Joints (a.k.a. Articulations)
I. Introduction
A.A.JointJoint
1. 1. Also called an articulationarticulation 2. Defined:
A joint is a point of contact between bones, cartilage and bones, or teeth and bone
I. Introduction
B. FunctionB. Function
1. 1. they hold the skeletal bones together
22.. Allows the rigid skeleton some flexibility so that
gross movements can occur
C. C. Relationship between Joints Relationship between Joints and and MovementsMovements
1. The closer the fit between bones at a joint, the
stronger the joint.2. Strong joints exhibit restricted
movements.3. The greater the distance
between articulating bones the greater range of
movements
II. Classification
A. Based on eitherA. Based on either
1. S1. Structure
based on the nature of the material comprising them
2. Function
based on degree of movement they allow
II. Classification
B. Functional B. Functional ClassificationsClassifications
1. 1. Synarthroses
arthrose=joint, syn=together
• Immovable jointsImmovable joints
• Examples: suturesExamples: sutures
Synarthroses
II. Classification
C. Functional ClassificationsC. Functional Classifications
2. 2. Amphiarthroses
arthrose=joint, amphi=both
• Slightly movable joints• Between tibia and fibula
Amphiarthroses
II. Classification
C. Functional C. Functional ClassificationsClassifications
3. 3. Diarthroses
arthrose=joint, dia=apart
a. freely movable joint
b. example: knee joint
II. Classification
b. no joint cavity
C. Structural C. Structural classificationsclassifications
1. 1. Fibrous Jointsa. joints held
together by fibrous connective tissue
SUTURESSUTURESBones are held together by a thin layer of dense fibrous tissue and also by interlocking projections of the bones.
Found only in the skull
GOMPHOSESGOMPHOSES
a peg-in-socket fibrous joint
Bones are held together by a cord or sheet of dense fibrous connective tissue
SYNDESMOSESSYNDESMOSES
II. Classification
B. Structural ClassificationsB. Structural Classifications
2. 2. Cartilaginous Jointsa.held together by
cartilaginous tissue
b. no joint cavity
SynchondrosSynchondroseses •
immovable
• only hyaline cartilage
SYMPHYSISSYMPHYSIS
VERY limited movement
Hyaline and fibrous cartilage
B. Structural ClassificationsB. Structural Classifications
3. 3. Synovial joints
a.held together by a synovial capsule
b. Have a joint cavity
c. Includes most joints
Gliding Gliding JointsJoints •Plane (=
gliding). Opposite bone surfaces are flat or slightly curved.
•Only sliding motion in all directions are allowed.
Hinge JointsHinge Joints
Convex surface of one bone fits smoothly into concave surface of the second bone .
Pivot JointsPivot Joints A rounded, pointed or conical surface of one bone is inserted into a ring made partly of another bone and partly of a ligament.
only movement allowed is the rotation of one bone around its own axis
Ellipsoidal (= condyloid) Ellipsoidal (= condyloid) JointsJoints
Oval-shaped surface fits into an oval-shaped cavity
Saddle JointsSaddle Joints
First bone's articular surface is concave in one direction and convex in the other while the second bone is just the opposite.
Ball and Socket JointsBall and Socket Joints
• head fits into a cup-shaped depression
• most freely moving of all joints
V. Joints (a.k.a. Articulations)C.C.Types of Movement Types of Movement
in Synovial Jointsin Synovial Joints1.1. GlidingGliding• slight movementslight movement • example:
vertebrae2.2.RotationRotation
• Movement around the long axis of limb
• Shoulder joint
V. Joints (a.k.a. Articulations)C.C.Types of Movement Types of Movement
in Synovial Jointsin Synovial Joints3. Angular
a.a. flexionflexion • decreasing angle
b.b. extensioextensionn• Increasing
angle
C. Types of Movement in C. Types of Movement in Synovial Synovial JointsJoints
C. Angular a.a. hyperextensionhyperextension • extension beyond
anatomical position
b.b. circumductioncircumduction • limb movement
with limb describing a cone
V. Joints (a.k.a. Articulations)C.C.Types of Types of
Movement in Movement in Synovial JointsSynovial Joints
3. Angular d. abduction abduction
movement away from midline
e.e. adductionadduction toward midline
C.C.Types of Movement in Types of Movement in Synovial JointsSynovial Joints4. Rotation
turns right to left
4. Rotationa.a. pronation
turns wrist so palm is facing dorsally
b.b. supinationsupination palm turned anteriorly
C. Types of Movement in C. Types of Movement in Synovial JointsSynovial Joints
5. Special Casesa.a. plantar
flexion and dorsiflexion
b.b. dorsiflexiondorsiflexion
C. Types of Movement in C. Types of Movement in Synovial JointsSynovial Joints