[4] The parts of a rib includes the head, neck, body (or shaft), tubercle, and angle.

[5] The crest gives attachment to the intra-articulate ligament that joins the rib to the vertebra of the same number, at the intervertebral disc.

The superior costotransverse ligament attaches from the non-articular facet of the tubercle to the transverse process of the vertebra.

[7] The rib cage is separated from the lower abdomen by the thoracic diaphragm which controls breathing.

When the diaphragm contracts, the thoracic cavity is expanded, reducing intra-thoracic pressure and drawing air into the lungs.

This happens through one of two actions (or a mix of the two): when the lower ribs the diaphragm connects to are stabilized by muscles and the central tendon is mobile, when the muscle contracts the central tendon is drawn down, compressing the cavity underneath and expanding the thoracic cavity downward.

Early in the developing embryo, somites form and soon subdivide into three mesodermal components – the myotome, dermatome, and the sclerotome.

[8] During the fourth week (fertilization age) costal processes have formed on the vertebral bodies.

These processes are small, lateral protrusions of mesenchyme that develop in association with the vertebral arches.

In the sixth week, the costovertebral joints begin to develop and separate the ribs from the vertebrae.

[8] The ribs begin as cartilage that later ossifies – a process called endochondral ossification.

One set, the dorsal ribs, are found in the dividing septum between the upper and lower parts of the main muscle segments, projecting roughly sideways from the vertebral column.

The sacral ribs were stout and short, since they formed part of the pelvis, connecting the backbone to the hip bones.

Frogs typically have no ribs, aside from a sacral pair, which form part of the pelvis.

The thoracic ribs of birds possess a wide projection to the rear; this uncinate process is an attachment for the shoulder muscles.

In therian mammals, the cervical and lumbar ribs are found only as tiny remnants fused to the vertebrae, where they are referred to as transverse processes.