shoulder joint, the ball and socket articulation of the humerus with the scapula. The joint includes eight bursae and five ligaments, including the glenoidal labrum that deepens the articular cavity and protects the edges of articulating bones. It is the most mobile joint in the body. Also called humeral articulation.
It is common for young women to have irregular periods when they first begin to menstruate. This means that ovulation (when a womanâs body makes eggs) may not happen for a few months or even for a few years. So you may not have menstrual cramps when you first begin your period. After one, two, or three years, when your hormonal system is more mature, you might have more severe menstrual cramps.
By Mayo Clinic Staff. During your menstrual period, your uterus contracts to help expel its lining. Hormone-like substances (prostaglandins) involved in pain and inflammation trigger the uterine muscle contractions. Higher levels of prostaglandins are associated with more-severe menstrual cramps. Severe contractions may constrict the blood vessels feeding the uterus. The resulting pain can be compared to the chest pain that occurs when blocked blood vessels starve portions of the heart of food and oxygen. Menstrual cramps may also be caused by: Endometriosis.