The hip joint is a ball-and-socket joint that allows flexion, extension, abduction, adduction, and rotation. It is formed by the acetabulum of the pelvis articulating with the femoral head. The primary function is to support the weight of the upper body. Key biomechanical aspects include the angles of inclination and torsion of the femur, congruence of the joint surfaces, and forces transmitted during weight bearing that are balanced by the joint capsule and trabecular bone structure. Motion occurs through tilting and rotation of the pelvis on a fixed femur. Surrounding muscles provide dynamic stability and control movement.
THis PPT will give you knowledge about the principles of shoulder; articulating surface, motions, ligamentous structure and musculature structure that related to shoulder region.
this slideshow describes about the hip joint anatomy, biomechanics and its pathomechanics along with angles of hip joint. the slide show also briefs about the pelvic femoral rhythm in daily activities
Matching Shoulder Job Demands To Functional Capacityslfischer
This lecture provides a review of shoulder anatomy, presents a number of shoulder related injuries that may occur in the workplace, then presents a method to reduce injury risks by matching shoulder functional capacity with the demands placed on the shoulder joint during work
THis PPT will give you knowledge about the principles of shoulder; articulating surface, motions, ligamentous structure and musculature structure that related to shoulder region.
this slideshow describes about the hip joint anatomy, biomechanics and its pathomechanics along with angles of hip joint. the slide show also briefs about the pelvic femoral rhythm in daily activities
Matching Shoulder Job Demands To Functional Capacityslfischer
This lecture provides a review of shoulder anatomy, presents a number of shoulder related injuries that may occur in the workplace, then presents a method to reduce injury risks by matching shoulder functional capacity with the demands placed on the shoulder joint during work
Includes detailed description of BIOMECHANICS & PATHOMECHANICS OF KNEE JOINT AND PATELLOFEMORAL JOINT with recent evidences . Hope you find it useful!!
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
2. INTRODUCTION
• The hip joint, or coxofemoral joint, is the articulation of
the acetabulum of the pelvis and the head of the femur
• diarthrodial ball-and-socket joint
• three degrees of freedom:
1. flexion/extension in the sagittal plane
2. abduction/adduction in the frontal plane
3. medial/lateral rotation in the transverse plane
3. • The primary function of the hip joint is to support the
weight of the head, arms, and trunk (HAT) both in static
erect posture and in dynamic postures such as
ambulation, running, and stair climbing.
4. STRUCTURE OF THE HIP JOINT
Proximal Articular Surface
Acetabulum
• The opening of the acetabulum is
approximately laterally inclined
50°; anteriorly rotated
(anteversion) 20°; and anteriorly
tilted 20° in the frontal, transverse,
and sagittal planes, respectively
6. • Center edge angles are classified as follows:
• definite dysplasia less than 16°
• possible dysplasia 16° to 25° and
• normal greater than 25°
• In addition, abnormalities in acetabular depth, inclination,
and version (abnormal positioning in the transverse plane)
can also affect femoral head coverage
7. • Anteversion of the acetabulum exists when the
acetabulum is positioned too far anteriorly in the
transverse plane
• Retroversion exists when the acetabulum is positioned
too far posteriorly in the transverse plane
8. Acetabular labrum
• The entire periphery of the acetabulum is rimmed by a
ring of wedge-shaped fibrocartilage called the acetabular
labrum
• Deepens the socket, increases the concavity of the
acetabulum, grasping the head of the femur to maintain
contact with the acetabulum
• It enhances joint stability by acting as a seal to maintain
negative intra-articular pressure
• Also provide proprioceptive feedback
9. Distal articular surface
• The head of the femur
ofovea or fovea capitis
oligament of the head of the femur (ligamentum teres)
10. ANGULATION OF THE FEMUR
• There are two angulations made by the head and neck of
the femur in relation to the shaft
Angle of inclination occurs in the frontal plane between an
axis through the femoral head and neck and the
longitudinal axis of the femoral shaft
Angle of torsion occurs in the transverse plane between
an axis through the femoral head and neck and an axis
through the distal femoral condyles
11. 1.ANGLE IF INCLINATION OF FEMUR
• The angle of inclination of the femur approximates 125°
• Normal range from 110° to 144° in the unimpaired adult
• With a normal angle of inclination, the greater trochanter
lies at the level of the center of the femoral head
• A pathological increase in the medial angulation between
the neck and shaft is called coxa valga
• A pathological decrease is called coxa vara
12. • Both coxa vara and
coxa valga can lead to
abnormal lower
extremity
biomechanics altered
muscle function,and
gait abnormalities
13. 2.ANGLE OF TORSION OF THE FEMUR
• The angle of torsion of the femur
can best be viewed by looking down
the length of the femur from top to
bottom
• An axis through the femoral head
and neck in the transverse plane
will lie at an angle to an axis
through the femoral condyles, with
the head and neck torsioned
anteriorly (laterally) with regard to
an angle through the femoral
condyles
14. • In the adult, the normal angle
of torsion is considered to be
10° to 20°, 15° for males and
18° for females
• Femoral anteversion is
considered to exist when
angle of anterior torsion is
greater than 15° to 20°
• A reversal of anterior torsion,
known as femoral
retroversion, occurs when
angles are less than 15° to
20°
15. • Femoral anteversion is associated with increased medial
rotation ROM and concurrent decreased lateral rotation
so that the total excursion of hip rotation motion remains
the same
• Anteversion of the femoral head reduces hip joint stability
because the femoral articular surface is more exposed
anteriorly
• The line of the hip abductors may fall more posterior to
the joint, reducing the moment arm for abduction
16. • When the femoral head is anteverted, pressure from the
anterior capsuloligamentous structures and the anterior
musculature may push the femoral head back into the
acetabulum, causing the entire femur to rotate medially
• The knee joint axis through the femoral condyles is now
turned medially
• Medial rotation of the femoral condyles alters the plane of
knee flexion/extension and results, at least initially,in a
toe-in gait and a compensatory lateral tibial torsion
develop
17. • An anteverted femur will also affect the biomechanics of
the patellofemoral joint at the knee and of the subtalar
joint in the foot
• The effect of femoral anteversion may also be seen at the
knee joint
18.
19. COXA VARA
• In adolescence, growth of the bone results in a more
oblique orientation of the epiphyseal plate
• The epiphyseal obliquity makes the plate more vulnerable
to shear forces at a time when the plate is already
weakened by the rapid growth that occurs during this
period of life
20. • Weight-bearing forces may slide the femoral head
inferiorly, resulting in a slipped capital femoral epiphysis in
case of coxa vara
• Disadvantage of increasing the bending moment along
the femoral head and neck
• The increased shear force along the femoral neck will
increase the predisposition toward femoral neck fracture
21. COXA VALGA
• Coxa valga also decreases the amount of femoral articular
surface in contact with the dome of the acetabulum.
• As the femoral head points more superiorly, there is a
decreasing amount of coverage from the acetabulum
superiorly.
• Consequently, decreases the stability of the hip and
predisposes the hip to dislocation
• The resulting need for additional abductor muscle force may
predispose the joint to arthrosis or may functionally weaken
the joint, producing energy-consuming and wearing gait
deviations
22.
23. ARTICULAR CONGRUENCE
• In the neutral or standing
position, the articular
surface of the femoral
head remains exposed
anteriorly and somewhat
superiorly
• Articular contact between
the femur and the
acetabulum can be
increased in the normal
non-weight-bearing hip
joint by a combination of
flexion, abduction, and
slight lateral rotation
24. HIP JOINT CAPSULE
• Both joint capsule and
ligamentum teres provide
stability of the hip joint during
distractive forces
25. HIP JOINT LIGAMENTS
• Iliofemoral ligament(Y ligament of Bigelow)
• Pubofemoral ligament
• Ischiofemoral ligament
26.
27. STRUCTURALADAPTATIONS TO
WEIGHT BEARING
• In standing or upright
weightbearing activities, at
least half the weight of the
HAT (the gravitational
force) passes down
through the pelvis to the
femoral head, whereas the
ground reaction force
(GRF) travels up the shaft.
28. • These two forces, nearly
parallel and in opposite
directions, create a force
couple with a moment arm
• (MA) equal to the distance
between the superimposed
body weight on the femoral
head and the GRF up the
shaft.
• These forces create a
bending moment (or set of
shear forces) across the
femoral neck
29. Trabecular system
• The medial (or principal
compressive) trabecular
system
• The lateral (or principal
tensile) trabecular system
• Accessory (or secondary)
trabecular systems
• zone of weakness
30. • The forces of HAT and the
ground reaction force that
act on the articular surfaces
of the hip joint and on the
femoral head and neck
also act on the femoral
shaft
31. • Ranges of passive joint motion typical of the hip joint :-
Flexion 90° with the knee extended and 120° when the
knee is flexed
Hip extension 10° to 20°
Abducted 45° to 50°
Adducted 20° to 30°
Medial and lateral rotations of the hip the typical range is
42° to 50°
32. Hip Joint Musculature
Movements
Flexion : chiefly by psoas major, iliacus
assisted by rectus femoris and sartorius
Adductor longus assists in early flexion following full
extension
Extension : gluteus maximus and the hamstrings.
Abduction : gluteus medius and minimus
assisted by sartorius,tensor fasciae latae and piriformis
Action is limited by adductor longus,pubofemoral ligament
and medial band of ilio femoral ligament
33. Adduction : by adductor longus, adductor brevis and
adductor fibers of adductor magnus
Lateral rotation : piriformis, obturator internus and
externus, superior and inferior gemelli and quadratus
femoris
assisted by the gluteus maximus
Medial rotation : the anterior fibers of the gluteus medius
and gluteus minimus, tensor fasciae latae
Piriformis muscle was a lateral rotator at 0° of hip flexion
but a medial rotator at 90° of hip flexion
34. MOTION OF PELVIS ON THE FEMUR
• Whenever the hip joint is weight-bearing, the femur is
relatively fixed, and motion of the hip joint is produced by
movement of the pelvis on the femur
35. Anterior and Posterior Pelvic Tilt
Anterior and posterior pelvic tilts are motions of the entire
pelvic ring in the sagittal plane around a coronal axis
In the normally aligned pelvis, the anterior superior iliac
spines (ASISs) of the pelvis lie on a horizontal line with
the posterior superior iliac spines and on a vertical line
with the symphysis pubis
Anterior and posterior tilting of the pelvis on the fixed
femur produce hip flexion and extension
36. Hip joint extension through posterior tilting of the pelvis
Hip flexion through anterior tilting of the pelvis
37. Lateral Pelvic Tilt
Lateral pelvic tilt is a frontal plane motion of the entire
pelvis around an anteroposterior axis
In the normally aligned pelvis, a line through the anterior
superior iliac spines is horizontal
In lateral tilt of the pelvis in unilateral stance, one hip joint
(e.g., the left hip joint) is the pivot point or axis for motion
of the opposite side of the pelvis (e.g., the right side) as
that side of the pelvis elevates (pelvic hike) or drops
(pelvic drop).
38. • If a person stands on the
left limb and hikes the
pelvis, the left hip joint is
being abducted because
the medial angle between
the femur and a line
through the anterior
superior iliac spines
increases.
• If a person stands on the
left leg and drops the
pelvis, the left hip joint will
adduct because the medial
angle formed by the femur
and a line through the
anterior superior iliac
spines will decrease
39. Lateral Shift of the Pelvis
• With pelvic shift, the pelvis
cannot hike; it can only drop.
• Because there is a closed
chain between the two
weight-bearing feet and the
pelvis, both hip joints will
move in the frontal plane in a
predictable way as the pelvic
tilt (or pelvic shift) occurs
40. Forward and Backward Pelvic Rotation
• Pelvic rotation is motion of the entire pelvic ring in the
transverse plane around a vertical axis.
41. • Forward (anterior) rotation of the pelvis occurs in
unilateral stance when the side of the pelvis opposite to
the weight-bearing hip joint moves anteriorly from the
neutral position
• Forward rotation of the pelvis produces medial rotation of
the weight-bearing hip joint
42. • Backward (posterior) rotation of the pelvis occurs when
the side of the pelvis opposite the weight-bearing hip
moves posteriorly
• Backward rotation of the pelvis produces lateral rotation of
the supporting hip joint
43. Pelvic Rotation in Gait
In normal gait, the pelvis forwardly rotates around the
weight-bearing hip while the other limb prepares for or is
in swing
Because this happens first on one leg and then on the
other, it appears to the eye as if the pelvis is forwardly
rotating and then backwardly rotating
44. Coordinated Motions of the
Femur,Pelvis,
and Lumbar Spine
Pelvifemoral Motion
When the femur, pelvis, and spine move in a coordinated
manner to produce a larger ROM than is available to one
segment alone, the hip joint is participating in what will
predominantly be an open-chain motion termed
pelvifemoral motion.
Also been referred to as pelvifemoral rhythm
45. 2 types of response
• The open-chain response (the ability of each joint in the
chain to move independently)
the head and trunk will follow the motion of the pelvis
(moving the head through space)
• Closed-Chain response
the head will continue to remain relatively upright and
vertical despite the pelvic motions
46. Moving the head and arms
through space
If the goal is to bend forward to
bring the hands (and head)
toward the floor, isolated flexion
at the hip joints (anteriorly
tilting the pelvis on the femurs)
is generally insufficient to reach
the ground
47. Moving the foot through
space
When a person is lying on
the right side, the left foot
may be moved through an
arc of motion approaching
90°
The abducting limb is in an
open chain
48. • A true open-chain response to
isolated hip flexion would
displace the head and trunk
forward, with the line of gravity
falling in front of the supporting
feet
• In a functional closed chain,
motion at the hip (one link in the
chain) is accompanied by an
essentially mandatory lumbar
extension to maintain the head
over the sacrum
49. • Compensatory motions of the lumbar spine that
accompany given motions of the pelvis and hip joint in a
functional closed chain
50. HIP JOINT FORCES AND MUSCLE
FUNCTION IN STANCE
Bilateral Stance
• The line of gravity falls just posterior to the axis for
flexion/extension of the hip joint
• In the frontal plane during bilateral stance, the superincumbent
body weight is transmitted through the sacroiliac joints and
pelvis to the right and left femoral heads
• joint axis of each hip lies at an equal distance from the line of
gravity of HAT
• The gravitational moment arms for the right hip(DR) and the left
hip (DL) are equal
51. • Because the body weight (W) on each femoral head is the
same (WR = WL), the magnitude of the gravitational torques
around each hip must be identical
• WR X DR =WL X DL
• The gravitational torques on the right and left hips occur in
opposite directions.
• The weight of the body acting around the right hip tends to
drop the pelvis down on the left (right adduction moment),
whereas the weight acting around the left hip tends to drop
the pelvis down on the right (left adduction moment)
52. • These two opposing gravitational
moments of equal magnitude
balance each other, and the
pelvis is maintained in
equilibrium in the frontal plane
without the assistance of active
muscles
53. • Assuming that muscular forces are not required to
maintain either sagittal or frontal plane stability at the hip
joint in bilateral stance, the compression across each hip
joint in bilateral stance should simply be half the
superimposed body weight (or one third of HAT to each
hip)
• In bilateral stance when both lower limbs bear at least
some of the superimposed weight, the contralateral
abductors and adductors may function as synergists to
control the frontal plane motion of the pelvis.
54. Unilateral stance
• The left leg has been lifted from the ground and the full
superimposed body weight (HAT) is being supported by
the right hip joint.
• The weight of the non-weightbearing left limb that is
hanging on the left side of the pelvis must be supported
along with the weight of HAT by right hip joint.
• Of the one-third of the portion of body weight found in the
lower extremities, the non-weightbearing limb must
account for half of that, or one sixth of the full body weight
55. • The magnitude of body
weight (W) compressing the
right hip joint in right
unilateral stance, therefore, is
• Right hip joint
compressionbody weight
=[2/3 x W] + [1/6 x W]= 5/6 x
W
56. • The force of gravity acting on HAT and the
nonweightbearing left lower limb (HATLL) will create an
adduction torque around the weight-bearing hip joint
• Gravity will attempt to drop the pelvis around the right
weight-bearing hip joint axis.
• The abduction countertorque will have to be supplied by
the hip abductor musculature
• The result will be joint compression or a joint reaction
force that is a combination of both body weight and
abductor muscular compression.
57. Compensatory Lateral Lean of
the Trunk
• the compensatory lateral lean
of the trunk toward the painful
stance limb will swing the line
of gravity closer to the hip joint,
thereby reducing the
gravitational moment arm
• It does reduce the gravitational
torque
58. Use of a Cane Ipsilaterally
Body wt passes mainly
through cane
Use of a Cane Contralaterally
Cane assists the abductor
muscles in providing counter
torque
59. Pathological Gaits
• When a lateral trunk lean is seen during gait and is due to
hip abductor muscle weakness, it is known as a gluteus
medius gait
• If the same compensation is due to hip joint pain, it is
known as an antalgic gait
• If lateral lean and pelvic drop occur during walking, the
gait deviation is commonly referred to as a Trendelenburg
gait
63. Reducing joint reaction force
Reduced by
Reducing the body weight-
generated momentum
By reducing body weight or
reducing the body weight lever
arm
Seen in Trelendenburg
gait(leaning towards the diseased
hip)
64. Reducing the required hip abductor force
Altering the neck-shaft angle through varus
osteotomy/varus placement of the femoral stem
Increasing offset or medialization of the socket
Use of cane in contralateral hand
65. Biomechanics of total hip arthroplasty
Stability and range of
motion depends on :
1. Head size
2. Head-neck ratio and
3. Implant design
66. Increasing the head
diameter increases the
jumping distance(i.e., the
radius of the femoral
head)
Reduction of rates of
revision for dislocation
with increasing head size
Primary arc of the joint
67. Increase in head-neck ratio increases this arc, improving
the range of motion
Head-neck ratio < 2:1 increase the risk of impingment
leading to fixation failure, limited function and dislocation
68. Acetabular design features that can help increase the
primary arc
Semicaptive sockets that are greater than hemisphere
reduce the primary arc and may have paradoxically
adverse effect on stability
69. Acetabular hemispherical
component
1. If relatively small , stress
transferred to the center
2. If relatively large , stress
transferred to the
periphery
Peripheral strains acting
on a force vector
perpendicular to the
tangent at the rim stabilize
the cup
70. Optimizing fixation and the low frictional torque
arthroplasty
CHARNLEY concept
Shorten lever arm of the body weight by deepening the
acetabulum and
To lengthen the lever arm of the abductor mechanism by
reattaching the osteotomized greater trochanter laterally
Leading to decrease in moment produced by body weight
there by reducing counterbalance force that the abductor
mechanism must exert
71.
72. Estimated load o femoral head in stance phase of gait is 3
times body weight
When standing on 1 leg abductor muscles work done is
2.5 times body weight
Load on femoral head during straight leg raising is 3 times
body weight
While lifting, running, jumping 10 times body weight
73. Abductor lever arm shortened in arthritis and also where
head is lost or neck is shortened
During the gait cycle, forces are directed against the
prosthetic femoral head from a polar angle between 15-25
degrees anterior to the saggital plane of the prosthesis
74. Body’s center of gravity is
posterior to the axis of the
joint making the stem to
deflect medially in coronal
plane and posteriorly in
saggital plane producing
torsion of the stem
As seen in arising from chair,
ascending and descending
stairs, lifting
75. Reducing the joint reaction force in total
hip arthroplasty
Lateralizing the femoral component by increasing the
horizontal femoral offset
Inadequate restoration of offset results in hip abductor
insufficiency and soft tissue laxity
Excessive femoral offset can also predispose to failure by
overtightening of the hip, increasing the stress placed on
the femoral fixation interface