Joints Flashcards
Describe the structural classifications of joints.
Based on anatomical characteristics. They include: fibrous, cartilaginous and synovial.
Describe the functional classifications of joints.
Based on the types of movements permitted. They include: synarthrosis, amphiarthrosis, and diarthroses.
Describe the main types of fibrous joints.
Suture - Bones are connected by a thin layer of connective tissues, and only found in between skull bones. Slightly moveable on children, immovable for adults.
Syndesmosis - Bones are joined by connective tissue that is arranged into a ligament.
Amphiarthrosis - slightly moveable. (ex. distal tibiofibular joints)
Interosseous Membrane - Bones are connected by a sheet of connective tissue. Present between radius/ulna and tibia/fibula.
Describe the main types of cartilagenous joints.
Synchondrosis - Bones are connected by hyaline cartilage (later ossifies into bones). Sternocostal joints or epiphyseal growth plates. Synarthrosis - immovable.
Symphysis - Bones are connected by fibrocartilage. Occurs in the middle of the body. Example - pubic symphysis and intervertebral discs. Amphiarthrosis - slightly movable.
Describe the main types of synovial joints.
Ligament - Thick band of dense connective tissue that is especially resistant to forces acting in a particular direction. Present in most synovial joints. Can be extracapsular or intracapsular.
Meniscus - Pad of fibrocartilage between the articular surfaces that absorbs shock and increases the stability of the joint. Ex. - knee joint.
Labrum - Ring of fibrocartilage surrounding the “socket” of the ball and socket joints that increase the stability of the joint. Present in the hip joint and shoulder joint.
Bursa - Fluid-filled sac-like structure located between tissues. Example - bones/ligaments, bones/tendons). Present throughout the body.
Describe gliding that occurs at synovial joints.
Gliding
- Side-to-side movements
- Flat bone surfaces (ex. Intercarpal joints, intertarsal joints)
- Little if any change in the angle between bones
Describe angular movements at synovial joints.
Angular - an increase/decrease in the angle between bones
Flexion - a decrease in the angle between bones (ex. Atlanto-occipital joint)
Extension - an increase in the angle between bones (ex. tibiofemoral joint)
Abduction - a movement of a bone away from the midline (ex. metacarpophalangeal joints - spreading fingers)
Adduction - a movement of bone towards the midline (ex. metacarpophalangeal joints - closing fingers)
Circumduction - Multiplanar motion. Continuous sequence of other angular movements that causes the distal end of a segment to move in a circle. Occurs primarily in the shoulder/hip joint
Describe rotational movement at synovial joints.
Rotation
- Movement of bone/segment such that it revolves around its longitudinal axis
- Occurs primarily in the vertebral column, shoulder joint and hip joint
- Some rotation occurs in the tibiofemoral (knee) joint
- Examples - atlanto-axial joint, intervertebral joints, glenohumeral joint, and hip joint
Describe sepcial movement at synovial joints.
Elevation - superior movement of a bone (uniplanar) (example - shoulder/scapula)
Depression - inferior movement of a bone (uniplanar) (example - shoulder/scapula)
Protraction - anterior movement of a bone (uniplanar) (example - temporomandibular joint)
Retraction - posterior movement of a bone (uniplanar) (example - temporomandibular joint)
Upward Rotation - movement of the scapula, such that the glenoid cavity turns upward
Downward Rotation - movement of the scapular such that the glenoid cavity turns downward
Supination - movement of the forearm such that the palm of the hand turns anteriorly
Pronation - movement of the forearm such that the palm of the hand turns posteriorly
Inversion - movement of the foot such that the soles turn medially
Eversion - movement of the foot such that the soles turn laterally
What are the 6 types of synovial joints?
Plane joints
Hinge joints
Pivot joints
Condyloid joints
Saddle joints
Ball-and-socket joints
Describe the plane joint.
- Both articulating surfaces are flat
- Permit gliding movements (biaxial or triaxial)
Intercarpal joints, intertarsal joints, sternoclavicular joints, acromioclavicular joints
Describe the hinge joint.
- The convex surface of one bone articulates with the concave surface of another bone
- Only permit flexion/extension (uniaxial)
- Elbow joint, knee joint, ankle joint, interphalangeal joints
Describe the pivot joint.
- The round surface of one bone is enclosed by a ring formed by another bone accompanying a ligament
- Only permit rotational movements (uniaxial)
- Atlanto-axial joint, radioulnar joints
Describe the condyloid joint.
- The oval-shaped convex surface of one bone articulates with the oval-shaped depression or another bone
- Permit flexion/extension & adduction/abduction (biaxial)
- Wrist joints, metacarpophalangeal joints, metatarsophalangeal
Describe the saddle joint.
- The saddle-shaped surface of one bone articulates with a “rider”-shaped surface of another bone
- Permit flexion/extension & abduction/adduction (biaxial)
- 1st carpometacarpal joint
Describe the ball-and-socket joint.
- The ball-like surface of one bones fits into a cup-shaped depression on another bone
- Permit flexion/extension, abduction/adduction, rotation (triaxial)
- Shoulder joint, hip joint
Describe the major anatomical features of the shoulder joint.
The shallowness of the glenoid cavity and glenoid labrum leads to enhanced joint mobility
Includes: subacromial bursa (“bursitis”), coracohumeral ligament (superior/anterior capsule), transverse humeral ligament (retinaculum - biceps/brachii), glenohumeral ligaments (anterior capsule), acromioclavicular ligament (“shoulder separation”)
Describe the major anatomical features of the hip joint.
Includes: iliofemoral ligament (limits extension of the hip), ischiofemoral ligament (limits medial rotation of the hip), pubofemoral ligament (limits abduction of the hip), ligament of the head of the femur - ligamentum teres, carries an artery for the femoral head
Describe the major anatomical features of the elbow joint.
- Radial collateral ligament (limits varus forces), annular ligament (supports the radial head), ulnar collateral ligament (limits valgus force), olecranon bursa (“bursitis”), ulna
- Valgus - lateral angulation of the distal segment
- Varus - medial angulation of the distal segment
Describe the major anatomical features of the knee joint.
Functions as a hinge joint - even though the articular surfaces incongruent
The round femoral condyles rolls and slide over the flat tibial condyles as the knee flexes and extends
This causes the points of contact between the condyle to change as the knee moves
The congruence of the joint surfaces is enhanced by the presence of the medial meniscus and lateral meniscus
The stability of the joints is highly dependent on the ligaments and muscles surrounding it
Includes: fibular collateral ligament (limits varus forces), fibula, tibia, tibial collateral ligaments (limits valgus forces), anterior cruciate ligament (ACL), posterior cruciate ligament (PCL)
Describe the major anatomical features of the ankle joint.
The stability of the ankle joints are very important since they support the weight of the entire body
Support is provided by the congruence of the articular surfaces, the ligaments and tendons that cross the ankle
Anterior portion of the articular surface on the talus - wider than the posterior portion
Has implication for ankle stability and injury mechanisms
Includes: anterior talofibular ligament, posterior talofibular ligament, calcaneofibular ligament (limits the inversion of the foot), deltoid ligament (limits inversion of the foot)
