A 24-year-old man is admitted to the hospital after a street fight. Radiographic examination reveals an inferior (blow-out) fracture of the orbit. Orbital structures would most likely be found inferiorly in which of the following spaces?
**Core Concept**
Inferior orbital blow-out fractures occur when there is a break in the thin bone floor of the orbit, allowing orbital contents to herniate into the surrounding space. This phenomenon is related to the anatomy of the orbit and its relationship with adjacent facial structures.
**Why the Correct Answer is Right**
The orbital contents, including fat, muscle, and nerves, would most likely herniate into the infraorbital fossa. The infraorbital fossa is a shallow depression in the maxilla bone that is located below the infraorbital foramen. This space is bounded by the maxilla, the zygomatic bone, and the palatine bone. The herniation of orbital contents into the infraorbital fossa is due to the decrease in pressure within the orbit following the fracture, causing the orbital fat and other structures to protrude into the adjacent space.
**Why Each Wrong Option is Incorrect**
**Option A:** The pterygomaxillary fissure is a narrow cleft between the maxilla and the sphenoid bone, and it is not the most likely space for orbital contents to herniate into following a blow-out fracture.
**Option B:** The infratemporal fossa is a larger space located below the zygomatic arch and lateral to the maxilla, but it is not the most direct space for orbital contents to herniate into following a blow-out fracture.
**Option C:** The submandibular space is located below the mandible and is not directly related to the orbital floor or the infraorbital fossa.
**Clinical Pearl / High-Yield Fact**
Inferior orbital blow-out fractures can be diagnosed with a combination of clinical examination, radiographic imaging, and CT scans. The presence of enophthalmos (sinking of the globe into the orbit) and infraorbital nerve anesthesia are common clinical findings in patients with this type of fracture.
**Correct Answer:** .