ANAT20006 Lecture Notes - Lecture 9: Hyaline Cartilage, Synovial Joint, Intervertebral Disc
12 Jun 2018
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LECTURE 9
ARTICULAR SYSTEM & JOINTS
TODAY
•(1) Articular System = Joints of the Body and associated ligaments
•Types of joints:
•Fibrous
•Cartilaginous
•Synovial
TYPES OF JOINTS
FIBROUS JOINTS
•(2) fibrous joints are relatively immobile, held
together by fibrous tissues. There are multiple
types of fibrous joints:
•A suture is the wavy line found between
bones of the skull. We give birth to fairly
small individuals and the skull bones are
malleable in order to pass through the birth
canal. So our brains actually grow a lot, so
the skull bones have to accommodate the
quick brain growth. When skull bones
ossify, sutures are obliterated and are
unseen sometimes.
•A syndesmosis is when you have a fibrous
tissue joining long bone parts together.
Doesn’t permit a lot of movement, it allows
the body to take the tension/stress placed
on one bone and transfer some to another
bone to even it out.
•A gomphosis is a fibrous joint holding teeth
in alveolar sockets in bone. This joint is a
ligament. Not overly mobile but allows for
movement.
CARTILAGINOUS JOINTS
•Cartilaginous joints are bones held together by cartilage. The primary cartilage is when a growing
bone has epiphysis and diaphysis and hyaline cartilage between bones. Not designed for
movement, just growth. Disappear during development.
•Secondary cartilage is wedges of fibrocartilage between layers of hyaline cartilage (Eg.
Intervertebral discs). Located in the midline.
•Lining each vertebral body is hyaline cartilage and
between the hyaline cartilage there is fibrous cartilage.
Fibrous cartilage is thicker, more irregular and dense
while hyaline cartilage is more smooth and glossy. A
secondary joint is not designed to
provide movement, it instead takes
stresses from bones.
SYNOVIAL JOINTS
•(3) highly mobile, most common in
body. Main characteristic is that there
Lecture 9 - Friday 11 August 2017
ANAT20006 - HUMAN STRUCTURE & FUNCTION
3
is a capsular ligament between bones. Collagen fibrous covering encircling bones meeting up.
•Bones separated by joint cavity
•Enclosed in fibrous joint capsule
•Lubricated by synovial fluid
•Allow extensive movement
•Tend to be associated with the limbs & limb girdles
TYPES OF SYNOVIAL JOINTS
NAMED BY SHAPE
•(4) uniaxial - movement in 1 axis. This includes plane, hinge and pivot joints.
•Biaxial - movement in 2 axes. This includes condylar and saddle joints.
•Multiaxial - multiple axes. This includes ball and socket joints.
•Hinge joints are when one bone has convexity and another bone has concavity, allowing flexion
and extension. Flexion and extension take place in 1 plane (uniaxial).
•A pivot joint is when one bone rotates relative to the other bone. One bone has a ring like
ligament encircling the other bone which moves inside the ring like ligament.
•Condylar joints allow flexion and extension and adduction and abduction.
•A saddle joint is when both surfaces are both concave and convex. Like a saddle on a horse.
•Ball and socket joint: convexity is ball shaped. Allows flexion/extension and abduction/adduction
and also rotation.
NAMED BY NUMBER OF ARTICULAR SURFACES
•(5) depending on number of surfaces they are named differently. Compound joint: enclosed in 1
capsule. The disc serves for 2 types of movement.
•Simple: One pair of articular surfaces (most synovial joints). 2 bones usually.
•Compound: More than one pair of articular surfaces (elbow and knee joints) enclosed within 1
capsule. Usually 3+ bones.
•Complex: Joint cavity subdivided into more than one joint compartment by:
•Fibrocartilaginous disc: TMJ, Sternoclavicular
•Incomplete menisci: Knee joint
•Allow separate movements to occur but maintain stability:gliding and side to side
BONE MOVEMENT AT SYNOVIAL JOINTS
•(6)
•Flexion/extension
•Sagittal plane (diving body into LHS and RHS).
•Abduction/adduction
•Coronal plane
•Abduction = body part away from midline. Plane parallel to coronal axis.
•Rotation (media (internal) & lateral (external) )
•Transverse plane
SYNOVIAL JOINT FEATURES
•(7) has articular cartilage. Have bones that meet up with hyaline
cartilage lining ends of bones.
•Remember cartilage is both avascular and aneural. This is important as
otherwise, movement would be painful. Synovial joints have an enclosure
of fibrous capsule. It goes around the bone and merges with the bone
periosteum. Essentially, the fibrous capsule merges at the point where the
epiphysis and diaphysis meet. Inside this plate, in the light purple, is the
synovial cavity. This has synovial fluid. Lining the cavity is the synovial
membrane, a really thin membrane layer of mesothelium. It lines the
internal side of the capsule. It doesn’t go along the articular cartilage. It
Lecture 9 - Friday 11 August 2017
ANAT20006 - HUMAN STRUCTURE & FUNCTION
Document Summary
Today: (1) articular system = joints of the body and associated ligaments, types of joints, fibrous, cartilaginous, synovial. Fibrous joints: (2) fibrous joints are relatively immobile, held together by fibrous tissues. There are multiple types of fibrous joints: a suture is the wavy line found between bones of the skull. We give birth to fairly small individuals and the skull bones are malleable in order to pass through the birth canal. So our brains actually grow a lot, so the skull bones have to accommodate the quick brain growth. When skull bones ossify, sutures are obliterated and are unseen sometimes: a syndesmosis is when you have a fibrous tissue joining long bone parts together. Cartilaginous joints: cartilaginous joints are bones held together by cartilage. The primary cartilage is when a growing bone has epiphysis and diaphysis and hyaline cartilage between bones. Disappear during development: secondary cartilage is wedges of fibrocartilage between layers of hyaline cartilage (eg.
