Spondylolisthesis describes the anterior displacement of a vertebra or the vertebral column in relation to the vertebrae below. It was first described in 1782 by Belgian obstetrician, Dr. Herbinaux. He reported a bony prominence anterior to the sacrum that obstructed the vagina of a small number of patients. The term “spondylolisthesis” was coined in 1854, from the Greek “spondyl” for vertebrae and “olisthesis” for slip. The variant "listhesis" is sometimes applied in conjunction with scoliosis. These "slips" occur most commonly in the lumbar spine.

X-ray picture of a grade 1 isthmic spondylolisthesis at L4-5

Clasificación anatómica: está determinada por el nivel de la línea de fractura. Así se las clasifica en:
Fractura sub-capital: aquella producida en un plano inmediatamente inferior al del borde del cartílago de crecimiento; generalmente tiene una orientación algo oblícua, de modo que compromete un pequeño segmento del cuello del fémur. Son las más frecuentes. 
Fractura transcervical (o medio cervical): el rasgo compromete la parte media del cuerpo del cuello femoral. 

A bezoar is a mass found trapped in the gastrointestinal system (usually the stomach), though they can occur in other locations.

There are several varieties of bezoar, some of which have inorganic constituents and others organic.

Hallux valgus is a common foot disorder of several etiologies,

which can lead to significant foot pain and deformity.

 Little has been published in the radiographic literature about

 the pre- and postoperative radiographic findings of this very

common and very treatable cause of foot pain.