Articulations!!
(the Joints)
Section 1: Joint Design and Movement
• Articulations (_____________________)
– Where two bones interconnect
– Bones are relatively inflexible so necessary to
allow movement
– Reflect compromise between need for strength
versus need for ______________________
– Anatomical structure of each joint determines
type and amount of movement possible
• Categories from range of motion and subgroups from
anatomical structure
Joint types
• No Movement
– Have we seen this before?
• Limited Movement
– Can you think of any?
• Free Movement
– Examples?
Joint Design and Movement
• Three functional categories
1.
2.
3.
–
_______________________ (no movement)
Amphiarthrosis (little movement)
____________________________ (free movement)
Synarthrotic and amphiarthrotic joints
•
•
–
Relatively simple structure
Direct connections between bones
Diarthrotic joints
•
•
Complex in structure
Permit greatest range of motion
Synovial joints
• Components of synovial
joints
– ___________________
cartilages
• Resemble hyaline
cartilages
– Matrix contains more
water comparatively
• Have no perichondrium
• Slick and smooth, so
reduce friction
• Are separated by thin film
of synovial fluid
Articular
Cartilage
Components of synovial joints
(continued)
– ______________ fluid
• Similar in texture to egg
whites
• Produced at the synovial
membrane
• Circulates from areolar
tissue to joint cavity
• Percolates through
articular cartilages
• Total quantity is less than
3 mL
Synovial
fluid
Components of synovial joints
(continued)
– _________________
capsule
• Dense and fibrous
• May be reinforced with
accessory structures
(tendons and ligaments)
• Continuous with
periosteum of each bone
Joint
capsule
Functions of synovial fluid
– Lubrication
• With articular cartilage compression, synovial fluid is squeezed out
and reduces friction between moving surfaces
– _______________________________ distribution
• Provide nutrients and oxygen, as well as waste disposal for the
chondrocytes of articular cartilages
• Compression and reexpansion of articular cartilages pump synovial
fluid in and out of cartilage matrix
– ________________________ absorption
• Distributes compression forces across articular surfaces and
outward to joint capsule
Joint Accessory
– ____________________
(a pouch)
• Small pocket filled with
synovial fluid
• Often form in areas
where tendon or ligament
rubs against other tissues
• Reduce friction and act as
shock absorbers
Bursa
Accessory structures in knee
(continued)
– Fat pads
• Adipose tissue covered by
synovial membrane
• Protect articular cartilages
• Act as packing material for
joint
– _____________________
(a crescent)
• Pad of fibrous cartilage
between bones of synovial
joint
• May subdivide joint cavity
and affect fluid flow or
allow variations in shapes
of articular surfaces
Meniscus
Fat pad
• Accessory structures in
knee
– Tendons of quadriceps
• Pass across joint
– Limit movement
– Provide
mechanical
support
• Accessory ligaments
• __________________,
strengthen, and reinforce joint
• Intrinsic ligaments
– Localized thickening of joint
capsule
– Example: cruciate liagments of
knee
• ___________________
ligaments
– Separate from joint capsule
– May pass inside (intracapsular) or
outside (extracapsular) the joint
capsule
– Intracapsular example: cruciate
ligaments
– Extracapsular example: patellar
ligament
Synovial joints
• _________________ vs. strength in joints
– Greater range of motion = ______________
joint
• Examples:
– Synarthrosis (strongest type of joint, no movement)
– Diarthrosis (far weaker but broad range of motion)
– _____________________________ (luxation)
•
•
•
•
Movement beyond normal range of motion
Articulating surfaces forced out of position
Can damage joint structures
No pain from inside joint but from nerves or
surrounding structures
Types of motion and structural types
of synovial joints
–
_____________________
•
–
Movement along two axes in
one plane
Angular motion
•
–
Movement along two axes in
one plane with additional
change in angle
______________________
–
–
–
Special complex angular
movement
Proximal end of bone
remains fixed while distal
end can move in a circle
(“trace circumference”)
Rotation
•
Bone ends remain fixed and
shaft rotates
The anatomical types of synovial joints, with joint models and examples
Types of Synovial Joints
Models of Joint Motion
Gliding joint
Examples
• Acromioclavicular and
claviculosternal joints
• Intercarpal and
intertarsal joints
• Vertebrocostal joints
• Sacro-iliac joints
Manubrium
Hinge joint
Humerus
• Elbow joints
• Knee joints
• Ankle joints
• Interphalangeal joints
Ulna
Pivot joint
Atlas
• Atlas/axis
• Proximal radio-ulnar
joints
Axis
Ellipsoid joint
Scaphoid bone
Radius
• Radiocarpal joints
• Metacarpophalangeal
joints 2–5
• Metatarsophalangeal
joints
Ulna
Saddle joint
• First carpometacarpal
joints
Metacarpal bone
of thumb
Trapezium
Ball-and-socket joint
Scapula
• Shoulder joints
• Hip joints
Humerus
Figure 8.2 6
•
Flexion and extension
–
–
•
Usually applied to
movements of long
bones of limbs but also
axial skeleton
_____________________
_
Anterior/posterior
movement that reduces
angle between
articulating elements
–
–
–
Lateral flexion
»
Vertebral column
bending to the
side
Dorsiflexion
»
Flexion at ankle
joint and
elevation of sole
___________________
flexion (planta, sole)
»
Extension at ankle
joint and
elevation of heel
–
Extension
•
Anterior/posterior
movement that
increases angle between
articulating elements
–
__________________
»
Extension past
anatomical
position
•
Abduction and Adduction
–
Always refers to movements
of appendicular skeleton,
not axial
Movements are usually
toward or away from body
midline
–
•
–
For fingers or toes,
movements are
spreading digits apart or
bringing them together
____________________
(ab, from)
•
–
Movement away from
body longitudinal axis in
frontal plane
____________________
(ad, to)
•
Movement toward body
longitudinal axis in frontal
plane
•
Circumduction
–
Moving arm or thigh as
if to draw a big
_________________ at
distal end of limb
• Wrist
• Arm
•
Rotation
–
When applied to the
trunk, described as left
and right
_____________________
When applied to limbs
–
•
Medial rotation (internal
or inward rotation)
–
•
Anterior surface of limb
toward trunk long axis
Lateral rotation (external
or outward rotation)
–
Anterior surface of limb
away from trunk long
axis
•
Rotation (continued)
–
Other special terms for
rotation of forearm
•
____________________
–
–
–
•
Proximal end of radius
rotates near ulna
Distal end rolls across
anterior ulnar surface
Turns the wrist and
hand from palm
facing front to palm
facing back
____________________
–
–
Opposing movement
Palm is turned
anteriorly
•
Special movements
–
_______________________
•
–
Movement of thumb toward palm surface or other fingers
Protraction
•
–
Movement forward in anterior plane
___________________
•
–
Reverse of protraction
Inversion (in, into + vertere, to turn)
•
–
Twisting foot motion to turn sole inward
________________________ (e, out)
•
Opposing movement to inversion
Special movements
Opposition
Eversion
Retraction
Protraction
Inversion
Depression
Elevation
Figure 8.4 2
Articulations
• ____________________skeleton articulations
– Typically are strong but very little movement
• ___________________________ skeleton
articulations
– Typically have extensive range of motion
– Often weaker than axial articulations
Joints of the
Axial Skeleton
Sutures of the skull
Temporomandibular joint
(temporal bone and
mandible)
Atlanto-occipital joint
(occipital bone and atlas)
and the atlanto-axial joint
(C1–C2)
Joints of the thoracic cage
Intervertebral joints
The lumbosacral joint,
which attaches the last
lumbar vertebra to the
sacrum
The sacrococcygeal and
intercoccygeal joints,
which structurally
resemble simplified
intervertebral joints
Figure 8 Section 2 1
Joints of the
Appendicular Skeleton
The sternoclavicular joint,
the only articulation between
the axial skeleton and the
pectoral girdle and upper
limb
Shoulder joint
The sacro-iliac joint, which
firmly attaches the sacrum
of the axial skeleton to the
pelvic girdle of the
appendicular skeleton
Elbow joint
Superior and inferior
radio-ulnar joints
Pubic symphysis
Wrist joint
Joints of the hand
and fingers
Hip joint
Knee joint
Ankle joint
Joints of the foot and toes
Figure 8 Section 2 2
• Vertebral articulations
– Between superior and inferior articular processes
of adjacent vertebrae
• Gliding ______________________________ joints
– Permit flexion and rotation
– Adjacent vertebral bodies form symphyseal joints
with _______________________________ discs
– Numerous ligaments attach bodies and processes
of vertebrae to stabilize column
• Intervertebral discs
– Composition
• __________________________ fibrosis
– Tough outer layer of fibrous cartilage
– Collagen fibers attach to adjacent vertebrae
• ___________________ pulposus
– Soft, elastic, gelatinous core
– Provides resiliency and shock absorption
– Account for ¼ length of vertebral column
• Water loss from discs causes shortening of vertebral column
with age and increases risk of disc injury
The ligaments attached to the bodies and processes of all vertebrae
Primary Vertebral Ligaments
Ligamentum flavum
Intervertebral disc
Anulus fibrosus
Posterior longitudinal ligament
Nucleus pulposus
Spinal cord
Interspinous ligament
Spinal nerve
Supraspinous ligament
Posterior
longitudinal
ligament
Anterior longitudinal ligament
Lateral view
Sectional view
Figure 8.5 2
• Primary vertebral ligaments
– Ligamentum ______________________
• Connects adjacent vertebral laminae
– Posterior longitudinal ligament
• Connects posterior surfaces of adjacent vertebral bodies
– Interspinous ligament
• Connects spinous processes of adjacent vertebrae
– Supraspinous ligament
• Connects spinous processes from sacrum to C7
– Ligamentum nuchae from C7 to base of skull
– _______________________________ longitudinal ligament
• Connects anterior surfaces of adjacent vertebral bodies
• Disorders of vertebral column
– _______________________ disc
• Posterior longitudinal ligaments weaken causing more
pressure on discs
• Nucleus pulposus compresses, distorts anulus fibrosus
• Disc bulges into vertebral canal (doesn’t actually slip)
– ________________________ disc
• Nucleus pulposus breaks through anulus fibrosus
• Spinal nerves are often affected
• Disorders of vertebral
column (continued)
– ______________________
(penia, lacking)
• Inadequate ossification
leading to loss of bone
mass
• Often occurs with age
beginning between ages 30
and 40
• More severe in women
than men
• Osteoporosis (porosus,
porous)
– Bone loss sufficient to
affect normal function
The effects of osteoporosis on spongy bone
Clinical scan of a compression
fracture in a lumbar vertebra
Figure 8.5 5
The effects of osteoporosis on spongy bone
Normal spongy bone
SEM x 25
Spongy bone with
osteoporosis
SEM x 21
Figure 8.5 5
Ball and Socket
•
Shoulder joint
(glenohumeral joint)
–
__________________ range
of motion of any joint
Most frequently dislocated
joint
–
•
•
–
Demonstrates stability
sacrificed for mobility
Most stability provided
by surrounding skeletal
muscles, associated
tendons, and various
ligaments
Ball-and-socket diarthrosis
•
Formed by head of
humerus and glenoid
cavity of scapula
•
Hip joint
–
Sturdy ball-and-socket joint
•
–
–
Although not directly
aligned with weight
distribution along femur
shaft, which can produce
fractures of femoral neck
or intertrochanteric
region
Permits _______________,
extension, adduction,
abduction, circumduction,
and rotation
Formed by head of femur
and acetabulum of hip bone
The ligaments of the hip joint
Reinforcing Ligaments
Pubofemoral ligament
Iliofemoral ligament
Ischiofemoral ligament
Greater
trochanter
Ischial
tuberosity
Posterior view
Intertrochanteric
line
Lesser trochanter
The ligaments of the hip joint in posterior view
Anterior view
The ligaments of the hip joint in anterior view
Figure 8.6 5
Hinge
•
Elbow joint
–
Complex __________________
joint involving humerus, radius,
and ulna
Extremely strong and stable due
to:
–
1.
2.
3.
–
•
–
Bony surfaces of humerus and
ulna interlock
Single, thick articular capsule
surrounds both humero-ulnar
and proximal radio-ulnar joints
Articular capsule reinforced by
strong ligaments
Severe stresses can still produce
dislocations or other injuries
Example:
___________________ elbow
Muscles flexing elbow attach on
anterior while those extending
attach on the posterior
The elbow joint
Humerus
Posterior
view
Olecranon
fossa
Humeroulnar joint
Ulna
Olecranon
Figure 8.7 1
Elbow and knee joints
• Elbow joint (continued)
– Specific joints of the elbow
•
_____________________joint
–
•
Humero-ulnar joint
–
–
–
–
•
Capitulum of humerus articulating with head of radius
Largest and strongest articulation
Trochlea of humerus articulates with trochlear notch of ulna
Shape of ulnar notch determines plane of movement
Shapes of olecranon fossa and olecranon limit degree of extension
Proximal radio-ulnar joint is ___________part of elbow
joint
Elbow and knee joints
• Elbow joint (continued)
– Reinforcing ligaments
•
Radial _________________ ligament
–
•
Ulnar collateral ligament
–
•
Stabilizes lateral surface of joint
Stabilizes medial surface of joint
____________________ ligament
–
Binds head of radius to ulna
Elbow and knee joints
•
Knee joint
–
Contains
_____________separate
articulations
1.
2.
3.
–
Medial condyle of tibia to
medial condyle of femur
Lateral condyle of tibia to
lateral condyle of femur
Patella and patellar
surface of femur
Permits flexion,
extension, and very
limited
_______________
Elbow and knee joints
•
Knee joint (continued)
–
External support
•
Quadriceps tendon to patella
–
•
Fibular collateral ligament
–
•
Medial support
_________________________ligaments
–
•
Lateral support
Tibial collateral ligament
–
•
Continues as patellar ligament to anterior tibia
Posterior support extending between femur and heads of tibia and
fibula
Tendons of several muscles that attach to femur and tibia
Elbow and knee joints
• Knee joint (continued)
– Internal support
•
___________________ ligaments limit
anterior/posterior movement of femur and
maintain alignment of condyles
–
–
Anterior cruciate ligament (ACL)
» At full extension, knee becomes “locked”
(slight
lateral rotation tightens ACL, and lateral meniscus
forced between tibia and femur)
» Opposite motion to “unlock”
Posterior cruciate ligament (PCL)
Elbow and knee joints
• Knee joint (continued)
– Internal support (continued)
•
Medial and lateral _______________
–
–
Fibrous cartilage pads between tibial and femoral
condyles
Act as cushions and provide lateral stability to joint
Disruption to normal joint function
•
Arthritis
–
Damage to articular cartilages but specific cause varies
•
•
–
Exposed surfaces change from slick, smooth-gliding to rough feltwork
of collagen fibers increasing friction
Rheumatism (pain and stiffness affecting the skeletal and/or muscular
systems) is often a symptom
Osteoarthritis
•
•
Also known as degenerative arthritis or degenerative joint disease
Generally affects individuals age 60 and older
–
•
25% of women, 15% of men
Can result from cumulative wear and tear of joints or genetic factors
affecting collagen formation
Comparisons of normal articular cartilage with articular cartilage damaged by osteoarthritis
Arthritic Joint
Normal Joint
Fibrous
remains
of the
articular
cartilage
Articular
cartilage
Degenerating
articular
cartilage
LM x 180
Arthroscopic view of normal cartilage
LM x 180
Arthroscopic view of damaged cartilage
Figure 8.8 1 – 2
Disruption to normal joint function
• Visualizing problematic joints
– Arthroscopic surgery
•
•
Optical fibers (arthroscope) inserted into joint through
small incision without major surgery to visualize joint
interior
If necessary, other instruments can be inserted through
other incisions to permit surgery within view of
arthroscope
– _____________________ resonance imaging
•
Cost-effective and noninvasive viewing technique that
allows examination of soft tissues around joint as well
An arthroscopic view of the interior of the left knee,
showing injuries to the anterior and
posterior cruciate ligaments.
PCL
Femoral
condyle
ACL
Meniscus
Figure 8.8 3
Figure 8.8 4
Disruption to normal joint function
• _____________________ joints
– May be last resort if other solutions (exercise,
physical therapy, drugs) for joint problems fail
– Not as strong as natural joints, so most suitable for
elderly
– Typically have service life of about 10 years
Figure 8.8 5
Next Monday
• Exam: Framework
• Start new section: Organization!