Immovable or fixed or fibrous joints are found between the skull bones. No movement occurs at these joints. So, parietal bone and the temporal bone of the skull are joined by fibrous joint. Invertebrates, the first vertebra is called atlas, while the second vertebra is axis. In humans, first seven pairs of ribs are called true rubs; 8th ,9th and 10th pairs of ribs are false ribs while 11th and 12th pairs of ribs are called floating ribs. Glenoid cavity is a socket-shaped cavity in the scapula (shoulder bone) that holds the head of the humerus in a ball and socket joint.