Joint Movements and Terminology

Terms to Distinguish Joint Movements

Understanding joint movements requires familiarity with anatomical regions of the limbs. The upper and lower limbs are subdivided for precise description of movement.

• Upper limb:

  • Arm – region between shoulder and elbow

  • Forearm – region between elbow and wrist

• Lower limb:

  • Thigh – region between hip and knee

  • Leg – region between knee and ankle

Additional info: These terms are essential for describing the location and type of movement occurring at specific joints.

Articulations

Definition and Importance

Articulation refers to the location where two or more bones meet, forming a joint. Each joint allows for specific types of movement and is classified based on its structure and function.

• Key Point: Students should know the bones that articulate at each joint (e.g., humerus and ulna at the elbow).

• Example: The shoulder joint is formed by the articulation of the scapula and humerus.

Types of Joints

Classification of Joints

Joints are classified based on the material joining the bones and the presence or absence of a cavity. The three main types are:

1. Fibrous joints

   • Bones are joined by dense connective tissue.

   • Examples: Sutures in the skull.

   • Movement: Typically immovable (synarthroses).

2. Cartilaginous joints

   • Bones are joined by cartilage.

   • Examples: Pubic symphysis, intervertebral discs.

   • Movement: Slightly movable (amphiarthroses).

3. Synovial joints

   • Bones are separated by a fluid-filled joint cavity.

   • Types:

     • Hinge joints – e.g., elbow & knee; allow movement in one plane (flexion/extension).

     • Ball-and-socket joints – e.g., shoulder & hip; allow movement in multiple planes and axes.

   • Movement: Freely movable (diarthroses).

Additional info: Synovial joints are the most common and versatile joints in the human body.

Joint Movements

Types of Movements at Joints

Joints permit various types of movement, which are described using specific anatomical terms:

• Abduction/Adduction: Movement away from (abduction) or toward (adduction) the midline of the body.

• Flexion/Extension: Decreasing (flexion) or increasing (extension) the angle between two bones.

• Supination/Pronation: Rotational movement of the forearm; supination turns the palm upward, pronation turns it downward.

• Dorsiflexion/Plantar Flexion: Movement at the ankle; dorsiflexion lifts the foot upward, plantar flexion points the toes downward.

• Rotation/Circumduction: Rotation is movement around an axis; circumduction is a circular movement combining flexion, extension, abduction, and adduction.

Example: The shoulder joint allows circumduction, while the elbow joint allows flexion and extension.

Summary Table: Joint Types and Examples

Additional info: This table summarizes the main joint types, their structural features, examples, and movements allowed.