Chapter 8 - Joints Flashcards
Joint
the area where two bones connect
- Help bind parts of the skeleton together
- Makes bone growth possible as there are more ends
- Allows for movement of bones
- 2 types of classifications; structural and functional
Structural Classifications of Joints
- Fibrous: held by dense connective tissue
- Cartilaginous: held by cartilage
- Synovial: complex joint capsule structure
- Cartilaginous: held by cartilage
Functional Classification of Joints
- Synarthrotic: immovable
- Amphiarthrotic: slightly movable
- Diarthrotic: freely moveable
Fibrous Joints
- Held by dense connective tissue and lots of collagen fibers; provides close contact
includes:
- syndesmosis
- sutures
- gomphosis
Fibrous Joints: Syndesmosis:
slightly moveable bones bound by a sheet of dense connective tissue(interosseous membrane or tissue)
○ e.g. between radioulnar and between tibia-fibula
Fibrous Joint: Sutures
immovable thin layers of connective tissue between cranial bones
○ Margin of suture on cranial bones are like teeth which prevent movement
○ Sutural bones: bones created by sutures
Fibrous Joints: Gomphosis
immovable cone shaped bony process in a socket
○ E.g. root of our teeth which are held in place by the periodontal ligament
Cartilaginous Joints
- Connected by hyaline or fibrocartilage
includes:
- Synchondrosis
- Symphysis
Cartilaginous Joints: Syndochondrosis
bands of hyaline cartilage which are immovable
○ Temporary ones like epiphyseal plates
Permanent ones like between the manubrium
Cartilaginous Joints: symphysis
slightly moveable pads of fibrocartilage between bones
○ e.g. pubic symphysis, interverbal discs
Synovial Joints
- all diarthrotic joints which have articular cartilage and joint capsules
includes:
- ball and socket
- condylar
- saddle
- pivot
- hinge
- plane/gliding
Ball and Socket Joint
round head in a cup shaped cavity which has the widest range of motion
- e.g. Shoulder, hip
- allows for circumduction
Condylar Joint:
oval condyle fits into the elliptical cavity allowing for circumduction, flexion/extension and abduction/adduction
○ Metacarpal-phalanges
Plane/Gliding Joint
almost flat or slightly curved joints that allow for sliding motions
- radioulnar-carpal
Hinge Joint
convex surface fits into concave surface of the other bone allowing for flexion/extension and slight rotation
- knee, elbow
Pivot Joint
cylindrical surface rotates around a ring of another bone
- neck
Saddle Joint
surfaces have both convex and concave surfaces which allows for biaxial movement
○ e.g. carpal-metacarpal
How joints move?
- Movement of joints is determined by the shape of the joint and the muscles attached
○ Origin: relatively fixed end
○ Insertion: more moveable end- When a muscle contracts, the insertion is brought towards the origin
Circumduction
movement of a part of the body in a circular path
Dislocation
displacement of articulating surfaces
Sprain
tearing of connective tissue in joint, without bone dislocation
- Torn Ligaments: resulting from overtwisting, overextension, lifting heavy objects and falling
Structure of Synovial Joints
- Articular(hyaline) cartilage covers the ends of bones
- Joint capsule
○ Outer fibrous layer is composed of ligaments
○ Synovial membrane
○ Synovial cavity which secretes synovial fluid
○ Menisci
○ Bursa; sacs of synovial fluid which cushions ligaments going over bony processes
Bursitis
inflammation of a bursa from overuse or stress
Arthritis
inflammation, swelling, pain in a joint
- Rheumatoid arthritis: autoimmune
- Osteoarthritis: degenerative due to aging
- Lyme arthritis: caused by lyme disease
- Gout: build up of uric acid crystal in joint
Joint Replacement
- Can use synthetic materials like steel, titanium for bigger joints and silicone or ceramic for smaller joint replacements
- Most common are hip and knee joint replacements
- New joint replacement tech also coats them with hydroxyapatite so that the body better receives it and grows over it
Jaw Joint
- Consists of the mandible and temporal bone articulating between the mandibular condyle and mandibular fossa
- An articular disc sits between the two surfaces and separates the synovial cavity in half
- A modified hinge joint inferior to the articular disc allows depression/elevation while eating and the superior surface allows for gliding movements in grinding of food
Shoulder Joint
- Consists of the glenoid cavity and head of the humerus protected by the coracoid and acromion processes as well as by dense connective tissue and muscle
- Tendons of several muscles blend with the fibrous layer of the shoulder capsule forming the rotator cuff
- The glenoid labrum composed of fibrocartilage helps deepen the cavity
Elbow Joint
- Includes the hinge joint between the trochlea of the humerus and the trochlear notch of the ulna, and the plane joint between the capitulum of the humerus and the shallow depression on the head of the radius
- Flexion extension occurs at the humerus-ulna connection while there is pronation/supination occurring due to the anular ligament at the head of the radius
Hip Joint
- Consists of the head of the femur and the acetabulum
- Ligamentum capitis attaches to the fovea capitis and connective tissue in the acetabulum and helps carry blood vessels
- Acetabular labrum in a horseshoe shaped ring of fibrocartilage deepens the cavity and encloses the head of the femur
Knee Joint
- Condyles of the femur and tibia are largely hinge joints but allow some rotation when the knee is flexed
- Femur-patella joint is a plane joint
- As the joint capsule is relatively weak the many ligaments and tendons strengthen it and cover the capsule anteriorly
- C shaped menisci separate the articulating surface of the femur and tibia and help align them
