Skeletal System

Pivot joint

Step 1: The neck connects the skull to the backbone (vertebral column). Step 2: The joint at the top of the vertebral column, where it meets the skull, is a pivot joint. Step 3: In a pivot joint, a rod-shaped end of one bone fits into a ring or hole of another bone, allowing rotation. Step 4: This enables the head to move up, down, and sideways — including left and right. Step 5: A hinge joint only moves forward and backward (like the elbow). A ball and socket allows all directions (like the shoulder). A gliding joint allows bones to slide (like the wrist). None of these are in the neck.

Radius and Ulna

Step 1: The forelimb (arm) is divided into the upper arm and the lower arm (forearm), joined at the elbow. Step 2: The upper arm has ONE long bone called the humerus. Step 3: The lower arm (forearm) has TWO bones — the radius and the ulna. Step 4: Tibia and fibula are the two bones in the lower leg — they are in the hindlimb, not the forelimb. Step 5: Femur is the thigh bone (upper leg). So the only correct answer for the lower arm is radius and ulna.

It covers the ends of bones and cushions the joint to prevent direct bone-to-bone contact

Step 1: At a joint, two or more bones meet. If bones touched each other directly, they would rub and cause pain and damage. Step 2: To prevent this, the ends of bones at a joint are covered with a layer of cartilage. Step 3: Cartilage is elastic (flexible) and acts as a cushion, absorbing shock and reducing friction. Step 4: Ligaments (not cartilage) join two bones together. Tendons (not cartilage) connect muscles to bones. Bone marrow (not cartilage) produces blood cells. Step 5: That is why cartilage's role is specifically to cushion and protect the joint surfaces.

Ligaments connect bone to bone; tendons connect muscle to bone

Step 1: The skeletal system has two important types of connective tissues — ligaments and tendons. Step 2: Ligaments are stretchy straps of tissue that join one bone to another bone at a joint. They hold the joint together and prevent dislocation. Step 3: Tendons are strong fibres that join muscles to bones, allowing muscles to pull on bones and create movement. Step 4: A common mistake is to confuse these two — remember: Ligaments = bone to bone; Tendons = muscle to bone. Step 5: Neither ligaments nor tendons produce blood cells or help bones grow — those are functions of bone marrow and grow