Transcript Chapter 8 : Articulations (pII)
Anat 1 Chapter 8 : Articulations
Functional
/ Structural Classification of Joints
1.
1.
2.
3.
Synarthrosis (no movement) Bony Fusion Fibrous
(Suture and Gomphosis)
Cartilaginous
(Synostosis) (Synchondrosis)
2.
1.
2.
Amphiarthrosis (little movement) Fibrous
(Syndesmosis)
Cartilaginous
(Symphysis)
3) Diarthrosis
(free movement)
Always
synovial joints
mono, di-, and triaxial Strength vs. motility
The greater the range of motion, the weaker the joint.
Dislocation = luxation Partial dislocation = ?
“Double jointed”
Diarthroses = Synovial Joints
Have synovial cavity = space between two bones
Components that are always present
(fig 8-1)
Components that are sometimes present
3 Types of Motion at Synovial Joints
Linear motion
= gliding
Angular motion :
flexion, extension, hyperextension ab-, adduction circumduction
Rotation
left - right, internal or medial, external or lateral supination, pronation
Special Movements
Dorsiflexion, plantar flexion Protraction, retraction Elevation, depression Eversion inversion
6 types of Diarthroses
1
Gliding Joint
2
Hinge Joint
3
Pivot Joint
4
Ellipsoidal joint
5
Saddle joint
6
Ball & Socket joint
Gliding Joint
articulating surfaces flat.
• also found between carpals and tarsals • only slight movement - rotation prevented by ?
Hinge Joint
Convex surface of bone 1 fits into concave surface of bone 2
found in ?
monoaxial
Pivot Joint
rotation Projection of bone 1 articulates within ring of bone 2 Also found in proximal ends of ulna and radius
pronation and supination
Ellipsoidal (Condyloid) Joint Oval shaped condyle of bone 1 fits into elliptical cavity of bone 2
Also found between phalanges & metacarpals/-tarsals
Angular motion in two planes (= )
Saddle Joint
Articular surfaces shaped like saddle and rider Modified condyloid joint
Extensive angular motion without rotation
Also between malleus and incus
Ball and Socket Joint
Ball like surface of bone 1 fits into cuplike depression of bone 2
Found in ___________
Allows for flexion, ab- or adduction and rotation (
_____axial)
Representative Articulations Temporomandibular Joint
Mostly hinge joint, some gliding and rotation Articular disc
Intervertebral articulations
Gliding joints between ____________________ Intervertebral discs: (Amphiarthroses)
annulus fibrosus: tough outer layer (fibrocartilage)
nucleus pulposus: soft, gelatinous core
Account for ~25% of vertebral column height – H 2 O loss during aging Intervertebral ligaments
Fig 8-8
Disc Problems
Slipped disc vs. herniated disc
Fig 8-9
Most common sites for disc problems: C5 - C6 L4 - L5 L5 - S1 Lumbago Laminectomy ( surgical removal vertebral arch by shaving laminae to access disc)
Glenohumeral Joint
Type?
Greatest range of motion (due to loose and shallow)
Most frequently dislocated
Stability provided by?
Hip Joint
Deep well fitted _______ joint Participants ?
Stabilization: Extracapsular and intracapsular ligaments (ligamentum teres = ligamentum capitis femoris) Surrounding muscles Most important normal movement?
Fig 8-15
Knee Joint
Much more complex than elbow Much less stable than other ______ structurally 3 separate joints Extra- and intracapsular ligaments Locking of knee due to external rotation of tibia
Figs 8-16 & 17