Maximum contribution to the floor of orbit is by which bone?
**Core Concept**
The floor of the orbit is a composite structure formed by the contributions of multiple bones. Understanding the anatomy of the orbital floor is crucial for diagnosing and managing conditions such as orbital fractures and entrapment of orbital contents.
**Why the Correct Answer is Right**
The floor of the orbit is primarily formed by the maxilla bone, which contributes approximately 70-80% of the orbital floor. The maxilla bone forms the anterior part of the floor, extending from the lacrimal groove to the inferior orbital fissure. The remaining 20-30% of the orbital floor is formed by the zygomatic bone, which contributes to the posterior part of the floor.
**Why Each Wrong Option is Incorrect**
**Option A:** The lacrimal bone makes a small contribution to the medial wall of the orbit, but it does not form part of the orbital floor.
**Option B:** The palatine bone forms part of the medial wall and the orbital roof, but it does not contribute significantly to the orbital floor.
**Option C:** The sphenoid bone forms part of the orbital roof and the lateral wall, but it does not contribute to the orbital floor.
**Clinical Pearl / High-Yield Fact**
The orbital floor is a common site for fractures, particularly in the setting of midfacial trauma. A high index of suspicion for orbital floor fracture should be maintained in patients with symptoms such as diplopia, enophthalmos, and infraorbital nerve anesthesia.
**Correct Answer: A. Maxilla.**