Anatomy Chapter 3: The Anterior Thigh

Lecture 3: The Anterior Thigh

• The anterior thigh is covered by superficial fascia
• The anterior thigh is divided into anterior, medial and posterior compartments by deep fascia
• The femur is the longest, biggest and strongest bone in the thigh
• It articulates with the patella, tibia, and pelvis
• The femur's landmarks include greater trochanter, femoral neck, lesser trochanter, intertrochanteric crest, gluteal tuberosity, linea aspera, lateral lip, and medial lip.
• The head of the femur has cortical and cancellous bone
• The head of femur is strong, dense, rigid, provides structural integrity
• The cancellous bone is less dense, spongier, more flexible, dissipates stress better
• The hip has ligaments: Iliofemoral, pubofemoral, ischiofemoral ligaments.
• The anterior compartment muscles are psoas major, iliacus, tensor fascia lata, sartorius, rectus femoris, vastus lateralis, vastus medialis, vastus intermedius, and articularis genu.
• Tensor fascia lata origin is lateral iliac crest, insertion is lateral condyle of the tibia (via ITB), it flexes and medially rotates the thigh, and stabilises the knee and pelvis
• Sartorius origin is ASIS, insertion is proximal, medial tibia, it flexes the hip, abducts and laterally rotates the hip, flexes the knee, and medially rotates the knee
• Rectus femoris origin is AIIS, groove above acetabulum, insertion is tibial tuberosity, via patella and tendon, it flexes the hip and extends the knee
• Vastus lateralis origin is great trochanter, lateral femur, linea aspera, insertion is tibial tuberosity, via patella and tendon, it extends the knee
• Vastus medialis origin is intertrochanteric line, spiral line, linea aspera, m supracondylar line, A magnus, insertion is tibial tuberosity, via patella and tendon, it extends the knee
• Vastus intermedius origin is anterior and lateral surfaces of femur, insertion is tibial tuberosity, via patella and tendon, it extends the knee
• Articularis genu origin is anterior surface of femur, inferior and deep to vastus intermedius, insertion is suprapatellar bursa, it retracts bursa during knee extension

Hip Flexors

• Psoas major and iliacus work together as a functional group (often referred to as iliopsoas).
• Psoas major origin is 12th thoracic and lumbar vertebrae, insertion is lesser trochanter, it flexes the hip, its antagonists are gluteus max and hamstrings, innervation is L1 - L3.
• Iliacus origin is upper 2/3rds of iliac fossa, insertion is lesser trochanter, it flexes the hip, its antagonists are gluteus max and hamstrings, innervation is L2 - L3.

Vascular Structures

• Arteries deliver blood from the heart to other structures
• Veins return blood from other locations back to the heart, assisted by the lymphatic system
• External iliac artery pierces the inguinal ligament, the femoral artery splits into profunda femoris and medial/lateral (internal/external) femoral circumflex branches.
• Femoral artery becomes popliteal artery as it passes behind the knee

Veins

• Femoral vein drains blood from the anterior thigh
• Popliteal vein, Great saphenous, and Profunda femoris veins supply the femoral vein.

Lymphatics

• Lymphatics generally follow the course of the veins
• They drain into lymph nodes, which act as filters
• Eventually, all drain back into the venous system

The Femoral Triangle

• The femoral triangle contains the femoral artery, femoral vein, and femoral nerve.
• Inguinal lymph nodes are contained within the femoral sheath.
• The femoral sheath is a continuation of the deep fascia
• The femoral branch of the genitofemoral nerve passes through the anterior wall of the sheath to reach the skin of the femoral triangle.

Nerves

• Anterior thigh nerves arise from the lumbar plexus
• Nerves are broadly described as motor (muscular), or sensory (cutaneous).
• Major motor nerves for hip flexors and knee extensors are femoral (L2, 3, 4).
• Exceptions for motor nerves are the TFL and PM
• Cutaneous nerves are branches of the femoral nerve: medial femoral cutaneous, intermediate cutaneous, and saphenous.
• Lateral femoral cutaneous arises directly from the lumbar plexus. It is also associated with obturator, ilioinguinal, and genitofemoral.

Practical Anatomy

• Students should be able to identify major landmarks of the femur, muscles (Vastus Medialis, Vastus Lateralis, Rectus Femoris, Iliotibial band), and the ASIS, iliac crest, great trochanter, and patella on a volunteer.

Summary

• Students should be able to recognise and name major landmarks of the femur, muscles of the anterior thigh and their relationships, major neural and vascular structures of the anterior compartment (where they go and what they do), and contents of the femoral triangle and their significance.