JOINTS AND SYNOVIAL JOINT MOVEMENTS A&P 1 LABORATORY

What joints are examples of Synarthrosis?

Fibrous joints such as the sutures between the skull bones and the teeth sockets.

What is a joint or articulation?

It's what connects a bone with another bone, cartilage, or tooth.

Define the various types of movements of allowed at synovial joints.

A. GLIDING: Nearly flat bone surfaces slide or glide over each other. B. ANGULAR: Flexion:to bend. Extension:to stretch out Hyperextension: excessive movement beyond normal anatomical position. Abduction:to move appendage away from the midline. Adduction:to move appendage toward midline. Circumduction:to move a distal part of an appendage in a circle. C. ROTATION:turn on a pivot with a circle; revolve. D. SPECIAL JOINT MOVEMENTS: Elevation: upward movement raising body part vertically. Depression: lowering body part downward vertically. Protraction:move body part forward or anterior on horizontal plane. Retraction:move body part backward or posterior. Supination:turn palm over and extend arm like you are holding soup. Palm is facing forward to be seen. Pronation:turn palm to face backward, turn palm downward not to be seen. Inversion:turn sole of the foot inward. Eversion:turn sole of foot outward. Dorsiflexion: point your toes up, stand on your heels. Plantar flexion: point your toes down, raise your heels.

What joints are examples of Amphiarthrosis?

Cartilaginous joints such as Intervertebral joints, the tibiofibular joint, and the joint between the manubrium and the body of the sternum, and the pubic symphysis.

Describe the 3 major structural categories of joints noting the types of tissues involved with each.

Fibrous, Cartilaginous, and Synovial. Fibrous joints have dense connective tissue with strong collagen fibers that hold the joints firmly together with no synovial cavity. This type of joint permits little to no movement. Cartilaginous joints have either hyaline cartilage or fibrocartilage connecting the bones with no synovial cavity. Usually there is a small degree of movement with this type of joint. Synovial joints have a small synovial cavity between 2 bones that permits a greater amount of movement than fibrous or cartilaginous joints. Dense fibrous connective tissue on the exterior of the joint holds the bones together.

Describe the 6 different types of synovial joints based on the structure of the articulating surfaces of the articulating bones surfaces and the accessory structures (ligaments and other soft tissues) Describe the movement allowed in each. Give one example of each.

Planar (gliding)- Articular surface description: Flat or slightly curved plane. Movement: Gliding motion back and forth and/or side to side. Example: Flex your arm and feel the gliding movement at the acromioclavicular joint. Hinge- Articular surface description: Convex bone surface articulates with a concave bone surface. Movement: Flexion and extension. Example: flex and extend your elbow and your knee as you feel this joint type. Note how this joint only moves by flexion and extension. Pivot -Articular surface description: Rounded or pointed projection articulates with ring formed by bone and ligament. Movement: Rotation. Example: Feel the proximal part of your forearm until you locate the head of the radius. Rotate the radioulnar joint as you palpate this rotation movement. Condyloid -Articular surface description: Oval convex projection articulates with oval concave depression. Movement: Flexion and extension, abduction and adduction, circumduction. Example: feel the joint between the 2nd metacarpal and the 2nd proximal phalanx. Extend and flex, abduct and adduct, and circumduct this joint. Saddle -Articular surface description: Saddle-shaped depression articulates with projection that fits into the saddle. Movement: Same as condyloid joint, except more exaggerated. Example: The thumb joint is the only saddle joint in the body. Feel the movement of trapezium(carpal bone) with the 1st metacarpal as you move this joint on two different axes. Ball-and-socket - Articular surface description: Ball shaped head articulates with cup-shaped socket. Movement: freely moveable joint; flexion and extension; abduction and adduction; circumduction; rotation. Example: feel your shoulder joints as you move your arm indifferent motions. Make a full circle with your shoulder joint.

Describe the 3 main functional categories of joints.

Synarthroses (syn=union; arthro= joint) - Immovable joints. Amphiarthroses (amphi=on both sides) - Slightly moveable Diarthroses (di=apart; away from) - Freely moveable

Describe the basic structure of a typical synovial joint (Most joints in the body are synovial.)

Synovial cavity -Small space between the two articulating bones. Articular cartilage -hyaline cartilage covering the ends of the bones in the synovial cavity. Articular Capsule -structure that encloses the synovial joint and synovial cavity; Has 2 layers: the fibrous membrane and synovial membrane. Fibrous membrane -outer dense fibrous connective tissue layer of the articular capsule that is continuous with the periosteum of the bone; also forms ligaments when fibrous bundles are parallel. Synovial membrane - inner layer of the articular capsule; composed of areolar connective tissue containing elastic fibers and adipocytes. Synovial fluid -secreted by the synovial membrane; lubricates the articular cartilages to reduce friction.

What joints are examples of Diarthrosis?

Synovial joints such as the shoulder, elbow, hip, and knee joints.

Describe the structure of the knee joint.

The structure of the knee joint: The knee joint is classified as a hinge joint, but when flexed it also demonstrates gliding and rotation movements.

Accessory structure's of the knee joint:

°medial meniscus - inside of the joint cavity; cushions knee joint. °lateral meniscus - inside of joint cavity; cushions knee joint °medial (tibial) collateral ligament - extracapsular ligament; adds strength to the joint medially. °lateral (fibular) collateral ligament - extracapsular ligament; adds strength to joint laterally. °anterior cruciate ligament ( cruci=cross) or ACL-intracapsular ligament; stabilizes joint posteriorly °patellar ligament -extension of tendon from quadriceps muscle; connects patella to tibial tuberosity and stabilizes the joint anteriorly. °infrapatellar fat pad (infra=beneath) - cushion between patellar ligament and synovial capsule °bursa - reduces friction; 13 bursae in knee.