An ostium (: ostia) in anatomy is a small opening or orifice. '' Ostia'', not as a plural, is also the name of a number of places. Ostium or ostia may refer to:

Human anatomy

* Ostium of fallopian tube * Ostium of the uterus (disambiguation) *

Ostium primum In the developing heart, the atria are initially open to each other, with the opening known as the primary interatrial foramen or ostium primum (or interatrial foramen primum). The foramen lies beneath the edge of septum primum and the endocardia ...

of the developing heart * Ostium secundum ( foramen ovale) of the developing heart * Ostium maxillare of the maxillary sinus * Ostium vaginae (vaginal orifice) * Coronary ostium – opening of

coronary arteries The coronary arteries are the arteries, arterial blood vessels of coronary circulation, which transport oxygenated blood to the Cardiac muscle, heart muscle. The heart requires a continuous supply of oxygen to function and survive, much like any ...

at root of

aorta The aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the Ventricle (heart), left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at ...

, superior to

aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. ...

Sinus ostium The human nose is the first organ of the respiratory system. It is also the principal organ in the olfactory system. The shape of the nose is determined by the nasal bones and the nasal cartilages, including the nasal septum, which separate ...

an opening that connects a sinus to the nasal cavity itself.

In other animals

Ostium (sponges) Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and are o ...

, the pores of living

sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

s * Ostium (insect anatomy), of female

Lepidoptera genitalia The study of the genitalia of Lepidoptera is important for Lepidoptera taxonomy in addition to development, anatomy and natural history. The genitalia are complex and provide the basis for species discrimination in most families and also in fami ...

Human anatomy

In other animals

See also