The space in the thoracic cavity between the concave inner surfaces of the lungs, in which (in a special pericardial cavity) the heart is located, is called the mediastinum. The thoracic cavity is lined with a serous membrane called the pleura. The lungs are enclosed in the so-called pleural cavities, which are separate in man but communicate with one another in the majority of mammals. The shape of the thoracic cavity depends upon the shape of the thorax and the position of the diaphragm.
We sell 5 hammock sizes on the Traditional Hammocks (no spreader wood bars). Therefore, the length of the hammock is the same for each size but the difference is the width. Width gives the size. The larger the size, the wider and bigger the hammock.
If trees aren't an option, install posts specifically for the hammock. Use sturdy 4-by-4s or large posts, set in a 12-inch deep concrete bed to ensure they stay upright under the weight of the hammock when in use. Set posts 15 feet apart for a 13-foot hammock. Another option is to combine a single post with a single tree, or to stretch the hammock between a wall and a post or tree. When using a post or wall as the hanging point, install 3/8-inch diameter or larger eyebolts a minimum of 2 inches into the support.