Thigh, knee, and popliteal fossa

The femur

Overview

Important landmarks

Muscles of the thigh

Anterior compartment of the thigh
Muscle Origin Insertion Nerve Function

Testing

Sartorius
  • Abduct, flex and externally rotate the thigh against resistance

Quadriceps femoris

Vastus lateralis
  • Greater trochanter, intertrochanteric line, gluteal tuberosity, and linea aspera
  • Extend the flexed knee against resistance
Vastus medialis
  • Linea aspera, intertrochanteric line, pectineal line
Vastus intermedius
  • Anterolateral surface of the upper two-thirds of the femural shaft
  • Superolateral part of the patella via the quadriceps tendon
Rectus femoris

Muscles of the posterior abdominal wall

Iliacus
  • Ala of the sacrum and iliac fossa
  • Lesser trochanter of the femur via the iliopsoas tendon
  • Flex the hip further (i.e., bring the thigh above the hip), against resistance
  • Clinical significance: iliopsoas abscess
Psoas major
Psoas minor
  • Iliopubic ramus
  • Cannot be tested in isolation

Posterior compartment of the thigh

(Hamstrings)

Muscle Origin Insertion Nerve Function Testing
Semimembranosus
  • Ischial tuberosity
  • Flex the knee against resistance
Semitendinosus
  • Superomedial surface of tibia
Biceps femoris
  • Long head: ischial tuberosity
  • Short head: upper supracondylar line and the linea aspera

Medial compartment of the thigh

(Adductor compartment)

Muscle Origin Insertion Nerve Function Testing

Obturator externus

  • Greater trochanter
  • Cannot be tested in isolation
Gracilis
  • Inferior pubic ramus
  • Superomedial aspect of the tibia
Pectineus
  • Pectineal line of the pubis
  • Pectineal line of the femur
  • Cannot be tested in isolation
Adductor magnus
  • Hamstring part: ischial tuberosity
  • Adductor part: ischiopubic ramus
  • Hamstring part: adductor tubercle and supracondylar line of the femur
  • Adductor part: linea aspera
  • Hamstring part: extension of the hip
  • Adductor part: adduction of the hip
  • Adduct the thigh against resistance with the knee in extension
Adductor longus
  • Linea aspera
Adductor brevis
  • Linea aspera
Adductor minimus
  • Inferior ramus of pubis
  • Linea aspera

Femoral triangle and fasial compartments of the thigh

Femoral triangle

To remember the order of the femoral canal contents, remember “NAVEL”: Nerve, Artery, Vein, Empty space (femoral canal), and Lymphatics

Femoral canal

Femoral sheath

Femoral ring

Adductor canal

Saphenous opening

Vascular supply of the thigh

Arteries

Femoral artery

Obturator artery

Veins

Innervation of the thigh

Motor and sensory innervation

The motor and sensory nerve of the thigh arise from the lumbar plexus and sacral plexus

Nerve Origin Motor supply Sensory supply Clinical significance
Mixed motor and sensory nerves

Femoral nerve

  • Intermediate cutaneous nerve of thigh: skin over the anterior aspect of the thigh
  • Medial cutaneous nerve of thigh (medial femoral cutaneous nerve): skin over the lower 2/3rd of the medial aspect of the thigh
  • Saphenous nerve (supplies the medial side of the leg and foot)

Obturator nerve

  • Muscles of the medial compartment of the thigh
  • Skin over the upper 1/3rd of the medial aspect of the thigh
Sciatic nerve
Pure sensory nerves

Lateral cutaneous nerve of thigh

(lateral femoral cutaneous nerve)

  • None
  • Skin over the anterolateral aspect of thigh (up to the knee)

Posterior cutaneous nerve of thigh

(posterior femoral cutaneous nerve)

  • None

Dermatomal distribution of the thigh and knee

References:[1][2]

Lymphatic drainage of the thigh

Inguinal lymph node groups

The knee joint

Overview

Soft tissue structures of the knee

Ligaments and menisci of the knee
Structure Anatomy Function Testing

Cruciate ligaments

Anterior cruciate ligament

(ACL)

  • Origin: anterior intercondylar part of the tibia
  • Insertion: lateral femoral condyle (posteromedial aspect)

Posterior cruciate ligament

(PCL)

Collateral ligaments

Medial collateral ligament

(Tibial collateral ligament; MCL)

  • Origin: medial femoral epicondyle
  • Insertion: medial tibial condyle

Lateral collateral ligament

(Fibular collateral ligament; LCL)

  • Origin: lateral femoral epicondyle
  • Insertion: head of the fibula

Other ligaments of the knee

Patellar ligament

(Patellar tendon)

  • Extension of the knee
Popliteofibular ligament
  • Stabilizes the posterolateral aspect of the knee
Transverse ligament
  • Prevents the anterior margin (horn) of the menisci from moving forward
  • Reduces the pressure exerted on the menisci by the articular surfaces of the tibia and femur
Menisci
(semilunar cartilages)
Medial meniscus
  • Deepen the articular surface and stabilize the knee joint structure
  • Decrease friction between the osseous surfaces
  • Periphery is better vascularized than the inner surface
  • Clinical significance: meniscal tear
Lateral meniscus

The unhappy triad: injury to the ACL, MCL, and medial meniscus caused by a lateral force to the knee!


Bursae of the knee

Bursae Anatomy Clinical significance
Suprapatellar bursa
Prepatellar bursa
  • Between the anterior surface of the patella and the skin
Infrapatellar bursa

Anserine bursa

(pes anserinus)

3-D model of the knee


References:[3][4]

The popliteal fossa


References:[5][6][7]

Clinical significance