IVRI Anatomy
A free veterinary anatomy learning platform for B.V.Sc., M.V.Sc., DVM and veterinary medicine students worldwide, developed at the Veterinary Anatomy Section, ICAR-Indian Veterinary Research Institute, Bareilly—covering VCI/MSVE and international university curricula through regional anatomy, histology, embryology, comparative biomechanics, clinical notes, quizzes and revision.
Located at the anterior margin of the orbit, articulating with the frontal, zygomatic, and maxillary bones.
Lacrimal Bulla (Bulla lacrimalis): A unique, thin-walled bony protuberance inside the orbit of the ox. It is fragile and contains the lacrimal sinus, a posterior extension of the maxillary sinus. Damage to this bulla during enucleation can lead to sinus infection.
Facial Plate: Large and flat on the face, extending rostrally.
Orbital Plate: Forms the medial wall of the orbit.
Nasolacrimal Canal: The entrance (fossa) leads to the duct carrying tears to the nose. In the ox, it is situated on the orbital surface.
Forms the ventral margin of the orbit and the rostral part of the zygomatic arch.
Facial Surface: Extensive in the ox, extending rostrally to the facial tuberosity.
Frontal Process: Projects dorsally to articulate with the zygomatic process of the frontal bone. This articulation completes the bony orbit caudally, a key distinction from carnivores where the orbit is open.
Temporal Process: Extends caudally to meet the zygomatic process of the temporal bone, forming the zygomatic arch.
| OX (BOS TAURUS) | Lacrimal: Bulla present (large, fragile). Facial part large. Lacrimal fossa near orbital rim. Zygomatic: Complete orbit (joins frontal). Bifurcated (frontal/temporal procs). Large/broad. |
| HORSE (EQUUS CABALLUS) | Lacrimal: Absent bulla. Small facial part. Funnel-like; inside orbit. Zygomatic: Complete orbit. Blade-like. Large. |
| DOG (CANIS LUPUS) | Lacrimal: Absent bulla. Very small (mostly orbital). On orbital rim. Zygomatic: Incomplete orbit (ligamentous closure). Curved bar. Small. |
| PIG (SUS SCROFA) | Lacrimal: Absent bulla. Small. Two foramina usually. Zygomatic: Incomplete orbit (ligamentous closure). Robust. Massive. |
| FOWL (GALLUS DOMESTICUS) | Lacrimal: Absent (different drainage). Large (Prefrontal bone). Absent. Zygomatic: Incomplete orbit (jugal bone). Rod-like (jugal). Very thin/rod-like. |
Explore the hidden mechanics of why structures are present, absent or modified across domestic and wildlife species—and how each anatomical design supports movement, function and clinical practice.
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