Case report: L3 Entrapped vertebra syndrome as a rare cause of low back pain in a semi-professional female soccer player.

Entrapped Vertebra Syndrome is a newly described, scarcely documented condition characterized by segmental restriction, facet dysfunction and neuromuscular involvement. We present the case of a 26-year-old semi-professional soccer player with chronic and disabling low back pain, exacerbated by sports activity. The clinical evaluation showed a positive lumbar extension test, unilateral pain at L3-L4 and alterations in core activation. Magnetic resonance imaging revealed anterior displacement of L3 without spondylolisthesis, facet hypertrophy, synovitis at L3-L4, thickening of the ligamentum flavum and edema in the L3 nerve root. Differential diagnosis was established with spondylolisthesis, disc protrusion and femoral nerve entrapment. A rehabilitation program based on central stability and motor control was implemented, achieving functional recovery without recurrence of pain. This case highlights the relevance of an accurate diagnostic approach and the role of therapeutic exercise periodization in the treatment of complex lumbar pathologies in athletes.