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ESS 3092: KINESIOLOGY Week 12

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+Review

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Name the thigh adductors:

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+Pectineus

Origin The superior ramus of the

pubis, between the pubic tubercle and the iliopubic eminence

Insertion Pectineal line on the posterior

aspect of the femur

Location Deep

Action Hip adduction Hip internal rotation (weak) Hip flexion (weak)

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+Adductor Brevis

Origin The body and the inferior

ramus of the pubis

Insertion Pectineal line and the

proximal half of the linea aspera

Location Deep Medial

Posterior to pectineus

Action Hip adduction Hip internal rotation (weak) Hip flexion (weak)

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+Adductor Longus

Origin The intersection of the

pubic crest and symphysis

Insertion Medial lip of the linea

aspera

Location Medial Superficial

Action Hip adduction Hip flexion

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+Adductor Magnus

Origin Inferior ramus of the pubis

Insertion Linea aspera to the

adductor tubercle

Location Medial Deepest of the adductors

Action Hip extension Hip adduction (role

unknown)

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+Gracilis Origin

Thin aponeurosis from the medial surface of the inferior body of the pubis

Insertion Proximal aspect of the medial

surface of the tibia

Location Medial Most superficial of the

adductors

Action Hip adduction Knee flexion Knee internal rotation

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+ The Knee Joint

+ The Knee Joint

Bones & bony landmarks

Joint Structure Ligaments & menisci

Movements

Muscles surrounding the joint & attachments

+Patella

PatellaThe largest sesamoid bone

+Knee Joint

Vulnerable to injury

Provides stability and mobility Extended – joint surfaces congruent Flexed – requires capsule,

ligaments, muscles

3 articulations1)Tibiofemoral (knee)2) Patellofemoral= gliding joint3) Superior tibiofibular

+ 15

Degrees of Freedom

a) Medial/lateral translation

b) Longitudinal rotation

c) Anterior/posterior translation

d) Tibial and femoral rotation

e) Varus/Valgus

f) Flexion/extension

16+Knee Malalignment (Varus ans Valgus)

Hip, knee and ankle should remain in line

Varus moves load medially and increases risk of AO, weight is a confounder increasing risk of AO 5x

Valgus moves load laterally. Less risk of AO compared to varus, but still a factor in AO, minisci, and ligament damage.

+Knee Joint

Bursae (>10) Absorb shock or prevent

friction

Synovial cavity (capsule) Lies under patella &

between surfaces of tibia & femur

Infrapatellar fat pad Posterior to patellar tendon

Osteoarthritis: Breakdown of articular

cartilage– decreased blood supply so does not self-regenerate

+Tibiofemoral Joint

Lateral condyle (c) Flatter, larger surface

area More superior than (b) ↑ stability Aligned w/ femur

Medial condyle (b) Convex Aligned w/ tibia Fits snug with tibia

(concave)

Posterior Anterior

c b

+Tibiofemoral Joint

Menisci form cushions between bones Attached to tibia Enhance stability Thicker outside border

& taper

Medial Larger & more open C

Lateral Closed C configuration

+Tears due to:

Compression & shear forces during rotation while flexing or extending

Quick directional changes in running

Menisectomies ↑ friction 50 % (leads to osteoarthritis)

+ Knee Joint Supporting Ligaments

Cruciate ligaments: (2) ACL & PCL Cross w/in knee between tibia & femur Maintain anterior & posterior stability & rotatory

stability

+Cruciate Ligaments

Posterior Cruciate Ligament (PCL) From posterior middle tibia to anterior medial femoral condyle. Limits posterior movement of tibia on femur PCL injury = direct contact injury

Anterior Cruciate Ligament (ACL) From (anterior) intercondylar eminences of tibia to lateral femoral

condyle Limits anterior movement of tibia on femur Common injury to knee Injury mechanism often involves noncontact rotary forces

Planting & cutting Hyperextension Violent quadriceps contraction (pulls tibia forward on femur)

+ACL Injury

Theories why females tear ACLs 2-7x more than males:

1. ↑ Q-angle in ♀

2. Neurological: when stimulate back of knee, ♀ contract quads, ♂ contract hamstrings.

3. Strength differences: ♂ is stronger than ♀

4. Hormonal: ♀↑ Estrogen => ↑ elasticity => ↑ tearing

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Lateral (fibular) Collateral Ligament (LCL) Supports knee against varus forces (medial

bending) Laterally directed force

Medial (tibial) Collateral Ligament (MCL) supports knee against valgus forces (lateral

bending) Injuries (contact) are common: more

exposed/vulnerable

Knee Joint Supporting Ligaments

+LCL and MCL

+ Q Angle

Assessment of Lower extremity alignment Patella position

Most efficient angle for quadriceps to function is ~10º Males: 10-14º Females: 15-17º

Genu valgum (knock kneed) > 17º = excessive

Genu varus (bowlegged) Negative

↑ Q angle => ↑ stress on MCL

+ Joint Movements

Flexion (145º ROM) accompanied by internal

rotation (tibia on femur)

Extension (<180º ROM) accompanied by external

rotation (tibia on femur)

+ Joint Movements

External rotation rotary movement of leg laterally

away from midline

Internal rotation rotary movement of lower leg

medially toward midline

Knee must be flexed ≥ 20-30º for motion

30º

45º

+Knee Musculature