Download Lecture 9

Joints
Articulations
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Joint
A point of contact between two bones,
between bone and cartilage, or between
bone and teeth
Structural Classification
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Presence of synovial cavity?
Type of connective tissue?
Types of Joints based on Structure
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Fibrous
Cartilaginous
Synovial
Fibrous
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Fibrous connective tissue
Lack a synovial cavity
Cartilaginous
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Cartilage
Lack a synovial cavity
Synovial
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Dense irregular connective tissue
Acessory ligaments
Synovial Cavity present
Functional Classification
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Degree of movement they permit
Type of Joints Based on Function
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Synarthrosis
Amphiarthrosis
Diarthrosis
Synarthrosis
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Immovable joint
Amphiarthrosis
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Slightly movable joint
Diarthrosis
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Freely movable joints
All are synovial joints
Three types of Fibrous Joints
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Sutures
Syndesmoses
Gomphoses
Suture
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A fibrous joint composed of dense fibrous
connective tissue that unite skull bones
only.
Suture
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Synarthrosis (immovable)
Suture
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Example: coronal suture
Syndesmoses
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A fibrous joint
Syndesmoses
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More distance between bones than
sutures
Syndesmoses
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Fibrous connective tissue arranged as a
ligament (bundle) or interosseous
membrane (sheet)
Syndesmoses
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Amphiarthrosis (slightly movable)
Syndesmoses
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Example: distal tibiofibular joint
Gomphosis
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A fibrous joint in which a cone-shaped peg
fits into a socket
Gomphosis
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Articulation between roots of teeth and
sockets of the maxillae and mandible.
Gomphosis
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Dense fibrous connective tissue is the
periodontal ligament
Gomphosis
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Synarthrosis (immovable joint)
Types of Cartilaginous Joints
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Synchondroses
Symphyses
Synchondroses
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Hyaline cartilage
Synchondroses
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Synarthrosis (immovable joint)
Synchondroses
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Example: epiphyseal plate and first rib
and manubrium of sternum
Symphyses
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Fibrocartilage connects the bones
Symphyses
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Amphiarthrosis (slightly movable)
Symphyses
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Example: pubic symphysis
Synovial Joints
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All diarthrosis
Synovial Joints
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Contain Synovial Cavity (presence of
space between articulating bones)
Synovial Joints
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Ends of bones covered by articular
cartilage
Articular Capsule of Synovial Joints
•
Encloses the synovial cavity and unites
the articulating bones
Articular Capsule of Synovial Joints
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Fibrous capsule – outer layer composed
of dense connective tissue
Articular Capsule of Synovial Joints
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Synovial membrane – inner layer
composed of areolar connective tissue
Synovial Fluid of the Synovial Joint
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Fluid in the joint cavity secreted by
fibroblasts of the synovial membrane
Synovial Fluid of the Synovial Joint
1.
Reduces friction
Synovial Fluid of the Synovial Joint
2. Supplies nutrients and removes wastes
from chondrocytes within articular
cartilage
Accessory Ligaments of the
Synovial Joint
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Extracapsular ligaments – lie outside the
articular capsule (Fibular and Tibular
Collateral Ligaments)
Accessory Ligaments of the
Synovial Joint
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Intracapsular ligaments – occur within the
articular capsule (Anterior and Posterior
Cruciate Ligament)
Articular Discs of Synovial Joints
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Fibrocartilage that lie between the
articular surfaces of the bones
Articular Discs of Synovial Joints
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Allow two bones of different shapes to fit
more tightly
Articular Discs of Synovial Joints
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Directs flow of synovial fluid to the areas
of greatest friction
Types of Synovial Joints
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Planar
Hinge
Pivot
Condyloid
Saddle
Ball and Socket
Planar
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Articulating surfaces are flat or slightly
curved
Planar
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Permits side to side and back and forth
gliding movement
Planar
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Example: intercarpal, intertarsal,
sternoclavicle, acromioclavicular,
sternocostal, vertebrocostal
Hinge
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Convex surface of one bone fits into the
concave surface of another bone
Hinge
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Monoaxial
Hinge
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Examples: knee, elbow, ankle, and
interphalangeal
Pivot
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Rounded or pointed surface of one bone
articulates with a ring formed by another
bone and ligament
Pivot
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Monoaxial
Pivot
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Example: radioulnar joint
Condyloid
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Convex oval-shaped projection of one
bone fits into the oval-shaped depression
of another bone
Condyloid
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Biaxial
Condyloid
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Example: wrist and metacarpophalangeal
joints
Saddle
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Articular surface of one bone is saddle
shaped, and the other bone fits into the
saddle
Saddle
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Biaxial
Saddle
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Example: carpometacarpal joint of the
thumb
Ball and Socket
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Consists of the ball-like surface of one
bone fits into a cup-like depression of
another bone
Ball and Socket
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Multiaxial
Ball and Socket
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Example: shoulder and hip joints
Torn Cartilage
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The tearing of articular discs or menisci in
the knee.
Occurs among athletes
Sprains
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This occurs when a joint is twisted and
stretches or tears its ligaments but does
not dislocate the bones.
Sprains
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Ankle joint and lower back are commonly
sprained
Dislocation
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The displacement of a bone from joint,
with resultant tearing of ligaments,
tendons, and articular capsules
Dislocation
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The shoulder joint is the most common
joint dislocated due to shallowness of the
socket.
Dislocation
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Hip joint not common due to acetabular
rim is smaller than the head of the femur
Shoulder Joint
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Glenohumeral joint
Shoulder Joint
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Ball and socket joint
Shoulder Joint
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Head of the humerus and glenoid cavity of
the scapula
Shoulder Joint / Anatomical
Features
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Glenoid labrum – A narrow rim of
fibrocartilage around the edge of the
glenoid cavity.
Shoulder Joint / Anatomical
Features
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Glenoid labrum deepens and enlarges the
glenoid cavity
Shoulder Joint / Anatomical
Features
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Bursae – fluid filled saclike structures that
reduce friction in synovial joints
Shoulder Joint / Movements
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Flexion, extension, abduction, adduction,
medial rotation, lateral rotation, and
circumduction
Shoulder Joint / Strength
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Attains most support from the rotator cuff
muscles (supraspinatus, infraspinatus,
teres minor, and subscapularis) which join
the scapula to the humerus
Shoulder Joint / Strength
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Rotator cuff muscles hold the head of the
humerus in the glenoid cavity
Elbow Joint
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Hinge joint
Elbow Joint
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Involves the trochlea of the humerus, the
trochlear notch of the ulna, and the head
of the radius
Elbow Joint / Movements
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Flexion and extension
Hip Joint
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Ball and socket
Hip Joint
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Head of the femur and the acetabulum of
the hip bone
Hip Joint / Anatomical Features
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Acetabular labrum – Fibrocartilage rim
attached to the margin of the acetabulum.
Hip Joint / Anatomical Features
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Acetabular labrum enhances the depth of
the acetabulum
Hip Joint / Movements
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Flexion, extension, abduction, adduction,
circumduction, medial rotation, and lateral
rotation of the thigh
Knee Joint
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One synovial cavity
Knee Joint
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3 joints
Knee Joint
1. Tibiofemoral joint – hinge joint/ between
the lateral condyle of the femur, lateral
meniscus, and lateral condyle of the tibia
Knee Joint
2. Tibiofemoral joint – hinge joint/ between
the medial condyle of the femur, medial
meniscus, and medial condylye of the tibia
Knee Joint
3. Patellofemoral joint – planar joint/
between the patella and the patellar
surface of the femur
Knee Joint / Anatomical Features
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Medial meniscus and Lateral meniscus
Knee Joint / Anatomical Features
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Contains bursae
Knee Joint
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Flexion, extension, slight medial rotation,
lateral rotation of leg in flexed position