that divides the body into right and left portions.
Saphenous
/səˈfiːnəs/
Relating to the two major superficial veins of the leg (great and small saphenous veins).
Sarcomere
/ˈsɑːrkoʊmɪər/
The fundamental unit of muscle contraction, composed of actin and myosin.
Sartorius
/sɑːrˈtɔːriəs/
The longest muscle in the human body, running down the length of the thigh.
Scapula
/ˈskæpjʊlə/
The shoulder blade; a large flat triangular bone of the shoulder.
Sclera
/ˈsklɪərə/
The white outer layer of the eyeball.
Scrotum
/ˈskroʊtəm/
The pouch of skin containing the testicles.
Sebaceous
/sɪˈbeɪʃəs/
Glands in the skin that secrete an oily matter (sebum) into the hair follicles.
Sella Turcica
/ˌsɛlə ˈtɜːrsɪkə/
A saddle-shaped depression in the sphenoid bone that holds the pituitary gland.
Septum
/ˈsɛptəm/
A partition separating two cavities, such as that between the nostrils or the chambers of the heart.
Serratus Anterior
/sɛˈreɪtəs ænˈtɪəriər/
A muscle that originates on the surface of the upper ribs and inserts at the scapula.
Sesamoid
/ˈsɛsəmɔɪd/
A small independent bone or bony nodule developed in a tendon (e.g., the patella).
Sigmoid
/ˈsɪɡmɔɪd/
An S-shaped part of the large intestine, leading into the rectum.
Sinus
/ˈsaɪnəs/
A cavity within a bone or other tissue, especially one in the bones of the face or skull.
Somatic
/soʊˈmætɪk/
Relating to the body, distinct from the mind or the germ cells.
Sphenoid
/ˈsfiːnɔɪd/
A compound bone that forms the base of the cranium, behind the eye and below the front part of the brain.
Sphincter
/ˈsfɪŋktər/
A ring of muscle surrounding and serving to guard or close an opening or tube.
Spinous Process
/ˈspaɪnəs ˈprɒsɛs/
A bony projection off the posterior of each vertebra.
Spleen
/spliːn/
An abdominal organ involved in the production and removal of blood cells.
Splenius
/ˈspliːniəs/
A pair of muscles in the back of the neck and upper back.
Squamous
/ˈskweɪməs/
Relating to, consisting of, or denoting a layer of epithelium that consists of flake-like cells.
Stapes
/ˈsteɪpiːz/
The stirrup-shaped small bone in the middle ear; the smallest bone in the human body.
Sternocleidomastoid
/ˌstɜːrnoʊˌklaɪdoʊˈmæstɔɪd/
A long muscle in the side of the neck that helps rotate the head.
Sternum
/ˈstɜːrnəm/
The breastbone; a long flat bone located in the central part of the chest.
Stomach
/ˈstʌmək/
The internal organ in which the major part of the digestion of food occurs.
Styloid Process
/ˈstaɪlɔɪd ˈprɒsɛs/
A slender pointed piece of bone just below the ear.
Subclavian
/sʌbˈkleɪviən/
Relating to the region under the clavicle (collarbone).
Sublingual
/sʌbˈlɪŋɡwəl/
Situated or applied under the tongue.
Sulcus
/ˈsʌlkəs/
A groove or furrow, especially one on the surface of the brain.
Superior
/suːˈpɪəriər/
Further above or higher in position; situated above another part.
Supination
/ˌsuːpɪˈneɪʃən/
Rotation of the forearm and hand so that the palm faces forward or upward.
Surfactant
/sɜːrˈfæktənt/
A substance that tends to reduce the surface tension of a liquid in the alveoli of the lungs.
Suture
/ˈsuːtʃər/
A seamlike immovable junction between two bones, such as those of the skull.
Symphysis
/ˈsɪmfɪsɪs/
A place where two bones are closely joined, either forming an immovable joint or completely fused.
Synapse
/ˈsaɪnæps/
A junction between two nerve cells, consisting of a minute gap across which impulses pass.
Synovial
/saɪˈnoʊviəl/
Relating to a type of joint which is surrounded by a fluid-filled capsule.
Systole
/ˈsɪstəli/
The phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers.