Transcript Kinesiology09_Hip1

HIP
Dr. Michael P. Gillespie
OSTEOLOGY
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Attachment point for many muscles of the lower extremity
and trunk.
 Transmits the weight of the upper body and trunk to the
ischial tuberosities during sitting and to the lower
extremities during standing or walking.
 Supports the organs of the bowel, bladder, and
reproductive system.
Dr. Michael P. Gillespie
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Each innominate is the union of three bones: the
ilium, pubis, and ischium.
The right and left innominates connect with each
other anteriorly at the pubic symphysis and
posteriorly at the sacrum.
An osteoligamentous ring known as the pelvis (Latin:
basin or bowel) is formed.
Functions of the pelvis:
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INNOMINATE
Ilium
 Pubis
 Ischium
 Acetabulum
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EXTERNAL SURFACE OF THE
PELVIS
Wing (ala) – the large fan-shaped wing of the
ilium forms the superior half of the innominate.
 Acetabulum – a deep, cup-shaped cavity below
the wing.
 Obturator-foramen – the largest foramen in the
body. Covered by the obturator membrane.
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OSTEOLOGIC FEATURES OF THE
ILIUM
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External Surface
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Internal Surface
Iliac fossa
 Auricular surface
 Iliac tuberosity
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Dr. Michael P. Gillespie
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Posterior, anterior, and
inferior gluteal lines
Anterior-superior iliac
spine
Anterior-inferior iliac
spine
Iliac crest
Posterior-superior iliac
spine
Posterior-inferior iliac
spine
Greater sciatic notch
Greater sciatic foramen
Sacrotuberous and
sacrospinous ligaments
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OSTEOLOGIC FEATURES OF THE
PUBIS
Superior pubic ramus
 Body
 Crest
 Pectineal line
 Pubic tubercle
 Pubic symphysis joint and disc
 Inferior pubic ramus
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OSTEOLOGIC FEATURES OF THE
ISCHIUM
Ischial spine
 Lesser sciatic notch
 Lesser sciatic foramen
 Ischial tuberosity
 Ischial ramus
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ANTERIOR ASPECT: PELVIS,
SACRUM, RIGHT PROXIMAL FEMUR
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LATERAL VIEW RIGHT INNOMINATE
BONE
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POSTERIOR ASPECT OF PELVIS,
SACRUM, & PROXIMAL FEMUR
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FEMUR
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Dr. Michael P. Gillespie
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The longest and strongest bone in the human body.
The femoral head projects medially and slightly
anterior to articulate with the acetabulum.
The femoral neck connects the head with the shaft.
The neck displaces the proximal shaft of the femur
laterally away from the joint, thereby reducing the
likelihood of bony impingement.
Distal to the neck, the shaft of the femur courses
slightly medially, placing the knees and feet closer to
the midline of the body.
The femur bows slightly when subjected to the weight
of the body. Stress along the bone is dissipated
through compression along the posterior shaft and
through tension along the anterior shaft.
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OSTEOLOGIC FEATURES OF THE
FEMUR
Lesser trochanter
 Linea aspera
 Pectineal (spiral) line
 Gluteal tuberosity
 Lateral and medial
supracondylar lines
 Adductor tubercle
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Dr. Michael P. Gillespie
Femoral Head
 Femoral Neck
 Intertrochanteric Line
 Greater trochanter
 Trochanteric fossa
 Intertrochanteric
crest
 Quadrate tubercle
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ANTERIOR ASPECT RIGHT FEMUR
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MEDIAL & POSTERIOR SURFACES
RIGHT FEMUR
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ANGLE OF INCLINATION
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The angle of inclination of the proximal femur
describes the angle within the frontal plane between
the femoral neck and the medial side of the femoral
shaft.
At birth this angle is about 140 – 150 degrees;
however, the loading across the femoral neck during
walking usually decreases this to the normal adult
value of about 125 degrees.
Coxa = hip, vara = to bend inward, valga = to bend
outward
Coxa vara – an angle of inclination markedly less
than 125 degrees.
Coxa valga – an angle of inclination markedly greater
than 125 degrees.
Abnormal angles can lead to dislocation or stressinduced degeneration of the joint.
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ANGLE OF INCLINATION
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FEMORAL TORSION
Femoral torsion describes the relative rotation
(twist) between the bone’s shaft and neck.
 Normally, as viewed from above, the femoral
neck projects about 15 degrees anterior to a midlateral axis through the femoral condyles (normal
anteversion).
 Femoral torsion significantly different than 15
degrees is considered abnormal.
 Excessive anteversion – significantly greater
than 15 degrees
 Retroversion – approaching 0 degrees
 Healthy infants are born with about 40 degrees of
femoral anteversion
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EXCESSIVE FEMORAL
ANTEVERSION
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Excessive anterversion that persists into adulthood can
increase the likelihood of hip dislocation, articular
incongruence, increase joint contact force, and increased wear
on the cartilage.
This can lead to secondary osteoarthritis of the hip.
It may be associated with an abnormal gait pattern called “intoeing”, a walking pattern with exaggerated posturing of hip
internal rotation.
The amount of “in-toeing” is generally related to the amount of
femoral anteversion.
It is a compensatory mechanism used to guide the excessively
anteverted femoral head more directly into the acetabulum.
Over time, shortening of the internal rotator muscles and
ligaments occurs, thereby reducing external rotation.
Most children with in-toeing eventually walk normally.
Excessive femoral anteversion is common in persons with
cerebral palsy. It typically does not resolve in this population.
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NORMAL ANTEVERSION
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EXCESSIVE ANTEVERSION
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RETROVERSION
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INTERNAL ROTATION IMPROVING
JOINT CONGRUITY
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IN-TOEING
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FUNCTIONAL ANATOMY OF THE
HIP JOINT
The hip is a classic ball-and-socket joint secured
within the acetabulum by an extensive set of
connective tissues and muscles.
 Articular cartilage, muscle, and cancellous bone
in the proximal femur help dampen the large
forces that cross the hip.
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FEMORAL HEAD
The head of the femur forms about two-thirds of
a nearly perfect sphere.
 The entire surface of the femoral head is covered
by articular cartilage except for the region of the
fovea, which is slightly posterior to the center of
the head.
 The fovea is a prominent pit that serves as the
attachment point for the ligamentum teres.
 The ligamentum teres is a tubular sheath that
runs between the transverse acetabular ligament
and the fovea of the femoral head. It is a sheath
that contains the acetabular artery.
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ACETABULUM
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The acetabulum (Latin – vinegar cup) is a deep,
hemispheric cuplike socket that accepts the femoral
head.
The femoral head contacts the acetabulum along the
horseshoe-shaped lunate surface, which is covered
with thick articular cartilage.
During walking, hip forces fluctuate from 13% of body
weight to over 300% of body weight during the midstance phase.
During stance phase, the lunate surface flattens
slightly as the acetabular notch widens. This serves
as a dampening mechanism to reduce peak pressure.
The acetabular fossa is a depression located deep
within the floor of the acetabulum. It does not
normally come into contact with the femoral head.
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HIP JOINT COMPRESSION AS A
PERCENT OF GAIT CYCLE
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ANATOMIC FEATURES OF THE HIP
JOINT
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Femoral Head
Fovea
 Ligamentum teres
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Acetabulum
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Acetabular notch
Lunate surface
Acetabular fossa
Labrum
Transverse acetabular ligament
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INTERNAL ANATOMY OF HIP JOINT
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ACETABULAR LABRUM
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The acetabular labrum is a flexible ring of fibrocartilage
that surrounds the outer circumference (rim) of the
acetabulum.
The acetabular labrum projects about 5 mm toward the
femoral head.
It provides significant stability to the hip by “gripping” the
femoral head and deepening the volume of the socket by
approximately 30%.
The seal formed by the labrum maintains a negative intraarticular pressure, thereby creating a modest suction that
resists distraction of the joint surfaces.
It also helps to hold synovial fluid within the joint space.
It decreases the contact stress (force / area) by increasing
the surface area of the acetabulum.
Poor blood supply – limited ability to heal
Well supplied with afferent nerves – proprioceptive
feedback / pain
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ACETABULAR ALIGNMENT
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Center-edge angle
 Acetabular anteversion angle
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In the anatomic position, the acetabulum typically
projects laterally from the pelvis with a varying
amount of inferior and anterior tilt.
Congenital or developmental conditions can result in
an abnormally shaped acetabulum.
A dysplastic acetabulum that does not adequately
cover the femoral head can lead to chronic dislocation
and increased stress, which can lead to osteoarthritis.
Two measurements are used to describe the extent to
which the acetabulum naturally covers and helps to
secure the femoral head:
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CENTER-EDGE ANGLE
The center-edge angle varies widely, but on
average measures about 35 degrees in adults.
 A significantly lower center-edge angle reduces
the acetabular coverage of the femoral head.
This increases the risk of dislocation and reduces
contact area within the joint.
 During the single-limb-support phase of walking,
this reduced surface area would increase joint
pressure (force / area) by about 50%.
 This increased joint pressure can lead to
premature osteoarthritis.
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CENTER-EDGE ANGLE
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ACETABULAR ANTEVERSION
ANGLE
The acetabular anteversion angle measures the
extent to which the acetabulum projects
anteriorly within the horizontal plane, relative to
the pelvis.
 Observed from above, the normal acetabular
anteversion angle is about 20 degrees, which
exposes part of the anterior side of the femoral
head.
 A hip with excessive acetabular anteversion is
more exposed anteriorly.
 When anteversion is severe, the hip is more
prone to anterior dislocation and associated
lesions of the labrum.
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ACETABULAR ANTEVERSION
ANGLE
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CAPSULE AND LIGAMENTS OF THE
HIP
A synovial membrane lines the internal surface
of the hip joint capsule.
 The iliofemoral, pubofemoral, and ischiofemoral
ligaments reinforce the external surface of the
capsule.
 Passive tension in the stretched ligaments, the
adjacent capsule, and the surrounding muscles
help to define end-range movements of the hip.
 Increasing the flexibility of parts of the capsule is
an important component of manual physical
therapy for restricted movement of the hip.
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ANTERIOR CAPSULE & LIGAMENTS
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POSTERIOR CAPSULE & LIGAMENTS
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PARAPLEGIC WITH SUPPORT
BRACES
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TISSUES THAT BECOME TAUT AT
THE END-RANGES OF PASSIVE HIP
MOTION
Taut Tissue
Hip flexion (knee extended)
Hamstrings
Hip flexion (knee flexed)
Inferior and posterior capsule;
gluteus maximus
Hip extension (knee extended)
Primarily iliofemoral ligament,
some fibers of the pubofemoral
and ischiofemoral ligaments;
psoas major
Hip extension (knee flexed)
Rectus femoris
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End-Range Position
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TISSUES THAT BECOME TAUT AT
THE END-RANGES OF PASSIVE HIP
MOTION
Taut Tissue
Abduction
Pubofemoral ligament; adductor
muscles
Adduction
Superior fibers of ischiofemoral
ligament; iliotibial band; and
abductor muscles such as the
tensor fascia latae and gluteus
maximus
Internal rotation
Ischiofemoral ligament; external
rotator muscles, such as the
piroformis or gluteus maximus
External rotation
Iliofemoral and pubofemoral
ligaments; internal rotator
muscles, such as the tensor
fascia latae or gluteus minimus
Dr. Michael P. Gillespie
End-Range Position
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CLOSE-PACKED POSITION OF THE
HIP
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Dr. Michael P. Gillespie
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Full extension of the hip (about 20 degrees beyond
neutral) in conjunction with slight internal rotation
and slight abduction twists or “spirals” the fibers of
the capsular ligaments to their most taut position.
This is considered the close-packed position of the hip.
The passive tension leads to stability of the joint and
reduces “joint play”.
The hip joint is one of the few joints in the body where
the close-packed position is NOT also the position of
maximal joint congruency. They fit most congruently
in about 90 degrees of flexion, moderate abduction,
and external rotation.
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NEUTRAL AND CLOSED PACKED
POSITIONS
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OSTEOKINEMATICS
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Reduced hip motion may be an early indicator of
disease or trauma.
Limited hip motion can impose functional limitations
on activities such as walking, standing upright, or
picking up objects on the floor.
Femoral-on-pelvic hip osteokinematics – rotation of
the femur about a relatively fixed pelvis.
Pelvic-on-femoral hip osteokinematics – rotation of
the pelvis, and often the superimposed trunk, over
relatively fixed femurs.
Movements:
flexion & extension in the sagittal plane, abduction &
adduction in the frontal plane, and internal and external
rotation in the horizontal plane.
The anatomic position is the 0-degree or neutral
reference point.
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FEMORAL-ON-PELVIC
OSTEOKINEMATICS
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Rotation of the Femur in the Sagittal Plane
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Hip flexion to 120 degrees
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Hip extension to 20 degrees
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Full knee flexion reduces hip extension due to tension in rectus femoris
Rotation of the Femur in the Frontal Plane
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Hip abduction to 40 degrees
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Limited by pubofemoral ligament and adductors
Hip adduction to 25 degrees
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Full knee extension limits hip flexion to 70 – 80 degrees due to
increased tension in the hamstrings
Dr. Michael P. Gillespie
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Limited by interference with contralateral limb, passive tension in hip
abductors, iliotibial band, and ischiofemoral ligament
Rotation of the Femur in the Horizontal Plane
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Internal rotation to 35 degrees
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Produces tension in piriformis and ischiofemoral ligament
External rotation to 45 degrees
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Produces tension in internal rotators and iliofemoral ligament
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SAGITTAL PLANE ROTATIONS
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FRONTAL PLANE ROTATIONS
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HORIZONTAL PLANE ROTATIONS
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FEMORAL-ON-PELVIC (HIP) MOTION
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PELVIC-ON-FEMORAL
OSTEOKINEMATICS
Pelvic rotation in the Sagittal Plane
 Pelvic rotation in the Frontal Plane
 Pelvic Rotation in the Horizontal Plane
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LUMBOPELVIC RHYTHM
The caudal end of the axial skeleton is firmly
attached to the pelvis by way of the sacroiliac
joints.
 Rotation of the pelvis over the femoral heads
typically changes the configuration of the lumbar
spine.
 This is referred to as lumbopelvic rhythm.
 Ipsidirectional lumbopelvic rhythm.
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Dr. Michael P. Gillespie
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The pelvis and lumbar spine rotate in the same
direction.
Contradirectional lumbopelvic rhythm.
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The pelvis and lumbar spine rotate in opposite
directions.
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LUMBOPELVIC RHYTHMS
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PELVIC ROTATION IN THE SAGITTAL
PLANE: ANTERIOR AND POSTERIOR
PELVIC TILTING
Pelvic Tilt – a short-arc, sagittal rotation of the
pelvis relative to stationary femurs.
 Anterior Pelvic Tilt
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Posterior Pelvic Tilt
Dr. Michael P. Gillespie
Increase in lumbar curvature offsets the tendency of
the supralumbar trunk to follow the forward rotation
 30 degrees
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Decrease in lumbar curvature
 15 degrees
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PELVIC ROTATION IN THE FRONTAL
PLANE
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The lumbar spine must bend in the direction opposite the
rotating pelvis.
 Slight lateral convexity within the lumbar region toward
the side of the abducting hip.
 30 degrees of abduction
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Dr. Michael P. Gillespie
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Pelvic-on-femoral rotation in the frontal and
horizontal planes is best described assuming a person
is standing on one limb. The weight bearing
extremity is referred to as the support hip.
Abduction of the support hip occurs by raising or
“hiking” the iliac crest on the side of the nonsupport
hip.
Adduction of the support hip occurs by a lowering of
the iliac crest on the side of the nonsupport hip.
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Slight lateral concavity within the lumbar region of the
side of the adducted hip.
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PELVIC ROTATION IN THE
HORIZONTAL PLANE
Pelvic-on-femoral rotation in the frontal and
horizontal planes is best described assuming a
person is standing on one limb. The weight
bearing extremity is referred to as the support
hip.
 Internal rotation of the support hip occurs as the
iliac crest on the side of the nonsupport hip
rotates forward in the horizontal plane.
 External rotation of the support hip occurs as the
iliac crest on the side of the nonsupport hip
rotates backward in the horizontal plane.
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PELVIC-ON-FEMORAL (HIP) MOTION
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ARTHROKINEMATICS
During hip motion, the nearly spherical femoral
head normally remains snugly seated within the
confines of the acetabulum.
 Hip arthrokinematics are based upon traditional
convex-on-concave or concave-on-convex
principles.
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MOTOR INNERVATION
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Lumbar Plexus
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Sacral Plexus
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Nerve to piriformis (S1-S2)
Nerve to obturator internus and gemullus superior
(L5-S2)
Nerve to quadratus femoris and gemullus inferior
(L4-S1)
Superior gluteal nerve (L4-S1)
Inferior gluteal nerve (L5-S2)
Sciatic nerve (L4-S3), including tibial and common
fibular (peroneal) portions
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Femoral nerve (L2-L4)
Obturator nerve (L2-L4)
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SENSORY INNERVATION
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As a general rule, the hip capsule, ligaments, and
parts of the labrum receive sensory innervation
through the same nerve roots that supply the
overlying muscles.
The anterior part of the capsule of the hip receives
sensory fibers from the femoral nerve.
The posterior capsule receives sensory fibers from all
nerve roots originating from the sacral plexus.
The connective tissues of the medial aspects of the hip
and knee joints receive sensory fibers from the
obturator nerve (Inflammation of the hip may be
perceived as pain in the medial knee region).
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OBTURATOR NERVE
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SCIATIC NERVE
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MUSCULAR FUNCTION AT THE HIP
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MUSCLES OF THE HIP, ORGANIZED
ACCORDING TO PRIMARY OR
SECONDARY ACTIONS
Adductors
Internal
Rotators
Extensors
Abductors
External
Rotators
Primary
Iliopsoas
Sartorius
TFL
Rectus femoris
Adductor longus
Pectineus
Pectineus
Adductor
longus
Gracilis
Adductor
brevis
Adductor
magnus
Not
applicable
Gluteus maximus
Biceps femoris
(long head)
Semitendinosus
Semimembranosus
Adductor magnus
(posterior head)
Gluteus
medius
Gluteus
minimus
TFL
Gluteus
maximus
Piriformis
Obturator
internus
Gemellus
superior
Gemellus
inferior
Quadratus
femoris
Secondary
Adductor brevis
Gracilis
Gluteus
minimus
(anterior fibers)
Biceps femoris
(long head)
Gluteus
maximus
(lower fibers)
Quadratus
femoris
Gluteus
minimus
(anterior
fibers)
Gluteus
medius
(anterior
fibers)
TFL
Adductor
longus
Adductor
brevis
Pectineus
Gluteus medius
(posterior fibers)
Adductor magnus
(anterior head)
Piriformis
Sartorius
Gluteus
medius
(posterior
fibers)
Gluteus
minimus
(posterior
fibers)
Obturator
externus
Sartorius
Biceps
femoris (long
head)
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Flexors
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MUSCLES OF THE ANTERIOR HIP
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HIP FLEXOR MUSCLES
The primary hip flexors are the iliopsoas,
sartorius, tensor fascia latae, rectus femoris,
adductor longus, and pectineus.
 Secondary hip flexors are adductor brevis,
gracilis, and anterior fibers of the gluteus
minimus.
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PELVIC-ON-FEMORAL HIP FLEXION:
ANTERIOR PELVIC TILT
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The anterior pelvic tilt is performed by a forcecouple between the hip flexor and low back
extensor muscles.
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FORCE COUPLE FOR ANTERIOR
PELVIC TILT
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FEMORAL-ON-PELVIC HIP FLEXION
Femoral-on-pelvic hip flexion often occurs
simultaneously with knee flexion as a means to
shorten the functional length of the lower
extremity during the swing phase of walking or
running.
 Moderate to high power hip flexion requires
coactivation of the hip flexor and abdominal
muscles.
 Rectus abdominus must create a strong posterior
pelvic tilt to neutralize the strong anterior pelvic
tilt potential of the hip flexors.
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STABILIZING ROLE OF
ABDOMINALS WITH UNILATERAL
LEG RAISING
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HIP ADDUCTOR MUSCLES
The primary adductors of the hip are the
pectineus, adductor longus, gracilis, adductor
brevis, and adductor magnus.
 Secondary adductors are the biceps femoris (long
head), the gluteus maximus (especially lower
fibers) and the quadratus femoris.
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HIP ADDUCTORS
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BILATERAL COOPERATIVE ACTION
OF ADDUCTORS
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DUAL ACTION OF ADDUCTOR
LONGUS
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HIP INTERNAL ROTATORS:
OVERALL FUNCTION
There are no primary internal rotators of the hip
because no muscle is oriented close to the
horizontal plane.
 Secondary internal rotators are the anterior
fibers of the gluteus minimus and gluteus
medius, tensor fasciae latae, adductor longus,
adductor brevis, and pectineus.
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HORIZONTAL PLANE LINES OF
FORCE OF SEVERAL MUSCLES THAT
CROSS THE HIP
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ADDUCTORS AS INTERNAL
ROTATORS
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HIP EXTENSOR MUSCLES
The primary hip extensors are the gluteus
maximus, the hamstrings (long head of the biceps
femoris, semitendinosus, semimembranosus),
and the posterior head of the adductor magnus.
 Secondary extensors are the posterior fibers of
the gluteus medius and the anterior fibers of the
adductor magnus.
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POSTERIOR MUSCLES OF THE HIP
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EXTENSION
PERFORMING A POSTERIOR PELVIC
TILT
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Hip extensors performing a posterior pelvic tilt.
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Hip extensors controlling a forward lean of the
body.
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The muscular support for this activity is primarily
the responsibility of the hamstrings.
Dr. Michael P. Gillespie
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The hip extensors and the abdominal muscles act as
a force couple to posteriorly tilt the pelvis.
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FORCE COUPLE FOR POSTERIOR
PELVIC TILT
Dr. Michael P. Gillespie
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HIP EXTENSORS CONTROLLING A
FORWARD LEAN OF THE BODY
Dr. Michael P. Gillespie
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FEMORAL-ON-PELVIC HIP
EXTENSION
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Dr. Michael P. Gillespie
Hip extensor muscles are required to produce
large and powerful femoral-on-pelvic hip
extension torque to accelerate the body forward
and upward (i.e. climbing a hill).
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HIP EXTENSOR ENGAGEMENT
WHILE CLIMBING
Dr. Michael P. Gillespie
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FULLY EXTENDABLE HIP
Dr. Michael P. Gillespie
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EFFECTS OF HIP FLEXION
CONTRACTURE ON THE
BIOMECHANICS OF STANDING
Dr. Michael P. Gillespie
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HIP ABDUCTOR MUSCLES
The primary hip abductor muscles are the
gluteus medius, gluteus minimus, and tensor
fasciae latae.
 Secondary abductors are the piriformis and
sartorius.
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Dr. Michael P. Gillespie
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DEEP MUSCLES OF POSTERIOR &
LATERAL HIP
Dr. Michael P. Gillespie
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ABDUCTOR CONTROL OF FRONTAL
PLANE STABILITY OF THE PELVIS
WHILE WALKING
The abduction torque produced by the hip
abductor muscles is essential to the control of the
frontal plane pelvic-on-femoral kinematics during
walking.
 The abduction torque produced by hip abductor
muscles is particularly important during the
single-limb-support phase of gait.
 The abduction torque on the stance limb prevents
the pelvis and trunk from dropping
uncontrollably toward the side of the swinging
limb.
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Dr. Michael P. Gillespie
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ABDUCTOR ROLE IN THE
PRODUCTION OF COMPRESSION
FORCE AT THE HIP
During single-limb support, the hip abductor
muscles (esp. gluteus medius) produce most of
the compression force across the hip.
 The hip abductor muscles must produce a force
that is twice that of body weight in order to
achieve stability during single-limb support.
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Dr. Michael P. Gillespie
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GREATER TROCHANTERIC PAIN
SYNDROME
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Dr. Michael P. Gillespie
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Excessive or repetitive action of the gluteus medius
and minimus can cause point tenderness adjacent to
the greater trochanter (the primary distal attachment
of these muscles).
This painful response suggests inflammation within
the hip abductor mechanism.
Pain associated with activation of the hip abductor
mechanism can be disabling considering the frequent
and relatively large demands placed upon these
muscles during the single-limb-support phase of the
gait cycle.
Pain can be due to inflammation of the bursa
associated with the distal attachments or with tears
of the distal tendons.
The term greater trochanteric pain syndrome
describes this condition.
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HIP ABDUCTOR MUSCLE
WEAKNESS

Several conditions are associated with weakness
of the hip abductor muscles.

Muscular dystrophy, Guillian-Barre syndrome, spinal
cord injury, greater trochanteric pain syndrome, hip
osteoarthritis or rheumatoid arthritis, poliomyelitis,
and undefined hip pain or weakness.
The classic indicator of hip abductor weakness is
the positive Trendelenburg sign.
The patient is asked to stand in single-limb support
over the weak hip.
 A positive sign occurs if the pelvis drops to the side of
the unsupported limb. The weak hip “falls” into
pelvic-on-femoral adduction.
Dr. Michael P. Gillespie
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HIP EXTERNAL ROTATOR MUSCLES
The primary external rotator muscles of the hip
are the gluteus maximus and five of the six
“short external rotators”.
 Secondary external rotators are the posterior
fibers of gluteus medius and minimus, obturator
externus, sartorius, and long head of biceps
femoris.

Dr. Michael P. Gillespie
92
OBTURATOR INTERNUS
Dr. Michael P. Gillespie
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FUNCTIONAL ANATOMY OF THE
“SHORT EXTERNAL ROTATORS”

Dr. Michael P. Gillespie
The six “short external rotators” of the hip are
the piriformis, obturator internus, gemellus
superior, gemellus inferior, quadratus femoris,
and obturator externus.
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EXTERNAL ROTATORS OVERALL
FUNCTION
The functional potential of the external rotators
is most evident during pelvic-on-femoral rotation.
 The action of planting a foot and “cutting” to the
opposite side is the natural way to abruptly
change direction while running.

Dr. Michael P. Gillespie
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EXTERNAL ROTATOR ACTION
Dr. Michael P. Gillespie
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FRACTURE OF THE HIP
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Dr. Michael P. Gillespie
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Fracture of the hip (i.e. proximal femur) is a major health
and economic problem in the United States.
About 95% of all fractures of the hip are the result of falls.
It is the 2nd leading cause of hospitalization in the elderly.
Age related osteoporosis and a higher incidence of falling
are reasons for a higher incidence of hip fracture in the
elderly.
Mortality is surprisingly high after hip fracture: studies
report 12% to 25% of persons die within 1 year of fracturing
a hip.
Only about 40% of persons are able to independently
perform their basic functional activities 6 to 12 months
after hip fracture.
About half of those persons continue to require an assistive
device to aid their walking.
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OSTEOARTHRITIS OF THE HIP

Dr. Michael P. Gillespie
Hip osteoarthritis is a disease manifested by
deterioration of the joint’s articular cartilage, loss
of joint space, sclerosis of subchondral bone, and
the presence of osteophytes.
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EFFECTS OF COXA VARA & COXA
VALGA
Dr. Michael P. Gillespie
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