Sciatic nerve

Question 1

Anatomical course

Answer 1

Leaves the pelvis via the greater sciatic foramen, entering the gluteal region inferior to piriformis.
In gluteal region, it crosses the posterior surface of gemelli, obturator internus, and quadratus femoris.
It then enters posterior thigh by passing deep to long head of biceps femoris.
Within posterior thigh, it gives off branches to hamstring muscles and hamstring part of adductor Magnus.
It reaches the apex of popliteal fossa and terminates by bifurcating into tibial and common fibular nerves

Question 2

What must be considered in intramuscular injections into gluteal region

Answer 2

Anatomical course of sciatic nerve

Question 3

How is gluteal region divided in intramuscular injections

Answer 3

Vertical line from highest point on iliac crest
Horizontal line half way between the highest point on iliac crest and ischial tuberosity.
An upper quadrant is then chosen and divided into 4 equal quadrants - the injection is done in the upper lateral smaller quadrant

Question 4

Motor Innervation

Answer 4

Sciatic nerve - Posterior thigh and hamstring portion of adductor Magnus
Tibial nerve - posterior leg muscles and some of the intrinsic muscles of foot
Common fibular nerve - anterior leg muscles and remaining intrinsic muscles of foot

Question 5

Sensory Innervation

Answer 5

Tibial nerve - skin over posterolateral leg, anterolateral leg and plantar surface of foot
Common fibular nerve - skin over lateral leg and dorsal surface of foot

Question 6

Nerve roots

Answer 6

L4-S3