For Transfemoral prosthesis Quadrilateral socket is a common socket design . This presentation is about the biomechanics of the Quadrilateral socket .

1. BANGLADESH HEALTH PROFESSIONS INSTITUTE
BHPI-CRP
School of Prosthetics and Orthotics
Biomechanics of Quadrilateral
Socket
Shishir Chandra Bin
Intern PO (01)

2. Content
 Objective
 Introduction
 Quadrilateral socket
 Quadrilateral socket shape
 Quadrilateral socket wall
 Biomechanical principles of Quadrilateral
socket
 Summary

3. Objective
To know about Quadrilateral socket
To know about the socket wall
To know about Quadrilateral socket
biomechanics

4. Introduction
Clinicians have 2 types of prosthetic sockets for patients
with a transfemoral amputation :
1. Quadrilateral socket introduced in the 1950s
2. Ischial containment socket introduced in the 1980s
For many years , the quadrilateral socket was
acceptable to clinicians and patients alike . But QL
socket has some disadvantage , and that’s why
Nowadays IRC socket has become more popular .

5. Quadrilateral socket
 Quadrilateral socket refers to socket shape viewed in transverse
plane .
 Quad = four
 Four walls are
 Medial
 Anterior
 Lateral
 Posterior

6. Quadrilateral socket shape

7. Quadrilateral socket wall
 Quadrilateral socket has four walls . Four walls are
 Medial wall
 Anterior wall
 Lateral wall
 Posterior wall

8. Quadrilateral socket biomechanics
Quadrilateral socket biomechanics :
 Total contact
 Firmness and softness of tissue
 The effect of sloped surfaces on stump/socket
pressures
 High anterior wall
 Stabilization of the femur and pelvis
 Initial flexion of the socket

9. Quadrilateral socket biomechanics
Total contact :
 Good blood circulation(prevent oedema)
 Increased surface area(reduced pressure)
 Improved proprioception(easy to control prosthesis)

10. Quadrilateral socket biomechanics
Firmness and softness
of tissue:
 Contracted large
muscles are related to
firm tissue (need relief )
 Femoral triangle and
lateral surface is soft
tissue area(increase
pressure over these
areas)

11. Quadrilateral socket biomechanics
The effect of sloped surface on stump:
 The best supporting surface to take weight is a horizo
ntal surface
 The TF stump does not tolerate end bearing
 Weight is distributed proximally at the Ischial Tuberosi
ty area

12. Quadrilateral socket biomechanics
High anterior wall:
 Ischial tuberosity tends to slide forward
(For this posterior counter force
needed )
 Pelvis also rotates anteriorly
 That’s why anterior wall is made 5 cm
higher than posterior wall

13. Quadrilateral socket biomechanics
Stabilization of the femur and pelvis:
 Pressure applied laterally during casting and rectificati
on( to resist abduction of femur )
 This adduction of femur stabilise the pelvis to drop on
the afected side
 This reduces lateral trunk bending

14. Quadrilateral socket biomechanics
Initial flexion of the socket :
 Gluteus maximus and hamstrings more effect in
generating hip extension forces
 Helps to maintain the ischial tuberosity on its seat
 It improves the gait of the amputee to reduce lumber
lordosis at heel off.

15. Summary
Quadrilateral socket has 6 biomechanical principles .
Among them 1st three are main principles to make a
proper TF socket . Quadrilateral socket walls have
functions to work the socket properly . If any wall does
not work properly then there will be problem with the
function of the prosthesis .