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B3.3.6 (HL)—Synovial joint movement

Synovial joints allow controlled movement using cartilage, synovial fluid, ligaments, tendons, joint capsules and muscles arranged around articulating bones safely.

Syllabus
First assessment 2025
Objective
B3.3.6
Level
HL

Exam analysis

Chance of appearing7%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1
Typical marks1

Common command terms

  • State
  • Identify
  • Compare
  • Label
  • Distinguish

Scoring notes

Common mistake
Mixing up ligaments, which connect bone to bone, with tendons, which connect muscle to bone.

Recent exam appearances

May 2025Paper1A ["HL"] · TZ323[ 1 ]B3.3.6 (HL)—Synovial joint movement
November 2024Paper1 ["HL"] · TZ037[ 1 ]B3.3.6 (HL)—Synovial joint movement
May 2019Paper1 ["HL"] · TZ138[ 1 ]B3.3.6 (HL)—Synovial joint movement
May 2015Paper1 ["HL"] · TZ138[ 1 ]B3.3.6 (HL)—Synovial joint movement
May 2014Paper1 ["HL"] · TZ136[ 1 ]B3.3.6 (HL)—Synovial joint movement

Coverage 2012–2025 · Updated 15 Jul 2026

Joint Shape Sets the Available Range of Motion

HL only

A synovial joint combines smooth cartilage, lubricating synovial fluid, stabilizing ligaments and force-transmitting tendons. Articulating surface shape constrains its directions of movement.

ball-and-socket hip/shoulder → movement in three planes, including circumduction
hinge knee/elbow → mainly flexion and extension
goniometer → angular change between starting and safe maximum positions

Summary: From Molecular Pull to Locomotion

HL only

motor signal → ACh → muscle action potential → SR Ca²⁺ → exposed actin sites → cross-bridge cycling → sarcomere shortening → tendon tension → joint rotation

ATP detaches and re-cocks myosin; Ca²⁺ reuptake stops new bridges; titin restores passive sarcomere length, while antagonistic muscle action reverses joint movement. Whole-body form then determines whether force becomes efficient locomotion.

Synovial joint movement

HL only

[ 2 ]

State the function of structures I and II.

I:

II:

Concept essentials

  • Synovial fluid lubricates joints and reduces friction.
  • Cartilage cushions bone ends and allows smooth movement.
  • Ligaments connect bones to bones and stabilise joints.
  • Tendons transmit muscle contraction force to bones.
  • Joint capsules help seal the joint and retain synovial fluid.