Anatomy MCQs with Explanations – Lower Limb – 1

[True/False] Type Questions

1. Regarding hamstring muscles

A. All arise from the ischial tuberosity.

B. All are inserted to the bones of the leg.

C. They flex the knee joint and extend the hip joint.

D. All are innervated by tibial nerve.

E. Semimembranosus has a broad tendon of origin passing deep to other hamstring muscles.

Explanation

(T, T, T, F, T)

  • You can find hamstring muscles in the posterior compartment of the thigh. The hamstring muscles are,
    • Semimembranosus
    • Semitendinosus
    • Biceps femoris

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  • First two sentences are about the attachments of the hamstring muscles. All hamstring muscles arise from the ischial tuberosity and inserted into the tibia or fibula. So, both choices are true.
0003

Attachments of hamstring muscles

  • If you know what is flexion of knee joint and extension of hip joint you know the answer for third choice. Understanding the flexion of knee joint is very easy. The movements of the hip joint are given below.
0006.jpg

Movements of hip joint

  • Then if you can workout, hamstring muscles should flex the knee joint and extend the hip joint. So, 3rd choice is correct. For your knowledge, when knee semiflexed biceps femoris is a lateral rotator, while semimembranosus and semitendinosus are medial rotators of the leg.
  • It’s true that the hamstrings are innervated by tibial component of the sciatic nerve. But, short head of biceps femoris is supplied by common peroneal component of the sciatic nerve. So, fourth sentence is incorrect.
  • Fifth sentence is true. Semimembranosus has a broad tendon of origin lying deep to the other hamstring muscles. Look at the first two pictures above in the explanation!

2. Sciatic nerve

A. Is formed by the ventral and dorsal divisions of sacral ventral rami

B. Emerges from the pelvis through the lesser sciatic foramen

C. It divides at a constant level

D. When the nerve is completely damaged plantar flexion is diminished

E. Is related to the upper lateral quadrant of gluteal region

Explanation

(T, F, T, T, F)

  • Sciatic nerve is formed by dorsal and ventral divisions of anterior rami of L4, L5, S1, S2 and S3 spinal nerves.

0001

  • Nerves emerging from various foramina of pelvis are given below in the picture. Sciatic nerve emerges through greater sciatic foramen.

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  • Sciatic nerve divides into tibial and common peroneal nerves at the upper angle of the popliteal fossa.
  • Plantar flexion is done by muscles of the posterior compartment of the leg and it is supplied by the sciatic nerve. Nerve supply of lover limb muscles is illustrated in the following image.

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  • Sciatic nerve does not related to the upper lateral quadrant of the gluteal region. That’s why intramuscular injection is administered to that area of the buttock.

3. Gluteus maximus

A. Has an origin from the sacrotuberous ligament.

B. Covers the gluteus medius completely

C. Is supplied by the inferior gluteal nerve from its deep surface

D. The main part of the muscle is inserted in to the gluteal tuberosity

E. Tendelenberg test is positive when the normal side is raised

Explanation

(T, F, T, F, F)

  • There are three gluteal muscles in the buttock.
    • Gluteus maximus
    • Gluteus medius
    • Gluteus minimus

0004.jpg

  • Refer some text book to read about the attachments of the gluteal muscles. You will see that gluteaus medius has an origin from the sacrotuberous ligament.
  • Only the posterior third of gluteus medius is covered by gluteus maximus.
  • Gluteus maximus is supplied by posterior gluteal nerve.
  • Only the deep half of its lower half is inserted into the gluteal tuberosity. Rest three-quarter is inserted into the iliotibial tract.
  • Trendelenburg test is done to check the action of abductor muscles of the thigh; gluteus medius and gluteus minimus. We tell the patient to stand on one limb. When the patient stand on the affected limb the normal side severly drops over the swing limb.

0005.jpg

4. Regarding joints of lower limb

A. Main abductors of hip joint are supplied by superior gluteal nerve

B. Tensor fascia lata stabilises the knee joint in the extended position

C. Acetabulum has both articular and non articular surfaces

D. Inversion and eversion both take place at ankle joint

E. Tendon of popliteus is intracapsular

Explanation

(T, F, T, T, F)

  • Hip joint is abducted by two muscles; gluteus medius and gluteus minimus. It is assisted by tensor fascia lata and sartorius. Both gluteus medius and minimus are supplied by superior gluteal nerve.
0001.jpg

Muscles acting on hip joint

  • Tensor fascia lata is a thin sheet of muscle arising from external lip of iliac crest and inserts into iliotibial tract. It assists gluteal muscles in various positions, but has nothing to do with knee joint.
0002.jpg

Tensor fascia latae

  • No need to explain C and D statements. Too easy! Both are true.
  • Popliteus is a muscle attached to the triangular area of the posterior surface of tibia above the soleal line and inserts into the lateral surface of the lateral condyle of femur through a cord like tendon. This tendon is intracapsular, but not the muscle.

0003.jpg

5. Regarding nerves of the lower limb,

A. Foot drop occurs due to damage in the tibial nerve

B. Pectineus is supplied by femoral nerve

C. Adductor hallucis is supplied by deep branch of lateral plantar nerve

D. Both knee joint & hip joint are supplied by obturator nerve

E. Saphenous nerve crosses femoral artery medial to lateral in the adductor canal

Explanation

(F, T, T, T, F)

  • Following figure shows a summery of lower limb nerves.

0004.gif

  • Foot drop occurs due to paralysis of extensor muscles in the leg which is supplied by deep branch of common peroneal nerve. Tibial nerve supplies flexor muscles of the leg.

0005.jpg

  • Both B anc C statements are about nerve supply of lower limb muscles. You should remember them. I believe that the best way is to make charts and tables.
  • Pectineus is supplied by the femoral nerve, occasionally it receives a twig from obturator nerve.
  • Adductor hallucis is a muscle in the foot and is supplied by deep branch of lateral plantar nerve.
  • Knee joint is supplied from,
    • femoral nerve through its branches vastus medialis, intermedius and lateralis,
    • sciatic nerve by the genicular branches of its tibial and common peroneal components,
    • obturator nerve by the twig from its posterior division.
  • Hip joint is supplied from,
    • femoral nerve via the nerve to rectus femoris,
    • obturator nerve directly from its anterior division,
    • the nerve to quadratus femoris,
    • articular twigs from the sciatic nerve.
  • Final statement is easy, but you need a mnemonic or a clear picture memory to answer this. Actually, saphenous nerve crosses femoral artery from lateral to medial side in the adductor canal. LSM is a mnemonic to remember this. Lateral-Saphenous-Medial. Below is a picture of the incident.

0006.png

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