Class #3
Pelvis
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Supports the trunk and organs in the lower
abdomen (pelvic cavity)
Absorbs stress from lower limbs when
moving (walking/jumping)
Female pelvis is adapted for pregnancy and
childbirth and is wider and lighter than
male pelvis
Bones of the pelvis
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Ilium-forms superior flared portion,
impt.for muscle attachment
Ischium- inferior portion and strongest
bone of the pelvis
Pubis- anterior portion of pelvis
Landmarks of the Pelvis:
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Iliac crest
Iliac fossa
Ant.Superior Iliac Spine (ASIS)
Ant. Inf. Iliac Spine (AIIS)
Post. Sup. Iliac spine (PSIS)
Post. Inf. Iliac spine (PIIS)
Greater Sciatic Notch
Gluteal Lines
Ischium
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Ischial tuberosity (what you are sitting on)
Ischial spine
Lesser sciatic notch
Ramus of the ischium (ramus=branch)
Pubis
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Pubic crest
Pubic symphysis
Superior ramus of pubis
Inferior ramus of pubis
Acetabulum
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On lateral pelvis where ilium, ischium, and
pubis fuse and create a deep socket;
articulates with the head of the femur to
form the hip joint(coxal, hip socket)
Obturator foramen
Sacrum
Coccyx
Quadriceps Group
Main action is to extend the leg at the knee
joint (kicking a ball) also to move the thigh
into extension at the knee; standing up
from seated position, coming up into
straight leg position from squat
Quad=four; cep=headed
Quadriceps muscle
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Rectus Femoris
Vastus Lateralis
Vastus Medialis
Vastus Intermedius
About Muscles
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O: (Origin)- Where the muscle begins
I: (Insertion)- Where the muscle ends
A: (Action)- This is what the muscle does
when it contracts or shortens.
Insertions point always moves close to the
origin.
Extension of the leg at the Knee
Rectus femoris
 Vastus lateralis
 Vastus medialis
 Vastus intermedius
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Quadriceps
Rectus Femoris
Rectus=straight or upright;
Femoris=related to thigh
Origin: AIIS
Insertion: Tibial Tuberosity, via the patella and
patellar ligament
Action: Ext. of the leg at the knee joint
Flexion of the thigh at the hip joint
Combined actions seen as leg is brought forward
in walking.
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Quadriceps
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Vastus Lateralis
Vastus=vast or large; lateralis=related to the
side
O: Linea aspera, ant. Aspect of greater trochanter
I: Tibial tuberosity, via patella & patellar lig.
A: Ext. of the leg at knee joint(also restrains
medial pull on patella by Vastus Medialis)
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Quadriceps
Vastus Medialis (Medialis=related to the
middle
O: linea aspera
I: Tibial tuberosity via the patella & patellar
lig.
A: Ext. of the leg at knee joint
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Quadriceps
Vastus Intermedius (intermedius=among the
middle, intermedius lies deep to the other
quadriceps muscles.
O: linea aspera, anterior and lateral femoral shaft.
I: Tibial tuberosity via the patella & patellar lig.
A: Ext. of the leg at the knee joint
All 4 muscles are innervated by the Femoral Nerve
All 4 have common insertion on the tibial tuberosity
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Osgood-Schlatter Dz
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Irritation and inflammation of the tibial
tuberosity; most often in boys between 1015. The tuberosity becomes inflammed
and/or separates from tibia, because of
irritation caused when patellar tendon pulls
on tuberosity during periods of rapid
growth or overuse of quadriceps.
Medial Thigh Muscles
Adduction of the Hip
Adductor magnus
 Adductor longus
 Adductor brevis
 Gracilis
 Pectineus
 Psoas major
 Iliacus
Gluteus maximus (lower fibers)
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Adductor group
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Muscles of medial thigh
Main action is hip adduction
Also do medial rotation of hip, and all but
Gracilis assist with hip flexion
Adductor Muscles
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Pectineus
Adductor Longus
Adductor Brevis
Adductor Magnus
Gracilis
Sartorius
Adductor Muscles
Pectineus (means related to the pubic bone)
O: Ring around the obturator foramen (ant.
Pubis)
I: linea aspera
A: adduction of femur at hip joint
Flexion of femur at hip joint
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Adductor Muscles
Adductor Longus
O: Ring around the obturator foramen (ant.
Pubis)
I: linea aspera
A: adduction of femur at hip joint
assists with flexion of femur at hip
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Adductor Muscles
Adductor Brevis
Brevis is deep to longus
O: ring around the obturator foramen (ant.
Pubis)
I: linea aspera
A: adduction of femur at hip joint
assist with flexion of femur at hip
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Adductor Muscles
Adductor Magnus (magnus=great)
Largest and deepest
O: ring around obturator foramen (inf. Ramus of
pubis and ramus of ischium, ischial tuberosity)
I: linea aspera; (gluteal tuberosity, adductor tubercle
of femur)
A: adduction of femur at hip
assists with ext. of femur at hip
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Adductor Muscles
Gracilis = slender
O: ring around the obturator foramen (inf ramus of
ant. Pubis)
I: Proximal anteromedial tibia at the pes anserinus
tendon.
A: adduction of femur at hip joint
assists with medial rotation of hip
assists with flexion of leg at knee
assists with medial rotation of leg at knee
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Adduction muscles
Common origin: ring around obturator
foramen
Common insertion: linea aspera
Nerve to adductor muscles is the Obturator
Adductor Muscles
Sartorius “tailor’s muscles”
Longest muscle in body, most superficial thigh
muscle
O: ASIS
I: proximal anteromedial tibia at the pes anserinus
A: hip: assists with flexion
abduction
Lateral rotaton
Knee: assists with flexion, and medial rotation of
leg at knee
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Posterior Thigh Muscles
Flexion of the leg at the knee
Biceps femoris
 Semitendinosus
 Semimembranosus
 Gracilis
 Sartorius
 Gastroncnemius
 Popliteus
 Plantaris
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Hamstring Group
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Named so because butchers used to hang
the carcass of a pig by the hamstring
tendons.
Cross two joints: hip and knee, so involved
with flexing leg at knee joint and extending
femur at hip joint.
Hamstring Muscles
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Biceps Femoris
Semitendinosus
Semimembranosus
Hamstrings Muscles
Biceps Femoris:
Biceps=two headed; femoris=related to thigh
O: Long head-ischial tuberosity
Short head-linea aspera
I: head of the fibula (lateral aspect)
A: Long head: ext. of femur at hip
Long and Short heads: flexion of leg at knee
lat. Rotation of leg at knee
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Hamstring Muscles
Semitendinosus:
Means half tendon
O: ischial tuberosity
I: pes anserinus (proximal anteromedial tibia)
A: flexion of leg at knee joint
med. Rot. Of leg at knee joint (knee must be
semiflexed for medial rot. To occur)
ext. of femur at hip joint
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Hamstring Muscles
Semimembranosus
Means half membrane
O: ischial tuberosity
I: posteromedial tibial condyle
A: flexion of leg at knee joint
med. Rot. Of leg at knee joint(knee must be
semiflexed for med. Rot. To occur)
extension of femur at hip joint
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Hamstring Muscles
Common origin of all hamstring muscles is
the ischial tuberosity(your sits bone).
Pes Anserinus
(the proximal anteriomedial tibia)
The common insertion for three thigh muscles
Anterior- Sartorious
Medial- Gracilis
Posterior- Semitendinosus
Flexion of the thigh at the hip
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Rectus Femoris
 Gluteus medius (ant. fibers)
 Gluteus minimus
 Adductor magnus (assists)
 Adductor longus (assists)
 Adductor brevis (assists)
 Pectineus (assists)
 TFL
 Sartorius
 Psoas major
 Iliacus
Extension of the thigh at the hip
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Biceps femoris
 Semitendinosus
 Semimembranosus
 Gluteus maximus
 Gluteus medius (post. fibers)
 Adductor magnus (post. Fibers)
End of Class 3