An ostium (plural ostia) in anatomy is a small opening or orifice. Ostium or ostia may refer to:

Human anatomy

Ostium of fallopian tube The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In ot ...

Ostium of the uterus (disambiguation) Orifice of the uterus may refer to: * External orifice of the uterus * Internal orifice of the uterus Internal may refer to: *Internality as a concept in behavioural economics *Neijia, internal styles of Chinese martial arts *Neigong or "internal ...

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 endocardial ...

of the developing heart * Ostium secundum ( foramen ovale) of the developing heart *

Ostium maxillare Below the bulla ethmoidalis, and partly hidden by the inferior end of the uncinate process of ethmoid bone, is the maxillary hiatus (or ostium maxillare, or maxillary sinus ostium, or maxillary ostium, or opening from the maxillary sinus); in a fro ...

of the maxillary sinus * Ostium vaginae (vaginal orifice) * Coronary ostium – opening of

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

at root of

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

, 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. The ...

Sinus ostium The human nose is the most protruding part of the face. It bears the nostrils and 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 a ...

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

In other animals

Ostium (sponges) Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through th ...

, the pores of living

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

s *Ostia 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 fam ...

Human anatomy

In other animals

See also