A&P Chapter 8 Joints

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Terms in this set (...)

What is the definition of a joint?
site where two or more bones meet.
What is the function of a joint?
Function = provide stability and mobility
Name the three main functional classifications of joints.
1) Synarthroses (immovable joints)

2) Amphiarthroses (slightly movable joints)

3) Diarthroses (freely movable joints)
Name the three main structural classifications of joints
1) Fibrous

2) cartilaginous

3) Synovial
Describe the general properties of fibrous joints
Bones joined by dense, fibrous connective tissue, no joint cavity

Types:
Suture
Syndesmosis
Gomphosis
Describe sutures, where are they found in the body? What is their functional classification?
Joint held together with very short interconnecting fibers, and bone edges interlock. Found only in the skull.

Classification: Synarthrosis (immobile)
Describe syndesmoses, where are they found in the body? What is their functional classification?
bones joined by dense, fibrous connective tissue, no joint cavity

Classification: Amphiarthroses (slightly movable)
Tibia and Fibia
Explain why the range of movement between the radius and ulna is greater than between the tibia and fibula?
During pronation, distal end of the radius crosses over the ulna, two bones form an "X". Interosseous membrane allows moderate movement
Describe gomphoses, where are they found in the body? What is their functional classification?
"Peg in socket" fibrous joint. Periodontal ligament holds tooth in socket

Classification: Synarthroses (immobile)
Name and describe the two types of cartilaginous joints, including what type of cartilage they contain, and examples of where they are located in the body. What is their functional classification?
1) Synchondrosis- A bar or plate of hyaline cartilage that unites the bone
Examples: Epiphyseal plates in long bones of children, or immovable joint between the costal cartilage of the first rib and the manubrium of the sternum
Classification: Synarthroses (immobile)

2) Symphysis- A joint where fibrocartilage unites the bone. These joints are designed for strength and flexibility
Examples: Intervertebral Joints and the pubic symphysis of the pelvis
Classification: Amphiarthroses (slightly movable)
Describe the five main structural features of synovial joints. Your answer should include: articular cartilage, joint cavity, fibrous layer of articular capsule, synovial membrane, synovial fluid, and reinforcing ligaments.

*Articular Cartilage
Articular Cartilage- Glassy-smooth hyaline cartilage covers the opposing surfaces as articular cartilage. These thin (1mm or less) but spongy cushions absorb compression placed on the joint and thereby keep the bone end from being crushed
Describe the five main structural features of synovial joints. Your answer should include: articular cartilage, joint cavity, fibrous layer of articular capsule, synovial membrane, synovial fluid, and reinforcing ligaments.

*Joint Cavity
Joint Cavity- A feature unique to synovial joints, the joint cavity is really just a potential space that contains a small amount of synovial fluid
Describe the five main structural features of synovial joints. Your answer should include: articular cartilage, joint cavity, fibrous layer of articular capsule, synovial membrane, synovial fluid, and reinforcing ligaments.

*Fibrous layer of articular capsule
The articular capsule or Joint capsule contains two layers. The tough external fibrous layer is composed of dense irregular connective tissue that is continuous with the periostea of the articulating bones. It strengths the joint so the bones are not pulled apart.
Describe the five main structural features of synovial joints. Your answer should include: articular cartilage, joint cavity, fibrous layer of articular capsule, synovial membrane, synovial fluid, and reinforcing ligaments.

*Synovial membrane
The inner layer is a synovial membrane composed of loose connective tissue. Besides lining the fibrous layer internally, it covers all internal join surfaces that are not hyaline cartilage . The synovial membrane's function is to make synovial fluid.
Describe the five main structural features of synovial joints. Your answer should include: articular cartilage, joint cavity, fibrous layer of articular capsule, synovial membrane, synovial fluid, and reinforcing ligaments.

*Synovial Fluid
Synovial fluid has a viscous, egg-white consistency. However, it thins and becomes less viscous during joint activity. The fluid derives from filtration from blood flowing through the capillaries in the synovial membrane. This fluid occupies all free spaces within the joint capsule. It is also found within the articular cartilages. Synovial fluid provides a slippery, weight-bearing film that reduces friction between the cartilages. Synovial fluid also contains phagocytic cells that rid the joint cavity of microbes and cellular debris.
Describe the five main structural features of synovial joints. Your answer should include: articular cartilage, joint cavity, fibrous layer of articular capsule, synovial membrane, synovial fluid, and reinforcing ligaments.

*Reinforcing ligaments
These band-like ligaments reinforce and strengthen the synovial joints. Most often these are (capsular ligaments), thickened parts of the fibrous layer. In other cases, they remain distinct and are found outside the capsule as (extracapsular ligaments) or deep into the capsule as (intracapsular ligaments). Intracapsular ligaments are covered with synovial membrane so they do not actually lie within the joint cavity.
What is the functional classification of synovial joints?
Classification: diarthroses (freely-moveable)

*All synovial joints are freely moveable.
How are joint mobility and joint stability related? What contributes most to the stability of a joint?
Inverse relationship......the more stable the joint, the less mobile it is

Shape of the the articular surfaces, presence of strong reinforcing ligaments, and tone of surrounding muscles
What does it mean to be "double" jointed? What are some potential causes for "double" jointedness?
It refers to joint hypermobility- joints that stretch farther than normal. There is greater flexibility in the articular capsules & ligaments that results in an increased mobility (ROM) but less structural stability.
NOT REALLY EXTRA JOINTS

Causes: abnormally shaped bone ends, shallow joint socket, collagen defect (weak ligaments), decreased muscle tone.
Describe the structure of the knee joint. How many joints are in the knee, and which bones articulate in these joints? What movement does the knee allow? Your answer should include: medial and lateral condyle of femur, medial and lateral meniscus, tibia, fibula, patella, and ligaments (patellar, fibular collateral, tibial collateral, ACL, PCL).
It has a single joint cavity that is partially enclosed by a capsule but consists of three joints in one, two tibiofemoral joints (articulating surfaces: condyle of femur,meniscus, and condyle of tibia). One femoropatellar joint (articulating surfaces: patella, patellar surface of femur. The knee allows flexion and extension movements.
Describe the damages that occur as a result of a typical sports knee injury. In which way is the knee a stable joint, in which way is it a weak joint?
A common knee injury is an injury to the ACL. The tibial collateral ligament, medial meniscus, and anterior cruciate ligament are all torn. The knee is stable in that it can withstand vertical force but it is weak in that it is extremely vulnerable to horizontal blows.
What does a total knee replacement involve? What is the name for these type of surgical procedures?
A total knee replacement involves distal femur, proximal tibia, back of patella, and menisci. The name for these types of surgical procedures is anthroplasty- surgical procedure of replacing damaged joints with artificial joints.
Describe an alternative option for someone who needs a knee replacement.
An alternative option for someone who needs knee replacement would be to put donor ligaments and other knee places into the knee rather than artificial ones, also stem cell paste graft for the damaged surface. If a donor is not available then animal parts may work.
Describe the general structure of the shoulder, elbow, hip, and temporomandibular joints (as we discussed in class). Your answer should include the names of the articulating bones and their parts, the presence and strength of reinforcing ligaments and muscles. Your answer should also include whether the structure of the joint is well suited for motility or for stability, what structures in particular contribute to this, and what type of movement the joint allows.

*temporomandibular joint
temporomandibular joint

combined hinge and planar joint formed by the mandible and the temporal bone
Describe the general structure of the shoulder, elbow, hip, and temporomandibular joints (as we discussed in class). Your answer should include the names of the articulating bones and their parts, the presence and strength of reinforcing ligaments and muscles. Your answer should also include whether the structure of the joint is well suited for motility or for stability, what structures in particular contribute to this, and what type of movement the joint allows.

*Shoulder Joint
Ball-and-socket joint: head of humerus and glenoid fossa of the scapula (the glenohumeral joint); smaller joint is the acromioclavicular (AC) joint

Stability: sacrificed for the greater freedom of movement.
-permits the highest ROM of any joint
-most frequently dislocated (luxated) joint

the muscles that move the humerus do more to stabilize the shoulder joint than all the ligaments and capsular fibers combined.
-the tendon of the long head of biceps secures humerus to glenoid cavity
Describe the general structure of the shoulder, elbow, hip, and temporomandibular joints (as we discussed in class). Your answer should include the names of the articulating bones and their parts, the presence and strength of reinforcing ligaments and muscles. Your answer should also include whether the structure of the joint is well suited for motility or for stability, what structures in particular contribute to this, and what type of movement the joint allows.

*Elbow Joint
hinge joint formed by the trochlea and capitulum of the humerus, the trochlear notch of the ulna, and the head of the radius.

the elbow joint is extremely stable because -the bony surfaces of the humerus and ulna interlock
-the articular capsule is very thick
-strong ligaments reinforce the capsule

anular ligament of the elbow surrounds head of radius

capsular ligaments of the elbow restrict side-to-side movement:
ulnar collateral ligament
radial collateral ligament
Describe the general structure of the shoulder, elbow, hip, and temporomandibular joints (as we discussed in class). Your answer should include the names of the articulating bones and their parts, the presence and strength of reinforcing ligaments and muscles. Your answer should also include whether the structure of the joint is well suited for motility or for stability, what structures in particular contribute to this, and what type of movement the joint allows.

*Hip Joint
hip joint ball-and-socket joint formed by the femur and the acetabulum of the os coxae; good ROM, but limited by the deep socket

the articular capsule of the hip is extremely dense and strong, enclosing both the head and neck of the femur. reinforced by four broad ligaments

the hip joint is an extremely stable joint because the combination of an almost complete bony socket, a strong articular capsule, supporting ligaments, and muscular padding.
provided by the bulk of surrounding muscles
Describe the two types of arthritis discussed in class. What are their causes? What types of joints do they affect? What are their treatments?
1) Osteoarthritis- caused by aging, obesity, muscle weakness, wear and abrasion or putting stress on bones. It affects synovial joints that get worn down from "wear and tear"
Medications, physical therapy, and sometimes surgery can help reduce pain and maintain joint movement

2) Rheumatoid arthritis- caused by an auto-immune disorder. It affects cartilage, joint lining, and inflammation of synovial membrane. While there's no cure for rheumatoid arthritis, physical therapy and medications can help slow the disease's progression.