Biomedical Ephemera, or: A Frog for Your Boils

Bones, cartilage, and muscles of the larynx.

The laryngeal folds are where voice is produced, and is located just below where the pharynx separates into the esophagus and the larynx. During the swallowing action, if solid matter enters the larynx, a strong coughing reflex is triggered to protect the lungs. This is also triggered at other times, if solid matter touches the glottis. Should that coughing reflex not dislodge the bolus, suffocation can occur.

During puberty, the protective laryngeal cartilage (specifically the thyroid cartilage) expands and forms the Adam's apple - in males, the cartilage fuses at approximately a 90° angle, and in females, it fuses at approximately 120°. Everyone has an Adam's apple! The difference in fusion means that the male vocal cords have more room to grow outward, and form a deeper voice. 

When an adult is hanged, throttled or strangled in a murder, the hyoid bone - the only bone in the body not directly connected to other bones - is almost always cracked or split apart. However, since it does not completely fuse until early adulthood, children and adolescents do not always show this distinctive sign.

Atlas d'Anatomie Descriptive du Corps Humain. C. Bonamy and Paul Broca, 1866.

Top: Primary mammary blood vessels, deep tissue of nipple, outer nipple and areola

Bottom: Lymphatic supply to breast, vertical view of mammary duct exit, lactiferous ducts

The human breast is an odd organ, even among mammals. It is significantly developed even before pregnancy, while most mammals develop only the ductal regions (the nipple and its connecting supply) prior to parturition, and its variance between individuals can be massive, even while they all function equally well for supplying nutriment to our offspring.

The lactiferous ducts are the smallest units of the lactation (milk-supplying) system of the breast, and the epithelial cells within them extract the nutrients and liquid from the lymphatic and circulatory system when they're triggered by the hormone prolactin, which is secreted both in response to labor and from suckling. Though the massive dose of prolactin from late-term pregnancy and giving birth is what kick-starts milk production, the suckling action is what keeps it going. In some humans (even some males), the prolactin secretion in response to sustained suckling is enough to begin producing milk, themselves.

Atlas d'Anatomie Descriptive du Corps Humain. C. Bonamy and Paul Broca, 1866.