Chapter 8: Articulations Flashcards
Articulations
the location where two or more bones come together; also known as a joint
Functions of Joints
Joints enable movement
Joints provide stability
Joints allow long bones to lengthen
Functional Classification:
Joints can be classified by how much motion they allow, & so the degree of stability, provided by a joint
- Increased movement; decreases stability
- Decreased movement; increases stability
- Synarthrosis – no movement
- Amphiarthrosis – small degree of movement
- Diarthrosis – freely moveable
Synarthrosis
no movement
Amphiarthrosis
small degree of movement
Diarthrosis
freely moveable
Structural Classification
Joints can be classified based on structural features. Two anatomical features are considered. 1)The type of connective tissue that links bones & 2) The presence or absence of a space between them.
- Fibrous joints- two bones are joined by collagenous connective tissue, no joint space is present. Collagen. Functionally synarthroses or amphiarthrosis
- Cartilaginous joints- cartilage (hyalin or cartilage) between the articulating bones, no joint space present. Sort of hard structure, w/ a little “give”. Functionally synarthroses or amphiarthrosis.
- Synovial joints- joint space, or cavity present filled w/ fluid between articulating bones. The greatest range of motion of any joint class. Functionally diarthroses.
Fibrous joints
two bones are joined by collagenous connective tissue, no joint space is present. Collagen. Functionally synarthroses or amphiarthrosis
Cartilaginous joints
cartilage (hyalin or cartilage) between the articulating bones, no joint space present. Sort of hard structure, w/ a little “give”. Functionally synarthroses or amphiarthrosis.
Synovial joints
joint space, or cavity present filled w/ fluid between articulating bones. The greatest range of motion of any joint class. Functionally diarthroses.
Fibrous Joints
Suture, Gomphoses, & Syndesmoses
Sutures Joint
immoveable joint between edges of bones that make up the cranium; fully fused sutures are very stable, well suited for protecting the brain. Functionally Synarthrosis & structurally fibrous.
Gomphoses
immoveable joint between each tooth and its bony socket in jaw. The only gomphoses in the human body. Functionally Synarthrosis & Structurally Fibrous.
Periodontal ligament: a strong fibrous membrane that links each tooth firmly to jawbone
Syndesmoses
joint between tibia, fibula, ulna, & radius; bones are joined by an interosseous membrane or ligament composed of dense regular collagenous connective tissue, which allows for small amount of movement, allowing the articulating bone to pivot around one another. Functionally Amphiarthrosis & structurally fibrous.
Cartilaginous Joints:
Synchondroses & Symphyses
Synchondroses
(cartilaginous joint) consists of bones linked together by hyaline cartilage. Functionally synarthroses.
Examples:
Epiphyseal plates – composed of hyaline cartilage that connects diaphysis and epiphyses of developing long bones; replaced with bone during maturation. Functionally Synarthrosis
First sternocostal & costochondral- joints are synchondroses that persist into adulthood. Functionally Synarthrosis & structurally cartilaginous.
Symphyses
joint where bones are united by a fibrocartilaginous pad or plug; best suited for regions of skeleton that must resist compression ^ tension while still allowing a small amount of motion. Functionally amphiarthrosis & structurally Cartilaginous.
Example:
Intervertebral joints – between adjacent vertebral bodies of spinal column. Functionally amphiarthrosis
Pubic symphysis – between pubic bones of pelvic girdle. Functionally amphiarthrosis
Synovial Joints
Knee
Structural elements of Synovial Joints
Joint cavity (synovial cavity), Articular capsule, Synovial fluid & Articular cartilage
- Avascular; slow healing
- Injury: the isolation from the surrounding blood supply can cause the articular cartilage to be permanently damaged of injured, & it can contribute to the development of arthritis
- Synovial membrane makes synovial fluid
Synovial Fluid Functions
- lubricant/reduces friction
- supplies nutrients to the tissues of the joint
- shock absorber
Synovial Joints Stabilized by
Ligaments, Tendons, Bursae, & Tendon Sheaths
•Ligaments- attaches bone to bone
- Composed of dense regular connective tissue
- Sprain:stretching/tearing of ligaments; only occurs in synovial joints
•Tendon- attaches muscle to bone
•Bursae- fluid-filled sacs; help reduce friction/compression
•Tendon Sheaths- broader segment of tendon; enclose a bursae like sac of fluid. Helps reduce friction/compression
Bursitis
inflammation of a bursa
•Most common sites of bursitis are shoulder, elbow, hip, & knee
•Clinical features of bursitis include pain both at rest and with motion of affected joint; joint may feel tender, swollen, and warm
Arthritis
inflammation/swelling of one or more joints which results in swelling, pain and limitations of joint movement; three common types of arthritis include
- Osteoarthritis – most common form; generally associated with wear and tear, injuries, and advanced age; is characterized by pain, joint stiffness, and lost mobility
- Rheumatoid arthritis – associated with joint destruction mediated by individual’s own immune system. Massive amounts of inflammation in joints.
- Gouty arthritis – (gout) causes joint damage by generating an inflammatory reaction to uric acid crystal deposits. Associated w/ consumption of red meat.
Specific Hing Joint
The knee
Hing Joint
the motion of is restricted to a movement in only one plane. Functionally diarthrosis.
-Primary motions are flexion & extension, commonly injured due to their structural complexity & relative instability
- Patellar ligament – distal continuation of quadriceps tendon; connects distal patella to anterior tibia
- Tibiofemoral joint – articulation between femoral and tibial condyles
- Patellofemoral joint – articulation between posterior surface of patella and anterior patellar surface of femur
- Medial and lateral meniscus – C-shaped fibrocartilaginous pads found between femoral and tibial condyles; provide shock absorption and stability to knee joint
- Tibial collateral ligament (medial collateral) – connects femur, medial meniscus, and tibia to one another to provide medial joint stabilization; prevents tibia from shifting too far laterally on femur
Knee Injuries
the “unhappy triad”–>common injury
•The “unhappy Triad”: three torn knee structures w/ lateral trauma
- Tibial collateral ligament,
- Medial meniscus &
- Anterior cruciate ligament (ACL)
- Despite supportive structures, knee joint is still susceptible to injury; any activity that involves quick changes in direction can injure knee
- Athletes who participate in contact sports (football or soccer) are also at risk, especially if knee is struck from side or from behind
- Fibular collateral and posterior collateral ligaments can also be damaged, but this is less common
Treatment for the unhappy Triad
depends on its severity
- Initial interventions include rest, ice, compression, and anti-inflammatory medications to reduce swelling and minimize pain
- More severe injuries may require surgical repair of damaged ligaments
- Physical therapy & rehabilitation to strengthen surrounding muscles are also helpful
