pectus

The doctor gently examined the patient's pectus for any swelling.

用法提示：这里 pectus 是名词，指医学语境中的“胸”。

The bird's pectus is protected by a thick layer of feathers.

用法提示：pectus 作单数名词，表示动物身体的胸部。

In the anatomy lab, we compared the pectora of the two specimens.

用法提示：pectora 是 pectus 的复数形式，仍为名词，指多个胸部。