Proximal neurovasculature Flashcards
Where does the sacral plexus sit?
Postero-lateral pelvic wall
What nerves are found in the sacral plexus?
Superior gluteal nerve (L4-S1) - gluteus medius and minimus
Sciatic nerve (L4-S3) - posterior compartment of thigh, leg compartments and foot
Pudendal nerve (S2-4) - sensation to external genitalia, voluntary sphincters (micturition)
Nerve to levator ani (S4) - pelvic floor
Lumbosacral trunk (L4-L5)
Sympathetic chain
What does the lumbar plexus innervate?
Anterior and medial thigh muscles
What nerves are found in the lumbar plexus?
Subcostal (T12) Iliohypogastric (L1) Ilioinguinal (L1) Lateral cutaneous nerve of thigh (L2,L3) Femoral ((L2-L4) Genitofemoral (L1,L2) Obturator (L2-L4) Lumbosacral trunk (L4,L5)
What is meralgia paraesthetica?
Compression of the lateral cutaneous nerve of the thigh causing loss of sensation to the lateral portion of the thigh - compression can be caused by underwear/ belts etc.
[Lateral cutaneous nerve of the thigh enters the anterior thigh close to the ASIS]
What nerves are found in the sacral plexus?
Superior gluteal nerve (L4-S1) - gluteus medius and minimus
Sciatic nerve (L4-S3) - posterior compartment of thigh, leg compartments and foot
Pudendal nerve (S2-4) - sensation to external genitalia, voluntary sphincters (micturition)
Nerve to levator ani (S4) - pelvic floor
Lumbosacral trunk (L4-L5)
Sympathetic chain
What does the lumbar plexus innervate?
Anterior and medial thigh muscles
What nerves are found in the lumbar plexus?
Subcostal (T12) Iliohypogastric (L1) Ilioinguinal (L1) Lateral cutaneous nerve of thigh (L2,L3) Femoral ((L2-L4) Genitofemoral (L1,L2) Obturator (L2-L4) Lumbosacral trunk (L4,L5)
What is meralgia paraesthetica?
Compression of the lateral cutaneous nerve of the thigh causing loss of (/ burning) sensation to the lateral portion of the thigh - compression can be caused by underwear/ belts etc.
[Lateral cutaneous nerve of the thigh enters the anterior thigh close to the ASIS]
At what point are you able to palpate the femoral artery?
Midinguinal point (+/- 1.5cm)
Where does the femoral vein sit in relation to the femoral artery?
Approx. 1cm medially
What happens to the femoral artery and the saphenous nerve once they have entered the thigh?
Enter the subsartorial/ adductor canal and then pass into the popliteal fossa
Where does the adductor (sartorius) canal run?
Deep to the sartorius down the middle 1/3 of the medial thigh to the adductor hiatus
Where do you find the superficial inguinal nodes?
Horizontal group sit just inferiorly to the inguinal ligament
Vertical group follow proximal part of saphenous vein
Where do you find the deep inguinal nodes?
One group in femoral triangle medial to femoral vein (Cloquet’s node)
What regions drain into the inguinal lymph nodes?
Lower limb Perineal region Penis Lower anal canal Lower vagina Anterior labia majora/ scrotal skin
Other than swollen lymph nodes, what can cause a lump in the groin region?
Dilation of the great saphenous vein (superficial) forming a saphena varix
What bones make up the leg?
Tibia (larger and medial) and Fibula (smaller and lateral)
What are the compartments of the leg?
Anterior
Posterior (biggest/ strongest)
Lateral
What is the function of the anterior compartment of the leg?
Foot + digit dorsiflexors (toe up, heel into floor) and invertors
What nerve innervates the anterior compartment of the leg?
Deep fibular nerve (L4-S1)
What artery supplies the anterior compartment of the leg?
Anterior tibial artery
What is the function of the lateral compartment of the leg?
Foot evertors
What nerve innervates the lateral compartment of the leg?
Superficial fibular nerve (L5, S1)
What artery supplies the lateral compartment of the leg?
Fibular artery
What is the function of the posterior compartment of the leg?
Foot and digit plantarflexors (standing on tip toes) and invertors
What nerve innervates the posterior compartment of the leg?
Tibial nerve (L4-S2)
What artery supplies the posterior compartment of the leg?
Posterior tibial artery
What kind of joint is the knee and what movements can it do?
Modified synovial hinge joint:
Flexion-extension
Rotation (medial and lateral)
Translocation (sliding - limits wear and tear)
What bones form the knee joint?
Tibia
Femur
Patella
[3 articulations = 2 x femero-tibial, 1 x femero-patella]
What are menisci?
Crescent shaped pieces of fibrocartilage sat on the tibial condyles
Spread weight distribution between femur and tibia to reduce wear/shock
What is the patella?
Sesamoid bone that articulates with the femoral condyles
Reduces ligament/ tendon wear
Increases bending force of quadricep muscles
What are the cruciate ligaments?
Two ligaments in the knee that cross each other (anterior and posterior - named by where they come off the tibia)
What are the functions of the cruciate ligaments?
Prevent anterior-posterior translocation and rotation of the knee
(posterior ligament prevents posterior movement of tibia and anterior ligament prevents anterior movement of tibia)
How can you test the function of the cruciate ligaments?
Patient lying down, knee flexed, one hand on femur and the other hand on the tibia and pull the tibia towards you) Drawer test (done at 90 degrees of flexion) Lachman test (done at 20 degrees of flexion)
What are the collateral ligaments?
Lateral collateral ligament attaches femur to fibula - resists adduction of tibia (varus)
Medial collateral ligament attaches femur to tibia - resists abduction of tibia (valgus)
Can be injured by excess force to opposite side of knee to ligament
If patient ruptures medial collateral ligament what is also most likely to be damaged?
Medial meniscus
What is the blood supply to the knee?
Genicular anastomoses supplied by genicular branches of the femoral and popliteal arteries
Bidirectional blood supply means supply is rarely cut off by trauma
What bursa are found around the knee?
Prepatellar bursa (anterior to patella) Infrapatellar bursa (below the patella) Suprapatellar bursa (superior-posterior to patella - communicates with knee joint)
How do you perform a patella tap?
Milk the suprapatellar bursa inferiorly then press on the patella posteriorly.
Tap sensation felt as patella hits femur if excess fluid (effusion) is present
What muscles are found in the anterior compartment of the leg?
Tibialis Anterior
Extensor digitorum longus (+ fibularis tertius)
Extensor hallucis longus
Where is the tibialis anterior found?
Anterior compartment of the leg
Originates from lateral surface of tibia, runs alongside the lateral surface of the tibia and inserts at the medial and inferior surfaces of the medial cuneiform and the base of metatarsal 1
Where is the extensor digitorum longus?
Anterior compartment of the leg
Originates from lateral condyle of tibia and medial surface of fibia
Runs laterally and posteriorly to the tibialis anterior
Converges into a tendon and travels along the dorsal surface of the foot before splitting into 4 and inserting into the 4 lateral toes
Where is the extensor hallucis longus?
Anterior compartment of the leg
Originates from medial surface of the fibula shift
Runs deep to the EDL and TA
Crosses anterior to the ankle join and inserts into the base of the phalanx of the big toe
What is the popliteal fossa?
Diamond shaped fat-filled region behind the knee
What are the borders of the popliteal fossa?
- Semimembranosus/ semitendinosus
- Biceps femoris
- Gastrocnemius medial head
- Gastrocnemius lateral head
What kind of fracture can damage the vessels running through the popliteal fossa?
Supracondylar fracture (femur)
What vessels run through the popliteal fossa?
Popliteal artery (deep) Popliteal vein Tibial nerve (superficial)
How does the sciatic nerve divide as it runs down the lower limb?
Into the tibial nerve and the common fibular nerve
What swellings can be identified in the popliteal fossa?
Popliteal cyst (from semimembranous bursa - above knee joint line)
Baker cyst (synovial cyst - below knee joint line)
Popliteal artery aneursym (pulsatile swelling)
Neuroma
