Lower limb nerves: Peripheral nerves

Question 1

What is a nerve plexus?

Answer 1

A network of intersecting nerves (multiple exist in the body)

Question 2

What is the origin, course and branches of the obturator nerve?

Answer 2

Origin – Lumbar plexus (L2-L4)

Course – Emerges from medial border of psoas major muscle. Descends along lateral wall of pelvic capacity, passes through obturator canal (allows access to medial compartment of thigh).

Branches – Anterior and Posterior branches

Question 3

What is the origin, course and branches of the femoral nerve?

Answer 3

Origin – Lumbar plexus (L2-L4)

Course – Emerges from the lower lateral border of the psoas major muscle. Descends over surface of iliacus muscle, deep to iliacus fascia and lateral to femoral artery. Passes underneath inguinal ligament to enter anterior compartment of the thigh.

Branches – Muscular and anterior cutaneous branches, saphenous nerve.

Question 4

What is the origin, course and branches of the lateral cutaneous nerve of the thigh?

Answer 4

Origin – Lumbar plexus (L2-L3)

Course – Emerges from lateral border of psoas major, transverses over iliacus muscle before passing underneath the inguinal ligament medial to anterior superior iliac spine

Branches – None

Question 5

What is the origin, course and branches of the superior gluteal nerves?

Answer 5

Origin – Posterior divisions of anterior rami of 4th lumbar to first sacral nerves (L4-S1)

Course – Emerges from sacral plexus to pass through greater sciatic foramen superior to piriformis. Enters gluteal region to provide motor innervation to gluteal muscles.

Branches – None

Question 6

What is the origin, course and branches of the inferior gluteal nerves?

Answer 6

Posterior divisions of anterior rami of 5th lumbar to 2nd sacral nerves (L5-S1)

Course – Emerges from sacral plexus to pass through greater sciatic foramen inferior to piriformis. Enters gluteal region to provide motor innervation to gluteus maximus

Branches – None

Question 7

What is the origin, course and branches of the sciatic nerve?

Answer 7

Origin – 4th lumbar to 3rd sacral nerves (L4-S3)

Course – Enters the gluteal region through greater sciatic foramen, beneath piriformis muscle. It descends over lateral rotators of the hip. It passes through posterior compartment of the thigh to reach superior border of popliteal fossa.

Branches – Muscular branches and tibial and common fibular nerve.

Question 8

What is the origin, course and branches of the tibial branch of sciatic nerve?

Answer 8

Origin – Sciatic nerve (L4-S3)

Course – Descends in the popliteal fossa and the posterior compartment of the leg

Branches – Articular and muscular branches, crural interosseous nerve, medial sural cutaneous nerve, medial calcaneal branches, medal and lateral plantar nerves

Question 9

What is the origin, course and branches of the common peroneal branch of sciatic nerve?

Answer 9

Origin - Sciatic nerve (L4-S2)

Course – Winds around the neck of fibula

Branches – Recurrent articular branch, lateral sural cutaneous nerve and sural communicating branch, superficial and deep fibular nerves