28.💗TOPOGRAPHY OF LOWER LIMB – SUPRAPIRIFORM FORAMEN, INFRAPIRIFOM FORAMEN, VASCULAR AND MUSCLULAR LACUNA, OBTURATOR AND FEMORAL CANAL.💗

What muscle travels through the sciatic foramen and is divided into supra- and infrapiriform parts?

- Piriformis muscle

What is the origin and insertion of the piriformis muscle?

- Origin: Anterior part of the sacrum
- Insertion: Greater trochanter of the femur

What actions does the piriformis muscle perform?

- Lateral rotation of the hip
- Abduction of the hip

What is the nerve supply to the piriformis muscle?

- Nerve to piriformis

What structures pass through the supra- and infrapiriform foramina?

- Suprapiriform foramen: Superior gluteal artery and nerve
- Infrapiriform foramen: Inferior gluteal artery and nerve

How can the piriformis muscle be used to locate the sciatic nerve?

- The sciatic nerve passes inferior to the piriformis muscle and can be seen as a flat band approximately 1-2 cm wide in the gluteal region.

What is the vascular lacuna and what are its borders?

- It's a compartment beneath the inguinal ligament allowing passage of femoral vessels, lymph vessels, and nodes.
- Borders: Iliopectineal arch, inguinal ligament, lacunar ligament, superior border of pubis

What are the contents of the vascular lacuna?

- Cloquet's node
- Femoral artery
- Femoral vein
- Femoral branch of genitofemoral nerve

What is the muscular lacuna and what structures pass through it?

- It's the lateral compartment of the thigh inferior to the inguinal ligament.
- Passes: Iliopsoas muscle, femoral nerve, lateral cutaneous nerve of thigh

What separates the vascular lacuna from the muscular lacuna?

- Iliopectineal arch

Describe the femoral canal, its borders, and contents.

- Smallest, most medial part of femoral sheath
- Borders: Medial (lacunar ligament), Lateral (femoral vein), Anterior (inguinal ligament), Posterior (pectineal ligament, superior ramus of pubic bone, pectineus muscle)
- Contents: Lymphatic vessels draining deep inguinal lymph nodes, deep lymph space (lacunar node), empty space, loose connective tissue

What is the obturator foramen, and what structures pass through it?

- A large opening created by the ischium and pubis bones of the pelvis.
- Passes: Obturator nerve and artery