Miller's anatomy - Lower extremity

Question 1

What separates the greater and lesser sciatic notch?

Answer 1

Iliac spine

The sacrospinous ligament separates the greater and lesser sciatic foramina.

Question 2

What is a potential risk of using the piriformis starting point for pediatric femoral nail insertion?

Answer 2

Threat to posterosuperior retinacular vessels

This can lead to avascular necrosis (AVN) of the femoral head.

Question 3

Where does slipped capital femoral epiphysis occur?

Answer 3

Through the femoral head physis

Specifically in the zone of hypertrophy.

Question 4

What is the function of the fibrocartilaginous labrum?

Answer 4

Enhances stability of the acetabulum

Functions include load transmission, maintenance of vacuum seal, regulation of synovial fluid hydrodynamics, and joint lubrication.

Question 5

What is the strongest ligament in the body?

Answer 5

Iliofemoral ligament (Y ligament of Bigelow)

Attaches the AIIS to the intertrochanteric line in an inverted Y manner.

Question 6

How do the medial and lateral tibial plateaus differ at the knee joint?

Answer 6

Medial is concave, lateral is convex

This results in greater osseous congruity medially than laterally.

Question 7

What does an accessory or ‘bipartite’ patella represent?

Answer 7

Failure of fusion of the superolateral corner of the patella

It is commonly confused with patellar fractures.

Question 8

What part of the menisci is vascular and amenable to repair?

Answer 8

Peripheral one third (red zone)

The inner two thirds (white zone) are nourished by synovial fluid and have limited healing capacity.

Question 9

What are the two bundles of the ACL?

Answer 9

• Anteromedial (tight in flexion)
• Posterolateral (tight in extension)

The PL bundle is tested with the pivot shift exam.

Question 10

What are the two bundles of the PCL?

Answer 10

• Anterolateral (tight in flexion)
• Posteromedial (tight in extension)

Question 11

What structures comprise the posterolateral corner (PLC)?

Answer 11

• Fibular collateral ligament
• Popliteus tendon
• Popliteofibular ligament
• Biceps femoris tendon
• Lateral head of gastrocnemius
• Biceps femoris
• Arcuate ligament
• Posterolateral capsule

Question 12

What does the dial test indicate at 30 degrees?

Answer 12

Rotational instability = PLC injury

At 30 and 90 degrees indicates combined PLC + PCL injury.

Question 13

What is the primary blood supply to the talar body?

Answer 13

Artery of the tarsal canal (posterior tibial artery)

Question 14

How does ankle position affect testing of the lateral ligament complex?

Answer 14

Plantar flexion tightens anterior talofibular ligament

Inversion with neutral flexion tightens the calcaneofibular ligament.

Question 15

What ligaments support the ankle syndesmosis?

Answer 15

• Anterior inferior tibiofibular ligament
• Posterior inferior tibiofibular ligament
• Transverse tibiofibular ligament
• Interosseous ligament

Syndesmotic injury is often referred to as a ‘high-ankle sprain.’

Question 16

What does the plantar calcaneonavicular ligament (spring ligament) support?

Answer 16

Head of talus

It is attenuated in pes planus deformity.

Question 17

What does the Lisfranc ligament connect?

Answer 17

The medial cuneiform to the second metatarsal

The Lisfranc ligament plays a crucial role in stabilizing the midfoot.

Question 18

What mnemonic can be used to remember the order of structures along the posterior border of the medial malleolus?

Answer 18

Tom, Dick, and Harry

This refers to tibialis posterior, flexor digitorum longus, and flexor hallucis longus.

Question 19

What does the mnemonic ‘POP’S IQ’ help to remember?

Answer 19

Nerves exiting the pelvis below the piriformis

This includes pudendal, nerve to obturator internus, posterior femoral cutaneous, sciatic, inferior gluteal, and nerve to quadratus femoris.

Question 20

What does the infrapatellar branch supply?

Answer 20

The skin of the medial side of the front of the knee and patellar ligament

This branch can be damaged during total knee replacement surgery or patella tendon harvest.

Question 21

What can injury to the obturator nerve and artery occur from?

Answer 21

Retractors placed behind the transverse acetabular ligament or screw placement in the anteroinferior quadrant of acetabulum

These injuries can lead to complications in hip surgeries.

Question 22

What is the most proximal branch of the lateral plantar nerve?

Answer 22

Nerve to the abductor digiti quinti (Baxter nerve)

This nerve is important for foot function and sensation.

Question 23

Which nerve supplies sensation to the dorsomedial aspect of the great toe?

Answer 23

Dorsal medial cutaneous nerve

This nerve is a branch of the superficial peroneal nerve and crosses the EHL in a lateral-to-medial direction.

Question 24

What is corona mortis?

Answer 24

An anastomotic connection between the inferior epigastric branch of the external iliac vessels and the obturator vessels

It is located in the obturator canal and is significant in pelvic surgeries.

Question 25

What are the medial and lateral femoral circumflex vessels named for?

Answer 25

Location relative to iliopsoas tendon ## Footnote These vessels are crucial for hip blood supply.

Question 26

What branches are given off in the popliteal fossa?

Answer 26

Medial and lateral geniculate arteries and middle geniculate artery ## Footnote These supply the menisci and cruciate ligaments.

Question 27

What does the Stoppa modification provide access to?

Answer 27

Pelvic brim and quadrilateral plate ## Footnote This modification uses a more extensive medial window.

Question 28

Where does the superior gluteal nerve pass relative to the gluteus medius and minimus?

Answer 28

Between them approximately 5 cm proximal to the tip of the greater trochanter ## Footnote This anatomical detail is important for surgical approaches to the hip.