Class 11 NEET Biology Locomotion and Movement

(a) : The bones of skulls are joined by white fibrous tissue which sustain no movement between the skull bones. This kind of joint is classified as fibrous or immovable joints. Thus, parietal and temporal bone of the skull are joined by fibrous joints. First cervical vertebra, atlas, joins the second cervical vertebra axis to form a joint (pivot joint) which allows movement in one plane. The atlas supports the head and allows movement of head over neck.
The last two pairs of ribs are called floating ribs because their anterior ends are not attached to either the sternum or the cartilage of anterior rib. Glenoid cavity is a depression to which humerus articulates.