Study the diagram below and use it to answer questions 4(a) to 4(d).

(a)      Name the parts labelled 1 to 1V.                                          [3 marks]
(b)      Identify the type of joint illustrated above                         [1 mark]
(c)     State the functions of the parts labelled 111 and V1      [2 marks]
(d)     Explain briefly the mechanism that brings about movement at the joint illustrated above.                                                                         [4 marks]

OBSERVATION

This question was attempted by many candidates and the performance was poor. Many candidates did not adequately understand the diagram. Some thought the diagram was on the lower limb (girdle) and few candidates labelled it correctly.
Question 4(b) required identification of the type of joint illustrated but candidates wrongly identified it as ball and socket joint.
In question 4(c) candidates were required to name the function of cartilage and tendon and many of them were unable to. Those who mistook tendon for cartilage also mixed up their functions.
In question 4(d) some candidates correctly explained the mechanism of lifting and lowering the forearm, actions of the Biceps and Triceps muscles to effect movement up and down.
The expected answers were as follows:
(a) 1 - Biceps muscle
11 - Humerus/shaft of humerus
111 - Cartilage/articular cartilage
1V - Radius
V - Ulna
V1 - Tendon/triceps
(b) Hinge joint
(c) Functions of parts
111 - Cartilage - Protects the articular ends of the bone from friction/wearing/cushions
V1 - Tendon - Attaches the muscles/triceps to the bone.
(d) - Biceps contract
- Triceps relax
- The simultaneous contraction and relaxation of both triceps and biceps cause the arm to bend or extend (straightening);
- There is an antagonistic movement of both the triceps and biceps at the joint.