Chapter 9: Joints Flashcards
1
Q
What is a joint and how does it get its name?
A
- A joint (AKA articulation) is any point where two bones meet, whether or not the bones are moveable at that interface
- Joint name: typically derived from the names of the bones / bone marking involved
2
Q
What are the 3 major joint (functional) categories?
A
- Synarthrotic
- immoveable
- Amphiarthrotic
- amphiarthrotic
- Diarthrotic
- freely moveable
3
Q
What are the 4 major (structural) joint categories?
A
- Bony joints
- between them is bone
- Fibrous joints
- Bones are bound by collagen fibers that emerge from one bone and penetrate into the other
- Cartilaginous joints
- between them is cartilage
- Synovial joints
- freely moving
- between them is space (capsule and cavity)
4
Q
WHat are the different types of bony joints?
A
- Synostosis
- immobile
- gap between two joints ossifies and becomes one bone
- E.g. light and right mandibular bones in infants, cranial sutures in elderly, attachment of rib to sternum in old age
5
Q
What are the different types of fibrous joints?
A
- Sutures
- immobile or slightly mobile
- short collagen fibers
-
Serrate (interlocking way lines)
- coronal, sagittal, lambdoid sutures
-
Lap (squamos): overlapping beveled edges
- temporal and parietal sutures
-
Plane (butt): straight
- palatine process of the maxillae
- Gomphoses
- attachment of a tooth to its socket
- Held in place by periodontal ligament (collagen made)
- Allows tooth to move a lit under stress of chewing
- Syndesmoses
- two bones bound by long collagen fibers
- mobile syndesmoses: interosseous membrane between radius and ulna
- less mobile syndesmoses: between tibia to fibula
6
Q
What are the types of cartilaginous joints?
A
- Synchondroses
- bones held together by hyaline
- Epiphysial plates (temporary joints)
- E.g. first rib attachment to sternum
- Symphyses
- bones held together by fibrocartilage
- e.g. pubic symphysis, bodies of vertebrae joined by intervertebral discs
- only slight movement between adjacent vertebrae
7
Q
What are some characteristics of synovial joints?
A
- These are often known as diarthrosis or diathrodial joints
- Two bones are separated by a joint (articular cavity) containing the lubricant synovial fluid (like an egg white)
- Most are free moveable
- Most are structurally complex
- They are most likely to develop painful disfunction
- They are most important joints for health professionals to understand
8
Q
What is the general anatomy of a synovial joint?
A
- Articular cartilage (very thin coating)
- reduces friction and absorbs shock
- Joint (articular) cavity
- Synovial fluid
- slippery lubricant in joint cavity
- Joint (articular) capsule
- outer fibrous capsule, contains periosteum
- Inner, cellular, synovial membrane
9
Q
What are accesory structures of a synovial joint?
A
- Fibrocartilage
- articular disc between bones (e.g. temporomandibular joint)
- Meniscus in knee
- absorbs shock and pressure
- improves fit together
- stabilizes joints, reducing the chance of dislocation
- Tendon
- Ligament
- Bursa
- fibrous sack filled with synovial fluid
- located between muscles where tendons pass over bone or between bone and skin
- cushion muscles, help tendons slide over joints, modifies direction of tendon pull
- tendon sheath
- elongated cylindrical bursa wrapped around a tendon
- in hand and foot
10
Q
How does exercise work with articular cartilage?
A
- Exercise warms synovial fluid
- presses it like a sponge, in and out
- synovial fluid is like blood replacement
- Cartilage then swells and provides a more effective cushion
- Repetitive compression exhanges fluid in and out of cartilage
- exhange metabolic waste and nutrients/oxygen (like blood)
- helps maintain health of cartilage longer
11
Q
What is range of motion (ROM) and what affects it?
A
- ROM is the degrees through which a joint can move
- aspect of joint performance
- physical assessment of a patient’s joint flexibility
- Determined by…. shape of articular surfaces
- olecranon ulna fits into olecranon fossa of humerus
- Strength and tautness of ligaments and joint capsules
- stretching of ligaments increases ROM
- Action of the muscles and tendons
- nervous system monitors joint position and muscle tone
- muscle tone: state of tension maintained in resting muscles
- nervous system monitors joint position and muscle tone
12
Q
What are the 6 classes of synovial joints and their general characteristics?
A
- Ball and socket joints
- only multiaxial joints
- hips, shoulder
- Condylar (ellipsoid) joints
- oval convex surface of one bone fits into a complementary shaped depression on the other
- biaxial (flexsion/extension and abduction/adduction usually)
- radiocarpal joint, metacarpophalangeal joint, atlanto-occipital joint
- Saddle joints
- both bones have articular surface shaped like a saddle, one is concave and the other convex
- Biaxial
- Trapeziometacarpal (opposeable thumb)
- Plane (gliding) joints
- flat articular surfaces slide over each other
- usually biaxial
- intercarpal/tarsal, between articular processes of vertebrae
- Hinge joints
- one bone with convex surface fits into concave depression of another bone
- monoaxial
- elbow, knee, joints within fingers and toes
- Pivot joints
- a bone spins on its longitudinal axis
- monoaxial
- atlantoaxial joint (shaking head), radioulnar joint
13
Q
What is zero position?
A
the position of a joint when a person is in the standard anatomical position
(joint movements described as deviation from the zero position or returning to it)
14
Q
Describe the following movements: flexsion, extension, hyperextension, abduction, and adduction
A
- flexion: movement that decreases joint angle
- common in hinge joints
- extension: movement that straightens a joint and returns the body to the zero position
- hyperextension: extension of a joint beyond zero position
- Abduction: movement of a body part in the frontal plane away from the midline of the body
- Adduction: movement in the frontal plane back toward the midline
- hyperadduction: crossing fingers, crossing ankles
15
Q
Describe the following movements: elevation and depression, protraction and retraction, circumduction, rotation, supination and pronation
A
- elevation: movement that raises a body part vertically in the frontal plane
- depression: movement that lowers a body part in the same plane
- protraction: the anterior movement of a body part in the transverse plane
- retraction: posterior movement in the same plane
- circumduction: one end of an appendage remains stationary while the other end makes a circular motion
- rotation: movement in which a bone spins on its longitudinal axis (can be medial/internal or lateral/external)
- Supination: forearm movement that turns the palm to face anteriorly or upward
- Pronation: forearm movement that turns palm to face either posteriorly or downward
18
Q
What are the basic elements of the shoulder joint?
A
- Glenhumeral joint–articulation of the glenoid cavity of scapula and the humerus
- Most freely moveable joint in the body
- Sacrifices stability for freedom of movement
- The joint is stabilized by tendons:
- biceps brachii tendon
- rotator cuff tendon (fused to joint capsule)
- stabilized in all directions except inferior, so most dislocations are downward
- ring of fibrocartilage (labrum) deepens glenoid cavity
20
Q
What are the basic elements of the hip joint?
A
- The coxal joint: head of femur inserts into acetabulum of coxal bone
- More stable than shoulder
- Dislocations are rare
- ring of fibrocartilage (labrum) deepens acetabulum socket
- Some infants have congenital dislocation
- stay in harness until acetabulum is deep enough for femur head
21
Q
What are the basic elements of the knee joint?
A
- Tibiofemoral joint: largest and most complex diarthrosis of the human body
- Primarily a hinge joint
- Patellofemoral joint is a gliding joint
- Stabilized by quadriceps tendon in front and hamstring tendon (semimembranous muscle) in back
- Popliteal region is stabilized by extracapsular ligaments and intracapsular ligaments (cross each other to form an X)
- Anterior cruciate ligament (ACL): prevents hyperextension of knee, common site of knee injury
- Posterior Cruciate Ligament (PCL): prevents femur from sliding off tibia
- Has lateral meniscus and medial meniscus
- C-shaped cartilages within joint capsule
- absorb shock and prevent side to side rocking
- joined by transverse ligament
23
Q
What are the basic elements of the ankle joint?
A
- Talocrural joint
- Medial articulation: between tibia and talus
- Lateral joint: between fibula and talus
- both articulations contained within one joint capsule
- Malleoli of the tibia/fibula overhang the talus on either side and prevent side to side motion
- More restricted range of motion than wrist
- Calcaneal (Achilles) tendon: extends from calf muscles to calcaneas
- Sprains (torn ligaments and tendons) are common at the ankle
