Features of the body bones in crocodiles (Caiman crocodylus)

The study was conducted to obtain information about the features of the crocodile (Caiman crocodylus) trunk bones. Using morphometric and statistical methods, the structural features of the axial skeleton of a 10-year-old female crocodile were studied. As a result of the conducted research, we noted that crocodiles have the front and back limbs located on the sides of the body and the elbow and tarsal joints are positioned at an angle that is open cranially. This tetroid arrangement of limbs is the most adaptive form, taking into account that movement on the ground is carried out by supporting on the ground and is the main form of motor activity. The spinal column of the caiman is straight, slightly curved upwards, has no cervical or thoracolumbar curves and consists of 58 vertebrae. There are 7 cervical vertebrae, which occupy 5% of the entire length of the body. The thoracic region has ten vertebrae, occupying 17.5% of the entire length of the body. This type of chest structure contributes to the emergence of a more advanced breathing mechanism in connection with the exit to land and first appears in reptiles with subsequent ventilation of the lungs with the participation of the chest muscles. The lumbar vertebrae, 6 in number, make up 10.73% of the total body length. The caiman has 33 tail vertebrae, which are a continuation of the axial skeleton, occupying 62.06% of the total body length, but at the same time the length of the tail in relation to the length of the entire axial section is 52.7%. The tail is 2.6 times longer than the entire body length of the vertebrate. Due to the presence of long spinous and transverse processes on all tail vertebrae, which have oval heads and concave pits on the bodies of the vertebrae, the tail allows active lateral movements during terrestrial movement and aquatic locomotion.