Lecture on Articulations www.AssignmentPoint.com

Functional / Structural Classification of Joints Synarthrosis (no movement) Bony Fusion (Synostosis) Fibrous (Suture and Gomphosis) Cartilaginous (Synchondrosis) Amphiarthrosis (little movement) Fibrous (Syndesmosis) Cartilaginous (Symphysis) Give example location for each

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 Gliding Joint Hinge Joint Pivot Joint Ellipsoidal joint Saddle joint Ball & Socket joint

Gliding Joint • also found between carpals and tarsals 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 – H2O loss during aging Intervertebral ligaments Fig 8-8

Disc Problems Slipped disc vs. herniated disc Most common sites for disc problems: C5 - C6 L4 - L5 L5 - S1 Lumbago Laminectomy ( surgical removal vertebral arch by shaving laminae to access disc) Fig 8-9

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