Morphological variability of the piriformis muscle

Area of Science:

• Anatomy
• Morphology
• Human Anatomy

Background:

• The piriformis muscle (PM) is crucial for hip joint function and can be implicated in sciatic nerve compression.
• Understanding its anatomical variations is essential for clinical diagnoses and surgical procedures.

Purpose of the Study:

• To classify the proximal and distal attachments of the piriformis muscle.
• To investigate potential fusions of the piriformis muscle with adjacent muscles.
• To analyze the relationship between the piriformis muscle and the sciatic nerve.

Main Methods:

• Anatomical dissection of 124 lower limbs from 62 human cadavers.
• Cadavers were preserved in 10% formalin for detailed examination.

Main Results:

• The piriformis muscle was present in 96.8% of specimens.
• Four types of proximal attachments and three types of distal attachments were identified.
• Muscle fusions occurred in 31.7% of cases, and four distinct patterns of sciatic nerve relationships were observed.

Conclusions:

• The piriformis muscle demonstrates high morphological variability in its attachments and sciatic nerve interactions.
• Four proximal and three distal attachment types, along with numerous fusions and a novel sciatic nerve relationship pattern, were documented.
• The piriformis muscle was absent in 4 specimens, highlighting its anatomical variability.