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Anatomy & Physiology I
Lecture 7
Chapter 8: Joints
Joints
• Also called articulations
– sites where two or more bones meet
• Functions of joints
– Give skeleton mobility
– Hold skeleton together
• Two classifications
– Functional
– Structural
Functional Classification
• Based on
– Amount of movement joint allows
• Three functional classifications:
– Synarthroses—immovable joints
– Amphiarthroses—slightly movable joints
– Diarthroses—freely movable joints
Structural Classification
• Based on
– Material binding bones together
– Presence/absence of joint cavity
• Three structural classifications:
– Fibrous joints
– Cartilaginous joints
– Synovial joints
Fibrous Joints
• Bones joined by dense fibrous connective
tissue
• No joint cavity
• Most synarthrotic (immovable)
– Depends on length of connective tissue fibers
• Three types:
– Sutures
– Syndesmoses
– Gomphoses
Figure 8.1a Fibrous joints.
Suture
Joint held together with very short,
interconnecting fibers, and bone edges
interlock. Found only in the skull.
Suture
line
Dense
fibrous
connective
tissue
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Figure 8.1b Fibrous joints.
Syndesmosis
Joint held together by a ligament.
Fibrous tissue can vary in length, but
is longer than in sutures.
Fibula
Tibia
Ligament
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Figure 8.1c Fibrous joints.
Gomphosis
“Peg in socket” fibrous joint.
Periodontal ligament holds
tooth in socket.
Socket of
alveolar
process
Root of
tooth
Periodontal
ligament
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Cartilaginous Joints
•
•
•
•
Bones united by cartilage
No joint cavity
Not highly movable
Two types:
– Synchondroses
– Symphyses
Figure 8.2a Cartilaginous joints.
Synchondroses
Bones united by hyaline cartilage
Epiphyseal
plate (temporary
hyaline cartilage
joint)
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Sternum
(manubrium)
Joint between first
rib and sternum
(immovable)
Figure 8.2b Cartilaginous joints.
Symphyses
Bones united by fibrocartilage
Body of vertebra
Fibrocartilaginous
intervertebral disc
(sandwiched between
hyaline cartilage)
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Pubic symphysis
Synovial Joints
• Bones separated by fluid-filled joint cavity
• All are diarthrotic (freely movable)
• Include ~ all limb joints; most joints of body
Synovial Joints: Six Distinguishing
Features
1. Articular cartilage: hyaline cartilage
– Prevents crushing of bone ends
2. Joint (synovial) cavity
– Small, fluid-filled potential space
Synovial Joints: Six Distinguishing
Features
3. Articular (joint) capsule
• Two layers
– External Fibrous layer
• Dense irregular connective tissue
– Inner Synovial membrane
• Loose connective tissue
• Makes synovial fluid
Synovial Joints: Six Distinguishing
Features
4. Synovial fluid
– Viscous, slippery filtrate of plasma and hyaluronic
acid
– Lubricates and nourishes articular cartilage
– Contains phagocytic cells to remove microbes and
debris
Synovial Joints: Six Distinguishing
Features
5. Different types of reinforcing ligaments
– Capsular
• Thickened part of fibrous layer
– Extracapsular
• Outside the capsule
– Intracapsular
• Deep to capsule; covered by synovial membrane
Synovial Joints: Six Distinguishing
Features
6. Nerves and blood vessels
– Nerve fibers detect pain, monitor joint position
and stretch
– Capillary beds supply filtrate for synovial fluid
Figure 8.3 General structure of a synovial joint.
Ligament
Joint cavity
(contains
synovial fluid)
Articular (hyaline)
cartilage
Fibrous
layer
Synovial
membrane
(secretes
synovial
fluid)
Periosteum
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Articular
capsule
Other Features of Synovial Joints
• Fatty pads
– For cushioning between fibrous layer and synovial
membrane or bone
– hip and knee joints
• Articular discs (menisci)
– Fibrocartilage separates articular surfaces to improve
"fit" of bone ends, stabilize joint, and reduce wear and
tear
– knee
Other Features of Synovial Joints
• Bursae
– Sacs lined with synovial membrane
• Contain synovial fluid
– Reduce friction where ligaments, muscles, skin,
tendons, or bones rub together
• Tendon Sheaths
– Elongated bursa wrapped completely around
tendon subjected to friction
Figure 8.4a Bursae and tendon sheaths.
Acromion
of scapula
Subacromial
bursa
Joint cavity
containing
synovial fluid
Fibrous layer of
articular capsule
Articular
cartilage
Tendon
sheath
Synovial
membrane
Tendon of
long head
of biceps
brachii muscle
Fibrous
layer
Humerus
Frontal section through the right shoulder joint
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Figure 8.4b Bursae and tendon sheaths.
Bursa rolls
and lessens
friction.
Humerus head
rolls medially as
arm abducts.
Humerus moving
Enlargement of (a), showing how
a bursa eliminates friction where
a ligament (or other structure) would
rubInc. against a bone
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Three Stabilizing Factors at Synovial
Joints
• Shapes of articular surfaces (minor role)
• Ligament number and location (limited role)
• Muscle tendons that cross joint (most
important)
– Muscle tone keeps tendons taut
• Extremely important in reinforcing shoulder and knee
joints and arches of the foot
Need a Summary?
• Refer to Table 8.2:
– Joint names
– Articulating bones
– Structural classification
– Functional classification
– Movements allowed
Synovial Joints: Movements Allowed
• All muscles attach to bone or connective
tissue at no fewer than two points
– Origin—attachment to immovable bone
– Insertion—attachment to movable bone
• Muscle contraction causes insertion to move
toward origin
Synovial Joints: Range of Motion
•
•
•
•
Nonaxial—slipping movements only
Uniaxial—movement in one plane
Biaxial—movement in two planes
Multiaxial—movement in or around all three
planes
Three General Types of Movements
at Synovial Joints
1. Gliding
2. Angular movements
– Flexion, extension, hyperextension
– Abduction, adduction
– Circumduction
3. Rotation
– Medial and lateral rotation
Gliding Movements
• One flat bone surface glides or slips over
another similar surface
• Examples:
– Intercarpal joints
– Intertarsal joints
– Between articular processes of vertebrae
Angular Movements
• Increase or decrease angle between two
bones
• Movement along sagittal plane
– Flexion—decreases the angle of the joint
– Extension—increases the angle of the joint
• Hyperextension—movement beyond the anatomical
position
Angular Movements
• Movement along frontal plane
– Abduction—movement away from the midline
– Adduction—movement toward the midline
• Circumduction
– Involves flexion, abduction, extension, and
adduction of limb
– Limb describes cone in space
Rotation
• Turning of bone around its own long axis
– Toward midline or away from it
– Medial and lateral rotation
• Examples:
– Between C1 and C2 vertebrae
– Rotation of humerus and femur
Special Movements
•
•
•
•
•
•
Supination and Pronation
Dorsiflexion and Planter Flexion
Inversion and Eversion
Protraction and Retraction
Elevation and Depression
Opposition
Lab Exercise
• Practice and understand the meaning of these
movements
Types of Synovial Joints
• Six types, based on shape of articular surfaces:
– Plane
– Hinge
– Pivot
– Condylar
– Saddle
– Ball-and-socket
Figure 8.7a The shapes of the joint surfaces define the types of movements that can occur at a synovial joint; they also determine the
classification of synovial joints into six structural types.
Plane joint
Metacarpals
Nonaxial movement
Flat
articular
surfaces
Gliding
Carpals
Examples: Intercarpal joints, intertarsal joints, joints between vertebral articular surfaces
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Figure 8.7b The shapes of the joint surfaces define the types of movements
that can occur at a synovial joint; they also determine the classification of
synovial joints into six structural types.
Hinge joint
Humerus
Ulna
Uniaxial movement
Medial/lateral
axis
Cylinder
Trough
Flexion and extension
Examples: Elbow joints, interphalangeal joints
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Figure 8.7c The shapes of the joint surfaces define the types of movements
that can occur at a synovial joint; they also determine the classification of
synovial joints into six structural types.
Pivot joint
Uniaxial movement
Vertical axis
Ulna
Radius
Sleeve
(bone and
ligament)
Axle (rounded
bone)
Rotation
Examples: Proximal radioulnar joints, atlantoaxial joint
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Figure 8.7d The shapes of the joint surfaces define the types of movements
that can occur at a synovial joint; they also determine the classification of
synovial joints into six structural types.
Condylar joint
Medial/
lateral
axis
Phalanges
Metacarpals
Biaxial movement
Anterior/
posterior
axis
Oval
articular
surfaces
Flexion and
extension
Examples: Metacarpophalangeal (knuckle) joints, wrist joints
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Adduction and
abduction
Figure 8.7e The shapes of the joint surfaces define the types of movements
that can occur at a synovial joint; they also determine the classification of
synovial joints into six structural types.
Biaxial movement
Saddle joint
Medial/
lateral
axis
Metacarpal 
Trapezium
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Articular
surfaces
are both
concave
and convex
Anterior/
posterior
axis
Adduction and
abduction
Example: Carpometacarpal joints of the thumbs
Flexion and
extension
Figure 8.7f The shapes of the joint surfaces define the types of movements
that can occur at a synovial joint; they also determine the classification of
synovial joints into six structural types.
Ball-and-socket joint
Cup
(socket)
Medial/lateral
axis
Multiaxial movement
Anterior/posterior
axis
Vertical axis
Scapula
Spherical
head
(ball)
Humerus
Flexion and extension
Examples: Shoulder joints and hip joints
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Adduction and
abduction
Rotation
Knee Joint
• Largest, most complex joint of body
• Three joints surrounded by a single joint cavity
– Femoropatellar joint
• Plane joint
• Allows gliding motion during knee flexion
– Lateral and medial tibiofemoral joints
• Femoral condyles with lateral and medial menisci of
tibia
• Allow flexion, extension, and some rotation when knee
partly flexed
Knee
• At least 12 associated bursae
• Capsule is reinforced by muscle tendons
– quadriceps and semimembranosus tendons
• Joint capsule is thin
• Anteriorly, quadriceps tendon gives rise to
three broad ligaments
– Medial and lateral patellar retinacula
– Patellar ligament
Figure 8.8a The knee joint.
Femur
Articular
capsule
Posterior
cruciate
ligament
Tendon of
quadriceps
femoris
Suprapatellar
bursa
Patella
Subcutaneous
prepatellar bursa
Synovial cavity
Lateral
meniscus
Lateral meniscus
Anterior
cruciate
ligament
Infrapatellar
fat pad
Deep infrapateller
bursa
Tibia
Patellar ligament
Sagittal section through the right knee joint
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Figure 8.8b The knee joint.
Anterior
cruciate
ligament
Articular
cartilage
on medial
tibial condyle
Medial
meniscus
Anterior
Articular
cartilage on
lateral tibial
condyle
Lateral
meniscus
Posterior
cruciate
ligament
Superior view of the right tibia in the knee joint, showing
the menisci and cruciate ligaments
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Figure 8.8c The knee joint.
Quadriceps
femoris
muscle
Tendon of
quadriceps
femoris
muscle
Patella
Lateral
patellar
retinaculum
Fibular
collateral
ligament
Fibula
Anterior view of right knee
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Medial
patellar
retinaculum
Tibial
collateral
ligament
Patellar
ligament
Tibia
Ligaments Stabilizing Knee Joint
• Capsular and extracapsular ligaments
– Help prevent hyperextension of knee
– Fibular and tibial collateral ligaments
– Oblique popliteal ligament
– Arcuate popliteal ligament
Figure 8.8d The knee joint.
Tendon of
adductor
magnus
Medial head of
gastrocnemius
muscle
Popliteus
muscle
(cut)
Tibial
collateral
ligament
Tendon of
semimembranosus
muscle
Femur
Articular
capsule
Oblique
popliteal
ligament
Lateral
head of
gastrocnemius
muscle
Bursa
Fibular
collateral
ligament
Arcuate
popliteal
ligament
Tibia
Posterior view of the joint capsule, including ligaments
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Ligaments Stabilizing Knee Joint
• Intracapsular ligaments
– Prevent anterior-posterior displacement
– Reside outside synovial cavity
– Anterior cruciate ligament
• Attaches to anterior tibia
– Posterior cruciate ligament
• Attaches to posterior tibia
Figure 8.8e The knee joint.
Lateral
condyle
of femur
Lateral
meniscus
Posterior
cruciate
ligament
Medial
condyle
Tibial
collateral
ligament
Anterior
cruciate
ligament
Tibia
Medial
meniscus
Fibular
collateral
ligament
Patellar
ligament
Fibula
Patella
Quadriceps
tendon
Anterior view of flexed knee, showing
the cruciate ligaments (articular
capsule removed, and quadriceps
tendon cut and reflected distally)
Shoulder (Glenohumeral) Joint
• Ball-and-socket joint
– Head of humerus with glenoid cavity of scapula
• Most freely moving joint in body
– Stability sacrificed
Figure 8.10a The shoulder joint.
Acromion
of scapula
Coracoacromial
ligament
Subacromial
bursa
Fibrous layer of
articular capsule
Synovial cavity
of the glenoid
cavity containing
synovial fluid
Articular
cartilage
Tendon
sheath
Tendon of
long head
of biceps
brachii muscle
Frontal section through right shoulder joint
Synovial membrane
Fibrous layer of
articular capsule
Humerus
Shoulder Joint
• Reinforcing ligaments
– Primarily on anterior aspect
– Coracohumeral ligament
• Helps support weight of upper limb
– Three glenohumeral ligaments
• Weak and sometimes absent
Figure 8.10c The shoulder joint.
Acromion
Coracoacromial
ligament
Subacromial
bursa
Coracohumeral
ligament
Greater
tubercle
of humerus
Transverse
humeral
ligament
Tendon sheath
Tendon of
long head
of biceps
brachii
muscle
Anterior view of right shoulder joint capsule
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Coracoid
process
Articular
capsule
reinforced by
glenohumeral
ligaments
Subscapular
bursa
Tendon of the
subscapularis
muscle
Scapula
Figure 8.10d The shoulder joint.
Acromion
Coracoid
process
Articular
capsule
Glenoid cavity
Glenoid labrum
Tendon of long
head of biceps
brachii muscle
Glenohumeral
ligaments
Tendon of the
subscapularis
muscle
Scapula
Posterior
Anterior
Lateral view of socket of right shoulder joint,
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Inc.
humerus
removed
Elbow Joint
• Articulation of radius and ulna with humerus
• Hinge joint
– Primarily trochlear notch of ulna with trochlea of
humerus
– Flexion and extension only
Figure 8.11a The elbow joint.
Articular
capsule
Synovial
membrane
Humerus
Synovial cavity
Articular cartilage
Fat pad
Tendon of
triceps
muscle
Bursa
Coronoid process
Tendon of
brachialis muscle
Ulna
Trochlea
Articular cartilage
of the trochlear
notch
Median sagittal section through right elbow (lateral view)
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Elbow Joint
• Anular ligament
– Surrounds head of radius
• Two capsular ligaments restrict side-to-side
movement
– Ulnar collateral ligament
– Radial collateral ligament
Figure 8.11b The elbow joint.
Humerus
Anular
ligament
Radius
Lateral
epicondyle
Articular
capsule
Radial
collateral
ligament
Olecranon
Ulna
Lateral view of right elbow joint
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Figure 8.11d The elbow joint.
Articular
capsule
Anular
ligament
Humerus
Coronoid
process
Medial
epicondyle
Radius
Ulnar
collateral
ligament
Ulna
Medial view of right elbow
Hip (Coxal) Joint
• Ball-and-socket joint
• Head of the femur articulates with
acetabulum
• Good range of motion, but limited by the
deep socket
– Rim of fibrocartilage - Acetabular labrum
• Enhances depth of socket so hip dislocations rare
Figure 8.12a The hip joint.
Articular cartilage
Acetabular labrum
Coxal (hip) bone
Ligament of the
head of the femur
(ligamentum teres)
Femur
Synovial cavity
Articular capsule
Frontal section through the right hip joint
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Hip (Coxal) Joint
• Reinforcing ligaments
– Iliofemoral ligament
– Pubofemoral ligament
– Ischiofemoral ligament
– Ligamentum teres
Figure 8.12c The hip joint.
Iliofemoral
ligament
Ischium
Ischiofemoral
ligament
Greater
trochanter
of femur
Posterior view of right hip joint, capsule in place
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Figure 8.12d The hip joint.
Anterior inferior
iliac spine
Iliofemoral
ligament
Pubofemoral
ligament
Greater
trochanter
Anterior view of right hip joint, capsule in place
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Lab Exercise for today
• Lab Exercise 13, not activities 3 and 4
– What to know?
• Types of joints
• Types of synovial joints and their movements
• Structural and Functional Characteristics of:
–
–
–
–
–
–
Intervetebral
Sternocostal
Elbow
Knee
Acromioclavicular and Shoulder
Sacroiliac and Hip
What else to know?
• The major ligaments of the hip joints (in bold)
• The major ligaments of the knee joint (in bold)
• The major ligaments of the shoulder joint (in
bold)