Gerard of Cremona in the context of "Sagittal plane"

The thoracic diaphragm, or simply the diaphragm (/ˈdaɪəfræm/; Ancient Greek: διάφραγμα, romanized: diáphragma, lit. 'partition'), is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the most important muscle of respiration, and separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity: as the diaphragm contracts, the volume of the thoracic cavity increases, creating a negative pressure there, which draws air into the lungs. Its high oxygen consumption is noted by the many mitochondria and capillaries present; more than in any other skeletal muscle.

The term diaphragm in anatomy, created by Gerard of Cremona, can refer to other flat structures such as the urogenital diaphragm or pelvic diaphragm, but "the diaphragm" generally refers to the thoracic diaphragm. In humans, the diaphragm is slightly asymmetric—its right half is higher up (superior) to the left half, since the large liver rests beneath the right half of the diaphragm.

Latin translations of the 12th century were spurred by a major search by European scholars for new learning unavailable in western Europe at the time; their search led them to areas of southern Europe, particularly in central Spain and Sicily, which recently had come under Christian rule following their reconquest in the late 11th century. These areas had been under Muslim rule for a considerable time, and still had substantial Arabic-speaking populations to support their search. The combination of this accumulated knowledge and the substantial numbers of Arabic-speaking scholars there made these areas intellectually attractive, as well as culturally and politically accessible to Latin scholars. A typical story is that of Gerard of Cremona (c. 1114–87), who is said to have made his way to Toledo, well after its reconquest by Christians in 1085, because he:

Many Christian theologians were highly suspicious of ancient philosophies and especially of the attempts to synthesize them with Christian doctrines. St. Jerome, for example, was hostile to Aristotle, and St. Augustine had little interest in exploring philosophy, only applying logic to theology. For centuries, ancient Greek ideas in Western Europe were all but non-existent. Only a few monasteries had Greek works, and even fewer of them copied these works.

The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The size of the pupil is controlled by the iris, and varies depending on many factors, the most significant being the amount of light in the environment. The term "pupil" was coined by Gerard of Cremona.

In humans, the pupil is circular, but its shape varies between species; some cats, reptiles, and foxes have vertical slit pupils, goats and sheep have horizontally oriented pupils, and some catfish have annular types. In optical terms, the anatomical pupil is the eye's aperture and the iris is the aperture stop. The image of the pupil as seen from outside the eye is the entrance pupil, which does not exactly correspond to the location and size of the physical pupil because it is magnified by the cornea. On the inner edge lies a prominent structure, the collarette, marking the junction of the embryonic pupillary membrane covering the embryonic pupil.