A girl with<unk>  of her right leg due to polio The following factors may be involved in causing this deformity: * Inherent laxity of the knee ligaments * Weakness of biceps femoris muscle * Instability of the knee joint due to ligaments and joint capsule injuries * Inappropriate alignment of the tibia and femur * Malunion of the bones around the knee * Weakness in the hip extensor muscles * Gastrocnemius muscle weakness (in standing position) * Upper motor neuron lesion (for example, hemiplegia as the result of a cerebrovascular accident) * Lower motor neuron lesion (for example, in post-polio syndrome) * Deficit in joint proprioception * Lower limb length discrepancy * Congenital<unk>  * Cerebral palsy * Muscular dystrophy * Limited dorsiflexion (plantar flexion contracture) * Popliteus muscle weakness * Connective tissue disorders. In these disorders, there are excessive joint mobility (joint hypermobility) problems. These disorders include: * Marfan syndrome * Loeys–Dietz syndrome * Ehlers–Danlos syndrome * Benign hypermobile joint syndrome * Osteogenesis imperfecta disease Mild<unk>  caused by familial joint hypermobility
Genu recurvatum
Dens evaginatus
Trichostasis spinulosa
Condylomata lata
Genital wart
Dens invaginatus
Supernumerary nipple
Mania errabunda