Nasal and lacrimal bones
These two paired bones participate in the formation of the most important anatomical spaces of the facial skull.
The nasal bone (Os nasale) is a thin plate. It does not feature separate anatomical parts. Located in the area of the nasal bridge, it actively articulates with neighboring structures:
- In the superior part — with the frontal bone (os frontale).
- On the lateral side — with the maxilla (maxilla).
- Along the midline — with the corresponding nasal bone of the opposite side.
- In the posterior part — with the ethmoid bone (os ethmoidale).
The lacrimal bone (Os lacrimale) is the smallest bone participating in the formation of the orbital walls. Like the nasal bone, it has no distinct anatomical parts, but its orbital surface features important landmarks. Here lies the posterior lacrimal crest (Crista lacrimalis posterior), anterior to which runs the lacrimal groove (Sulcus lacrimalis). This groove joins the lacrimal groove of the frontal process of the maxilla (sulcus lacrimalis maxillae) and the inferior nasal concha, resulting in the formation of the nasolacrimal canal (Canalis nasolacrimalis).
Zygomatic bone (Os zygomaticum)
This is a paired bone with no distinct parts, but possessing three surfaces and two processes. It plays a key role in forming the lateral facial contours and the orbital walls.
Surfaces of the zygomatic bone:
- Lateral (Facies lateralis) — faces outwards.
- Temporal (Facies temporalis) — faces towards the temporal fossa.
- Orbital (Facies orbitalis) — participates in the formation of the orbit. It may feature the orbital tubercle (Tuberculum orbitale), and near the posterior margin of the frontal process — the marginal tubercle (Tuberculum marginale).
Processes of the zygomatic bone:
- Temporal process (Processus temporalis) — connecting with the zygomatic process of the temporal bone (processus zygomaticus ossis temporalis), it completes the zygomatic arch.
- Frontal process (Processus frontalis) — takes part in building the lateral wall of the orbit.
On the orbital surface is the zygomaticoorbital foramen (Foramen zygomaticoorbitale). From it, a canal begins within the thickness of the bone, which then bifurcates. This results in two output openings: the zygomaticofacial foramen (Foramen zygomaticofaciale) on the lateral surface and the zygomaticotemporal foramen (Foramen zygomaticotemporale) on the temporal surface.
Bones of the nasal cavity: inferior nasal concha and vomer
Two independent small bones participate in the formation of the nasal cavity, one of which is paired and the other unpaired.
The inferior nasal concha (Concha nasalis inferior) is a paired and completely independent bone of the nasal cavity. Its main functional role is forming the lateral wall of the nasal cavity. In addition, it obstructs the nasolacrimal canal with its own lacrimal crest.
The vomer (Vomer) is an unpaired, vertically oriented bone plate. In studying its basic anatomy, no small landmarks are distinguished. The main function of the vomer is forming the posteroinferior part of the nasal septum.
To remember the branching of the zygomatic bone canal, imagine the Latin letter "Y": one entrance (in the orbit), and two exits (on the face and on the temple).
Class and exam questions
Which bones participate in the formation of the nasolacrimal canal?
The nasolacrimal canal is formed by the lacrimal groove of the lacrimal bone, the lacrimal groove of the frontal process of the maxilla, and the inferior nasal concha.
Which bones does the nasal bone articulate with?
The nasal bone articulates superiorly with the frontal bone, laterally with the maxilla, medially with the opposite nasal bone, and posteriorly with the ethmoid bone.
Where does the canal inside the zygomatic bone begin and end?
The canal begins with the zygomaticoorbital foramen on the orbital surface. It then branches and opens with the zygomaticofacial foramen on the lateral surface and the zygomaticotemporal foramen on the temporal surface.
What else to study on this topic
- Topography and walls of the orbit
- Structure of the bony nasal septum
- Formation of the lateral wall of the nasal cavity
- Anatomy of the zygomatic arch
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