anterior thigh, medial thigh, knee joint

lower limb - interosseous membrane

fibrous (collagenous) sheet connecting the shafts of the tibia & fibula in the lower limb

• provides stability - strengthens tibiofibular joint

• serves as an attachment for deep flexor & extensor muscles

lateral malleolus

the bony prominence on the outer side of the ankle formed by the distal end of the fibula

• provides stability to the ankle joint

• acts as a site for ligament attachments

  • anterior talofibular ligament

  • posterior talofibular ligament

  • posterior tibiofibular ligament

  • calcaneofibular ligament

  • superior fibular retinaculum

medial malleolus

the bony prominence on the inner side of the ankle formed by the distal end of the tibia

• provides stability to the ankle joint

• serves as an attachment site for ligaments

  • deltoid ligament

  • flexor retinaculum

tibial tuberosity

a bony prominence on the anterior aspect of the tibia where the patellar ligament attaches

• important site for muscle attachment - quadriceps femoris (rectus femoris, vastus lateralis, vastus medialis, & vastus intermedius) via patellar ligament

tibia - lateral condyle

the rounded portion of the upper tibia that articulates with the femur at the knee joint via the lateral meniscus (forms femorotibial joint)

• attachment point: lateral patellar retinaculum

• origins: extensor digitorum longus

tibia - medial condyle

the rounded portion of the upper tibia that articulates with the femur at the knee joint via the medial meniscus (forms medial femorotibial joint)

• attachment site: lateral patellar retinaculum

• insertions: semimembranosus

fibula - head

the upper end of the fibula that articulates with the tibia at the proximal tibiofibular joint

• ligaments: lateral (fibular) collateral ligament (LCL)

• origins: fibularis longus + soleus + fibularis brevis + extensor digitorum longus + extensor hallucis longus + tibialis posterior + flexor hallucis longus

• insertions: biceps femoris (short head)

knee joint

unstable, weak joint formed from the articulation of the distal femur, patella, & proximal tibia

• 3 joint articulations

  • lateral tibiofemoral joint

  • medial tibiofemoral joint

  • patellofemoral joint

• commonly injured

lateral tibiofemoral joint

the joint formed by the lateral FEMORAL condyle & the lateral TIBIAL condyle

• allows for flexion & extension of the knee

medial tibiofemoral joint

the joint formed by the medial FEMORAL condyle & the medial TIBIAL condyle

• allows for flexion & extension of the knee

patellofemoral joint

the joint formed by the patella & the anterior surface of the femur

• allows for gliding motion during knee movement

knee joint movement

main, normal actions of flexion & extension

• slight rotation during flexion → limited by ligaments

medial (tibial) collateral ligament (MCL)

a ligament on the medial side of the knee that provides stability & prevents excessive sideways movement

• attachment

  • superior: femoral medial epicondyle

  • inferior: tibial medial surface

• fused to medial meniscus & articular capsule of knee joint

• weaker & commonly damaged → unhappy triad

lateral (fibular) collateral ligament (LCL)

a ligament on the lateral side of the knee that stabilizes the joint and prevents excessive sideways movement

• attachment

  • origin: femoral lateral epicondyle

  • inferior: head of fibula

• not fused to lateral meniscus & articular capsule of knee joint → more flexible

• stronger, cord-like

anterior cruciate ligament (ACL)

a key ligament in the knee that connects the femur to the tibia anteriorly playing a critical role in maintaining knee joint stability

• prevents anterior sliding of tibia under femur

• prevents hyperEXTENSION of knee joint

• weak, more commonly damaged → unhappy triad

posterior cruciate ligament (PCL)

a ligament in the knee that connects the femur to the tibia posteriorly playing a critical role in maintaining knee joint stability

• prevents posterior sliding of the tibia under the femur

• limits hyperFLEXION of the knee

• strong and is less commonly injured

meniscus

crescent-shaped fibrocartilage pads in the knee joint

• deepens articular surface between tibia & femur

• shock absorption

medial meniscus

flat, crescent-shaped fibrocartilage located on the medial side of the tibia in the knee joint that provides cushioning & stability

• attached to the intercondylar area of the tibia

• partially fused to medial (tibial) collateral ligament (MCL)

• commonly damage → unhappy triad

lateral meniscus

flat, crescent-shaped fibrocartilage on the lateral side of the tibia in the knee joint that provides cushioning & stability

• attached to the intercondylar area of the tibia

• not fused to lateral (fibular) collateral ligament (LCL)

• more mobile → less prone to damage

patellar bursae

synovial fluid-filled sacs that reduce friction between the patella and surrounding tissues such as skin, bone, tendons, & ligaments during joint movements

• 3 locations

  • suprapatellar

  • prepatellar

  • infrapatellar

anterior [compartment] thigh muscles

group of muscles in the front part of the thigh responsible for extending the leg at the knee joint & flexing the thigh at the hip joint

• muscles: quadriceps femoris + sartorius + iliopsoas + pectineus + pectineus

• nerve: femoral (L2 - L4)

• vasculature: femoral artery + vein

sartorius

action: flexes, ABducts, & laterally rotates thigh at HIP joint + flexes the leg at KNEE joint

• produces the cross-legged sitting position

nerve: femoral nerve (L2 - L4)

blood supply: femoral artery + vein

origin: anterior superior iliac spine (ASIS)

insertion: tibia (superomedial aspect)

iliopsoas

major hip flexor composed of the psoas major & iliacus muscles that responsible for flexing the thigh at the hip joint

• fused into 1 muscle below the inguinal ligament

iliopsoas - iliacus

action: major FLEXOR of thigh at HIP joint

nerve: femoral nerve (L2 - L4)

blood supply: femoral artery + vein & iliolumbar artery (iliac) & deep circumflex iliac artery & obturator artery

origin: iliac fossa

insertion: lesser trochanter of femur

iliopsoas - psoas major

action: major FLEXOR of thigh at HIP joint

nerve: anterior rami of L1 - L3

blood supply: femoral artery + vein & iliolumbar artery (lumbar) & external iliac artery & obturator artery

origin: vertebral bodies of T12 - L5 vertebrae

insertion: lesser trochanter of femur

pectineus

action: flexes & ADducts thigh at HIP joint + assists with MEDIAL rotation of thigh

nerve: femoral nerve (L2 - L4) & obturator nerve (L2 - L4)

blood supply: medial femoral circumflex artery + vein & obturator artery

origin: superior pubic ramus

insertion: pectineal line of femur just inferior to lesser trochanter

quadriceps femoris

group of four muscles - rectus femoris, vastus medialis, vastus intermedius, & vastus lateralis - responsible for knee joint extension (thigh extension) & hip joint flexion (thigh flexion)

• powerful KNEE EXTENSOR used in climbing, running, jumping, & rising from a seated position

• innervation: femoral nerve (L2 - L4)

quadriceps femoris - rectus femoris

action: EXTEND leg at KNEE joint + FLEX thigh at HIP joint

nerve: femoral nerve (L2 - L4)

blood supply: deep femoral artery + vein & lateral circumflex femoral artery

origin: anterior inferior iliac spine (AIIS) & ilium superior to acetabulum

insertion: patella via tendon & tibial tuberosity via patellar ligament

quadriceps femoris - vastus MEDIALIS

action: EXTEND leg at KNEE joint

nerve: femoral nerve (L2 - L4)

blood supply: femoral artery + vein & deep femoral & descending genicular artery

origin: intertrochanteric line & linea aspera of femur

insertion: patella via tendon & tibial tuberosity via patellar ligament

quadriceps femoris - vastus LATERALIS

action: EXTEND leg at KNEE joint

nerve: femoral nerve (L2 - L4)

blood supply: deep femoral arteries + veins & lateral circumflex femoral artery

origin: greater trochanter & linea aspera

insertion: patella via tendon & tibial tuberosity via patellar ligament

quadriceps femoris - vastus INTERMEDIUS

action: EXTEND leg at KNEE joint

nerve: femoral nerve (L2 - L4)

blood supply: deep femoral arteries + veins

origin: shaft of femur

insertion: patella via tendon & tibial tuberosity via patellar ligament

quadriceps femoris tendon

strong, common tendon of the four quadriceps muscles (rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius) that attaches to the patella

• allows for extension of the leg at the knee joint

patellar ligament

strong ligament formed from the continuation of the distal part of quadriceps femoris tendon that connects the patella to the tibial tuberosity

• maintains alignment of patella relative to femur

patellar reflex

"knee jerk reflex" - it tests the integrity of the femoral nerve by eliciting a reflex response

• procedure: patient sits with leg dangling → firm tap with reflex hammer on patellar ligament

• NORMAL = quadriceps femoris muscle contracts due to stretch (tap) → leg to extend at the knee joint

medial [compartment] thigh muscles

group of muscles in the inner part of the thigh responsible for ADduction of thigh at HIP joint

• muscles: adductor longus + adductor brevis + adductor magnus + gracilis + obturator externus

• nerve: obturator (L2 - L4)

• vasculature: obturator artery + vein

adductor LONGUS

action: ADduct thigh at HIP joint

nerve: obturator nerve (L2 - L4)

blood supply: obturator artery + vein & deep femoral artery & medial circumflex femoral artery

origin: pubis inferior to pubic crest

insertion: linea aspera of femur

adductor BREVIS

action: ADduct thigh at HIP joint + some FLEXION of thigh

nerve: obturator nerve (L2 - L4)

blood supply: obturator artery + vein & profunda femoris artery (deep femoral artery)

origin: inferior ramus of pubic bone

insertion: pectineal line & proximal part of linea aspera of femur

adductor magnus

a muscle with dual innervation

• adductor muscle innervated by the obturator nerve

• hamstring part innervated by the tibial division of the sciatic nerve

adductor magnus (ADDUCTOR)

action: ADduct thigh at HIP joint + FLEXES thigh at HIP joint

nerve: obturator nerve (L2 - L4)

blood supply: obturator artery + vein & profunda femoris artery (deep femoral artery)

origin: ischiopubic ramus

insertion: gluteal tuberosity + linea aspera + medial supracondylar line

adductor magnus (HAMSTRING)

action: ADduct thigh at HIP joint + EXTENDS thigh at HIP joint

nerve: tibial division of the sciatic nerve

blood supply: obturator artery + vein & profunda femoris artery (deep femoral artery)

origin: ischial tuberosity

insertion: adductor tubercle of femur

adductor hiatus

opening in the adductor magnus muscle that allows passage of the femoral artery & vein from the anterior thigh to the posterior knee (popliteal fossa)

• femoral artery → popliteal artery

• femoral vein → popliteal vein

gracilis

action: ADduct thigh at HIP joint + FLEXES leg at KNEE joint + helps MEDIALLY rotate leg

nerve: obturator nerve (L2 - L4)

blood supply: obturator artery + vein & medial circumflex femoral artery

origin: inferior pubic ramus

insertion: superior part of medial tibia

obturator externus

action: LATERALLY rotate thigh at HIP joint

nerve: obturator nerve (L2 - L4)

blood supply: obturator artery + vein & medial circumflex femoral arteries

origin: obturator foramen & membrane

insertion: trochanteric fossa of femur

femoral nerve (L2 - L4) injury

motor: weakness or inability to EXTEND knee & FLEX thigh

sensory: decrease or loss of skin sensation along the pathway (anterior thigh & medial leg)

obturator nerve (L2 - L4) injury

motor: weakness or inability to ADDUCT thigh

sensory: decrease or loss of skin sensation on medial aspect of thigh

lateral cutaneous nerve (thigh)

sensory nerve that provides sensation to the skin on the lateral aspect of the thigh

anterior cutaneous branch (femoral nerve)

sensory branches of the femoral nerve that provide sensation to the skin of the anterior thigh

cutaneous branch (obturator nerve)

sensory branch of the obturator nerve that supplies sensation to the skin on the medial thigh

saphenous nerve (femoral nerve)

sensory nerve that provides sensation to the skin on the medial aspect of the leg & foot

great saphenous vein

a superficial vein running along the length of the leg & thigh that enters through saphenous opening in the fascia lata

• drains directly into the femoral vein

• receives deoxygenated blood from small, superficial tributary veins from anterior & medial thigh

femoral triangle

an anatomical region in the anterosuperior thigh

• borders

  • superior: inguinal ligament

  • lateral: sartorius muscle

  • medial: adductor longus muscle

• floor: iliopsoas & pectineus

• contents (lateral → medial): N-A-V-E-L

  • femoral Nerve, femoral Artery, femoral Vein, Empty space (canal for lymphatics), Lacunar Ligament

femoral pulse

the pulse palpated over the femoral artery just distal to midpoint of inguinal ligament (between anterior superior iliac spine & pubic tubercle)

• can be located via the femoral triangle

femoral hernia

a type of hernia that occurs at the area of the femoral triangle - in the femoral canal located below the inguinal ligament

• more common in women

adductor canal

a fascial compartment (tunnel) in the thigh located posterior to the sartorius muscle that facilitates the passage of

• femoral artery & vein

• saphenous nerve

• nerve to vastus medialis

ANTERIOR drawer sign

a clinical test used to assess the integrity of the anterior cruciate ligament (ACL) by pulling the tibia forward while stabilizing the femur

• POSITIVE = [excessive] anterior movement of tibia

POSTERIOR drawer sign

a clinical test used to evaluate the integrity of the posterior cruciate ligament (PCL) by pushing the tibia backward while stabilizing the femur

• POSITIVE = [excessive] posterior movement of the tibia

VALGUS stress test

a clinical assessment used to evaluate the integrity of the medial collateral ligament (MCL) by applying a lateral force to the knee while stabilizing the ankle

• POSITIVE = excessive gapping at the medial joint and/or pain

VARUS stress test

a clinical assessment used to evaluate the integrity of the lateral collateral ligament (LCL) by applying a medial force to the knee while stabilizing the ankle.

• POSITIVE = excessive gapping at the lateral joint and/or pain

McMurray test - INTERNAL rotation

a clinical test used to assess the integrity of the medial meniscus by flexing the knee & applying a rotational force while extending the knee

• POSITIVE = a click or pain in the joint

McMurray test - EXTERNAL rotation

a clinical test used to assess the integrity of the lateral meniscus by flexing the knee & applying a rotational force while extending the knee

• POSITIVE = a click or pain in the joint

unhappy triad injury

common knee injury in contact sports caused by hit to lateral side of extended knee or excessive lateral twisting of flexed knee resulting in simultaneous tear / rupture to:

• anterior cruciate ligament (ACL) → positive anterior drawer sign

• medial collateral ligament (MCL) → positive valgus stress test

• medial meniscus → positive McMurray test (internal rotation)

genu varum

bow-leg - condition characterized by medial angulation of the tibia relative to the femur

• weight-bearing more on medial knee

  • stresses medial joint, cartilages, medial meniscus

• stresses lateral (fibular) collateral ligament

genu valgum

knock-knee - condition characterized by lateral angulation of the tibia relative to the femur

• weight-bearing more on lateral knee

  • stresses lateral joint, cartilages, lateral meniscus

• stresses medial (tibial) collateral ligament

patella dislocation

displacement of the kneecap from its normal position often due to a sudden twist or impact

• commonly dislocates LATERALLY

  • due to normal angulation of femur & angle of lateral pull of quadriceps femoris

  • if vastus medialis is weak → vastus lateralis pulls patella laterally

compartment syndrome of thigh

increased pressure in the fascial compartment of the thigh leading to restricted blood flow & compressed nerves

• cause: fracture, contusion / compression to thigh → tissue swelling or blood leaking into tissues

• signs / symptoms: PAIN, pressure, pulselessness, pale skin, paralysis, burning

• treatment: FASCIOTOMY

• complication: tissue necrosis → amputation