Session 8: Review of Nerves and Vessles of the Lower Limb Flashcards
Which spinal levels supply which parts of the body?
C1-4 : neck C5-T1 : upper limb T2-L1 : trunk L2-S3 : lower limb S2-C1 : perineum
What does C1-C4 supply?
neck
What spinal levels supply the neck?
C1-C4
What spinal levels supply the upper limb?
C5-T1
What spinal levels supply the trunk?
T2-L1
What spinal levels supply the lower limb?
L2-S3
What spinal levels supply the perineum?
S2-C1
What does C5-T1 supply?
upper limb
What does T2-L1 supply?
trunk
What does L2-S3 supply?
lower limb
What does S2-C1 supply?
Perineum
What are the types of innervation?
- Segmental (dermatomes)
- Peripheral (nerves to muscles, cutaneous nerves)
- Peripheral nerves to the limbs emerge from nerve plexuses
What is a nerve plexus?
- A nerve plexus is formed when peripheral spinal nerve roots merge and split to produce a network of nerves from which new multi-segmental peripheral nerves emerge.
- Both upper and lower limbs are supplied by plexuses.
Where do the nerves to the lower limb emerge from?
- from the lumbosacral plexus
What does the femoral nerve supply?
Femoral n. supplies anterior compartment of thigh.
Femoral nerve
- originates from the lumbosacral plexus on the posterior abdominal wall (L2-L4)
- enters femoral triangle of the thigh by passing under the inguinal ligament
- in the femoral triangle it lies lateral to the femoral artery and is outside the femoral sheath which surrounds the vessels)
- supplies branches to iliacus and pectineus
- immediately after passing under the inguinal ligament it divides into anterior and posterior branches, which supply the muscles of the anterior compartment of the thigh and the skin of the medial and anterior aspects of the thigh
What are some branches of the femoral nerve?
- anterior cutaneous branch: supplies skin on the front of the thigh and knee.
- numerous motor nerves which supply the quadriceps and the sartorial muscle
- one long cutaneous nerve: SAPHENOUS nerve which supplies the skin as distally as the medial side of the foot.
What does the obturator nerve supply?
Obturator n. supplies medial (adductor) compartment of thigh.
Obturator nerve
- branch of the lumbar plexus in the posterior abdominal wall
- L2-L4
- descends in the psoas muscle to enter the pelvis
- continues along lateral pelvic wall and then enters the medial compartment of the thigh by passing through the obturator canal
- supplies most of the adductor msucles and skin on the medial aspects of the thigh.
- divided into 2 branches (separated by adductor brevis msucle) upon entering thigh: posterior and anterior branch
= posterior branch supplies obturator externes and adductor brevis - anterior branch supplies branches of the adductor longus, gracilis, and adductor brevis and often contributes to the supply of the pectineus muscle; cutaneous branches innervate the skin on the middle of the thigh.
What does the sciatic nerve innervate?
Sciatic n. (or its terminal branches Tibial and Common Peroneal ns.) supply the remaining compartments (i.e. post. thigh, ant. and post. leg, foot)
Sciatic nerve
- largest nerve in the body (2 nerves stuck together)
- L4-S3
- branch of the lumbosacral plexus
- descends into the posterior compartment of the thigh and then its branches continue to the leg and foot.
- lies on the adductor Magnus muscle in the thigh and is crossed by the long head of the biceps femoris muscle s
- proximal to the knee and sometimes in the pelvis, the sciatic nerve divides into two terminal branches: the tibial nerve and the common fibular nerve.
- these travel vertically down the knee and enter the popliteal fossa posterior to the knee where they meet the popliteal artery and vein.
Lumbo-sacral plexus
- L2 to S3
- Details are not as important; terminal branches have a variety of fibers from different roots.
