Disproportionate dwarfism is characterized by shortened limbs or a shortened torso. The sirens are aquatic salamanders with stumpy forelimbs and no hind limbs. Abnormalities in the limbs and extremities may occur in Noonan syndrome. Arthropods are invertebrates with segmented bodies and jointed limbs. Disproportionate dwarfism is characterized by either short limbs or a short torso. Later it descends down and supplies branches to abdomen, pelvis, perineum and the lower limbs. Most rodents are small animals with robust bodies, short limbs, and long tails. He is unable to regenerate missing limbs or organs. Biomechanics also aids in creating prosthetic limbs and artificial organs for humans. Pectoral and pelvic fins have articulations resembling those of tetrapod limbs. Sloths have long limbs and rounded heads with tiny ears. Somites are required for the development of things such as muscles within limbs. The proprioception of the lower limbs differs from the upper limbs and upper trunk. The medial pathway helps control gross movements of the proximal limbs and trunk. Human gait refers to locomotion achieved through the movement of human limbs.