Joints and Movement

Anatomy Lab Exam 1

Hinge joint

• Uniaxial movement in one plane

  • Ex. elbow

Pivot joint

• Uniaxial rotation in one plane

  • Ex. atlantoaxial joint (turn the head “no”)

Condyloid joint

• Biaxial movement (two planes)

  • Ex. fingers

Ball and socket joint

• Multiaxial movement (all planes)

  • Ex. hip

Plane joint

• Gliding movement

  • Ex. intercarpal (wrist)

Saddle joint

• Biaxial (two planes of movement)

  • Ex. thumb

Ligaments

• Dense regular or irregular connective tissue

• Connects bone to bone

• Bands of connective tissue associated with other organs

Tendons

• Dense regular connective tissue

• Connects muscle to bone

Muscles

• Skeletal muscle tissue

• Tissues that contract to create movement across a joint

Muscles and joint movements

• Muscles must cross over a joint in order to cause movement of that joint

• Where a muscle crosses a joint with tell you the direction it pulls on a body segment

Flexion

Decreases the angle between two body parts. Usually moves a body segment away from the body line anteriorly

Extension

Increases the angle between two body parts. Usually moves a body segment posteriorly

Abduction

Moves a body part laterally away from the midline

Adduction

Moves a body part medially toward the midline

Rotation

Around the long axis of the body segment being moved. Movement at proximal joints, most noticeable distally

Medial (internal) rotation

Moves the anterior surface of the body segment towards the midline

Lateral (external) rotation

Moves the anterior surface away from the midline

Circumduction

Movement of a body region in a circular manner (drawing a circle, compound motion)

Supination

Radius parallel to the ulna. Standard anatomical position

Pronation

Radius crosses over the ulna.

Inversion

Turning the bottom of the foot towards the midline

Eversion

Turning the bottom of the foot outwards, away from the midline

Dorsiflexion

Lifts the front of the foot so that the top of the foot moves towards the front of the leg

Plantar flexion

Action at the ankle that points the toes downward

Sesamoid bones

• Names for their shape somewhat resembling a sesame seed

• Bones that develop inside a tendon and increase leverage (sometimes stability) across a joint

• Found in the knee, thumb, wrist, and big toe

Medial and lateral meniscus

Fibrocartilage discs that stabilize the joint and increase conformity between round distal femur and flat proximal tibia

Medial collateral ligament (MCL)

Medial femur to tibia: prevents abduction

Lateral collateral ligament (LCL)

Lateral femur to fibula: prevents adduction

Anterior cruciate ligament (ACL)

Femur to anterior tibia: precents anterior sliding

Posterior cruciate ligament (PCL)

Femur to posterior tibia: precents posterior sliding