Lower Limb Anatomy Quiz

Lower Limb Anatomy

• The lower limb is divided into the gluteal region, thigh, leg, and foot.
• The thigh is further divided into the anterior, medial, and posterior compartments.
• The femoral triangle, popliteal fossa, and ankle are important transition areas.

Fascia Lata

• The fascia lata is a thick layer of connective tissue that surrounds the muscles of the thigh and gluteal region.
• It limits the outward extension of contracting muscles, making muscle contraction more efficient in compressing veins.
• The fascia lata is thickened laterally to form the iliotibial tract (IT tract), which extends from the tuberculum of the iliac crest to just below the knee.
• The tensor fascia lata and gluteus maximus muscles attach to the IT tract and work to keep the leg in extension once the leg is extended.

Superficial Veins of the Leg

• The small saphenous vein originates on the lateral side of the dorsal venous arch, runs posterior to the lateral malleolus, ascends in the posterior leg, and drains into the popliteal vein.
• The great saphenous vein originates on the medial side of the dorsal venous arch, runs anterior to the medial malleolus, ascends on the medial side of the leg, knee, and thigh, and drains into the femoral vein.

Varicose Veins

• Varicose veins occur when the valves in veins fail to prevent backward blood flow, causing blood to accumulate in superficial veins.
• This accumulation leads to dilated, elongated, and tortuous superficial veins with incompetent or congenitally absent valves.

Femoral Triangle

• The femoral triangle is a wedge-shaped depression in the upper thigh that is formed by muscles.
• The boundaries of the femoral triangle are:
  • Superior: Inguinal ligament
  • Medial: Medial margin of the adductor longus
  • Lateral: Medial margin of the sartorius muscle
• The floor of the femoral triangle is formed by the:
  • Adductor longus (medial)
  • Pectineus (medial)
  • Iliopsoas (lateral)
• The roof of the femoral triangle is formed by the fascia lata.
• The contents of the femoral triangle are:
  • Femoral nerve
  • Femoral artery
  • Femoral vein
  • Lymph nodes
  • Empty space where the great saphenous vein penetrates the roof to drain into the femoral vein.

Femoral Canal (Adductor Canal)

• The apex of the femoral triangle is continuous with the adductor canal, a fascial canal containing the femoral artery and vein.
• The adductor canal passes through the adductor hiatus and opens into the popliteal fossa.

Femoral Sheath

• The femoral sheath surrounds the femoral artery and vein but not the femoral nerve.
• The femoral sheath is divided into three compartments:
  • Lateral: Femoral artery
  • Intermediate: Femoral vein
  • Medial: Femoral canal, which contains loose connective tissue, fat, and lymphatics. The entrance to the canal is the femoral ring.
• The femoral sheath continues superiorly with the transversalis fascia and inferiorly with connective tissue around the vessels.

Femoral Hernia

• A femoral hernia occurs when abdominal content protrudes through the femoral ring, a weak point in the body.
• The boundaries of the femoral ring are:
  • Anterior: Inguinal ligament
  • Lateral: Femoral vein
  • Medial: Lacunar ligament
  • Posterior: Pectineal ligament

Patellar Fractures and Dislocations

• Patellar Fractures
  • Frequently caused by a hard blow to the front of the knee.
  • Non-displaced fractures are typically treated with immobilization in a cast for 4-6 weeks.
  • Displaced fractures require surgical treatment followed by quadriceps strengthening.
• Patellar Dislocations
  • Can occur due to a direct blow or sudden twisting of the leg.
  • The patella slips out of its normal position in the patellofemoral groove, causing intense pain.
  • Dislocation often occurs laterally.
  • Typically treated with manual repositioning by extending the leg or an orthopedic reduction.
  • Swelling and impaired mobility are common.
  • Rehabilitation can take anywhere from 6 to 16 weeks.

Blood Supply to the Thigh

• The femoral artery is a continuation of the external iliac artery.
• The femoral artery is palpable in the femoral triangle at the mid-inguinal point, inferior to the inguinal ligament.
• It passes through the adductor canal and hiatus before becoming the popliteal artery at the popliteal fossa.
• Main Branches:
  • Deep (profunda) artery of the thigh: The main artery of the anterior compartment that gives off:
    • Lateral and medial circumflex femoral branches
    • Perforating branches (4x) that penetrate the adductor magnus.
  • Superficial epigastric artery
  • Superficial circumflex iliac artery
  • Superficial and deep external pudendal artery
• The obturator artery is the main artery of the medial compartment and is a branch of the internal iliac artery.

Deep Veins

• The deep veins of the thigh include:
  • Popliteal vein
  • Femoral vein
  • Deep femoral vein
  • Anterior and posterior tibial veins
  • Fibular veins
• The deep veins receive drainage from the superficial veins via the great saphenous vein and the small saphenous vein.
• Blood flow eventually progresses to the external iliac vein, common iliac vein, and inferior vena cava (IVC).

Deep Venous Thrombosis (DVT)

• Can occur when blood in the veins stagnates due to inactivity or injury, leading to the formation of clots in the lumen called thrombi.
• Thrombi can break loose and become emboli, potentially lodging in a vessel and preventing circulation.
• DVT can cause swelling in peripheral tissues and is generally found in the lower extremities, often propagating into the femoral veins.

Lymphatics

• Superficial inguinal lymph nodes are located in the femoral triangle.
• These nodes receive lymphatic drainage from the lower limb, external genitalia, and the lower abdominal wall.

Femoral Region

• Bones of the pelvis and lower limb: The pelvis is made up of three bones: ilium, pubis and ischium.
• Fascia lata and intramuscular septae: Fascia lata is a strong layer of deep fascia surrounding the thigh.
• Long and short saphenous veins: The great saphenous vein is located on the medial side of the leg, while the small saphenous vein runs on the lateral side.
• Varicose veins: Varicose veins develop when valves in veins become incompetent, causing blood to pool and distend the veins.
• Muscles and innervation: The anterior and medial compartments of the thigh contain several muscles responsible for various movements (e.g., hip flexion, knee extension).
• Femoral triangle: It is a space in the anterior thigh, bordered by the inguinal ligament (superior), sartorius (lateral), and adductor longus (medial). It contains the femoral artery, vein, and nerve.
• Femoral hernias: These occur when the abdominal contents protrude through a weak spot in the abdominal wall in the femoral canal, below the inguinal ligament. Typically present as a lump or bulge in the groin.
• Clinical landmarks: Several clinical landmarks are used to assess the anterior and medial thigh, such as the inguinal ligament, the femoral triangle, and the adductor canal.
• Radiological imaging: Radiological imaging techniques (e.g., X-rays, CT scans, MRI) are used to visualize the bones, vessels, and soft tissues within the thigh and pelvis, helping diagnose various conditions.

Blood Supply

• Femoral artery: It originates from the external iliac artery. It is palpable in the femoral triangle (mid-inguinal point) and supplies the thigh.
• Deep femoral (profunda) artery: It is a branch of the femoral artery and is the main arterial supply to the anterior compartment of the thigh.
• Medial circumflex artery: It is a branch of the external iliac artery and contributes to the blood supply of the medial compartment of the thigh.
• Obturator artery: It is a branch of the internal iliac artery, which supplies the medial compartment of the thigh.

Deep veins

• Deep veins of the thigh: These veins accompany the major arteries and include the femoral vein, deep femoral vein (profunda femoral vein), and popliteal vein.
• Deep venous thrombosis (DVT): DVT is a serious condition involving the formation of a blood clot in a deep vein, often in the legs.

Lymphatics

• Superficial inguinal nodes: These are located in the groin region and receive lymph drainage from the lower abdomen, perineum, and lower limbs.

Bones of the Pelvis and Lower Limb

• The bones of the pelvis and lower limb are important structures that support the body and allow for movement.
• It is important to identify the bones of the pelvis and lower limb and understand their relationships to each other.

Fascia Lata and Intramuscular Septae of the Lower Limb

• The fascia lata is a thick sheet of connective tissue that surrounds the muscles of the thigh.
• It is thickened laterally to form the iliotibial tract (IT tract), which runs from the iliac crest to the knee.
• The IT tract is important for maintaining leg extension.
• Intramuscular septae divide the thigh into compartments, providing structural support for the muscles within.

Anatomy of the Long and Short Saphenous Veins

• The long saphenous vein is the longest vein in the body, beginning on the medial side of the foot and ascending to the thigh, draining into the femoral vein.
• The short saphenous vein ascends on the posterior leg and drains into the popliteal vein.

Varicose Veins

• Varicose veins are dilated, elongated, and tortuous superficial veins with incompetent valves.
• Valve incompetence allows blood to flow backward, causing pooling and dilation of the veins.
• Varicose veins are common in the lower limbs and can cause pain, swelling, and fatigue.

Anatomy of the Anterior and Medial Compartments of the Thigh

• The anterior compartment of the thigh contains the following muscles:
  • Sartorius
  • Quadriceps femoris (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius)
• The medial compartment of the thigh contains the following muscles:
  • Adductor longus
  • Adductor brevis
  • Adductor magnus
  • Gracilis
  • Pectineus
• The anterior compartment of the thigh is responsible for knee extension and hip flexion.
• The medial compartment is responsible for hip adduction.

Boundaries and Contents of the Femoral Triangle

• The femoral triangle is a wedge-shaped depression on the anterior thigh.
• Boundaries:
  • Superior: Inguinal ligament
  • Medial: Adductor longus muscle
  • Lateral: Sartorius muscle
• Floor:
  • Iliopsoas muscle
  • Pectineus muscle
  • Adductor longus muscle
• Roof: Fascia lata
• Contents:
  • Femoral nerve
  • Femoral artery
  • Femoral vein
  • Lymph nodes

Femoral Hernias

• A femoral hernia occurs when abdominal contents protrude through the femoral ring, a weak area within the femoral canal.
• Femoral hernias are more common in women.

Femoral Sheath

• The femoral sheath surrounds the femoral artery and vein.
• It is a continuation of the transversalis fascia and provides support and allows for smooth movement of the vessels during hip motion.

Clinical Landmarks on Examination of the Anterior and Medial Thigh

• The inguinal ligament, the adductor longus, and the sartorius are important landmarks to identify during examination of the anterior and medial thigh.

Radiological Imaging of the Bones and Vessels of the Thigh and Pelvis

• Radiological imaging techniques, such as x-rays, CT scans, and MRIs, are essential for the evaluation of the bones and vessels of the thigh and pelvis.

Blood Supply to the Thigh

• The main blood supply to the thigh is provided by the femoral artery, a continuation of the external iliac artery.
• The femoral artery gives off several branches that supply the muscles and tissues of the thigh.
• The deep femoral artery (profunda femoris) is the main artery of the anterior compartment and gives off branches that supply the muscles of the medial compartment.

Obturator Artery

• The obturator artery supplies blood to the medial compartment of the thigh and is a branch of the internal iliac artery.

Deep Veins of the Lower Limb

• The deep veins of the thigh and lower limb are responsible for returning blood from the legs to the heart.
• The deep veins of the thigh and lower limb run alongside the arteries, with the same names as the arteries, such as the femoral vein and popliteal vein.

Deep Venous Thrombosis (DVT)

• DVT is a serious condition that occurs when blood clots form in the deep veins of the legs.
• These clots can break loose and travel to the lungs, causing a pulmonary embolism.
• Risk factors for DVT include inactivity, injury, and certain medical conditions.

Lymphatics of the Lower Limb

• The lymphatic system is responsible for draining excess fluid from the body.
• The superficial inguinal lymph nodes are located in the region of the groin and drain lymph from the lower limbs, external genitalia, and lower abdominal wall.