Question

Glenoid cavity is found in
A) Pelvic girdle
B) Skull
C) Pectoral girdle
D) Sternum

Answer 1

The glenoid cavity is a slight depression in a bone into which another bone can fit into to form a joint. They help in preventing muscle dislocation and also allow mobility of all joints.

Complete answer:
Let us look at each option one by one.

Option A: The pelvic girdle refers to the bones of the hip-ilium, ischium and pubis- which are fused together in the form of a ring and helps to connect the bones of the lower spine to the bones of the lower limbs i.e., the legs. Since legs are connected to the girdle by means of a deeper cavity, this is possible only by means of the ball and socket joint; there is no scope for the presence of the glenoid cavity here. Therefore this is an incorrect option.
Option B: The skull is the bony structure that forms the head and gives shape to the face of vertebrates. The skull is also responsible for the protection of the brain and other cranial structures it encloses from external shock. It is composed of two bones, the cranium and the mandible. The structure of the skull does not allow for the presence of glenoid cavities; thus, this is an incorrect option.
Option C: The pectoral girdle or the shoulder girdle is a set of two bony structures on either side of the neck composed of two bones each; the clavicle and the scapula. At the outermost end of the scapula, humerus is attached with the help of a very shallow cavity, allowing 120° free movement. This joint between the scapula and humerus satisfies the definition of the glenoid cavity perfectly. Therefore, this is the correct option.
Option D: Sternum is also known as the breastbone and is a flat bone which lies in the centre of the chest and acts as a connector for the bones of the rib-cage. There is no scope of presence of the glenoid cavity on the sternum; thus, this is an incorrect option.

Thus, the correct option is (C) Pectoral girdle.

Note: : In the options mentioned above, the girdles help in connecting the limbs to the torso whereas the skull and the sternum act as a protective cage for the brain and the heart and lungs respectively, which are very essential organs in an organism for survival.