1. DPT-FA12-036
Department of Physical Therapy
The University of Faisalabad

2. Biomechanics of Joints
and joint architecture
Reference:…….Basic Bio Mechanics
by Susan J hall

3.  Anatomist classified joints on basis
◦ Joint Complexity
◦ Number of axis present
◦ Joint Geometry
◦ Movement capabilities

4.  On basis of motion capabilities
joints are classified as
1. Immovable joints
2. Slightly moveable joints
3. Freely moveable joints

5.  Fibrous Joints
 Attenuate applied force (absorb shocks)
 Permit very little or no movement
 Subtypes are
a Sutures
b Syndesmoses

6.  Irregularly grooved articulating
bone sheets mete closely
 Tightly connected by fibers that
are continuous with periostium
 Fibers ossify in early childhood
and evetually replaced by bones
 Examples
◦ Sutures of skull

7.  Syndesmosis=held by bands
 Dense fibrous tissur binds the bones togather
 Permit extreamly limited movements
 Examples
◦ Coracoacromial joint
◦ Mid radioulnar
◦ Mid tibiofibular
◦ Inferior tibiofibular

8.  Cartilagenious joints
 Attenuate applied forces
 Permit relatively more motion than
synarthroses
 Subtypes
a Synchondroses
b Symphyses

9.  Synchondrosis= Held by cartilage
 Bones are held together by thin layer of
hyaline cartilage
 Examples
◦ Sternocostal joints
◦ Epiphysial plates
before ossification

10.  Thin plates of hyaline cartilage
separate disk of fibro cartilage
from bones
 Examples
◦ Vertibral joints
◦ Pubis symphyses

11.  Only slight limitation to
movement
 Articulating bone surfaces are
covered with hyaline cartilage
 Articular capsule surrounds joint
 Synovial membrane on inner
surface of capsule secretes
synovial fluid

12. a) Gliding (plane
arthrodial)
b) Hinge (ginglymus)
c) Pivot (screw; trochoid)
d) Condyloid (ovoid
Ellipsoidal)
e) Saddle (sellar)
f) Ball and Socket
(Spheroidal)

13.  Flat auricular surfaces
 Only movement permitted is non axial gliding
 Examples
◦ Inter metatarsal joints
◦ Facet joints of vertibrae

14.  One articulating bone surface is convex other
is concave
 Strong collateral ligaments restrict
movements to a single plane
 Hing like motion
 Examples
◦ Ulnohumeral joints
◦ Inter phalengeal joints

15.  Rotation is permitted around
one axis
 Examples
◦ Atlantoaxial joint
◦ Proximal radioulnar joint
◦ Distal radioulnar joint

16.  One articulating bone surface is
an ovular convex shape and other
is reciprocally shaped concave
surface
 Flexion, extension, adduction,
abduction and circumduction are
permitted
 Examples
◦ 2-5 metacarpophylengeal joints
◦ Radiocalpal joints

17.  Both articulating surfaces are
shaped like a seats of a saddle
 Movement capabilities are same as
in condyloid joints but at greater
range
 Example
◦ Carmometacarpal joint of thumb

18.  Surfaces of articulating bones are
reciprocally convex and concave
 Rotation in all three planes of
movement is permitted
 Examples
◦ Hip joint
◦ Shoulder joint

19.  Synovial joints are catagorized
according to number of axis of
rotation present
 There are four types
◦ Uniaxial: permit movement about one
axis
◦ Biaxial: permit movement about two
directions
◦ Triaxial: permit movement about three
directions

20.  Joint motion capabilities also sometimes
described in terms of degrees of freedom (df)
 A uniaxial joint has one df
 A biaxial joint has two df
 A triaxial joint has three df

21.  Two synovial structures are associated
with diarthroidal joints
◦ Bursae
◦ Tendon sheaths

22.  Bursae:
◦ capsules lined with synovial
membrane and filled with
synovial fluid
◦ Cousions th structures they
separate
◦ Mostly they separate tendons
from bones
◦ Some bursae separate bone from
skin eg olicronon bursae

23.  Tendon sheaths:
◦ Doubled layered synovial structures
◦ Srounds tendons that are placed in close
association with bones
◦ Many of long tendons passing from wrist joints are
protected by tendon sheaths