Chapter 9, Problem 9BYGO

Summary Introduction

Introduction:

Synovial joints are movable joints and is the most commonly found joints in the human body. It is also called as diarthrosis. The synovial joint constitutes a synovial cavity filled with synovial fluid. The articulating bone surfaces have an articular cartilage that allows smooth mobility of the bones.

Synovial joints have various axis of rotation. The axis of rotation is an imaginary line that projects through the pivot in a joint. Movements around an axis of rotation can occur in either sagittal, frontal, or transverse plane of motion.

The rotation of joints is classified into: (i) Uniaxial joints which rotates in one axis and one plane. It allows forward-backward movement in the sagittal plane; (ii) Biaxial joints can rotate in two axes and in two planes. It allows side-to-side movement in the frontal plane and forward-backward movement in the sagittal plane; (iii) Multiaxial joints rotate in three axes and three planes. It allows forward-backward movement in the sagittal plane, side-to-side movement in the frontal plane and internal-external rotation in the transverse plane.