Vessels and nerves of the lower limb Flashcards
Overall, outline the organisation of spinal nerves in terms of what they supply
C1-4 : neck C5-T1 : upper limb T2-L1 : trunk L2-S3 : lower limb S2-C1 : perineum
Where do nerves to the lower limb emerge from the spinal cord
Lumbosacral plexus
Femoral n. supplies anterior compartment of thigh.
Obturator n. supplies medial (adductor) compartment of thigh.
Sciatic n. (or its terminal branches Tibial and Common Peroneal ns.) supply the remaining compartments (i.e. post. thigh, ant. and post. leg, foot)
Outline the nerves present in the buttock and posterior thigh
ABOVE piriformis:
Superior gluteal nerve
BELOW piriformis
Inferior gluteal nerve (winds back up toward gluteus maximus)
Sciatic nerve
Posterior cutaneous nerve of thigh
Outline the nerves present in the leg and foot
Sciatic nerve splits into tibial nerve (medially) and common peroneal nerve (laterally)
Common peroneal winds around the fibula to the lateral and anterior portions of the leg. Gives off sural communicating branch
Tibial branch continues down the posterior leg, gives off medial sural cutaneous nerve, which connects with the sural communicating nerve to form the sural nerve (sensory to the calf)
Tibial branch then splits into the medial and lateral plantar nerve
Which spinal cord segments make up the common peroneal nerve.
What about the superficial peroneal nerve
What about the deep peroneal nerve
Common= L4-S2
Superficial peroneal nerve (for the lateral muscles of the leg) L4-S1
Deep peroneal nerve (for anterior muscles of the leg) .. L5-S2
Which muscles does the tibial nerve supply
The posterior leg
and its branches supply the muscles on the plantar side of the foot too
T/F the tibial nerve supplies all the intrinsic muscles of the foot
F… tibial supplies all the muscles in the sole of the foot via medial and plantar nerves
but intrinsic muscle on the dorsum of the foot (extensor digitorum brevis) is supplies by the deep peroneal nerve
Which muscles are suppied by the medial and lateral plantar nerves
These nerves are branches of the the tibial nerve
Medial plantar:
Abductor hallucis,
FDB, FHB, lumbrical to the second digit
Lateral plantar: all other muscles in the sole of the foot (but not any that come from the posterior leg e.g. FHL, which is supplies by tibial)
Outline the spinal cord levels contributing to femoral nerve
Femoral Nerve (L234, posterior fibres)
Iliopsoas (+L1), ant. thigh
Outline the spinal cord levels contributing to obturator nerve
(L234, anterior fibres)
Medial (adductor) compartment of thigh
Outline the spinal cord levels contributing to sciatic nerve
(L345S123, ant. & post. fibres)
Post. thigh; leg; foot
Outline the spinal cord levels contributing to superior gluteal nerve
(L45S1)
Gluteus medius and minimus, Tensor fascia lata
Outline the spinal cord levels contributing to inferior gluteal nerve
(L5S12) (Gluteus maximus)
What type of mucles do the anterior divisions and the posterior divisions of a limb plexs supply
Anterior divisions = flexor muscles
Posterior divisions = extensor muscles
(C5-T1 = upper limb L2-S3 = lower limb)
referring to SEGMENTAL MOTOR SUPPLY
State the principles of segmental supply
Muscles supplied by two adjacent segments
Same action on joint = same nerve supply
Opposing muscles 1-2 segments above or below
More distal in limb = more caudal in spine
Outline the segmental supply to the lower limb (Hip, knee and ankle)
HIP
Flex L2L3
Extend L4L5
KNEE
Extend L3L4
Flex L5S1
ANKLE
Dorsiflex (ext) L4L5
Plantarflex (flex) S1S2
Inversion L4
Eversion L5S1
Fibers from which root make up th posterior cutaneus nerve of the thigh
S1, S2
T/F the area to which sensory innervation from S1 is provided medial to the area for S2
F…. on the posterior surface, S1 has a strip running straight down the leg laterally, and S2 medially
S1 then innervates the lateral side of the plantar surface of foot, and S2 the medial side of the plantar surface of the foot, with a bit of L5 in between the two on the plantar surface
Remember L3 runs to the knee and L4 runs to the floor
Which spinal nerves provide sensation to the genitals
S2/3
What are autonomous zones
These are the regions where single nerve roots supply distinct and non-overlapping areas of skin
Where can autonomous zones be found in the lower limb
S1, in the lateral calf (S1)
L3 (in the upper thigh an infero-medially point ing segment) and
L4 in lower thigh and over the knee also inferomedially )
The obturator nerve supplies sensory cutaneous innervation where
Medial thigh
You just have to learn the peripheral cutaneous nerves
…..
Outline the large peripheral cutaneous nerve areas
Anterior cutaneous branches of emoral nerve (lateral group) supplies most of the front of the thigh)
Interior clunial nerves/posterior cutanous nerve of the thigh supplies back of thigh and buttock
Saphenous nerve from femoral supplies medial anterior side of leg and wraps around to the medial posterior side too
Lateral sural cutaneous nerve (from common peroneal nerve) supplies the lateral side of the anterior and posterior leg
Outline the cutaneous innervation to the foot
Note the small area (1st and 2nd toe) supplied by the dorsal digital nerve from the deep peroneal
Outline the consequence of prolapsed intervertebral disc prolapse at L5/S1
Motor – loss of eversion
Sensory – loss of sensation outer border of foot
Reflex – loss of ankle jerk (S1)
Autonomic – minimal
Consequence of Lesion of Common Peroneal Nerve at Fibular Neck
Motor – foot drop (loss deep peroneal nerve function which dorsiflexes foot)
Sensory – dorsum of foot at least
Reflex – none
Autonomic – minimal
Give an overview of the arterial anatomy of the lower limb
Aorta Common iliac arteries External iliac / internal iliac arteries Femoral artery (Profunda femoris artery Circumflex femoral arteries) Popliteal artery “Trifurcation” Anterior tibial artery – dorsalis pedis artery Posterior tibial artery Peroneal artery
The pulses of which arteries can be felt in the lower limb
Femoral artery pulse (femoral triangle)
Politeal artery (popiteal fossa)
Posterior tibial artery pulse
Dorsalis pedis (a continuation of the anterior tibial artery)
At which point does the femoral artery and vein become popliteal artery and vein
The femoral artery and vein pass from the anterior compartment to the posterior of the knee (the popliteal fossa) through the hiatus of adductor magnus muscle. After passing posteriorly, they are named the popliteal artery and vein.
Where does the anterior tibial artery travel
Through the interosseus membrane
Outline the arterial supply of the foot
Anterior tibial –> dorsalis pedis
Posterior tibial artery –> medial and lateral plantar artery
Where can the dorsalis pedis be palpated
Lateral to tibialis anterior tendon
Where can the posterior tibial artery be palpated
Between the medial malleolus and the calcaneal tendon
Outline the superficial veins of the lower limb
Dorsal venous arch Long saphenous vein (into femoral) Short saphenous vein (into popliteal) Perforating veins Sapheno-femoral junction Blood flow from SUPERFICIAL TO DEEP
T/f great saphenous is a deep vein
F it is a superficial one
Which veins drain the knee region
Genicular veins
Which vein can be found at the medial malleolus
Long saphenous vein
What is the clinical application of the LSV at the medial malleolus
Cut down can occur (veins collapsed due to shock, but you know there is a vein at the medial malleolus)….Shocked patient, ATLS
2cm lateral and proximal to medial malleolus
now the interosseous administratin of fluid can occur
What would result from arterial emboism
Sudden occlusion
Acute ischaemia
Intermittent claudication (muscle pain commonly in calf during activity, associated with arterial disease)
What is compartment syndrome
The neuromuscular compartments of the limbs are enclosed in fibrous sheaths which confines them.
Differentiate acute compartment syndrome and chronic compartment syndrome
Acute compartment syndrome (trauma associated)
Chronic compartment syndrome (exercise-induced)
What compartments of the leg are affected by compartment sydrome
Commonly the anterior, posterior and lateral compartments of the leg
What happens in compartment syndrme
Ischaemia caused by trauma-induced increased pressure in a confined limb compartment
Normal pressure = 25mmHg; only need 50-60 to collapse vessels, so pulse still present
How can acute compartment syndrome be resolved
Emergency fasciotomy required to prevent the death of muscles in the affected compartment.
When can varicose veins result
Perforating veins connecting superficial and deep veins contain a valve that will allow flow only from superficial to deep. If such a valve is compromised, blood is pushed from deep to superficial veins leading to varicose veins.
In which veins are valves present
Valves in superficial, deep and perforating veins
Which valve in the lower limb venous system is important in varicose veins
Sapheno-femoral junction valve most important
What is lipodermatosclerosis
Skin thickening, of a chronic inflammatory cause in varicose vein
What can be a conequence of varicose veins
Venous ulcers
Venous leg ulcers can develop after a minor injury, where persistently high pressure in the veins of the legs has damaged the skin.
Deep veins follow what
The arterial supply
What is a DVT
Deep venous thrombosis
Clot in deep veins
Proximal or distal
What is post-phlebitic syndrom
Damage to veins of the leg during DVT
valve dysfunction
Reduced blood being carred out of the foot and leg
Pain swelling and ulcers
What is superficial thombophlebitis
an inflamed vein near the surface of the skin (usually a varicose vein) caused by a blood clot.
Outline venous grafts
CABG… arterial by-pass surgery
Vales only allow flow in one direction so graft must be oriented in the correct direction
How does venous return usually occur from the calf
Deep vessels in the leg are sandwiched between muscle layers, during waling and running the contractions squueze the thin walled veins and push blood up the calves= the calf pump
Outline the use of the surgical stockings
Immobility (e.g. a long plane journey) means less efficient venous return from the foot and leg. Sluggish deep venous return can lead to Deep Vein Thrombosis (DVT). Elastic surgical socks compress the superficial veins promoting more vigorous deep venous return.
