Bio 111 Lecture 12
Fibrous Joints Are?
Bones joined by dense fibrous connective tissue
• No joint cavity
• Most are immovable (synarthrosis or amphiarthroses)
– Depends on length of connective tissue fibers
What are the three types of Fibrous Joints?
Three types of fibrous joints
– Sutures
– Syndesmoses – Gomphoses
Fibrous Joint Examples?
Fibrous Joints
Example: Sutures
• Rigid, interlocking joints of skull • Allow for growth during youth
– Contain short connective tissue fibers that allow for expansion
• By middle age, sutures are completely ossified and fused
– Immovable joints join skull into one unit that protects brain
– Closed, immovable sutures referred to as synostoses
What are Syndesmoses?
Bones connected by ligaments, bands of fibrous tissue
• Fiber length varies, so movement varies
– Short fibers offer little to no movement
What are some Examples of Syndesmoses Joints?
Example: inferior tibiofibular joint
– Longer fibers offer a larger amount of movement
• Example: interosseous membrane connecting radius and ulna
What Are Gomphoses?
Peg-in-socket joints
• Only examples are the teeth
in alveolar sockets
• Fibrous connection is the
periodontal ligament
– Holds tooth in socket
What are Cartilaginous Joints
Bones united by cartilage
• Like fibrous joints, have no joint cavity
• Not highly movable
What are the Two Types Of Cartilaginous Joints?
– Synchondroses – Symphyses
What is Synchondroses?
Bar or plate of hyaline cartilage unites bones
• Almost all are synarthrotic (immovable)
What are some Examples of Synchondroses?
– Temporary epiphyseal plate joints
Become synostoses after plate closure
– Cartilage of 1st rib with manubrium of sternum
What is Symphyses?
Fibrocartilage unites bone in symphysis joint
– Hyaline cartilage also present as articular cartilage on bony surfaces
• Symphyses are strong, amphiarthrotic (slightly movable) joints
What are some Examples of Symphyses?
– Intervertebral joints – Pubic symphysis
What are Synovial Joints?
Bones separated by fluid-filled joint cavity
• All are diarthrotic (freely movable)
• Include almost all limb joints
• Characteristics of synovial joints
Fig 8.3
– Have six general features
– Have bursae and tendon sheaths associated with them
– Stability is influenced by three factors
– Allow several types of movements
– Classified into six different types based on shape of articular surface and range of movement
Synovial joints have six general features are?
1. Articular cartilage: consists of hyaline cartilage covering ends of bones • Prevents crushing of bone ends
2. Joint (synovial) cavity: small, fluid-filled potential space that is unique to synovial joints
3. Articular (joint) capsule: two layers thick
• External fibrous layer: dense irregular connective tissue
• Inner synovial membrane: specialized loose connective tissue that makes synovial fluid
4. Synovial fluid: viscous, slippery filtrate of plasma and hyaluronic acid § Lubricates and nourishes articular cartilage
Contains phagocytic cells to remove microbes and debris
5. Different types of reinforcing ligaments
- Capsular: thickened part of fibrous layer of joint capsule
- Extracapsular: outside the capsule
-Intracapsular: deep to capsule; covered by synovial membrane
6. Nerves and blood vessels
Other features of some Synovial Joints?
– Fatty pads
• For cushioning between fibrous layer of capsule and synovial membrane or bone
– Articular discs (menisci)
• Fibrocartilage separates articular surfaces to
improve “fit” of bone ends, stabilize joint, and reduce wear and tear
Types of Synovial Joints?
There are six different types of synovial joints
– Categories are based on shape of articular surface, as well as movement joint is capable of
What are the Six Types of Synovial Joints?
• Plane
• Hinge
• Pivot
• Condylar • Saddle
• Ball-and-socket
What is Syndesmosis?
Joint held togther by a ligament fibrous tissue can vary in length but is longer than suture.
What are Bursae and Tendon Sheaths?
• Bags of synovial fluid that act as lubricating “ball bearing” – Not strictly part of synovial joints, but closely associated
Bursae Function?
Bursae: reduce friction where ligaments, muscles, skin, tendons, or bones rub together
What are Tendon Sheaths?
Tendon sheaths: elongated bursae wrapped completely around tendons subjected to friction
What Specifically is a Tendon Sheath?
Is a elongated fluid-filled sac that wraps around to decrease friction.
What specifically is a Bursa?
Is a fluid-filled sac that decreases friction where a ligament (or other structure) would rub against bone.
Factors Influencing Stability of Synovial Joints?
Three factors determine stability of joints to prevent dislocations:
1. Shape of articular surface (minor role)
• Shallow surfaces less stable than ball-and-socket
2. Ligament number and location (limited role) • The more ligaments, the stronger the joint
3. Muscle tone keeps tendons taut as they cross joints (most important)
• Extremely important in reinforcing shoulder and knee joints and arches of the foot
What are Interesting Synovial Joints?
Synovial joints are diverse
All have general features, but some also have unique structural features, abilities, and weaknesses
Interesting synovial joints
– Jaw (Temporomandibular Joint) – Shoulder
– Hip
– Knee
What is the Temporomandibular Joint (TMJ)?
Jaw joint is a modified hinge joint
• Mandibular condyle articulates with temporal bone
– Posterior temporal bone forms mandibular fossa, while anterior portion forms articular tubercle (lateral ligament attachment)
• Articular capsule thickens into strong lateral ligament
What are the Two Types of Movements of Temporomandibular Joint (TMJ)?
Two types of movement
– Hinge: depression and elevation of mandible
– Gliding: side-to-side (lateral excursion) grinding of teeth
• Most easily dislocated joint in the body
Shoulder (Glenohumeral) Joint is?
Most freely moving joint in body
• Stability is sacrificed for freedom of movement
• Ball-and-socket joint
– Large, hemispherical head of humerus fits in small, shallow glenoid cavity of scapula
• Like a golf ball on a tee
• Articular capsule enclosing
cavity is also thin and loose
– Contributes to freedom of movement
Knee Joint Is?
• Largest, most complex joint of body
Knee Joint Consists of three joints surrounded by
single cavity that Are?
1. Femoropatellar joint
• Plane joint
• Allows gliding motion during knee
flexion
2. Lateral joint and
3. Medial joint
• Lateral and medial joints together
are called tibiofemoral joint
• Joint between femoral condyles and
lateral and medial menisci of tibia
• Hinge joint that allows flexion, extension, and some rotation when knee partly flexed
Anteriorly, quadriceps tendon gives rise to three broad?
Ligaments that run from Patella to Tibia – Medial and lateral patellar retinacula that flank the patellar ligament
Doctors tap patellar ligament to test?
Knee-jerk reflex
• At least 12 bursae associated with knee joint
Capsular and extracapsular ligaments help prevent?
hyperextension of knee
Fibular and Tibial collateral ligaments Prevent?
Rotation when knee is extended
Intracapsular ligaments reside within?
capsule, but outside synovial cavity
Intracapsular ligaments help to prevent?
Help to prevent anterior-posterior displacement
Anterior cruciate ligament (ACL) Is What?
• Attaches to anterior tibia
• Prevents forward sliding of tibia and stops hyperextension of knee
Posterior cruciate ligament Is What?
• Attaches to posterior tibia
• Prevents backward sliding of tibia and forward sliding of femur
Knee absorbs great amount of?
Vertical force; however, it is vulnerable to horizontal blows
Common knee injuries involved the 3 C’s That Are?
• Collateral ligaments
• Cruciate ligaments
• Cartilages (menisci)
– Lateral blows to extended knee can result in tears in tibial collateral ligament, medial meniscus, and anterior cruciate ligament
– Injuries affecting just ACL are common in runners who change direction, twisting ACL
– Surgery usually needed for repairs
The “Unhappy Triad” Is?
Ruptured ACL, Ruptured Tibial Collateral Ligament, and Torn Meniscus
Inflammatory and Degenerative Conditions Are?
Bursitis
– Inflammation of bursa, usually caused by blow or friction
– Treated with rest and ice and, if severe, anti-inflammatory drugs
Tendonitis
– Inflammation of tendon sheaths, typically caused by overuse – Symptoms and treatment similar to those of bursitis
• Arthritis
– >100 different types of inflammatory or degenerative diseases that
damage joints
– Most widespread crippling disease in the U.S.
– Symptoms: pain, stiffness, and swelling of joint
– Acute forms: caused by bacteria, treated with antibiotics
– Chronic forms: osteoarthritis, rheumatoid arthritis, and gouty
arthritis
Developmental Aspects of Joints Are?
By embryonic week 8, synovial joints resemble adult joints
• Joint’s size, shape, and flexibility modified by use
– Active joints have thicker capsules and ligaments
• Advancing years take toll on joints
– Ligaments and tendons shorten and weaken – Intervertebral discs more likely to herniate
– Most people in 70s have some degree of OA
• Full-range-of-motion exercise key to postponing joint problems
What is Arthroplasty?
Arthroplasty is a surgical procedure to restore the function of a joint. A joint can be restored by resurfacing the bones. An artificial joint (called a prosthesis) may also be used.
What Is Chondromalacia patellae?
Chondromalacia patella is the breakdown of cartilage on the underside of the kneecap (patella). When the kneecap rubs against the thigh bone, it hurts and swells. It is common among runners and other athletes and has been given the nickname “runner's knee.”
What Is Synovitis?
Synovitis (or synovial inflammation) is when the synovium of a joint becomes inflamed (swollen). The synovium, which is also sometimes called the stratum synoviale or synovial stratum, is connective tissue that lines the inside of the joint capsule.