structure of physis

1. STRUCTURE OF
PHYSIS
PRESENTER:DR.TARUN KUMAR
JUNIOR RESIDENT
DEPT OF ORTHOPAEDICS
RLJH TAMAKA KOLAR

2. SPECIFIC LEARNING OBJECTIVES
• At the end of the class , participants should be able to answer:
• What is physis
• What are zones of physis
• Vascular supply of physis
• Types of physeal injuries and management

3. PHYSIS
• Physis is also known as Growth plate
• The physis is a unique cartilaginous structure that varies in
thickness depending on age and location
• Located between epiphysis and metaphysis of growing bones
• Responsible for longitudinal growth of the bones
• Appears radiolucent on X ray

4. The cells on epiphyseal surface of the epiphyseal cartilage plate
continously proliferate until growth in length is completed.
• The mature cells on the diaphyseal surface of the epiphyseal
cartilage plate degenerate and are replaced by bone from the
diaphysis.

5. • When full growth is attained, the epiphyeal cartilage turns into
bone and can longer be found. This occurs between 18 to 25
years.

7. • The peripheral margin of the physis consist of two specialized
areas :-
• ZONE OF RANVIER
• It is a wedge-shaped group of germinal cells that is continous
with the physis.
• It consists of three cell types-osteoblast , chondroblast and
fibroblast.

8. • Osteoblasts form the bony portion of the perichondrial ring at
the metaphysis.
• Chondroblasts contribute to the longitudinal growth
• Fibroblasts circumcsribe the zone and anchor it to
perichondrium above and below the growth plate.

9. • PERICHONDRIAL RING OF LACROIX
• It is a fibrous structure that is continous with the fibroblasts of the zone of
ranvier and the periosteum of the metaphysis.
• Perichondrial ring of LaCroix provides strong mechanical support for the
bone-cartilage junction of the growth plate.

11. 1.GERMINAL ZONE (RESERVE ZONE)
Chondrocytes here are spherical and seperated by more matrix
compared with cells in other zones.
The cells contain many lipid vacuoles and abundant endoplasmic
reticulum, which is indicative of protien production.

12. • ZONE OF PROLIFERATION
• In the proliferative zone , chondrocytes are flattened and alinged in
columns parallel to the long axis of the bone.
• The oxygen tension is higher than in the other zones as is the cell
metabolism, resulting in high concentration of cell metabolism.
• The primary function of this zone is cellular proliferation, other
functions include the formation of intracellular matrix, proteoglycan
and collagen.

13. • ZONE OF HYPERTROPHY
• The chondrocyte become spherical and, at the base of the zone, are
five times the size of chondrocyte in the proliferative zone.
• It has been found that insulin-like growth factor stimulates the
hypertrophy of the chondrocytes in this zone, thus promoting
longitudinal growth.
• The oxygen tension inn this part of the hypertrophic zone is low,
anaerobic metabolism develops, and lactate accumulates.

14. • ZONE OF PROVISIONAL CALCIFICATION
• Very thin layer and adjoins directly to the diaphysis.
• The cells are necrotic and the calcified substance undergoes
cavitation and dissolution.

15. • HISTOLOGY OF PHYSIS

16. • VASCULAR SUPPLY OF PHYSIS
• EPIPHYSEAL ARTERIES supply blood to the epiphysis via
multiple branches to the growth plate, providing
vascularization into the proliferative zone.
• PERICHONDRIAL ARTERIES supply the fibrous structures
of the growth plate.

17. NUTRIENT ARTERY provides four-fifths of the metaphyseal
blood supply.
METAPHYSEAL ARTERIES supply the remainder of the blood
supply. The terminal branches of these vessels end in small
vascular loops or capillary tufts below the last intact row of
chondrocyte lacunae of growth plate.

18. VASCULAR SUPPLY OF PHYSIS

19. PHYSEAL INJURIES
It has been estimated that 30% of fractures in children
involve a physis and most heal with out any long-term
complication.
The hypertrophic zone has the lowest resistance to shear
forces and thus is the most common anatomic site of
physeal injuries.
Ligaments in children are functionally stronger than the
physis. Therefore a higher proportion of injuries that
produce sprain in adults result in physeal fractures in
children.

20. • ETIOLOGY OF PHYSEAL INJURIES
• Trauma
• Infection
• Tumors
• Vascular injuries
• Repetitive stress

21. • CLASSIFICATION –SALTER AND HARRIS

22. • Type 1 fractures occur through the physis only , with or with out
displacement.
• It has good prognosis
• Type 2 fractures have a metaphyseal spike attached to the
seperated epiphysis with or with out displacemet.
• It is the most common type

23. • Type 3 fractures occur through the physis and epiphysis into the
joint with joint incongruity when the joint is displaced.
• Poor prognosis as the proliferative and reserve zones are
interrupted.
• Type 4 fractures occur in the metaphysis and pass through the
physis and epiphysis into the joint. Joint incongruity occurs with
displaced fractures.

24. • Poor prognosis as the proliferative and reserve zones are
interrupted.
• Type 5 fractures, which are usually diagnosed only in
retrospect, are compression or crush fractures of the physis ,
producing permanent damage and growth arrest.
• It has worst prognosis

25. • MANAGEMENT:
• TYPE 1 and 2 fractures can be treated non operatively by
closed reduction and immobiliztion with cast or slab
• Other types: open reduction and internal fixation

26. REFERENCES
• Turek’s textbook of orthopedics
• Campbell’s operative orthopedics

27. THANK YOU