Week 8 - Synovial Joints Anatomy and Movements

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Questions and Answers

Which characteristic defines the mobility of cartilaginous joints?

They allow significant range of motion.

They can be either immobile or slightly mobile. (correct)

They are freely mobile due to their joint cavities.

They are always immobile.

Which statement about fibrocartilage pads in symphyses is correct?

They serve primarily as a connection for synovial joints.

They resist compression and act as shock absorbers. (correct)

They are composed mainly of hyaline cartilage.

They provide complete immobility to the joints.

Which joint type is characterized by bones joined by hyaline cartilage and classified as immobile?

Synovial joints.

Symphyses.

Sutures.

Synchondroses. (correct)

What primary feature distinguishes synovial joints from cartilaginous joints?

Inclusion of a joint cavity. Signup and view all the answers

Which of the following describes gomphoses?

They involve conical projections fitting into socket-like structures. Signup and view all the answers

What characteristic is primarily associated with synovial joints?

Highly mobile and flexible Signup and view all the answers

Which type of fibrous joint allows for the least movement?

Sutures Signup and view all the answers

Gomphoses are specialized fibrous joints that connect which of the following?

Teeth to the jawbone Signup and view all the answers

What is the primary function of sutures in the skull?

Allow growth and expansion of the brain Signup and view all the answers

In which of the following joints can you find hyaline cartilage?

Synchondroses Signup and view all the answers

Which type of movement is characterized by decreasing the angle between two bones at a synovial joint?

Flexion Signup and view all the answers

What type of joint allows movement in only one plane, primarily through flexion and extension?

Hinge joint Signup and view all the answers

What does lateral flexion refer to in joint movement?

Trunk movement to the side in the coronal plane Signup and view all the answers

Which type of synovial joint allows for movement in only one plane?

Uniaxial joint Signup and view all the answers

What is the main characteristic of a ball-and-socket joint?

Most freely mobile type of joint Signup and view all the answers

Which joint classification permits rotation on a longitudinal axis?

Pivot joint Signup and view all the answers

What type of joint is characterized by having an oval convex surface articulating with a concave surface?

Condylar joint Signup and view all the answers

Which of the following joints is least mobile?

Plane joint Signup and view all the answers

Which accessory structure in joints acts as protective packing material?

Fat pads Signup and view all the answers

What type of joint allows for movement in two planes?

Biaxial joint Signup and view all the answers

Which joint type resembles the joint between the thumb and the first metacarpal?

Saddle joint Signup and view all the answers

Which structure helps to reduce friction around tendons?

Tendon sheaths Signup and view all the answers

Which type of synovial joint is formed when one bone fits into a cup-like socket of another?

Ball-and-socket joint Signup and view all the answers

What movement is characterized by the lateral movement of a body part away from the midline?

Abduction Signup and view all the answers

Which term describes the action of bringing a body part back toward the midline?

Adduction Signup and view all the answers

Which movement results in an imaginary cone shape created by the distal end of an appendage while the proximal end remains stable?

Circumduction Signup and view all the answers

What is the term for the medial rotation of the forearm where the palm of the hand turns to face posteriorly?

Pronation Signup and view all the answers

Which type of rotation involves turning the anterior surface of a bone laterally?

Lateral rotation Signup and view all the answers

What is the composition of a gomphoses joint?

Dense regular connective tissue Signup and view all the answers

Which type of tissue primarily connects the bones in sutures?

Dense regular connective tissue Signup and view all the answers

Regarding syndesmoses, which of the following statements is true?

They are bound by interosseous membranes. Signup and view all the answers

What type of joint are sutures classified as?

Synarthroses Signup and view all the answers

Which of the following joints is classified as a gomphosis?

Articulation between teeth and mandible/maxillae Signup and view all the answers

What is the primary function of fibrous joints such as sutures and gomphoses?

Provide stability and limit movement Signup and view all the answers

Syndesmoses primarily allow what type of joint movement?

Limited movement Signup and view all the answers

In older adults, what do sutures become as they ossify?

Synostoses Signup and view all the answers

Which type of synovial joint is characterized by its ability to allow movement in multiple planes or axes?

Ball-and-socket joint Signup and view all the answers

What type of joint allows for a limited side-to-side gliding movement in a single plane?

Plane joint Signup and view all the answers

Which joint classification permits movement primarily in flexion and extension?

Hinge joints Signup and view all the answers

Which joint type has surfaces resembling a saddle configuration?

Saddle joint Signup and view all the answers

What is the primary function of tendon sheaths in synovial joints?

To wrap around tendons where friction is excessive Signup and view all the answers

Which statement is true regarding condylar joints?

They consist of an oval convex surface articulating with a concave surface. Signup and view all the answers

Which joint type is characterized by only movement around a longitudinal axis?

Pivot joint Signup and view all the answers

In terms of mobility, which of the following synovial joints is considered the most mobile?

Ball-and-socket joint Signup and view all the answers

What defines a uniaxial joint?

Confines movement to a single plane or axis. Signup and view all the answers

Which accessory structure in joints functions as protective packing material?

Fat pads Signup and view all the answers

What type of movement describes the action of a ballerina standing on tiptoes?

Plantar flexion Signup and view all the answers

Which of the following movements occurs at the intertarsal joints of the foot?

Inversion Signup and view all the answers

What is a defining feature of protraction as a special movement?

The anterior movement from an anatomical position Signup and view all the answers

Which movement is the opposite of opposition in thumb movement?

Reposition Signup and view all the answers

What does dorsiflexion specifically refer to in terms of foot movement?

Foot moving superiorly towards the leg Signup and view all the answers

During inversion of the foot, which direction does the sole face?

Medially Signup and view all the answers

Which action would be characterized as depression?

Opening the mouth Signup and view all the answers

Which special movement allows for grasping objects with the thumb?

Opposition Signup and view all the answers

Eversion of the foot specifically involves what movement?

Turning the sole outward Signup and view all the answers

Which special movement best describes retracting the jaw?

Retraction Signup and view all the answers

What characterizes a third-class lever system in the human body?

Effort applied between the fulcrum and resistance. Signup and view all the answers

Which joint is primarily responsible for the greatest range of motion in the human body?

Glenohumeral Joint Signup and view all the answers

What happens when the acromioclavicular ligament is torn?

The acromion and clavicle no longer align. Signup and view all the answers

Which feature primarily contributes to the stability of the glenohumeral joint?

Rotator cuff muscles. Signup and view all the answers

What is the role of the fibrocartilaginous glenoid labrum in the shoulder joint?

To encircle the socket and enhance joint stability. Signup and view all the answers

Which type of joint is formed by the head of the humerus and the glenoid cavity of the scapula?

Ball-and-Socket Joint Signup and view all the answers

What anatomical structure works with the joint capsule to provide stability to the shoulder joint?

Glenohumeral ligament Signup and view all the answers

The acromioclavicular joint is classified as which type of joint?

Plane Joint Signup and view all the answers

How are the rotator cuff muscles relevant to shoulder function?

They stabilize the shoulder joint. Signup and view all the answers

What does the presence of abundant bursae in the shoulder joint accomplish?

Decreases friction where tendons and muscles cross. Signup and view all the answers

Study Notes

Synovial Joints: Characteristics and Functions

All synovial joints have a joint cavity, articular capsule, synovial fluid, articular cartilage, ligaments, nerves, and a blood supply.
Synovial fluid lubricates the joint, provides nutrients to the cartilage, and absorbs shock.
The articular capsule, made of fibrous connective tissue, surrounds the joint and helps maintain joint stability.
Articular cartilage, a specialized hyaline cartilage, covers the ends of bones, reducing friction and absorbing shock.
Ligaments are fibrous connective tissues that connect bones and limit joint movement.

Synovial Joint Movements

Gliding: Limited movement in multiple directions, occurs in plane joints such as those between carpals or tarsals. Imagine a flat surface sliding across another flat surface.
Angular: Increases or decreases the angle between bones. This includes:
- Flexion: Decreases the angle between bones, bringing them closer together (like bending your fingers).
- Extension: Increases the angle between bones, straightening them (like straightening your fingers after making a fist).
- Hyperextension: Extending a joint beyond its normal range, possible with certain joints or due to injury.
- Lateral Flexion: Movement of the trunk of the body laterally, occurring between vertebrae in the cervical and lumbar regions.
- Abduction: Moving a limb away from the midline of the body (like raising your arm out to the side).
- Adduction: Moving a limb towards the midline of the body (like lowering your arm back down).
- Circumduction: Moving a limb in a circular motion, combining flexion, extension, abduction, and adduction.
Rotational: Occurs when a bone rotates around its longitudinal axis (like turning your head side to side).
Special Movements: Specific motions that occur only at certain joints, including:
- Dorsiflexion and Plantar Flexion (at the ankle joint)
- Pronation and Supination (at the elbow joint)
- Eversion and Inversion (at the foot)
- Opposition (at the thumb)

Synovial Joint Classifications

By Movement:
- Uniaxial: Allows movement in one plane or axis. (Examples: Hinge joints for flexion/extension, Pivot joints for rotation)
- Biaxial: Allows movement in two planes. (Examples: Condylar joints, Saddle joints)
- Multiaxial: Allows movement in multiple planes. (Example: Ball-and-socket joints)
By Shape:
- Plane Joints: Flat surfaces, allow for limited gliding movements. (Examples: Between carpals, some in the foot)
- Hinge Joints: Convex surface fits into a concave depression, allows for flexion/extension only. (Examples: Elbow, knee, ankle)
- Pivot Joints: Rounded surface fits into a ligament ring, allows for rotation only. (Examples: Proximal radioulnar joint, between C1 & C2 vertebrae)
- Condylar Joints: Oval convex surface articulating with a concave surface, allows for flexion/extension, abduction/adduction, and limited rotation. (Examples: Wrist, knee joints)
- Saddle Joints: Convex and concave surfaces shaped like a saddle, allows for flexion/extension, abduction/adduction, and limited rotation. (Examples: Carpometacarpal joint of the thumb)
- Ball-and-Socket Joints: Spherical head of one bone fits into a cuplike socket, allows movement in all planes. (Examples: Shoulder joint, hip joint)

Other Accessory Structures of Synovial Joints

Tendon Sheaths: Elongated bursae that wrap around tendons to minimize friction.
Fat Pads: Act like protective packing material in the joint periphery.

Synovial Joint Anatomy

Tendon sheaths wrap around tendons where friction is excessive
Tendon sheaths are common in the wrist and ankle
Fat Pads act as protective packing material in joint periphery
Fat pads can fill spaces when joint shape changes

Classification of Synovial Joints - By Movement

Uniaxial joint - bone moves in one plane (e.g., hinge joint)
Biaxial joint - bone moves in two planes (e.g., condylar joint)
Multiaxial joint - bone moves in multiple planes (e.g., ball-and-socket joint)

Classification of Synovial Joints - By Shape

Plane Joints
- Articular surfaces are flat
- Least mobile synovial articulation
- Uniaxial: limited gliding movement
Hinge Joints
- Convex surface within concave depression
- Uniaxial: like a hinge, allows flexion and extension
Pivot Joints
- Bone with rounded surface fits into a ligament ring
- Uniaxial: rotation on longitudinal axis
Condylar Joints
- Oval, convex surface articulating with concave surface
- Biaxial: allows flexion, extension, adduction, abduction
Saddle Joints
- Convex and concave surfaces resembling a saddle
- Biaxial: allows flexion, extension, abduction, and adduction
Ball-and-Socket Joints
- Spherical head of one bone fitting into cup-like socket
- Multiaxial: permits movement in three planes, the most freely mobile type

Fibrous Joints

Connected by dense regular connective tissue, no joint cavity
Immobile or slightly mobile
Three types: Gomphoses, Sutures, and Syndesmoses

Gomphoses

"Peg in a socket"
Articulation of teeth with sockets of mandible and maxillae
Held in place by fibrous periodontal membranes
Synarthroses (immovable)

Sutures

Found between some skull bones
Short fibers interlock, providing stability and reducing fracture risk
Synarthroses (immovable)
Allow growth in childhood
Become ossified synostoses in older adults

Syndesmoses

Bound by an interosseous membrane (broad ligament)
Found between radius/ulna and tibia/fibula
Amphiarthroses (slightly movable)
Allow pivot for two long bones

Angular Motion

Abduction - lateral movement away from the midline
Adduction - medial movement towards the midline

Circumduction

Proximal end stationary, distal end makes a circular motion
Movement creates an imaginary cone shape

Rotational Motion

Rotation - bone pivots on its longitudinal axis
Lateral rotation - anterior surface of bone turns laterally
Medial rotation - anterior surface of bone turns medially
Pronation - medial rotation of forearm (palm faces posterior)
Supination - lateral rotation of forearm (palm faces anterior)

Special Movements

Depression - inferior movement (e.g., opening the mouth)
Elevation - superior movement (e.g., closing the mouth)
Dorsiflexion - bending the talocrural (ankle) joint, dorsum of foot moves towards leg
Plantar flexion - bending the talocrural joint, dorsum of foot points inferiorly
Eversion - sole of foot turns laterally
Inversion - sole of foot turns medially
Protraction - anterior movement from anatomical position
Retraction - posterior movement from anatomical position
Opposition - thumb movement towards fingertips
Reposition - opposite movement of opposition

Levers

A rigid structure that moves around a fixed point (fulcrum)
Three classes based on the position of effort, fulcrum, and resistance
First-Class Lever
- Fulcrum in the middle (e.g., seesaw)
Second-Class Lever
- Resistance in the middle (e.g., wheelbarrow)
Third-Class Lever
- Effort in the middle (e.g., forceps, most common in the body)

Temporomandibular Joint (TMJ)

Complex joint between mandible and temporal bone
Allows for jaw movements like speaking, chewing, and yawning
Can be affected by arthritis, dislocation, and other conditions

Shoulder Joint

Acromioclavicular Joint:
- Plane joint between acromion (scapula) and clavicle
- Fibrocartilaginous articular disc inside
- Ligaments include: acromioclavicular, coracoclavicular
- If torn, the joint dislocates (shoulder separation)
Glenohumeral Joint:
- Ball-and-socket joint between head of humerus and glenoid cavity of scapula
- Most mobile joint but also most unstable and prone to dislocation
- Glenoid labrum deepens the socket
- Abundant bursae reduce friction
- Ligaments include: coracoacromial, coracohumeral, and glenohumeral
- The rotator cuff muscles (subscapularis, supraspinatus, infraspinatus, teres minor) provide most stability.

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Description

Explore the characteristics and functions of synovial joints in this quiz. Learn about the structure, including the joint cavity, articular capsule, and the role of synovial fluid. Test your knowledge on different types of movements that these joints can perform.