A fissure in a bone is essentially an open slit or groove, often serving as a passageway for nerves and blood vessels.
Understanding Bone Fissures
Here's a breakdown of what bone fissures are:
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Definition: A fissure is a natural cleft or groove in a bone. These aren't fractures or breaks, but rather structural features designed to accommodate important anatomical elements.
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Function: The primary function of a fissure is to provide a protected channel for nerves and blood vessels to pass through bones, allowing them to reach other parts of the body.
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Location: Fissures are commonly found in the skull and other bones where numerous nerves and blood vessels need to be routed.
Examples of Bone Fissures
Here are a couple of examples of fissures found in the skull:
- Superior Orbital Fissure: Located in the sphenoid bone of the skull, the superior orbital fissure transmits several cranial nerves (III, IV, V1, and VI) that control eye movement and sensation in the forehead, as well as the superior ophthalmic vein.
- Inferior Orbital Fissure: Also located in the sphenoid bone, the inferior orbital fissure transmits the maxillary nerve (V2), the infraorbital artery and vein, and branches of the inferior ophthalmic vein. It connects the orbit with the infratemporal and pterygopalatine fossae.
Fissures vs. Foramina
It's important to distinguish fissures from foramina. While both serve as passageways, a fissure is an elongated slit or groove, whereas a foramen is a more rounded hole.
| Feature | Fissure | Foramen |
|---|---|---|
| Shape | Slit-like or groove | Hole-like |
| Function | Passage for nerves & vessels | Passage for nerves & vessels |
| Examples | Superior Orbital Fissure | Supraorbital Foramen |
In summary, fissures in bones are normal anatomical features that create protected pathways for nerves and blood vessels. They are distinct from foramina, which are more rounded openings.
