位置、形態與功能

子宮( uterus,拉丁語：發源地)是一個肌肉狀器官，位於兩側卵巢之間、略靠下，約在下腹部的中央。這個大約3英寸（7cm）長的器官，其形狀像似一個倒置的小鴨梨。在其頂端的兩側，有輸卵管進入。其寬闊的上端，稱為子宮底，倚靠在圓隆的膀胱上方，而且與略微縮小的窄小下端相分隔。子宮的這個窄小下端部分稱為子宮頸，其末端向下延伸入陰道。子宮頸有一個開口，精子通過這個開口能夠從陰道進入子宮。但是，除排卵的特定時間以外，子宮頸的開口由難以滲透的粘液所栓塞。

子宮壁
厚厚的子宮壁由三層結構所組成：

子宮內膜由特殊的組織所組成，當子宮預備為受精卵植入作好準備時，它按月會增厚。如果沒有植入發生，子宮內膜會在月經期潰破和通過子宮頸和陰道排放出去（既形成月經-譯者注）。

妊娠期的子宮
假若懷孕了，子宮會隨著胎兒的生長而擴張。子宮肌層的這些非凡的肌肉結構不僅適應於如此的膨脹，而且在胎兒最終分娩時收縮，提供必需的壓力。在性高潮期，子宮肌也會收縮。

Location, form and function
The uterus (lat.: womb) is a muscular organ which is situated between and slightly below the ovaries, approximately in the center of the lower abdomen. The shape of the uterus, which is about 3 inches (ca. 7 cm) long, resembles that of a small pear turned upside down. The Fallopian tubes enter the uterus on either side near the top. The wide upper part, known as the body of the uterus, is usually tilted forward over the dome of the urinary bladder, and it is separated from the narrow lower part by a slight constriction. This lower part is called the cervix or neck of the uterus, and it ends in the deep portion of the vagina. The cervix contains a small opening through which sperm cells can travel from the vagina into the uterus. However, except for a certain period during ovulation, the cervical opening is plugged by an impenetrable mucus.

The three layers of the uterine wall
The thick walls of the uterus are made up of three layers:

This endometrium consists of special tissue which thickens every month as the uterus prepares for the possible implantation of a fertilized egg. If no implantation occurs, the endometrium deteriorates and is discharged through the cervix and the vagina during menstruation.

The uterus during pregnancy
In case of a pregnancy, the uterus expands with the growing fetus. The extraordinary muscular structure of the myometrium not only allows for such vast expansion, but also provides the necessary pressure during labor when the fetus is finally expelled. The uterine muscles also contract during orgasm.