The Ribs

Ribs are flat, curved bones that form the framework of the chest and make up a cage to protect the heart, lungs and other upper organs. There are twelve pairs of ribs, each joined at the back of the cage to a vertebra in the spine. Between the ribs, and attached to them, are thin sheets of muscle that help to expand and relax the chest during breathing. The spaces between the ribs contain nerves and blood vessels. There are seven true ribs attached to the sternum (breastbone) directly by their costal cartilages. The remaining five pairs are called "false ribs," because their cartilages do not reach the sternum directly. Instead, the cartilages of the upper three false ribs join the cartilages attached to the ribs above, while the last rib pairs have no cartilaginous attachments to the sternum at all. These last two pairs are sometimes called "floating" ribs." The front ends of the upper ribs are linked to the sternum by cartilage, which is tough, thick and elastic. It has no blood supply of its own, but obtains nutrients from tissue fluid. The ligaments which join the costal cartilages of the ribs to the clavicle (collarbone) are called the "costoclavicular ligaments."

The Mammary Glands

The mammary glands are accessory organs of the female reproductive system that are specialized to secrete milk following pregnancy. They are located in the subcutaneous tissue of the front thorax within the elevations which are called breasts. A "nipple" is located near the tip of each breast, and it is surrounded by a circular area of pigmented skin called the "areola." A mammary gland is composed of fifteen to twenty irregularly shaped lobes, each of which includes alveolar glands, and a duct (lactiferous duct) that leads to the nipple and opens to the outside. The lobes are separated by dense connective tissues that support the glands and attach them to the tissues on the underlying pectoral muscles. Other connective tissue, which forms dense strands called "suspensory ligaments," extends inward from the skin of the breast to the pectoral tissue to support the weight of the breast. The breasts are really modified sweat glands, which are made up of fibrous tissues and fat that provide support and contain nerves, blood vessels and lymphatic vessels.

Breasts

The breasts are two protruding, milk-producing glands, which are located on the front of the chest. Male breasts are an undeveloped version of those on the female. Each breast is divided into fifteen to twenty lobes that radiate inward from the nipple and hold small clusters of milk-producing glands that have ducts which open out at the nipple of the breast for breast feeding new-born babies. The primary function of the breast is to nourish a baby, but from ancient times, it has also been a symbol of femininity, beauty and eroticism. The size and shape of the female breasts probably differ more than any other part of the body. These not only differ in individuals but at separate phases of a woman's life - during pregnancy, during the menstrual cycle, and after menopause. The breasts are really modified sweat glands, which are made up of fibrous tissues and fat that provide support and contain nerves, blood vessels and lymphatic vessels. The darker pigment around the nipples are called, "areola," and the nipples themselves become erect because of cold, breast feeding or during sexual activity. The size of the breast cannot be increased by exercise because there are no muscles within it, but only ligaments which interlace the fat and tissue. The amount of milk is not dependent upon the size of the breast (which is set by genetic heritage.) The red, irritation of "jogger's nipples," as well as strain and stress of tissues leading to "sagging" breasts, can be corrected by wearing a good, supportive bra.

Lungs (An Overview)

Air, which is inhaled through the mouth and nasal passages, travels through the windpipe or "trachea" into two main air passages. These divide into smaller branches which separate into even smaller "twigs" like an upside-down tree. The respiratory system is mainly contained in two lungs. The little air sacs at the end of the twigs comprise the fruit of the tree, and through its thin walls gasses pass into and out of the blood. The right lung is made up of three compartments, each of which contain a branch and each of which stems off into smaller "twigs," which hold the air sacs (or "fruit" of the tree) that process the oxygen in the air to be released into the blood and expel carbon dioxide, which is exhaled through the nose and mouth. The left lung cavity contains only two sections (each with its own branches, twigs and fruit) and encloses the heart, which processes the oxygenated blood and returns deoxygenated blood into the lungs for exhalation. Breathing is an automatic process which comes from the brain stem and is so strong a force that the involuntary reflexes will not allow us to stop breathing for any length of time. The passageways in the respiratory system are lined with various types of epithelia to prepare the air properly for utilization and with hair-like fibers called cilia that move in a wave-like motion to sweep debris out of the lungs for expulsion. The women in ancient Greece and Rome wore corsets of linen to restrain their figures. The female waistline has been moved up and down over the passage of time, but this became a real health hazard when whalebone corsets came into use during the last part of the 19th and early part of the 20th centuries, because they constricted the vital organs in the body - especially those of the respiratory and digestive systems. Women with "wasp-like" waists fainted so often that those who were well-off purchased "fainting" couches; and when a woman "swooned," the cry, "Cut her laces!" often allowed her enough air to recover.

Pectoral Muscles

The pectoral is a term relating to the chest. The "pectoralis major" is a large, fan-shaped muscle that covers much of the front upper chest. It begins at the breastbone (sternum) and the cartilage of the second to the sixth ribs and is attached to the collarbone (clavicle) to converge on the upper arm bone (humerus) just below the shoulder. Its main use is in moving the arm across the body. The "pectoralis minor" is a smaller, triangular muscle beneath the pectoralis major. It stems from the third to fifth ribs and converges at the shoulder blade (scapula), which it moves up and down.