Transcript CHAPTER 9 “Joints and Articulations”

CHAPTER 9
“Joints”
COMMON COURSE OBJECTIVES:
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Joints: Structural and functional
classification
Structure of a typical synovial joint
Types of synovial joints
Terms for descriptions of movements
JOINTS
– Defined: any place where two bones come
together
– General Function of Joints:
- Hold the skeleton together
- Allow for increased mobility and flexibility of
skeleton
CLASSIFICATION OF JOINTS

Joints can be classified based on:
-function (what kind of movement they
allow)
-structure (what material is found in the
joint and if is there a joint cavity present).

You are required to know each of these categories.
Functional classification
 Synarthroses – joints that have NO
movement.
– Examples: sutures of the skull, gomphoses- teeth
 Amphiarthroses – partially movable joints.
– Examples: intervertebral disc and pubic symphysis
 Diarthroses – freely movable joints.
The most common type of functional joint in
the body.
– Examples: knee joint, shoulder joint,finger joints,ankle and
wrist joints, etc.
Structural Classification
1.
Bony joints (synostoses): immovable joint
formed when the gap between 2 bones ossifies.
2.
Fibrous joints (synarthroses): adjacent bones
are joined by collagen fibers. 3 kinds:
- sutures, gomphoses and syndesmoses.
3.
Cartilaginous joints (amphiarthroses): two
bones are joined by cartilage. 2 kinds:
- synchondroses and symphyses
4.
Diarthroses: freely movable and most common
joint in the body. Synovial joints are diarthrodial.
Fibrous joints (synarthroses)
Suture: immovable fibrous
joints that fuse skull
bones
 Syndesmoses: fibrous
joint where 2 bones are
joined by longer collagen
fibers; more movable.
 Gomphoses: attachment
of teeth to tooth socket by
a periodontal ligament.

Synovial Joints (diarthroses)
 this type of joint is defined by the
presence of a joint cavity filled with fluid.
 Most joints of the body fall into this class.
Examples: knee joint, elbow joint, shoulder and hip
joints and the phalanges of hands and feet, etc.
Structures in a Synovial Joint
articular capsule – external and internal
2. joint/synovial cavity – filled with synovial fluid
3. articular cartilage – Hyaline cartilage
4. synovial fluid – viscous/ clear colorless fluid
5. ligaments – give the joint reinforcement and
strength
6. Nerves – provide feelings of pain and stretch
7. Vessels - provide nutrients to joint
1.
Typical Synovial Joint
Additional joint structures

Ligaments- join bones to bones
– Consists of dense regular connective tissue.
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Tendons- join muscles to bone
– Consists of dense regular connective tissue.

Bursae- fibrous sac lined with synovial
membrane and containing synovial fluid
– Occurs between bones and tendons or muscles
– Acts to decrease friction during movement
Accessory joint structures
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fatty pads - cushioning
menisci – tough fibrocartilage
bursae -flattened fibrous sac lined by
synovial membrane.
tendon sheaths -fibrous tissue connecting a
muscle to a bone
Knee joint structures
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Articular capsule
Synovial membrane
Medial and lateral menisci
Suprapatellar, infrapatellar and prepatellar
bursae
Anterior and posterior cruciate ligaments
Tibial and fibular collateral ligaments
Patellar capsule
Articular cartilage
Tendon of quadriceps femoris
Knee Joint
Types of Synovial Joints
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Plane (gliding) Joints
Hinge Joints
Pivot Joints
Condyloid Joints
Saddle Joints
Ball and Socket Joints
Movements allowed by Synovial Joints
1. gliding – - bony surfaces of bone slide or glide over
each other
2. flexion –- bending movement that decreases the angle
3. extension – movement the increases the angle,
opposite of lexion
4. abduction –moving away from longitudinal axis
5. adduction –movement toward the longitudinal axis
6. circumduction –movement of the limb such that it
describes a cone
7. rotation – turning the bone or limb around its long axis
8. supination –rotating the forearm laterally such that the
palm faces superiorly
Movements allowed by Synovial Joints
9. pronation –- rotating the forearm medially such that
the palm faces inferiorly
10. inversion –- sole of the foot faces or turns medially
11. eversion –- sole of the foot turn laterally
12. protraction –-juttting out of the jaw
13. retraction –- moving the jaw backward
14. elevation –- lifting the limb or body superiorly
15. depression –- moving the body part inferiorly
16. opposition –- to bring the thumb and index finger
tips together
Body movements
Extension and flexion
Abduction and adduction
Elevation/Depression; Protraction/Retraction
Inversion/Eversion;
Pronation/Supination
Circumduction