Identify the incorrect. Pair of skeletal parts category

Options

A. Sternum and ribs-Axial skeleton
B. Clavicle and Pelvic girdle- glenoid cavity
C. Humerus and ulna -appendicular skeleton
D. Malleus and stapes- Ear ossicles

Answer

To solve the question of identifying the incorrect pair of skeletal parts category, we will analyze each option provided.

### Step-by-Step Solution:

1. **Option 1: Sternum and Ribs - Axial Skeleton**
- The sternum (breastbone) and ribs are indeed part of the axial skeleton, which includes the skull, vertebral column, and rib cage.
- **Conclusion:** This pair is correctly matched.

2. **Option 2: Clavicle and Pelvic Girdle - Glenoid Cavity**
- The clavicle (collarbone) is part of the pectoral girdle, not the pelvic girdle. The glenoid cavity is the socket in the scapula that receives the head of the humerus, forming the shoulder joint.
- **Conclusion:** This pair is incorrectly matched.

3. **Option 3: Humerus and Ulna - Appendicular Skeleton**
- The humerus (upper arm bone) and ulna (one of the forearm bones) are part of the appendicular skeleton, which includes the limbs and their attachments.
- **Conclusion:** This pair is correctly matched.

4. **Option 4: Malleus and Stapes - Ear Ossicles**
- The malleus (hammer) and stapes (stirrup) are indeed part of the ear ossicles, which are small bones in the middle ear.
- **Conclusion:** This pair is correctly matched.

### Final Answer:
The incorrect pair of skeletal parts category is **Option 2: Clavicle and Pelvic Girdle - Glenoid Cavity**.