Question

A pivot joint can be found between
A. Clavicle and sternum
B. Radius and ulna
C. Scapula and humerus
D. Tibia and fibula

Answer 1

Hint: The junction where two ends of bones meet is a pivot joint which is a synovial joint; one being the central bony cylinder, the other being a ring structure which is made up of bones and ligament. The pivot joint can be found in the bones associated with the forearm.

Complete answer: The ulna and the radius are long and slightly curved bones which lie parallel to the elbow, where they articulate with the wrist, humerus and with the carpals. Near to the thumb, the radius is located laterally and the ulna is medially located near to the little finger. The ulna and the radius have a styloid process at the end; for many muscles, they are the attachment site. Therefore, a pivot joint can be found between the radius and ulna. A pivot joint is also called a rotary joint, or trochoid joint. It is a free movable joint that rotates movement on a single axis.
a) Clavicle and sternum: The sternoclavicular articulation or the sternoclavicular joint is the joint which is between the manubrium of the sternum and clavicle bone. This is classed structurally as the synovial saddle joint and it is functionally classed as the diarthrosis and multiaxial joint.
 b) Scapula and humerus: The shoulder joint is a ball and a socket joint which is between the scapula and the humerus this is the major joint connection between the upper limbs to the trunk. This is one of the mobile joints of the human body, at the cost of joint stability.
c) Tibia and fibula: The two long bones which are situated in the lower leg are the tibia and the fibula. On the inner side, the larger bone is located which is the tibia and on the other hand, the fibula is the smaller bone that is located outside. The tibia is thicker than the fibula. It is the weight-bearing bone out of the two bones.
Hence the correct answer is option B.

Note: The moving bone rotates within a ring that is formed from a second bone and adjoining ligaments. The pivot joint is exemplified by the joint between the atlas and the axis directly under the skull which allows for turning off the head from side to side.