Anterior compartment of thigh

Question 1

Tensor fasciae latae:
* Origin
* Insertion
* Nerve supply
* Action

Answer 1

• Origin - ASIS and anterior aspect of iliac crest
• Insertion - ITB
• Nerve supply - superior gluteal nerve (L4, 5, S1)
• Action - pulls upon the iliotibial tract, so assisting gluteus maximus in extending the knee joint.
  Also active in helping to stabilise the pelvis during walking when it assists gluteus medius and minimus in resisting adduction at the hip.

Question 2

Iliotibial band:
* Origin
* Insertion
* Nerve supply
* Action

Answer 2

• Thickening of the fascia lata on the lateral side of the thigh.
• Origin - the upper end of the tract splits to enclose tensor fasciae latae and the superficial layer is attached to the iliac crest.
• Insertion - Gerdy’s tubercle on lateral condyle of tibia.
• Action - proximal ITB function includes hip extension, hip abduction and hip ER. Distally, ITB function depends on the position of the knee joint
• Full extension to 20-30˚ of flexion - active knee extensor, ITB lying anterior to the lateral femoral epicondyle.
• 20-30˚ of flexion to full flexion ROM - active knee flexor, ITB lies posterior relative to the lateral femoral epicondyle

Question 3

Femoral triangle:
* Borders
* Floor
* Contents

Answer 3

• Borders - inguinal ligament, medial border of sartorius and medial border of adductor longus.
• Floor - iliacus, psoas major, pectineus and adductor longus.
• Contents - femoral nerve, femoral artery, femoral vein, lymphatics

Question 4

Sartorius:
* Origin
* Insertion
* Nerve supply
* Action

Answer 4

• Origin - ASIS.
• Insertion - superomedial surface of tibia. Joins with the tendon of the gracilis and semitendinosus in the pes anserinus before its final insertion.
• Nerve supply - branch of the anterior division of the femoral nerve (L2-4).
• Action - hip flexion, abduction, ER. Knee flexion. When the knee is flexed, it also rotates the leg medially.

Question 5

Iliacus:
* Origin
* Insertion
* Nerve supply
* Action

Answer 5

• Origin - iliac fossa
• Insertion - lesser trochanter of femur. Its fibres are often inserted in front of those of the psoas major and extend distally over the lesser trochanter.
• Nerve supply - femoral nerve (L2, 3).
• Action - hip flexion.

Question 6

Psoas major:
* Origin
* Insertion
* Nerve supply
* Action

Answer 6

• Origin - superficially, it originates along the lateral surface of the distal thoracic vertebrae and adjacent intervertebral discs. The deeper portion originates at the first four lumbar vertebrae.
• Insertion - forms a long tendon, which is joined within the pelvic region by fibres from the iliacus muscle, finally inserting into the lesser trochanter of the femur.
• Nerve supply - branches from the anterior rami of lumbar spinal nerves L1-L4 before they join to form the lumbar plexus.
• Action - hip flexion. Also assists lumbar spine.

Question 7

Pectineus:
* Origin
* Insertion
* Nerve supply
* Action

Answer 7

• Origin - pectineal line of the pubis and from a narrow area of bone below.
• Insertion - inserted into a vertical line behind and below the lesser trochanter.
• Nerve supply - anterior division of the femoral nerve (L2, 3). Occasionally it receives a twig from the anterior division of the obturator nerve (L2, 3).
• Action - Hip flexion, adduction.

Question 8

Outline the femoral sheath, canal and ring

Answer 8

• Femoral sheath - a fascial tube encapsulating the key vascular structures passing through the retro-inguinal space (transversalis fascia in front and the psoas fascia behind). Its lateral compartment contains the femoral artery, intermediate compartment contains the femoral vein and the medial compartment contains the lymph drainage from the deep inguinal nodes (e.g. Cloquet’s node).
• Femoral canal - thefemoral canalis the medial compartment of the femoral sheath, an inverted cone-shaped fascial space medial to the common femoral veinwithin the upper femoral triangle. It is only 1-2 cm long and opens superiorly as the femoral ring. It serves two purposes: Allows the femoral vein to expand when there is increased venous return from the lower limb and a route for efferent lymphatic drainage from the deep inguinal nodes (e.g. Cloquet’s node) to the external iliac chain.
• Femoral ring - the superior opening of the femoral canal under the inguinal ligament. Its boundaries are the lacunar ligament (medial), medial part of the inguinal ligament (anterior), femoral vein within the intermediate compartment of the femoral sheath (lateral) and pectineal ligamentoverlying the pectineusand its fascia covering the superior pubic ramus (posterior).

Question 9

Rectus femoris:
* Origin
* Insertion
* Nerve supply
* Action

Answer 9

• Origin - Arises from the ilium by 2 heads. The reflected head arises from a groove above the acetabulum. The straight head arises from the upper half of AIIS above the iliofemoral ligament.
  The 2 heads unite to form the anterior lamina of the quadriceps tendon.
• Insertion - Together with vastus medialis, vastus lateralis and vastus intermedius joins the quadriceps tendon to insertat the patella and tibial tuberosity (via patellar ligament).
• Nerve supply - supplied by its own branch from the femoral nerve (L3, 4).
• Action - Main extensor of knee. Can assist iliopsoas to flex the hip.

Question 10

Vastus lateralis:
* Origin
* Insertion
* Nerve supply
* Action

Answer 10

• Origin - linear origin from the upper part of the intertrochanteric line, the greater trochanter and the lateral lip of the linea aspera of the femur.
  It also arises from the lateral intermuscular septum.
• Insertion - quadriceps tendon
• Nerve supply - Posterior division of the femoral nerve (L3, 4) - nerve to vastus lateralis.
• Action - knee extension.

Question 11

Vastus intermedius:
* Origin
* Insertion
* Nerve supply
* Action

Answer 11

• Origin - anterior and lateral surfaces of the upper 2/3rds of the shaft of the femur.
• Insertion - quadriceps tendon.
• Nerve supply - Nerve to vastus intermedius (L3, 4).
• Action - knee extension.

Question 12

Articularis genu:
* Origin
* Insertion
* Nerve supply
* Action

Answer 12

• Origin - Arises from the anterior surface of the lower femoral shaft, deep to vastus intermedius.
• Insertion - Inserted into suprapatellar bursa and the joint capsule.
• Nerve suppy - Medial deep division of femoral nerve (L2-4)
• Action - During extension, it pulls the synovial membrane of the knee joint superiorly. Prevents synovial membrane impingement between femur and patella. Supports the patella and assists to stabilise the knee joint. Assists in the lubrication of the knee joint.

Question 13

Vastus medialis:
* Origin
* Insertion
* Nerve supply
* Action

Answer 13

• Origin - arises from the lower part of the intertrochanteric line and the medial lip of the linea aspera and from the tendon of adductor magnus below the hiatus for the femoral vessels.
• Insertion - Quadriceps tendon, medial border of patella.
• Nerve supply - Nerve to vastus medialis - posterior division of the femora nerve (L2-4).
• Action - Knee extension. Also contributes to correct tracking of the patella.

Question 14

Stability of patella:
* Bony factor
* Ligamentous factor
* Muscular factor

Answer 14

• Bony factor - forward prominence of the lateral condyle of femur.
• Ligamentous factor - tension of the medial patellar retinaculum
• Muscular factor - lowest fibres of vastus medialis, inserted into the border of the bone, hold the patella medially when the quadriceps contracts. These fibres are indispensable to the stability of the patella.

Question 15

Adductor canal:
* Borders
* Contents

Answer 15

• Borders - vastus medialis (anterolateral), sartorius (medial) and adductor longus/magnus (posterior)
• Contents - femoral artery, femoral vein, saphenous nerve and in the upper part, the nerve to vastus medialis.