HYPOGASTRIUM. The lower anterior region of the abdomen. HYPOGLOSSAL. The name of the _lingualis_, or ninth pair of nerves, situated beneath the tongue. I, J ICHOR. A thin, acrid discharge, issuing from wounds, ulcers, &c. JEJUNUM (L. _jejunus_, hungry). The upper two-fifths of the small intestines; so named from this portion being generally found _empty_. ILEUM (to turn about). The lower three-fifths of the _small intestines_; so called from their convolutions or peristaltic motions. ILIAC BONE. Another name for the _os innominatum_, derived from the circumstance that this compound bone supports the parts which the ancients called _ilia_, or the flanks. ILIAC REGION. The region situated on each side of the hypogastrium. INDEX (L. _indico_, to point out). The forefinger; the finger usually employed in _pointing_ at any object. INFRA-SPINATUS. A muscle arising from the scapula below the spine, and inserted into the humerus. INNOMINATUS (L. _in_, priv., _nomen_, name). Hence, _Innominatum os_, a bone composed of three portions, viz: 1, The _ilium_, or haunch-bone; 2, The _ischium_, or hip-bone; 3, The _os pubis_, or share bone. INTEGUMENT (L. _in_, and _tego_, to cover). The covering of any part of the body, as the cuticle, cutis, &c. INTER-COSTAL. The name of two sets of muscles between the ribs—the _external_ and the _internal_. INTESTINES (L. _intus_, within). That part of the alimentary canal which extends from the stomach to the anus. JUGULAR. Belonging to the neck; applied chiefly to the principal veins of the neck. K KINGDOM. A term denoting any of the principal divisions of nature. Thus we have the _organic kingdom_, comprehending substances which organize; and the _inorganic kingdom_, comprehending substances which crystallize. KNEE-PAN. Patella; the small round bone at the front of the knee-joint. KIDNEYS. Two oblong glands, which secrete the urine. L LABIA. The lips. They are laterally united by means of two acute angles, which are called their _commissures_. LABYRINTH. The name of a series of cavities of the inner ear, viz: the vestibule, the cochlea, and the semi-circular canals. LACHRYMA. A tear; the fluid secreted by the _lachrymal gland_, and flowing on the surface of the eye. LACTEALS (L. _lac_, milk). Numerous minute tubes which _absorb_ or take up the chyle, or _milk-like_ fluid, from the alimentary canal. LACTIC ACID (L. _lac_, _lactis_, milk). An acid produced whenever milk—and perhaps most animal fluids—become spontaneously sour. LAMINA. Literally, a small plate of any metal. A term applied to the foliated structure of bones or other organs. LARYNX (Gr. _larungx_, the larynx). The superior part of the trachea, situated immediately under the os hyoïdes. LENS (L. _lens_, _lentis_, a bean). Properly, a small roundish glass, shaped like a _lentil_, or bean.