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Related to ostium: Ostium primum, Ostium secundum


n. pl. os·ti·a (-tē-ə)
1. A small opening or orifice, as in a body organ or passage.
2. Any of the small openings or pores in a sponge, through which water is drawn in.

[Latin ōstium, door, opening, from ōs, mouth; see ōs- in Indo-European roots.]


n, pl -tia (-tɪə)
1. (Zoology) any of the pores in sponges through which water enters the body
2. (Zoology) any of the openings in the heart of an arthropod through which blood enters
3. (Biology) any similar opening
[C17: from Latin: door, entrance]


(ˈɒs ti əm)

n., pl. -ti•a (-ti ə)
a small opening or orifice of the body.
[1655–65; < Latin ōstium entrance, river mouth]
References in periodicals archive ?
Ostium Lab work in the field of basic research of neurophysiology and neurocybernetics.
The aim of the present study is to assess the normal anatomy and variations of SA nodal artery by studying the number, origin, course, length and distance of its origin from the ostium of parent artery.
The natural ostium of the sphenoid sinus is located at its superior aspect anteriorly and drains into the sphenoethmoid recess.
The distance of an individual ostium from the base of cusps of aortic valve by using Vernier caliper (Figure 2).
According to the Neri's definition of coronary malperfusion in aortic dissection,[sup][2] we differentiated among three types of lesions based upon operative findings: type A ( n = 23), ostial dissection is defined as a disruption of the inner layer limited to the area of the coronary ostium without disrupting coronary vessel; type B ( n = 8), dissection with a coronary false channel; and type C ( n = 5), circumferential detachment with an inner cylinder intussusception.
Bony ostium was enlarged to an extent of approximately 1x1.
The above abnormality was accompanied by an ostium secundum-type atrial septal defect.
All patients with isolated atrial septal defect (ostium secundum, ostium primum and sinus venosus with or without partial anomalous pulmonary venous connection) were included.
The calcified left coronary cusp partially obstructed the left main coronary ostium during the aortic balloon valvuloplasty without hemodynamic compromise (Fig.
In this rare anomaly only one coronary artery arises from a single ostium (0.
The patented methods include advancing a balloon through a guide and using the balloon to dilate a paranasal sinus ostium.