The rib cage consists of 12 pairs of ribs, sternum, and thoracic vertebrae. True ribs connect directly to sternum, false ribs indirectly via cartilage. Floating ribs (11th and 12th) are not attached to sternum. Each rib has head, neck, and shaft with articular facets
Ribs form the axial skeleton and protect vital organs in the thorax. Humans have 24 ribs in 12 pairs, with 1 in 500 having cervical ribs. Ribs connect to vertebrae at costovertebral joints and sternum via costal cartilage. Ribs consist of head, neck, body, tubercle, and angle
Mammals evolved from cynodonts during Late Triassic to Early Jurassic. First mammals appeared 225-0 million years ago. Modern diversity reached after dinosaur extinction 66 million years ago. Placentals diverged from other groups in Late Cretaceous
Fish anatomy studies form, physiology studies function in living fish. Body divided into head, trunk, and tail, often fusiform or compressed. Skeleton made of cartilage (cartilaginous) or bone (bony). Vertebral column consists of lightweight vertebrae with ribs
Approximately 1,500 species of elongated arachnids with venomous stinger and pincers. Average size is about 6 cm, with largest reaching 21 cm in South Africa. Most desert species are yellowish or light brown, others brown or black
Spine consists of 24 vertebrae from skull to sacrum. Each vertebra has cylindrical body and bony ring. Spinal canal contains spinal cord, nerves exit through neuralforamina