He hit his occipital bone hard.

He fractured his frontal bone.

He fractured his ilium.

Strengthening the occipitalis muscle can reduce neck pain.

By training the frontalis muscle, your facial expressions will become more expressive.

His coracoid process was fractured.

When the arrector pili muscles contract, goosebumps occur.

The cold caused my arrector pili muscles to contract, giving me goosebumps.

He is immersed in the study of the rostrum bone.

What is the constant term of this equation?