Thumb CMC Joint Mobilizations [with Convex-Concave Rules]

The video tutorial explains the biomechanics of the thumb's carpometacarpal (CMC) joint, focusing on its movement in different planes. It covers how the joint's saddle shape affects mobilization during flexion and abduction. For flexion, the first metacarpal is concave, moving on a convex trapezium, resulting in a palmar mobilization. In abduction, the roles reverse, with the first metacarpal being convex, requiring a medial mobilization. The tutorial emphasizes understanding the joint's anatomy to determine the correct mobilization direction.

What type of joint is the thumb's carpometacarpal joint?

• Hinge joint

• Saddle joint

• Ball and socket joint

• Pivot joint

In the sagittal plane, what is the surface type of the first metacarpal during flexion?

• Flat

• Concave

• Irregular

• Convex

When mobilizing for flexion at the thumb's carpometacarpal joint, in which direction should the first metacarpal be moved?

• Lateral

• Dorsal

• Medial

• Palmar

What happens to the concave and convex surfaces when moving in a different plane?

• They become flat

• They remain the same

• They reverse

• They become irregular

During abduction at the thumb's carpometacarpal joint, what is the direction of the roll?

• Lateral

• Medial

• Dorsal

• Palmar

For abduction mobilization, in which direction should the first metacarpal be moved?

• Dorsal

• Lateral

• Medial

• Palmar

What is the relationship between roll and slide in a convex on concave movement?

• Same direction

• Opposite direction

• No relationship

• Random direction