Joints connect bones and allow movement. Their structure matches their function, with more complex joints providing a greater range of motion. Joints have intra-articular structures like cartilage and menisci within the joint cavity, and extra-articular structures like ligaments and tendons outside the cavity. Motion at joints involves osteokinematics of bone movement as well as arthrokinematics of joint surface movement, including rolling, sliding, and spinning. The shape of joint surfaces determines the direction of these motions.

1. Joint Structure and
Function
Dr Tabassum Saher
Assistant Professor
SOP, DPSRU

2. It is an articulation connecting two or more components
of a structure. - Cynthia Norkin.
Joint structure consists of: bony articular parts, meniscii,
cartilage, synovial fluid, capsule, ligaments, tendons, fat
pads, bursae, nerves and blood vessels.
Structures in and around are classified into two types:
intra-articular strutures and extra-articular structures.
Joint

3. Intra-articular Structures Extra-articular Structures
Articular surfaces Tendons
Meniscii Bursae
Cartilage Ligaments
Synovial lining along with synovial fluid Muscles
Capsule

4. 1. The design of a joint and the materials used in its
construction depend partly on the function of the
joint and partly on the nature of components.
2. Joints providing stability have different design than
those providing mobility.
3. The compelxity of design and composition matches
the range of functional demands- i.e. the more varied
the demand the more complex the joint.
4. Human joints serve many functions, hence are more
complex than most-man made joints.
5. Wolff’s law
Basic Principles

5. Range of motion: therange or the arc
through which the movement of one bony
lever occurs with respect to another.
There are two types of ROM’s:
a. Anatomical ROM: Movement of the joint within
anatomical limits.
b. Physiological ROM: movement of the joint beyond the
anatomical limit.
Joint motion

6. The extent of the anatomicrange is determined by a number
of factors, including the shape of the joint surfaces, the joint
capsule, ligaments, muscle bulk,
musculotendinous and bony structures.
Eg:
and surrounding
i. The humeroulnar joint at the elbow is limited in extension
by bony contact of the ulna on the olecranon fossa of the
humerus.
ii. The tibifemoral joint at the knee is limited in flexion by soft
tissue approximation at the popliteal fossa.

7. Given by cyriax
Experience felt by the therapist during the motion carried out
passively at the end of the range of passive physiologic ROM.
End feel

8. Hypermobility
Hypomobility
Ankylosed
Pathological ROM

9. Osteokinematics refers to the movement of the bones
in space during physiologic joint motion.
These are the movements in the sagittal, frontal, and
transverse planes that occur at joints.
The movements are typically described by the plane
in which they occur, the axis about which they occur,
and the direction of movement.
Eg: Osteokinematic movements at the ulnohumeral
joint include flexion or extension (direction) of the
ulna on the humerus (or humerus on the ulna) in the
sagittal plane about a frontal axis.
Osteokinematics

10. Physiologic joint motion involves motion of bony
segments (osteokinematics) as well as motion of the
joint surfaces in relation to another.
Accompany voluntary movements, but can’t b
e
produced voluntarily.
The term arthrokinematics is used to refer to these
movements of joint surfaces on one another.
Arthrokinematics

11. 3 movements clustering
arthrokinematics of
joint
The arthrokinematic motion
of the moving
segment is described in
relation to the nonmoving
segment.

12. Roll:
Rolling of one joint surface on another, as in a tire rolling on
the road.
The direction of rolling is described by the direction of
movement of the bone; thus, the femur rolls forward during
knee extension in standing.
During a pure rolling motion, a progression of points of contact
between the surfaces occurs.
Eg: In the knee, the femoral condyles roll on the fixed tibial
surface during knee flexion or extension in standing.

13. Slide:
Pure translatory motion.
Gliding of one component over another, as when a
braked wheel skids. The point of contact changes in the
fixed component as the sliding component moves over it.
Eg: In the hand, the proximal phalanx slides over t
h
e
fixed end of the metacarpal during flexion and extension.

14. Spin:
Spin is a pure rotatory motion. The same points remain
in contact on both the moving and stationary
components.
Eg: elbow, the head of the radius spins on t
h
e
capitulum of the humerus during supination and
pronation of the forearm.

15. Convex-concave rule: Convex joint surfaces roll
and glide in opposite directions, whereas concave
joint surfaces roll and slide in the same direction.
CONVEX: OPPOSITE
CONCAVE: SAME
CONCAVE-CONVEX RULE

16. OVOID SELLAR
One surface is convex and other
surface is concave
Each joint surface is both convex and
concave
DEPENDING ON THE SAHPE OF
ARTICULAR SURFACES

17. Joint motions commonly include a combination o
f
sliding, spinning, and rolling.
Although we typically describe the axis of rotation f
o
r
various joints in the body and use anatomical
landmarks to represent these axes, the combination of
sliding and spinning or rolling produces curvilinear
motion and a moving axis of motion.
The axis of rotation at any particular point in t
h
e
motion is called the instantaneous axis of rotation
(IAR).
NOTE

18. Combination motions, wherein a moving component
rolls in one direction and slides in the opposite
direction, help to increase the ROM available to the
joint and keep opposing joint surfaces in contact with
each other. Another method of increasing the range of
available motion is by permitting both components to
move at the same time.

19. All connective tissues will adapt to increased load
through changes in structural and/or material properties
(form follows function).
The load must be gradual and progressive; as the tissue
adapts to the new loading conditions, the load must
change to induce further adaptation.
The type of connective tissue formed will match t
h
e
type and volume of the load:
i. compression: cartilage or bone
ii. tension: ligament or tendon
Connective Tissue Response to
loads

20. Fracture
Subluxation
Dislocation
Avulsion fracture
Overuse injury
Pathological effects