Illustration of the normal anatomy of a human brain, cutaway side view. Shown are the skull, cerebrum, cerebellum, brain stem, and spinal cord. The areas of the brain responsible for thinking, cognitive behavior, memory, language, and sensations are in the cerebrum (blue), while the areas responsible for muscular movements are in the cerebellum (red).

Illustration of an obstruction of the small intestine and a hernia in a circumcised male, frontal view.

Illustration of the normal anatomy of a female torso, frontal view.

Illustration of the normal anatomy of a male torso, frontal view.

Illustration of the normal musculature of a female torso, frontal view. Shown are the pectoralis major muscle, serratus anterior muscle, latissimus dorsi muscle, external oblique muscle, internal oblique muscle, pectoralis minor muscle, and rectus abdominis muscle.

Illustration of the normal musculature of a female torso, dorsal view. Shown are the trapezius muscle, deltoid muscle, infraspinatus muscle, latissimus dorsi muscle, serratus anterior muscle, teres major muscle, teres minor muscle, and rhomboid muscle.

Illustration of the inner ear. Shown are the eardrum, hammer (malleus), anvil (incus), stirrup (stapes), and semicircular canals.

Grayscale illustration of the anatomy of a knee. The bony view (left) shows the femur, cut edge of the synovial capsule, meniscus, fibula, tibia, patella, anterior cruciate ligament, posterior cruciate ligament, and medial collateral ligament. The muscular view (right) shows the hamstring muscles, fibula, gastrocnemius muscles, and quadriceps muscles.

Grayscale illustration of how a walking foot strikes the ground. Shown are three stages: 1) before the foot strikes the ground, the rounded arch is poised like a steel spring (left); 2) as the foot hits the ground, the impact flattens the arch, and the Achilles tendon stretches; and 3) the arch springs back to shape and the Achilles tendon contracts (right).

Illustration of the layers of human skin. Shown are the upper epidermis, squameous cells, spinous cells, and basal cells. The epidermis may produce substances contributing to the chemistry of the body, including chemicals that repel infection. Interferons, interleukens, and hormone-like substances are produced as cells mature from one layer into another.

Grayscale illustration of how the kidney filters blood. Shown are the renal vein, arteriole, glomerular tuft, nephron, and collecting ducts. An enlarged view of a nephron is shown in the inset.

Grayscale illustration of muscles and nerves near the human eye, showing the orbicularis muscle, levator palpebrae superioris muscle, and branches of the facial nerves.

Illustration of some heart attack symptoms in a male patient: sweating, shortness of breath, and an open mouth. The patient's heart is highlighted in the illustration of his chest and head.

Grayscale illustration of the head of a normal femur bone, cutaway cross section.

Illustration of a human eye, showing a quarter dissection (left) and a detail of the retinal membrane (right). Shown are the cornea, iris, lens, retina, blood vessels (supplying zinc and other nutrients), macula, optic nerve, and eye muscle (quarter dissection view); and the nerve ending, rod, and cone (detail view).

Grayscale illustration of a human female pelvis, highlighting the uterus, vagina, fallopian tubes, and ovaries.

Grayscale illustration of a human female pelvis highlighting normal anatomical bones. Included are the ilium, iliac crest, sacrum, coccyx, superior pubic ramus, inferior pubic ramus, and femurs. Also shown is the symphysis pubis.

Grayscale illustration of a normal female breast, showing blood vessels.

Grayscale illustration of a human brain superimposed on a stylized head, side view. Shown are the cerebrum, cerebellum, brain stem, and spinal cord.

Grayscale illustration of a female pelvis (cutaway cross section), showing internal organs.