Anatomy of Synovial Joints

A uniaxial joint allows movement in one plane, while a biaxial joint allows movement in two planes.

Convex and concave regions that resemble the shape of a saddle.

A pivot joint, which permits the radius to rotate.

<p>Anteriorly and posteriorly.</p> Signup and view all the answers

<p>The carpometacarpal joint of the thumb.</p> Signup and view all the answers

<p>A plane joint, which allows limited side-to-side movements in a single plane.</p> Signup and view all the answers

<p>A ball-and-socket joint.</p> Signup and view all the answers

<p>The elbow joint.</p> Signup and view all the answers

<p>The atlantoaxial joint.</p> Signup and view all the answers

<p>A condylar joint is biaxial, while a hinge joint is uniaxial.</p> Signup and view all the answers

<p>Synovial joints are distinguished from other joint types by the presence of a joint cavity, a space between the articulating bones filled with synovial fluid. This cavity is absent in other joint types.</p> Signup and view all the answers

<p>Synovial fluid is a viscous fluid composed primarily of hyaluronic acid and lubricin. It acts as a lubricant, reducing friction between articulating surfaces, and provides nutrients to the articular cartilage. Its presence is crucial for smooth joint movement and reduces wear and tear on joint surfaces.</p> Signup and view all the answers

<p>The articular capsule, a double-layered structure, surrounds the joint cavity. The outer fibrous layer provides strength and prevents bone separation, while the inner synovial membrane secretes synovial fluid. Together, they contribute to joint stability and allow for controlled movement.</p> Signup and view all the answers

<p>Articular cartilage covers the articulating surfaces of bones in a synovial joint. Its smooth, resilient structure reduces friction during movement, absorbs shock, and provides a cushioning effect. This structure is vital for protecting the underlying bone and facilitating smooth joint articulation.</p> Signup and view all the answers

<p>Synovial joints are functionally classified as diarthroses, meaning they are freely movable joints. This classification is directly related to their structural features, particularly the presence of a joint cavity, synovial fluid, and articular cartilage, which collectively allow for a wide range of motion.</p> Signup and view all the answers

<p>Ligaments are strong, fibrous connective tissues that connect bones to each other in a synovial joint. They provide stability by limiting excessive movement and preventing dislocation. For example, the anterior cruciate ligament (ACL) in the knee joint prevents the tibia from sliding forward relative to the femur.</p> Signup and view all the answers

<p>Blood vessels supply nutrients and oxygen to the tissues within a synovial joint, including the articular cartilage, synovial membrane, and ligaments. Nerves provide sensory information about joint position, movement, and pain. These structures are vital for maintaining joint health and ensuring proper function and sensation.</p> Signup and view all the answers

<p>The fibrous layer, composed of dense connective tissue, provides strength and stability to the joint, preventing excessive movement and bone separation. The synovial membrane, a specialized connective tissue, lines the inner surface of the capsule and secretes synovial fluid, which lubricates and nourishes the joint.</p> Signup and view all the answers

<p>Tendons pass across or around a joint, providing mechanical support. They can also limit the range of motion at a joint.</p> Signup and view all the answers

<p>Bursae reduce friction between bones, ligaments, muscles, skin, or tendons that rub together during movement.</p> Signup and view all the answers

<p>A tendon sheath is an elongated bursa that wraps around a tendon to reduce friction in areas of high stress, such as the wrist and ankle.</p> Signup and view all the answers

<p>Fat pads act as packing material and provide cushioning and protection for the joint.</p> Signup and view all the answers

<p>Stretching a synovial joint causes a decrease in pressure, leading to the formation of bubbles (cavitation) from dissolved gases in the synovial fluid. These bubbles burst, producing the cracking sound.</p> Signup and view all the answers

<p>Synovial fluid lubricates the joint, nourishes the articular cartilage, and absorbs shock.</p> Signup and view all the answers

<p>Uniaxial joints allow movement in one plane or axis, biaxial joints in two planes, and multiaxial joints in multiple planes.</p> Signup and view all the answers

<p>Plane, hinge, pivot, condylar, saddle, and ball-and-socket joints.</p> Signup and view all the answers

<p>A hinge joint, like the elbow, allows for uniaxial movement in a single plane (flexion and extension). A ball-and-socket joint, like the shoulder, allows for multiaxial movement in multiple planes (flexion/extension, abduction/adduction, and rotation).</p> Signup and view all the answers

<p>A saddle joint, like the thumb joint, has articulating surfaces that resemble a saddle and rider, permitting biaxial movement (flexion/extension and abduction/adduction) but limiting rotation.</p> Signup and view all the answers

<p>Articular cartilage lacks blood vessels, making it difficult to heal after injury. The lack of blood supply limits nutrient delivery and waste removal, hindering the repair process. This avascularity results in slow or incomplete healing, often requiring surgical intervention.</p> Signup and view all the answers

<p>Synovial fluid's viscous and oily nature allows it to effectively lubricate the articular cartilage surfaces, reducing friction during joint movement. Its viscosity also enables it to distribute forces evenly across the joint surfaces, acting as a shock absorber to protect the cartilage from excessive stress.</p> Signup and view all the answers

<p>Proprioceptors within the joint capsule and ligaments provide sensory information about joint position, movement, and stretch. This information is transmitted to the nervous system, allowing it to monitor and control body movements, maintain posture, and adjust movements based on feedback from the joints.</p> Signup and view all the answers

<p>The movement of synovial fluid within the joint cavity is essential for delivering nutrients and removing waste products from the avascular articular cartilage. Continuous compression and re-expansion of the cartilage during movement facilitates this circulation, promoting the health and maintenance of the cartilage tissue.</p> Signup and view all the answers

<p>Both ligaments and tendons are composed of dense regular connective tissue. Ligaments connect bone to bone, providing stability and reinforcement to joints. Tendons, on the other hand, attach muscle to bone, facilitating movement by transmitting muscle force to bones.</p> Signup and view all the answers

<p>Hilton's law states that the nerves innervating a joint also innervate the muscles that move the joint and the skin covering the joint. This principle helps predict the specific nerves involved in joint innervation and understand the complex interplay between muscles, nerves, and joints.</p> Signup and view all the answers

<p>Nociceptors located in the joint capsule detect painful stimuli, such as pressure, stretch, or injury. When activated, they transmit pain signals to the nervous system, providing sensory input about potential damage to the joint, prompting protective responses and alerting the individual to potential injury.</p> Signup and view all the answers

<p>Articular cartilage's smooth, hyaline structure, with its specialized chondrocytes and matrix, minimizes friction between bone surfaces during movement. Its ability to resist compression and distribute forces evenly across the joint surface allows it to effectively absorb shock and protect the underlying bone from excessive stress.</p> Signup and view all the answers

<p>Intrinsic ligaments are thickenings within the articular capsule itself, such as the medial collateral ligament of the knee. Extrinsic ligaments are located outside the capsule, physically separate from it, like the lateral collateral ligament of the knee.</p> Signup and view all the answers

<p>Synovial fluid provides nutrients and removes waste products from the avascular articular cartilage. Movement at the joint compresses and re-expands the cartilage, circulating the synovial fluid into and out of the cartilage matrix, facilitating nutrient delivery and waste removal.</p> Signup and view all the answers