Final answer:
Synovial joints contain articular cartilage, synovial fluid, and a joint capsule with sensory nerve endings to detect damage and joint angle. Ligaments, tendons, and muscles provide indirect support and stabilize the joint.
Step-by-step explanation:
The structures in a synovial joint that detect damage and help determine joint angle include the articular cartilage, joint cavity with synovial fluid, and the sensory nerve endings within the capsule and surrounding tissues. Synovial fluid within the joint cavity provides nutrients and lubrication for the joint, reducing friction and wear on the articular cartilage, the smooth, white tissue at the ends of bones where they come together to form joints.
While the joint capsule contains the synovial fluid and encloses the joint structure, the sensory nerve endings within it have proprioceptive functions, detecting stretch or tension in the joint that can signal damage or convey the angle of the joint. Additional structures like ligaments, tendons, and muscles also provide indirect support by controlling movement and stabilizing the joint during activities.