Illustration of the cervical, thoracic, lumbar, and sacral dermatomes, anterior and posterior views. A dermatome is an area of skin supplied by a single, specific spinal nerve root.

Illustration of the superficial muscles in a human figure, frontal and rear views. Visible are the muscles of the head, neck, torso, arms, and legs.

Illustration of the upper cervical spine and vertebral arteries: normal anatomy (left) contrasted with rotational injury of the vertebral artery (right), which sometimes occurs in violent whiplash injuries.

Illustration of the skeletal system and nerves in a female figure, posterior view.

Illustration of the vertebral spine in a figure, posterior view (left), and a detail of the superior articular process, facet joint, and inferior articular process of a typical vertebra in the spinal column (right).

Illustration of the gastrointestinal tract, anterior view. Labels identify the mouth, esophagus, stomach, and intestines.

Illustration of the brain, lateral view, shown within an outline of a head.

Illustration of the stomach, anterior view. Shown are the location of the stomach in a figure (left) and a detail of the stomach showing the gastric folds, or rugae (right), cutaway view.

Illustration of the breast anatomy, sagittal view, from the deep chest wall to the nipple. Structures shown include the ribs, intercostal muscles, major and minor pectoralis muscles, and skin, with labels identifying the mammary glands (with milk ducts), areola, nipple, and fatty tissue.

Illustration of an anterior view of the upper torso showing the structures of the respiratory system and the path that air travels from the mouth and throat to the lung bronchioles.

Illustration of the blood supply to and from the liver. Shown are the location of the liver and heart in a figure, anterior view (left), and a detail of the hepatic artery and hepatic portal vein (right).

Illustration of skin tissue anatomy in cross section, showing the epidermis, dermis, and fat cell layers. Also shown are hair follicles, sebaceous glands, arteries, and veins.

Illustration of a normal pregnancy in the third trimester. Shown is the woman's abdomen, sagittal cutaway view, with the fetus in utero during the thirty-sixth week of development.

Illustration of the brain and brain stem with normal arteries and cranial nerves, inferior view. Shown are the vertebral, basilar, and the cerebral arteries; the circle of Willis; the olfactory, trigerminal, and optic nerves; the optic chiasma; and other cranial nerves.

Illustration of the brain and brain stem with normal arteries and cranial nerves, inferior view. Shown are the vertebral, basilar, and the cerebral arteries; the circle of Willis; the olfactory, trigerminal, and optic nerves; the optic chiasma; and other cranial nerves.

Illustration of the normal heart and arteries of the brain.

Illustration of the normal heart and arteries of the brain.

Illustration of the normal arteries of the brain.

Illustration of the normal arteries of the brain.

Arteries of the brain including the carotid, communicating, and cerebral arteries; and the vertebral and basilar arteries that supply blood to the brain stem.