Anatomy & Physiology Musculoskeletal #33

Question

Which diarthrotic joint allows the greatest freedom of motion?

Answers

  1. Biaxial joint
    • Rationale:

      A biaxial joint is one where there are two principal axes of movement situated at right angles to each other. This type of diarthrotic joint does not allow the greatest freedom of motion.

  2. Uniaxial joint
    • Rationale:

      A uniaxial joint only allows for a motion in a single plane (i.e., around a single axis). This type of diarthrotic joint does not allow the greatest freedom of motion.

  3. Ellipsoidal joint
    • Rationale:

      An ellipsoidal joint permits movement in two planes thus allowing abduction, adduction, circumduction, flexion and extension. While this type of diarthrotic joint allows for many movements, it does not allow for the greatest freedom of motion.

  4. Multiaxial joint
    • Rationale:

      A multiaxial joint is one where the round end of one bone fits into the cavity of another bone. This joint is often referred to as a ball-in-socket joint and allows the greatest freedom of motion within the human body.

Overview

Diarthrotic joints are those in which the contiguous bony surfaces are covered by articular cartilage and are joined by ligaments lined with synovial membrane; they’re freely movable.

Explanation

Learning Outcomes

Diarthrotic joints are joined by ligaments lined with synovial fluid. They are classified as freely moveable. While all of these joints are classified as diarthrotic, the joint that allows the greatest freedom of motion is the multiaxial joint.

Test Taking Tip

Use your knowledge of medical terminology to assist in choosing the correct choice for this question.

Video Rationale