Joint between humerus and radio-ulna is
(a) Saddle joint
(b) Hinge joint
(c) Fibrous joint
(d) Ball and socket

Options

A. Saddle joint
B. Hinge joint
C. Fibrous joint
D. Ball and socket

Answer

To determine the type of joint between the humerus and the radio-ulna, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Bones Involved**: The question asks about the joint between the humerus and the radio-ulna. The humerus is the upper arm bone, while the radio-ulna refers to the radius and ulna, which are the two bones of the forearm.

2. **Understand the Joint Location**: The joint between these bones is located at the elbow. The humerus articulates with the proximal ends of the radius and ulna.

3. **Classify the Joint Type**:
- The elbow joint primarily functions as a hinge joint, which allows for flexion and extension of the arm.
- Additionally, there is a pivot joint formed by the radius and ulna, which allows for rotational movement.

4. **Conclusion**: Since the question specifically asks about the joint between the humerus and the radio-ulna, the primary joint type is a hinge joint.

5. **Select the Correct Option**: Based on the classification, the correct answer is (b) Hinge joint.

### Final Answer:
(b) Hinge joint

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