4. Posterior Thigh Musculature

Functional Anatomy of the Posterior Thigh

• The posterior thigh is organized into 3 compartments separated by intermuscular septa.
• The posterior thigh contains muscles that extend the hip and flex the knee. The hamstrings are a key muscle group in this region.
• Cluneal Nerves:
  • Superior cluneal nerves are located above the iliac crest.
  • Medial (middle) cluneal nerves are near the sacrum's midline.
  • Inferior cluneal nerves are below the gluteus maximus inferior border.
  • These nerves arise from either dorsal or ventral rami of the sacral spinal nerves.

Organization of the Thigh

• The thigh is categorized into anterior, medial, and posterior compartments.
• These compartments are separated by intermuscular septa.
• The posterior thigh muscles primarily extend the hip and flex the knee.
• The hamstring muscles are a significant component of the posterior thigh.

Bursa in the Region

• Bursae are located in areas prone to friction. They are lined with synovial membrane.
• Types of bursae in the posterior thigh region include:
  • Ischial bursa: separates gluteus maximus from ischial tuberosity.
  • Iliopsoas bursa: separates iliopsoas muscle from the joint.
  • Trochanteric bursa: separates gluteus maximus from greater trochanter.
  • Gluteofemoral bursa: separates iliotibial band from vastus lateralis.

Hamstring Musculature

• Semitendinosus:
  • Originates from the ischial tuberosity.
  • Inserts on the medial surface of the superior tibia (pes anserinus).
• Semimembranosus:
  • Originates from the ischial tuberosity.
  • Inserts on the posterior part of the medial tibial condyle.
  • Also attaches to the oblique popliteal ligament (SMOP).
• Biceps Femoris:
  • Long head: originates from the ischial tuberosity.
  • Short head: originates from the linea aspera and lateral supracondylar line of the femur.
  • Inserts distally into the lateral head of the fibula.

Bony Attachments of Muscles of Hip and Thigh

• The posterior thigh muscles have various origins on the ischial tuberosity, linea aspera, and lateral supracondylar line of the femur.
• They insert on various bony locations in the leg and thigh.

Popliteal Fossa

• A diamond-shaped depression in the posterior aspect of the knee.
• Superiorly bounded by the hamstring muscles.
• Inferiorly bounded by the gastrocnemius and plantaris muscles.
• Posteriorly lined by skin and fascia.
• Anteriorly bounded by the surface of the femur and the oblique popliteal ligament.

Popliteal Fossa Contents

• The popliteal fossa houses popliteal arteries and veins (deeper structures).
• The lesser saphenous vein (superficial) is also present here as superficial structure.
• Nerves (e.g., tibial and common peroneal nerves, and sural nerves) are within the fossa.
• Lymph nodes and vessels are part of the popliteal fossa's vasculature.
• Posterior femoral cutaneous nerve innervates skin in the region.

Knee - Medial View

• Muscles that surround the knee joint are described.
• Bony landmarks and ligaments are identified on the medial aspect of the knee.
• Important anatomical structures like the oblique popliteal ligament are discussed.

Knee - Lateral View

• Muscles, ligaments and important anatomical structures of the knee are detailed on the lateral aspect of the knee joint.

Nerves

• Major nerves in the posterior thigh region, like the sciatic nerve, common fibular (peroneal) branch, and tibial branch are named within the context of structures of the posterior thigh.
• Plantaris muscle is discussed, with location and innervations.
• Sural nerves are mentioned.

Popliteus Muscle

• Popliteus is a muscle located in the popliteal fossa.
• Origin and insertion are described.

Plantaris Muscle

• Plantaris is a small muscle in the posterior compartment of the lower leg.
• Origin and insertion are detailed.