The Knee Joint
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Knee joint
Largest joint
in body.
Very
complex.
Primarily a
hinge joint.
Tibia bears
most of the
weight.
Consists of
three
articulations.
Bones
• Femur
• Lateral & Medial
Condyle.
• Lateral & Medial
Epicondyle.
• Intercondylar
Fossa.
• Serves as the
attachment point for
the Gastrocnemius,
Popliteus & 3 of the
Quadriceps.
Bones
• Tibia- (Medial)
• Medial & Lateral
Condyle.
• Intercondylar eminence.
• Tibial Tuberosity.
• Support most of the
weight
• Attachment point for all
of the Quadriceps and all
of the hamstrings (except
Biceps Femoris)
Bones
• Fibula - (lateral)
• Serves as the
attachment for Biceps
Femoris.
• Does not articulate with
femur or patella.
• Not part of knee joint.
• Acts as support for the
Tibia
Bones
• Patella
• Largest sesamoid
(floating) bone.
• Imbedded in quadriceps
& patellar tendon
• Serves as a pulley in
improving angle of pull,
resulting in knee
extension.
Movements
• Flexion
– bending or decreasing
angle between femur &
leg, characterized by
heel moving toward
buttocks
• Extension
– straightening or
increasing angle
between femur & lower
leg
Muscles
• Quadriceps muscle group
– extends knee
– located in anterior
compartment of thigh
– consists of 4 muscles
• Rectus Femoris- hip flex,
knee extension
• Vastus Lateralis- knee
extension
• Vastus Intermediusknee extension
• Vastus Medialis- knee
extension
Quadriceps Muscles
• Rectus Femoris (two-joint), Vastus Medialis,
Vastus Intermedius, Vastus Lateralis (largest)
• All attach to patella then to tibial tuberosity via
patellar tendon
• All superficial & palpable except Vastus
Intermedius (under Rectus Femoris)
• Strength & endurance is essential for maintenance
of Patellofemoral stability
• Generally desired to be 25% to 33% stronger than
hamstring group
Rectus Femoris Muscle
Flexion of
hip
O. Anterior
inferior iliac
spine
Extension
of knee
I. Tibial
Tuberosity
Vastus Lateralis Muscle
Extension
of knee
O. Linea Aspera
I. Tibial tuberosity
via patellar tendon
Vastus Intermedius Muscle
Extension
of knee
O. Anterior
Femur
I. Tibial Tuberosity via
patellar tendon
Vastus Medialis Muscle
Extension of
knee
O. Linea Aspera
I.
Tibial Tuberosity via
Patellar tendon
Knee Extension
• Agonists
– Rectus Femoris
– Vastus Lateralis
– Vastus Intermedius
– Vastus Medialis
Muscles
• Hamstring muscle group
– located in posterior
compartment of thigh
– responsible for knee flexion
– consists of 3 muscles
• Semitendinosus – extend
hip, flex knee
• Semimembranosus –
extend hip, flex knee
• Biceps Femoris – long
head- extend hip, flex
knee. Short head- flex
knee
Hamstring Muscles
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Hamstring muscle strains very common
“Running muscles” function in acceleration
Antagonists to quadriceps muscles at knee
Named for cordlike attachments at knee
All originate on ischial tuberosity of pelvis
Semitendinosus inserts on anteromedial tibia
Semimembranosus inserts on posteromedial
tibia
• Biceps Femoris inserts on lateral tibial
condyle & head of fibula
Biceps Femoris Muscle
Flexion of
knee
O. Long head-Ischial
tuberosity
Extension
of hip
O. Short headLateral lip Linea
Aspera
I. Head of Fibula
Semitendinosus Muscle
Flexion of knee
Extension of
hip
Semimembranosus Muscle
Flexion of knee
Extension of
hip
Knee Flexion
• Agonists
– Biceps Femoris
(Long & Short
Head)
– Semitendinosus
– Semimembranosus
Muscles
• Gastrocnemius
– Origin- posteriorly on medial & lateral femoral
condyles
– Insertion- posterior calcaneus
– assist with knee flexion, ankle plantar flexion
• Popliteus
– Origin- lateral condyle of the femur
– Insertion- posterior medial condyle of Tibia
– assist medial hamstrings in knee internal rotation
Popliteus Muscle
Flexion of knee
O. Lateral
condyle of
Femur
I. Posteriorly on
the medial
Condyle of the
Tibia
Surface Anatomy
Surface Anatomy
Tendons vs Ligaments
• Tendon: dense regular connective tissue
that attaches muscle to bone.
• Ligament: elastic dense regular connective
tissue that attaches bone to bone.
• Quadriceps tendon:
– Formed by the tendons of four
muscles.
• Rectus Femoris
• Vastus Lateralis
• Vastus Medialis
• Vastus Intermedialis
– Inserts into patella
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• Patellar Ligament:
– Distal part of
quadriceps tendon.
– Adjoins patella to
tibial tuberosity.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Patellar
Ligament
• Tibial Collateral
Ligament (TCL):
– Flat band
– Medial epicodyle of
femur to medial/superior
condyle of tibia.
• Fibular Collateral
Ligament (FCL):
– Cord-like
– Lateral epicondyle of
femur to lateral surface of
head of fibula.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• Anterior Cruciate
Ligament (ACL):
– Weakest of the two
– Anterior intercondylar of
tibia to posterior/medial
lateral condyle of femur.
– Prevents poserior
displacement of femur &
hyperextension of the
knee.
• Posterior Cruciate
Ligament (PCL):
– Posterior intercondylar of
tibia to anterior/lateral of
medial condyle of femur.
– Prevents anterior
displacement of femur
and hyper flexion of
knee.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• Arcuate Popliteal
Ligament:
– Posterior fibular head
– Spreads over surface of
posterior knee joint.
– Reinforces joint capsule
posteriorly.
• Oblique Popliteal
Ligament:
– Part of semimembranosus
tendon.
– Strengthens joint capsule
posteriorly.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• Transverse
Ligament:
– Slender fibrous ban
– Joins menisci for
movement
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Bursae
• Flattened fibrous
sacs
• Fluid filled
• Occur where
ligaments, muscles,
skin, tendons or
bones rub together.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
•Suprapatellar:
-Anterior femur and deep
quadriceps femoris.
-Movement of quadriceps
tendon over femur.
•Patella:
Suprapatellar
Bursa
-Patella and Skin
-Movement of skin over
patella.
•Deep Infrapatella:
-Upper part of tibia and patellar
ligament.
-Movement of patellar ligament
over tibia.
•Subcutaneous Infrapetallar:
-Patellar ligament and skin
-Movement of skin
Patella
Bursa
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Deep
Infrapatellar
Bursa
Subcutaneous
Infrapatellar
Bursa
Cartilage
• Medial Meniscus:
– C-Shaped
– Anterior horn attaches to
anterior intercondylar of
tibia, anterior to ACL.
– Posterior horn attaches to
posterior intercondylar,
anterior to PCL.
– Adheres to tibial collateral
ligament.
• Lateral Meniscus:
– Circular
– Smaller & moves easily
– Adheres to popliteus
tendon.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Torn Meniscus
– Either or both menisci may be torn in several different
areas from a variety of mechanisms, resulting in
varying degrees of problems
– A torn meniscus is one of the most common knee
injuries. Any activity that causes you to forcefully twist
or rotate your knee, especially when putting the
pressure of your full weight on it, can lead to a torn
meniscus.
– Conservative treatment — such as rest, ice and
medication — is sometimes enough to relieve the pain
of a torn meniscus and give the injury time to heal on its
own. In other cases, however, a torn meniscus requires
surgical repair.
Torn ACL
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Torn Anterior Cruciate Ligament (Torn ACL) Facts
The anterior cruciate ligament (ACL) is one of four ligaments that help
stabilize the knee. It is the most commonly injured knee ligament.
ACL injury usually occurs when the knee is hyperextended (straightened)
and a pivot occurs simultaneously. The injury may occur with or without
contact.
Women have an increased risk of ACL injury because of differences in
anatomy, muscle mass, and training.
Symptoms of ACL tear include hearing a loud pop as the ligament tears,
pain, knee swelling, and difficulty walking.
Diagnosis is made clinically by physical examination and usually confirmed
by MRI.
Surgery and rehabilitation is the most commonly suggested treatment,
though in patients who are sedentary or do little sports activity, a
nonoperative approach is a possibility.
Postoperative rehabilitation may take six to nine months to return to full
activity.
From http://www.emedicinehealth.com/torn_acl/article_em.htm
Nerves - Posterior
FEMORAL L2, L3, L4
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The femoral nerve arises from
the 2nd, 3rd, & 4th lumbar nerves.
The nerve emerges from the
from the lateral border of the
psoas major and innervates the
iliacus and passes deep into the
inguinal ligament of the anterior
thigh supplying the flexors of the
hip and extensors of the knee.
Innervates: Rectus Femoris,
Vastas intermedialis, Vastas
lateralis, Vastas medialis,
Nerves
Sciatic Nerve
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The sciatic nerve is the largest
nerve in the body and is in
continuation of the main part of
the sacral plexus L4-S3.
Descends deep into the biceps
femoris; bifurcates into the tibial
and common fibular nerves at
apex of popliteal fossa.
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The tibial nerve is the larger of
the two terminal branches of the
sciatic nerve. Its runs through
the popliteal fossa with the
popliteal artery and vein. The
nerve supplies all muscles in
the posterior compartment of
the leg.
Tibial Nerve
Nerves - Anterior
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The superficial fibular (peroneal) nerve is
one of the terminal branches of the common
fibular nerve. It descends anterior to the
fibula. It supplies the fibularis longus and
brevis (and sometimes the extensor digitorum
brevis) and provides cutaneous branches to
usually all five toes. Section of the superficial
fibular nerve may result in impairment and
loss of eversion.
The deep fibular (peroneal) nerve is one of
the terminal branches of the common fibular
nerve. It continues around the neck of the
fibula and descends on the interosseous
membrane in company with the anterior tibial
artery. It supplies the tibialis anterior,
extensor digitorum longus, extensor hallucis
longus, fibularis tertius, and extensor
digitorum brevis muscles, and it gives off
dorsal digital nerves to the first two toes.
Damage to the deep fibular nerve may result
in footdrop and a "steppage" gait, owing to
paralysis of the dorsiflexors of the foot and
the extensors of the toes. This gait is
characterized by lifting the knee high in order
to allow the drooping toes to clear the floor.
Right anterior view of knee
Superficial fibular
Nerve
Deep Fibular (peroneal) Nerve
Sciatic Nerve
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The largest and longest nerve in the
body. The sciatic nerve leaves the pelvis
via the greater sciatic notch, descends
deep to the gluteus maximus muscle, and
continues down the posterior aspect of
the thigh. There it supplies the hamstring
muscles and part of the adductor
magnus. The sciatic nerve divides
immediately above the knee to give rise
to the peroneal nerve and tibial nerve.
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The sciatic nerve innervates the skin on
the posterior aspect of the thigh and
gluteal regions, as well as the entire
lower leg (except for its medial aspect).
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Muscles it innervates: Rectus femoris,
vastas intermedialis, vastas lateralis,
vastas medialis.
Arteries
Femoral Artery
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The femoral artery is first known as the
common femoral artery, because it has not yet
given off branches. It gives off a branch known
as the deep artery of the thigh (profunda
femoris) while continuing down the thigh medial
to the femur. After giving off other branches,
the femoral artery goes behind the knee and
becomes the popliteal artery.
The popliteal artery is the extension of the
"superficial" femoral artery after passing through
the adductor canal and adductor hiatus above
the knee. The termination of the popliteal artery
is its bifurcation into the anterior tibial artery and
posterior tibial artery. The popliteal artery
supplies blood to the knee joint and muscles in
the thigh and calf. It is accompanied, along its
length, by the popliteal vein.
The posterior Tibial Artery of the lower limb
carries blood to the posterior compartment of the
leg and plantar surface of the foot, from the
popliteal artery. It is accompanied by a deep
vein, the posterior tibial vein, along its course.
Right Knee
Anterior View
Popliteal Artery
Posterior Tibial Artery
Anterior Tibial Artery
Arteries
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The anterior tibial artery branches
off from the popliteal artery just below
the knee area. The anterior tibial
artery supplies vital oxygenated blood
and nutrients to the anterior shin or
lower leg area. Blood flows from the
common iliac artery to the external
iliac artery, the femoral artery, the
popliteal artery, and finally the
anterior tibial artery.
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Dorsalis Pedis artery (dorsal artery
of foot), it carries oxygenated blood
from the dorsal surface of the foot. It
arises at the anterior aspect of the
ankle joint and is a continuation of the
anterior tibial artery. Along its
course, it is accompanied by the
dorsalis pedis vein.
Arteries
Tibial Nerve
Posterior tibial artery
Artery
• The fibular artery (also
known as the peroneal
artery) supplies blood
to the lateral
compartment of the leg
and is typically a branch
of posterior tibial artery.
Inferior gluteal artery
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The inferior gluteal artery
(sciatic artery), the larger of the
two terminal branches of the
anterior trunk of the internal iliac
artery, is distributed chiefly to the
buttock and back of the thigh.
It passes down on the sacral plexus
of nerves and the Piriformis, behind
the internal pudendal artery, to the
lower part of the greater sciatic
foramen, through which it escapes
from the pelvis between the
Piriformis and Coccygeus.
It then descends in the interval
between the greater trochanter of
the femur and tuberosity of the
ischium, accompanied by the sciatic
and posterior femoral cutaneous
nerves, and covered by the Glutæus
maximus, and is continued down the
back of the thigh, supplying the skin,
and anastomosing with branches of
the perforating arteries.
Lateral and Medial circumflex femoral arteries
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Lateral circumflex femoral
artery
The lateral femoral circumflex artery arises from
the lateral side of the profunda femoris artery,
passes horizontally between the divisions of the
femoral nerve, and behind the sartoriusand
rectus femoris, and divides into ascending,
transverse, and descending branches.
Innervates: Rectus femoris, Vastas
intermedialis, Vastas lateralis, Vastas medialis.
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Medial circumflex femoral
artery
The medial femoral circumflex artery arises from
the medial and posterior aspect of the profunda
femoris artery, and winds around the medial side
of the femur, passing first between the pectineus
and iliopsoas muscles, and then between the
obturator externus and the adductor brevis
muscles.
- helps supply blood to the neck of the femur
Veins
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The anterior tibial vein of the lower limb
carries blood from the anterior
compartment of the leg to the popliteal
vein which is forms when it joins with the
posterior tibial vein. Like most deep
veins, the anterior tibial vein is
accompanied by an artery of the same
name, the anterior tibial artery, along its
course.
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The Popliteal vein is formed at the distal
border of the popliteus as a continuation
of the posterior tibial veins. The vein lies
superficial to the fibrous sheath as the
popliteal artery. Superiorly, the popliteal
vein becomes the femoral vein.
The femoral vein is the continuation of
the popliteal vein. The vein lies posterior
to the femoral artery. Eventually the
femoral vein becomes the external illiac
vein.
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Veins
• Posterior tibial vein
of the lower limb carries blood from the
posterior compartment and plantar
surface of the foot to the popliteal vein
which it forms when it joins with the
anterior tibial vein.
Like most deep veins, the posterior tibial
vein is accompanied by an artery of the
same name, the posterior tibial artery,
along its course.
• Fibular (Peroneal)
vein
The fibular veins are deep veins that
help carry blood from the lateral
compartment of the leg. They drain
into the posterior tibial veins, which will
in turn drain into the popliteal vein.
The fibular veins accompany the
fibular artery.
Greater and lesser saphenous
veins
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Lesser saphenous vein originates where
the dorsal vein from the fifth digit merges
with the dorsal venous arch of the foot,
which attaches to the great saphenous vein.
The vein and is subcutaneous (just under
the skin). From its origin, it courses around
the lateral aspect of the foot and runs along
the posterior aspect of the leg, passes
between the heads of the gastrocnemius
muscle, and drains into the popliteal vein,
approximately at or above the level of the
knee joint.
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Greater saphenous vein originates from
where the dorsal vein of the first digit
merges with the dorsal venous arch of the
foot. After passing anterior to the medial
malleolus (where it often can be visualized
and palpated), it runs up the medial side of
the leg. At the knee, it runs over the
posterior border of the medial epicondyle of
the femur bone. The great saphenous vein
then courses medially to lie on the anterior
surface of the thigh before entering an
opening in the fascia lata called the
saphenous opening. It joins with the femoral
vein in the region of the femoral triangle at
the saphenofemoral junction.
References
• http://medchrome.com/wp-content/uploads/2010/06/ligamentsof-knee.jpg
• http://www.hughston.com/hha/a.extmech.htm
• http://classroom.sdmesa.net/eschmid/F07.11.L.150.jpg
• http://www.gla.ac.uk/ibls/US/fab/tutorial/anatomy/kneet.html
• http://www.riversideonline.com/health_reference/DiseaseConditions/DS01031.cfm
• Wikipedia
• Essential Clinical Anatomy 4th edition. Wolters Kluwer
• http://www.genericlook.com/anatomy/Lower-Extremity-Veins/