Step deformity of mandibular body fracture may be due to?
- A- Forward pull of lateral pterygoid muscle.
- B- Upward pull of masseter and temporalis.
- C- Inward pull of medial pterygoid muscle.
- D- Downward pull of geniohyoid and mylohyoid.
The most likely cause of a step deformity in a mandibular body fracture is: B. Upward pull of masseter and temporalis muscles
Here's why the other options are less likely:
A. Forward pull of lateral pterygoid muscle:
While the lateral pterygoid muscle can contribute to a slight forward displacement of the mandibular fragment, it wouldn't cause a significant upward step deformity.
C. Inward pull of medial pterygoid muscle:
The medial pterygoid muscle primarily pulls the mandible medially, not upwards. It wouldn't create a step deformity in the body of the mandible.
D. Downward pull of geniohyoid and mylohyoid:
These muscles do pull the mandible downward, but they primarily affect the symphysis and anterior portion of the mandible. They wouldn't cause a step deformity in the body.
The masseter and temporalis muscles are the main elevators of the mandible. When a fracture occurs in the body of the mandible, the unfractured segment pulled by these muscles can move upwards, creating a step deformity with the fractured segment remaining in place.
Additional Points
Here are some additional points to consider:
- The direction and severity of the step deformity can vary depending on the location and angle of the fracture, as well as the surrounding muscle tone.
- Other factors, such as swelling and hematoma formation, can also contribute to the appearance of a step deformity.
- A thorough clinical examination and imaging studies are necessary to accurately diagnose and manage a mandibular body fracture.
