Chapter 9 - Joints Flashcards
What is a joint?
A point at which two bones meet
What are the 3 (or 4) classifications based on how joints are connected?
- Fibrous
- Cartilaginous
- Synovial
- (bony)
What tissues make up joints?
HyalineFibrous (loose/dense regular) CT, supportive (cartilage/bone) CT, fluid (blood) CT
What type of cartilage is articular cartilage?
Hyaline
Where is articular cartilage found in joints?
Longbones @ synovial joints
Where is fibrocartilage found in joints?
Intervertebral disks, pubic symphysis
What are the two types of cartilage found in joints?
Hyaline Cartilage
Fibrocartilage
How are joints classified?
- Based on how they’re connected
2. Based on movement
What are the 3 classifications of joints based on movement?
- Synarthrosis (relatively immovable)
- Amphiarthrosis (slightly moveable)
- Diarthrosis (freely moveable)
What are bony joints?
Immobile joint formed when the gap between two bones ossifies
Ex: cranial sutures in elderly, L/R mandibular and frontal bones fuse
Match up the classifications of joints based on movement with the classifications based on how they are connected
Synarthrosis - fibrous
Amphiarthrosis - cartilaginous
Diarthrosis - synovial
What are fibrous/synarthrosis joints?
Adjacent bones bound by collagen fibers
What are the three types of fibrous/synarthrosis joints?
- Suture (between skull bones)
- Syndesmoses (two bones bound by sheets of fibrous CT/ interosseous membranes)
- Gomphoses (teeth to jaw bones)
What are the 3 classifications of sutures?
- Serrate - interlocking, wavy lines (ex: coronal)
- Lap (squamous) - overlapping beveled edges (ex: squamous)
- Plane (butt) - straight, non-overlapping edges (ex: intermaxillary)
Describe syndesmoses
Greater mobility than sutures
Radius/ulna - pronation and supination of forearm (tib/fib has less mobility)
Long collagenous fibers
Describe gomphoses
Fibrous periodontal ligaments
Holds tooth to mandible or maxilla
Very minimal mobility
What are cartilaginous/amphiarthrosis joints?
Two bones linked by cartilage (fibrocartilage or hyaline)
Slightly moveable
What is synchondrosis and give an example of what joints are joined this way?
Cartilaginous joints joined by hyaline cartilage
Ex: 1st rib to the sternum via costal cartilage
What is symphysis and give an example of what joints are joined this way?
Cartilaginous joints joined by fibrocartilage
Ex: Pubic symphysis (more flexible before childbirth), intervertebral discs (slight movements, collective effect)
What are synovial/diarthrosis joints? Give an example
Most moveable and most familiar
Ex: shoulder, elbow, hip, knee
What type of joints tend to be the most complex and problematic?
Synovial/diarthrosis joints
What is the joint cavity?
Narrow space separating bone
What does synovial fluid do?
Acts as a lubricant
Reduces friction
Gives nourishment and removes waste
What type of cartilage is found in synovial joints?
Articular cartilage (hyaline cartilage)
What makes up the joint capsule of CT?
Fibrous capsule, synovial membrane
What is the fibrous capsule?
Encloses cavity, connects to the bone
Continuous with periosteum
What is the synovial membrane?
Inner layer of joints capsule
Secretes synovial fluid
Has macrophages to remove debris
What is an articular disc?
A pad between articulating joints
What is the meniscus and what joint is it found in?
Moon-shaped cartilage
Knee Joint
Extends inward from both left and right
What structures job is to absorb shock and pressure, guide bones across each other, and stabilize joints (in the knee)?
The meniscus
What is a tendon made of and what does it do?
Tough collagenous (dense regular) CT Connects muscle to bone, gives joints most stability
What does a ligament do?
Connects bone to bone
What are bursa? What do they do?
Fibrous sac filled with synovial fluid
They cushion muscles and help tendons slide, can modify the direction a tendon pulls
Where can you find bursa?
- Between adjacent muscles
- Between bone and skin
- Where tendon passes over bone
What is the tendon sheath?
Elongated cylindrical bursa (wrapped around tendon)
What is bursitis?
Inflammation of bursa
Due to overuse
What is the purpose of warming up before exercising?
Exercise warms the synovial fluid, which makes it more easily absorbed by cartilage. When the cartilage swells, you have a better cushion in your joints
What is range of motion?
- The degrees through which a joint can move
- Aspect of joint performance
- Physical assessment of joint flexibility
How do you determine range of motion?
- Structure of the articular surfaces
- Strength and tautness of ligaments and joint capsules
- Action of the muscles and tendons (muscle tone)
What does degrees of freedom refer to in terms of joints?
How many ways a joint can move/how many axes of rotation a joint has
What are the 3 classifications for joints based on degrees of freedom?
- Multiaxial (3 degrees of freedom)
- Biaxial (2 degrees of freedom)
- Monoaxial (1 degree of freedom)
What are the six types of synovial joints?
Multiaxial: 1. ball and socket Biaxial: 2. Condylar 3. Saddle 4. Plane Monoaxial: 5. Hinge 6. Pivot
What are ball and socket joints? What two joints are ball and socket joints?
One bone with hemispherical head fits into a cupcake depression on the other
Ex: shoulder and hip (only ones)
What are condylar joints? Give an example
Oval convex surface on one bone fits in complementary depression on the other
Ex: phalanges –> metacarpals
What are saddle joints? Give an example
Have a saddle-shaped surface, concave in one direction, convex in the other
Ex: Clavicle/sternum, Trapezium/metacarpal (@thumb)
What are gliding joints? Give an example
Surfaces are flat or slightly concave and convex
Complex movements
Ex: wrist and ankle bones
What are hinge joints? Give an example
One bone has a convex surface and fits into the concave depression in the other
Ex: elbox, knee, interphalangeal joints
What are pivot joints? Give an example
Bone spins on longitudinal axis
Ex: joints between radius/ulna, joint between atlas/axis
What is an example of a joint that is hard to classify because it shows aspects of several joint types?
Temporomandibular joint (TMJ) - elements of condylar, hinge, and plane joints
What bones articulate at the TMJ?
Mandibular condyle articulates with mandibular fossa of temporal bone
What is unique about the synovial cavity of the TMJ?
It is divided into superior and inferior chambers
Has an articular disc that allows for lateral/medial excursion
What ligaments support the TMJ
- Lateral ligament (prevents posterior displacement of mandible)
- Sphenomandibular ligament (medial side)
What is TMJ Syndrome?
Generalized name for jaw problems Causes: 1. psychological tension 2. misalignment of teeth 3. arthritis 4. injury
What bones articulate int he glenohumeral joint?
The head of the humorous articulates with the glenoid cavity of the scapula
What is the glenoid labrum and where is it found?
Fibrocartilage ring that deepens the glenoid cavity
How is the glenohumeral joint stabilized?
The biceps brachii tendon and rotator cuff tendons
Biceps brachii tendon –> inter tubercular sulcus –> superior margin of glenoid cavity
What ligaments are found int he glenohumeral joint (5)?
1-3. glenohumeral ligaments
- coracohumeral ligament (coracoid process –> greater tubercle)
- Transverse humeral ligament (tubercle –> tubercle, stabilizes biceps brachii tendon)
What are the four bursa found in the glenohumeral joint?
- subdeltoid
- subacromial
- subcoracoid
- subscapular
What makes up the rotator cuff (SITS)?
supraspinatus, infraspinatus, teres minor, subscapularis
What is the most common shoulder dislocation? Why?
Downward displacement of the humorous
Why?
The rotator cuff protects the joint in all directions but inferiorly
What type of joint is the elbow and what are the two specific joints and their articulations?
Hinge joint
- Humeroulnar joint (trochlea of the humorus joins trochlear notch of the ulna)
- Humeroradial joint (capitulum of humerus meets head of radius)
Where are the olecranon bursa found?
Posterior side of elbow
What ligaments restrict side-to-side movement in the elbow?
Radial (lateral) collateral ligament
Ulnar (medial) collateral ligament
Where is the proximal radioulnar joint found and what type of joint is it?
Found in the elbow region
Pivot joint
Head of the radius articulates with radial notch of the ulna
Held in place by annular ligament
What is the purpose of the proximal radioulnar joint?
Pronation and supination
What type of joint int he tibiofemoral joint?
Diarthrosis - hinge
In the tibiofemoral joint, what does the joint capsule enclose?
Lateral and posterior parts
What covers the anterior of the tibiofemoral joint?
Patellar ligament
What helps to stabilize the knee?
- quadriceps tendon (front)
- tendon of semimembranosus muscle (rear of thigh)
- lateral and medial menisci (c-shaped cartilages within joint capsule, absorb shock, prevent side-to-side rocking)
What are the extra capsular ligaments in the knee joint?
Fibular (lateral) collateral ligament (LCL)
Tibial (medial) collateral ligament (MCL)
What shape to the intracapsular ligaments make? What are the intracapsular ligaments of the knee?
Cross to form an X
1. Anterior cruciate ligament (ACL) - prevents hyperextension of the knee
2. Posterior crucial ligament (PCL) - prevents femur from sliding off tibia (anteriorly)
(both are named for their attachment portion on the tibia)
How many bursa are in the knee?
At least 13
What is the importance of the knee joint?
Ability to lock and unlock knees
Important in bipedalism
How does your knee lock when fully extended? How does it unlock?
Lock: help of ACL, femur rotates medially on tibia, major knee ligaments taut
Unlock: Popliteus contracts and rotates femur laterally, which untwists ligaments
Where are the most common injuries in the tibiofemoral joint?
Menisci
ACL
What is arthroscopy?
Interior of joint is viewed with a pencil-thin arthroscope inserted through a small incision
What is the difference in autograft and allograft?
Autograft = your own material Allograft = donated material
How do you prevent injuries to the knee?
Stabilization…
Anteriorly: quadriceps tendon
Posteriorly: semimembranosus tendon
What is arthritis? What are the two main types?
Inflammation of the joint
- Osteoarthritis arthritis (most common)
- Rheumatoid arthritis
What is osteoarthritis?
Deterioration of the articular cartilage
Bone spurs develop and grow into joint cavity
What is rheumatoid arthritis?
Synovial membrane becomes inflamed and thickens
Autoimmune disease - body attacks tissues
Articular cartilage deteriorates = ossification
More common in women (30-40 y/o)
What are some treatments for arthritis?
Pain management
Physical therapy
Exercise
Joint replacement
Synovial joints: The opposing surfaces of bones that are connected via synovial joints are covered with a thin layer of _______
Articular cartilage
Synovial joints: Between the articular surfaces, a thin cavity is filled with ________, which acts to lubricate the joint surface and nourish the tissues of the internal joint surface
synovial fluid
Synovial joints: The ____ maintains the boundary of the joint and contains the synovial fluid
Joint capsule
Synovial joints: The outermost layer of the joint capsule is the ______- capsule, which is continuous with the periosteum, and provides support to the joint
Fibrosous
Synovial joints: The deeper portion of the capsule is the ______, which contains cells that synthesize the synovial fluid
Synovial membrane
Synovial joints: An example of fibrocartilage that provides additional padding and stability to the joint is the ________ of the knee
Meniscous
