AN15.1-5 | Front & Medial side of thigh — Gate Quiz

Correct! The medial boundary of the femoral triangle is the medial border of adductor longus. The lateral boundary is the medial border of sartorius, and the base is the inguinal ligament.

Femoral triangle boundaries: Base (superior) = inguinal ligament; Lateral = medial border of sartorius; Medial = medial border of adductor longus. The apex is where sartorius crosses adductor longus.

Incorrect. Sartorius forms the lateral boundary; the medial boundary is the medial border of adductor longus.

Correct! From lateral to medial: Nerve, Artery, Vein (NAV — remember NAVEL where E = empty femoral canal and L = lymphatics are medial to the vein).

Lateral to medial in femoral triangle: N (Nerve) → A (Artery) → V (Vein) → E (Empty canal) → L (Lymphatics). The femoral nerve is outside the femoral sheath; artery and vein are inside.

Incorrect. The lateral-to-medial order is: Nerve (most lateral, outside sheath), Artery (in femoral sheath), Vein (medial to artery in sheath).

Correct! This is a psoas (cold) abscess. TB of L3–L4 destroys the vertebral bodies, pus collects in the psoas sheath, and tracks inferiorly through the muscular lacuna (under the inguinal ligament, lateral to the femoral vessels) to present in the femoral triangle lateral to the femoral artery.

Psoas abscess pathway: Lumbar vertebra (TB) → psoas sheath → muscular lacuna (under inguinal ligament, lateral to femoral sheath) → femoral triangle (lateral to femoral vessels). Cold abscess = no fever, no redness, painless (granulomatous).

Incorrect. Femoral hernia would emerge through the femoral canal (medial to femoral vein). This "cold" abscess in a TB patient tracking from the lumbar spine via the psoas sheath is the classic psoas abscess.

Correct! The lacunar (Gimbernat's) ligament forms the sharp medial boundary of the femoral ring. It is a rigid, fan-shaped ligament with a sharp edge — it cannot stretch to accommodate the herniated content, making strangulation more likely. To relieve strangulation, a surgeon cuts the lacunar ligament medially (with caution — an aberrant obturator artery may run along it).

Femoral ring boundaries: inguinal ligament (anterior), femoral vein (lateral), lacunar/Gimbernat's ligament (medial, sharp — primary strangulation cause), pectineal ligament/pectineus (posterior). To release strangulation: cut lacunar ligament; beware the aberrant obturator artery.

Incorrect. While all boundaries contribute, the lacunar ligament is the primary culprit — it is sharp, rigid, and inelastic, predisposing to strangulation.

Correct! The femoral artery enters the thigh at the midinguinal point — the midpoint of the inguinal ligament (between the ASIS and pubic tubercle). This is where the pulse is palpated and where femoral arterial access is obtained for cardiac catheterisation.

Midinguinal point (midpoint of inguinal ligament, ASIS to pubic tubercle) = femoral artery pulse. Do NOT confuse with the "mid-inguinal point" sometimes used to describe the deep inguinal ring (midpoint of ASIS to pubic symphysis). The femoral pulse is the most superficial large artery pulsation accessible in the body.

Incorrect. The femoral artery pulsation is at the midinguinal point — midpoint of the inguinal ligament (ASIS to pubic tubercle).

Correct! All four heads of quadriceps femoris (rectus femoris, vastus medialis, vastus lateralis, vastus intermedius) are innervated by the femoral nerve (L2, L3, L4). Femoral nerve injury causes quadriceps paralysis — the patient cannot extend the knee and the knee jerk is absent.

Femoral nerve (L2-L4) motor supply: quadriceps (all 4 heads), sartorius, pectineus (shared). Sensory: anterior + medial thigh, medial leg and foot (via saphenous nerve). Femoral nerve palsy: cannot extend knee, absent knee jerk, wasting of quadriceps, sensory loss medial thigh + leg.

Incorrect. The obturator nerve supplies the medial compartment (adductors). The femoral nerve supplies quadriceps and sartorius.

Correct! The obturator nerve (L2–L4) supplies both the hip joint and the medial knee region. By Hilton's law (a nerve supplying a muscle acting on a joint also supplies the joint), the obturator nerve carries sensory fibres from the hip joint and the medial knee. Hip pathology → referred pain to the medial knee via the obturator nerve is a classic clinical pitfall.

Hilton's law: a nerve supplying muscles moving a joint also supplies that joint. Obturator nerve supplies hip joint AND medial knee area → hip pathology can present as medial knee pain. Always examine the hip in a child or adult with medial knee pain!

Incorrect. This is the classic obturator nerve referred pain pattern from hip to medial knee — an important clinical point to avoid misdiagnosis as a knee problem.

Correct! The femoral nerve main trunk does NOT pass through the adductor canal — it divides immediately in the femoral triangle into anterior and posterior divisions. The adductor canal contains: femoral artery, femoral vein, saphenous nerve, nerve to vastus medialis, and descending genicular artery.

Adductor canal (Hunter's canal) contents: Femoral artery, femoral vein, saphenous nerve, nerve to vastus medialis, descending genicular artery. The main femoral nerve trunk does NOT enter — it divides in the femoral triangle. The femoral artery exits through the adductor hiatus to become the popliteal artery.

Incorrect. The femoral nerve main trunk divides in the femoral triangle and does not enter the adductor canal. The saphenous nerve (a branch of the femoral nerve) does pass through the canal.

Correct! The profunda femoris (deep femoral artery) is the largest branch of the femoral artery, arising 3–4 cm below the inguinal ligament in the femoral triangle. It is the main blood supply to all thigh muscles via its perforating branches and the circumflex femoral arteries.

Profunda femoris arises from femoral artery ~3–4 cm below inguinal ligament; it is the dominant supply to thigh muscles through: medial circumflex femoral (femoral head – retinacular), lateral circumflex femoral (greater trochanter), and 4 perforating branches (posterior thigh). If the femoral artery is blocked above, profunda femoris provides collateral flow.

Incorrect. The profunda femoris arises from the femoral artery, not the external iliac or obturator artery.

Correct! The saphenous nerve travels alongside the great saphenous vein (GSV) in the medial leg and is vulnerable during GSV harvesting for CABG. It is purely sensory (terminal branch of femoral nerve) — injury causes numbness of the medial leg and dorsal foot but NO motor deficit.

Saphenous nerve: terminal branch of femoral nerve (L3, L4); purely sensory; accompanies the GSV in the medial leg; supplies medial leg and medial foot. Injury during GSV harvesting for CABG → medial leg/foot numbness, no motor loss. Important for patient counselling before surgery.

Incorrect. The saphenous nerve is the sensory nerve that runs with the GSV; it supplies the medial leg and foot and is commonly injured during vein stripping or harvesting.