Illustration of the normal eye and orbital anatomy, cutaway view. Labeled structures include the superior and inferior rectus muscles, inferior oblique muscle, orbicularis oculi muscle, optic nerve, fovea, choroid, sclera, posterior chamber, retina, vitreous chamber, lens, iris, pupil, and cornea.

Illustration of the placenta and its role in gas exchange between the mother and fetus. Orientation of the fetus in utero is shown at left. The detail shows the uterine lining, placenta, and umbilical cord (right).

Illustration of the female abdominal and pelvic organs, anterior cutaway view. Structures shown include the liver, stomach, cecum, ascending colon, transverse colon, descending colon, small intestine, pelvis, uterus, and urinary bladder.

Illustration of triplets in utero at 24 weeks, anterior cutaway view. Shown are the placenta, umbilical cords, and fetal membranes protecting each fetus from bacteria. Also depicted are the mother's uterus, vagina, and early dilated cervix.

Illustration of triplets in utero at 24 weeks, anterior cutaway view. Shown are the placenta, umbilical cords, and fetal membranes protecting each fetus from bacteria. Also depicted are the mother's uterus, cervix, and vagina.

Illustration of the female pelvic organs, midsagittal section, showing the mons pubis, symphysis pubis, urinary bladder, ovary, fallopian tube, uterus, cervix, vagina, vulva, umbilicus, small intestine, rectum, anus, spine, and spinal cord (cauda equina).

Illustration of the female pelvic organs, with fibrous adhesions extending from the abdominal wall to the small intestines, fallopian tube, and uterus, midsagittal section, Other structures shown include the mons pubis, symphysis pubis, urinary bladder, ovary, cervix, vagina, vulva, umbilicus, rectum, anus, spine, and spinal cord (cauda equina).

Illustration the external female genitalia, perineal view. Structures shown include the perineum with the mons veneris, clitoris, labium majous, labium minus, hymen, vestibule, fossa navicularis, the urethral and vaginal orifices, and the anus.

Neurons (brain cells) subject to axonal shearing, or post-concussion syndrome, left to right: 1. normal neuron with labels for the nerve cell body, Nissl bodies, nucleus, neuroglial cells, axon, dendrites, myelin sheath, and axon terminal; 2. trauma causing twisting and tearing of the neuronal axon; 3. post-traumatic condition with death of the brain cells.

Illustration of the digestive system, including the oral cavity, tongue, glottis, esophagus, stomach, liver, gallbladder, small intestine, large intestine, and rectum.

Normal ear anatomy, coronal cross section, showing the outer ear: auricle (pinna) and external auditory meatus (canal); tympanic membrane (eardrum); middle ear and ossicles: malleus (hammer), incus (anvil), and stapes (stirrup); fenestra of cochlea (round window); auditory tube; and inner ear: semicircular canals, cochlea, and vestibulocochlear nerve.

Illustration of internal and external eye anatomy: cornea, iris, lens, retina, sclera, ciliary zonular fibers, canal of Schlemm, bulbar conjunctiva, rectus muscles, inferior oblique muscles, macula (with fovea centralis), optic nerve, optic disc, retinal vessels, and lacrimal caruncle.

Illustration of the brain, showing the anatomy and areas of function. Anatomy shown: cerebral cortex, cerebellum, brainstem, frontal lobes, temporal lobes, parietal lobes, occipital lobes, and pituitary gland. Areas of function shown: vision, association, motor function, Broca's speech, hearing, emotion, sensation, smell, written language, and balance.

Illustration showing the rule of nines for body surface area by region. These regions are used by medical professionals to determine the percentage of body surface involvement for widespread defects or trauma, especially burns.

Illustration of the circulatory, or cardiovascular, system within a skeletal figure.

Illustration of the normal anatomy of the liver, gallbladder, and biliary system. Other anatomical structures shown are the esophagus, right lobe of the liver, left lobe of the liver, stomach, cystic duct, common hepatic duct, common bile duct, stomach, pylorus, duodenum, pancreas, small intestine, cystic artery, hepatic arteries, and celiac trunk.

Illustration of the skull, lateral and anterior views. Labeled bones include the frontal bone, temporal bone, orbit, nasal bone, maxilla, mandible, zygomatic bone, zygomatic arch, mandibular condyle, external acoustic meatus, mastoid process, occipital bone, and parietal bone.

Illustration of the thoracic cage, anterior and posterior views, showing the ribs, sternum, scapula, and vertebrae.

Illustration of the spine, or vertebral column, showing the skeletal and neural elements, including the spinal cord, vertebral bodies, intervertebral discs, dura mater, conus medullaris, and cauda equina; and a posterior (rear) view of the spine, labeling each vertebral level from C1 to the coccyx.

Illustration of the respiratory system: nasal cavity, nasopharynx, oropharynx, epiglottis, glottis, trachea, lungs, bronchus, and bronchioles. The top detail shows the anatomy and functions of the trachea, bronchi, and bronchioles. The close-up detail shows gas exchange within an alveolus, the thin-walled sac of the terminal bronchioles.