The glabella is well defined, slightly tapering forward, with a large subhorizontal spine extending from the back of the glabella.

There are no spines extending from the angle between the side and the back of the cephalon (called genal spines).

Some forms had large serrated spines extending backwards from the neck.

The most prominent feature of Dimetrodon is the large sail on its back formed by elongated spines extending from the vertebrae.

There may be small spines extending from the frontal corners of the pygidium.

Acanthonautilus, like Solenochilus, has an involute, globular shell of few volutions that enlargens with fair rapidity, with prominent lateral spines extending from the umbilical area at maturity.

The cactus cat was generally described being a bobcat-like creature, covered in hair-like thorns, with particularly long spines extending from the legs and its armored, branching tail.

There are yellowish middorsal and lateral stripes and a number of dorsal, subdorsal, and lateral fleshy spines extending from the body.

Ford suggested that earlier reconstructions of Gigantspinosaurus attached the shoulder spines upside-down, and his new reconstruction shows the spine extending somewhat upwards, ending higher than the top of the animal's back.

A common side-effect was a loss of the lumbar lordosis - the natural curve caused by the spine extending inwards in the low back.