Skeletal System
Articulations
Articulations
• Articulation (joint): a point of contact
between bones.
• Some allow movement, others are
immovable (sutures).
• Most joints allow considerable movement
as a result of muscle contractions.
Classification of Joints
• Categories
– Structural (by connective tissue or fluid)
• Fibrous
• Cartilaginous
• Synovial
– Functional
• Synarthrosas
• Amphiarthrosis
• diarthrosis
Table 9-1 pg 256 classifies
Each joint. Refer to it
Often.
Fibrous Joints (Synarthroses)
• Fibrous joints fit close.
• Connective tissue permit limited
movement; most joints are fixed
(immovable.)
• 2 sub types
– Syndesmoses
– Sutures
– Gomphoses
Syndesmoses
• Joints in which fibrous tissue connect two
bones.
• Some movement possible because of
ligament flexibility.
– Example: Distal ends of radius and ulna
Sutures
• Found only in skull.
• Thin layer of fibrous tissue between
bones.
• Immovable.
Gomphoses
• Unique joints between root of teeth and
mandible or maxilla.
Cartilaginous Joints (Amphiarthrosis)
•
•
•
•
Bones joined by hyaline or fibrocartilage.
Hyaline joints- Synchondroses
Fibrocartilage joints- symphyses
Joints are slightly movable in certain
circumstances.
Synchondroses
• Hyaline cartilage
between articulating
bones
• Examples: Articulation
between first rib and
sternum.
Symphyses
• Fibrocartilage pads bones
• Slight movement possible when pressure is
applied.
• Example: Symphysis pubis opens pelvis during
childbirth.
• Other examples of symphysis joints: vertebrae.
Synovial Joints (diarthroses)
• Freely movable.
• A majority of joints
are synovial.
• Ex: knee, hip
• Subcatagories:
– Uniaxial
– Biaxial
– Muliaxial
Flashcards: Will be used during first dissection
• Requirements:
• Required Cards:
– Front of card
– Synarthroses: Syndesmoses
• Name of the joint
– Synarthroses: Sutures
type.
– Synarthroses: Gomphoses
– Back of card
– Amphiarthrosis: Synchondroses
• Definition of joint
– Amphiarthrosis: symphyses
• Example of the
– Diarthroses
joint.
• Picture of the joint
Diarthroses
These joints are freely
Movable.
Examples: Hip & knee
Types of Synovial Joints (Diarthroses)
• 3 main groups:
– Uniaxial
• Hinge
• Pivot
– Biaxial
• Saddle
• Condyloid
– Multiaxial
• Ball and socket
• Gliding
Uniaxial Joints
• Synovial joints that permit movement
around one axis and in one plane.
• Hinge: Hinge shape; only back and force
movement.
– Example: Knee; ulna & humerus
• Pivot: Projection articulates with a ring or
notch of another bone.
– Example: 2nd & 1st cervical vertibrae.
Biaxial Joints
• Movement around 2 perpendicular axes in
two perpendicular planes.
• Saddle: Joint resembles a saddle.
– Example: Thumbs are the only 2 saddle joints
in the body.
• Condyloid: Where a condyle (rounded
projection) fits into a socket.
– Example: Occipital condyles & cervical
vertebrae; Distal end of radius into carpal
bones.
Saddle
Condyloid
Condyle
Multiaxial Joint
• Joints that allow movement around
multiple axes & around multiple planes.
• Ball & socket: Most moveable joint; ball
shaped head fits into circular depression.
– Example: Should; hip
• Gliding joints: Flat articulating surfaces
that allow limited gliding along various
axes; least moveable synovial joint.
– Example: Vertebrae; carpals & tarsals.
Gliding
Ball & Socket
Flashcards: Will be used during first dissection
• Requirements:
• Required Cards:
– Front of card
– Uniaxial: Hinge
• Name of the joint
– Uniaxial: Pivot
type.
– Biaxial: Saddle
– Back of card
– Biaxial: Condyloid
• Definition of joint
– Multiaxial: Ball & socket
• Example of the
– Multiaxial: Gliding
joint.
• Picture of the joint
Uniaxial: Hinge
Only back and force
movement
Examples: knee
Structure of synovial joints
•
•
•
•
•
•
•
Joint capsule
Synovial Membrane
Articular cartilage
Joint cavity
Menisci (articular Disks)
Ligaments
Bursae
Joint Capsule
• Sleeve-like extension of
periosteum (bone
membrane)
• Forms a casing around
ends of bones, binding
them.
Synovial Membrane
• Membrane that
lines joint capsule
and attaches to
margins of articular
cartilage.
• Secretes synovial
fluid.
Articular Cartilage
• Thin layer of hyaline cartilage.
• Cushions articular (connecting) ends of
bone.
Joint cavity
• Space between
articulating bones.
• More space More
movement.
Menisci (articulating disks)
• Pads of fibrocartilage
between articulating
ends of some
diarthroses.
• Usually divide joint
cavity into two
separate spaces.
• Knee joint has 2
menisci.
Ligaments
• Strong cords of dense fibrous tissue.
• Keep bones together.
Bursae
• Closed pillow like
structure.
• Filled with synovial fluid.
• Cushion joint and
facilitate movement of
tendons.
• Bursitis- Inflammation of
bursae.
Disorders of the Joints
• Osteoarthritis: Degenerative joint disease; wear
& tear of articular cartilage. Cartilage thins,
bony spurs form at articulations, ligaments
calcify. Symptoms: stiffness, pain, limited
mobility.
Disorders of the Joints
• Traumatic Injuries:
– Dislocations- damages nerve & blood vessels.
– Damage to cartilage- tears produce edema, pain,
instability, & limited motion.
– Sprain- injury to ligaments surrounding a joint,
disrupting synovial membrane. Bruising and
swelling may result from ruptured blood vessels.
Disorders of the Joints
• Arthritis: inflammatory joint disease.
Inflammation of synovial membrane, destruction
of cartilage, erosion of bone. Can be crippling
and cause deformities.
– Juvenile arthritis: Onset during childhood.
– Gouty arthritis: Arthritis caused by a metabolic
disorder- excess uric acid deposit into synovial fluid.