Chapter 8 : Articulations (pII)

Anat 1 Chapter 8 : Articulations

Functional / Structural Classification of Joints 1.

Synarthrosis (no movement) 1. 2. 3.

2.

Bony Fusion (Synostosis) Fibrous (Suture and Gomphosis) Cartilaginous (Synchondrosis)

Amphiarthrosis (little movement) 1.

2.

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 – H2O loss during aging

Intervertebral ligaments Fig 8-8

Disc Problems  Slipped  Most  C5

disc vs. herniated disc

Fig 8-9

common sites for disc problems:

- 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  Most

muscles

important normal movement?

Fig 8-15

Knee Joint  Much

more complex than elbow

 Much

less stable than other ______

 structurally  Extra-

3 separate joints

and intracapsular ligaments

 Locking

of tibia

of knee due to external rotation Figs 8-16 & 17

The end