Q.Write an example of hinge joint.
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Synovial Joints Types
Synovial Joints: The Freedom of Movement
Think about your shoulder. You can swing your arm in a circle, raise it above your head, reach behind your back. Now think about your elbow. It only bends one way — forward and back. Both are joints, but they move very differently. Why?
The answer lies in the shape of the bones that meet and the type of connection they form. All freely movable joints (called synovial joints) share a common structure — a fluid-filled cavity, cartilage, and a capsule — but the geometry of the meeting surfaces determines what movements are possible.
The Big Idea
A synovial joint is like a mechanical coupling. The shape of the two bone ends dictates the kind of motion allowed. Engineers use the same principle: a door hinge lets the door swing in one plane; a ball joint on a car's suspension lets the wheel move in many directions. Your body uses five main designs.
The Five Types, From Most to Least Mobile
Ball-and-Socket Joint — A spherical head fits into a cup-like socket.
Hinge Joint — A convex surface fits into a concave surface, like a door hinge.
Pivot Joint — A rounded or pointed bone rotates within a ring formed by another bone and a ligament.
Gliding Joint — Flat or slightly curved surfaces slide over each other.
Saddle Joint — Each bone surface is concave in one direction and convex in the perpendicular direction, like a rider on a saddle.
1. Ball-and-Socket Joint
Intuition: Imagine a ball sitting in a bowl. You can roll the ball in any direction — forward, backward, sideways, and in circles. That's your shoulder and hip.
Precise statement: The rounded head of one bone (the ball) fits into the hollow depression of another bone (the socket). This allows movement in three planes: flexion-extension, abduction-adduction, and rotation. It is the most mobile type of synovial joint.
Examples: Shoulder joint (glenohumeral joint), hip joint.
The hip is also a ball-and-socket joint, but its socket is much deeper than the shoulder's. That's why the hip is more stable but less mobile than the shoulder.
2. Hinge Joint
Intuition: A door hinge. The door only swings open and shut — it cannot slide sideways or rotate. Your elbow and knee work the same way.
Precise statement: A convex cylindrical surface of one bone fits into a concave surface of another. Movement is restricted to one plane — only flexion and extension (bending and straightening).
Examples: Elbow joint (humeroulnar joint), knee joint (tibiofemoral joint), ankle joint (talocrural joint).
The knee is not a pure hinge — it allows a small amount of rotation when bent — but for exam purposes, it is classified as a hinge joint.
3. Pivot Joint
Intuition: Shake your head "no." The movement comes from the top of your neck, where the atlas (first vertebra) rotates around the dens of the axis (second vertebra). It's like a wheel spinning on an axle.
Precise statement: A rounded or pointed bone rotates within a ring formed partly by another bone and partly by a ligament. Movement is rotation only — turning around a single axis.
Examples: Atlantoaxial joint (between C1 and C2 vertebrae), proximal radioulnar joint (where the radius rotates against the ulna to turn your palm up and down).
4. Gliding Joint
Intuition: Place two flat, smooth stones on top of each other. You can slide them forward, backward, and sideways, but you cannot tilt or rotate them much. That's how the small bones of your wrist and ankle move.
Precise statement: Articular surfaces are flat or only slightly curved. Bones slide over each other in multiple directions, but there is no significant rotation or angular movement. The range of motion is limited.
Examples: Intercarpal joints (between wrist bones), intertarsal joints (between ankle bones), joints between the articular processes of vertebrae.
Gliding joints are often grouped together — many small gliding joints working together give the wrist and ankle their flexibility.
5. Saddle Joint
Intuition: Think of a rider sitting on a horse saddle. The saddle is concave from front to back but convex from side to side. The rider's body fits into that shape. Your thumb's base joint works exactly like this — it allows your thumb to move in two perpendicular directions, giving you the ability to grasp. …
A hinge joint is defined by allowing movement in only one plane, much like a door hinge, and among the joints of the human body, a specific one between the upper and lower arm bones fits that descrip …
A hinge joint allows movement in only one plane, like the hinge of a door.
Joints are classified by the type/range of movement they permit. A hinge joint is a uniaxial synovial joint that permits movement (flexion-extension) in only one plane, similar to how a door hinge works. The elbow joint (between the humerus and the ulna/radius) and th …
- CBSE 2026Set ANNUAL1 markMCQQ.Which type of joint allows for the widest range of movement?(a) Ball and socket joint(b) Gliding joint(c) Fibrous joint(d) Hinge joint
›Reveal solutionSolution
Ball-and-socket joints permit the greatest freedom of movement of any joint type.
Joints are classified by the type and range of movement they allow. A ball-and-socket joint, where a rounded (ball-like) end of one bone fits into a cup-shaped (socket) depression of another (e.g. the humerus head in the glenoid cavity at the shoulder, or the femur head in the acetabulum at the hip), permits movement in almost every direction — flexion, extension, abduction, adduction, and rotation — making it multiaxial and giving it the widest range of movement of all joint types.
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- CBSE 2026Set ANNUAL1 markMCQQ.Which of the following is not a hinge joint ?(a) Elbow joint(b) Knee joint(c) Shoulder joint(d) Ankle joint
›Reveal solutionSolution
The shoulder joint is not a hinge joint (it is a ball-and-socket joint), so the answer is (C).
A hinge joint allows movement in only one plane (like a door hinge), permitting bending and straightening. The elbow, knee and ankle are hinge joints.
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- CBSE 2025Set ANNUAL1 markMCQQ.What type of movable joint is present between Atlas and Axis vertebra ?(a) Pivot(b) Saddle(c) Hinge(d) Gliding
›Reveal solutionSolution
Atlas and Axis form a pivot joint, allowing rotational (side-to-side, "no") movement of the head.
Joints are classified by the type of movement they permit:
- Pivot joint: one bone rotates around a peg/process of another — allows only rotatory movement. Example: Atlas–Axis joint, where the ring-shaped atlas rotates around the peg-like odontoid process of the axis, letting us turn the head sideways ("no" movement).
- Hinge joint: movement in one plane only, like a door hinge — e.g. elbow, knee. …
- CBSE 2020Set ANNUAL1 markQ.Write an example of hinge joint.
›Reveal solutionSolution
A hinge joint allows movement in only one plane, like the hinge of a door.
Joints are classified by the type/range of movement they permit. A hinge joint is a uniaxial synovial joint that permits movement (flexion-extension) in only one plane, similar to how a door hinge works. The elbow joint (between the humerus and the ulna/radius) and th …
- CBSE 2020Set ANNUAL1 markMCQQ.Elbow joint is as example of :(a) Pivot Joint(b) Hinge joint(c) Gliding joint(d) Ball and socket joint
›Reveal solutionSolution
The elbow is a classic example of a hinge joint, allowing back-and-forth (flexion-extension) movement in a single plane, much like a door hinge.
Hinge joints permit movement along only one axis/plane (flexion and extension), unlike ball-and-socket joints (multi-axial, e.g. shoulder/hip) or pivot joints (rotational, e.g. atlas-axis). The elbow, formed between the humerus and the radius/ulna, is the textbook example of a hinge joint, along with the knee joint.
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