Lumbar Plexus and Anterior Thigh Part 1 Flashcards
Lumbar plexus
- Ventral rami L1-4
- Ventral and dorsal divisions
Nerves of the lower extremity
- Subcostal
- Iliohypogastric
- Ilioinguinal
- Genitofemoral
- Lateral femoral cutaneous
Subcostal nerve
- Ventral rami T12
- Cutaneous supply to superior anterolateral thigh
Iliohypogastric nerve
- Ventral division of L1)
- Gives off a cutaneous branch to posterolateral gluteal region
Ilioinguinal nerve
- Ventral division of L1
- Gives off a cutaneous innervation of superomedial thigh
Genitofemoral nerve
- Ventral divisions of L1,2
- Femoral branch passes deep to inguinal ligament (vascular compartment)
- Cutaneous supply over femoral triangle
Lateral femoral cutaneous nerve
- Dorsal divisions of L2,3
- Enters thigh deep to inguinal ligament near ASIS (can pass through it)
- Cutaneous supply to anterolateral thigh
Nerves to psoas major muscle
- Dorsal divisions of L2-4
- Branch directly off of ventral rami to innervate muscle
Nerve to iliacus muscle
- Branch from femoral nerve
Femoral nerve
- Dorsal divisions of L2-4
- Travels between psoas major and iliacus muscles
- Enters thigh deep to inguinal ligament, through muscular lacuna
Femoral nerve supplies branches to
- Anterior thigh muscles (motor)
- Hip and knee joints (sensory)
- Cutaneous to anterior and inferomedial thigh and medial leg
Obturator nerve
- Ventral divisions of L2-4
- Passes through lesser pelvis and through obturator canal to enter the thigh
Obturator nerve supplies branches to
- Medial thigh muscles (motor)
- Hip and knee joints (sensory)
- Skin medial thigh
Accessory obturator nerve
- Ventral divisions of L3,4
- Not always present (10-30%)
- If present passes over superior pubic ramus
Accessory obturator nerve supplies branches to
- Pectineus muscle
- Hip joint (sensory)
- Skin of medial thigh
Lumbosacral trunk (L4,5)
- Formed by a portion of L4 and all of L5
- Passes over pelvic brim, anterior to SI joint
- Joins sacral plexus
Psoas major origin
- TP of lumbar vertebrae
- Vertebral bodies/discs T12-L5
Psoas major insertion
- Lesser trochanter of femur
Psoas major pathway
- Descends over pelvic brim, beneath inguinal ligament
- Through muscular lacuna
- Anterior to hip joint
- Joins the tendon of iliacus
Psoas major innervation
- Ventral rami L1-4
- Mostly from L2-4
Psoas major blood supply
- Muscular branches of the iliac arteries
- Lumbar arteries
Psoas major function
- Flex thigh
Iliacus origin
- Upper 2/3 iliac fossa
- Internal lip of iliac crest
- Ala of sacrum
- Anterior sacroiliac ligaments
- Iliolumbar ligament
Iliacus insertion
- Psoas major tendon/lesser trochanter of femur
- Similar path as the psoas major
Iliacus innervation
- Femoral nerve (L2-4)
Iliacus blood supply
- Muscular branches of the iliac arteries
- Lumbar arteries
- (same as psoas major)
Iliacus function
- Flex thigh
- (same as psoas major)
Iliopsoas
- Combination of iliacus and psoas major
- Advances the lower extremity during gait
Fascia lata
- Deep fascia of the thigh
- Surrounds thigh muscles
Fascia lata attaches to
- Inguinal ligament, pubic tubercle
- Scarpa fascia
- Iliac crest
- Sacrum, coccyx, sacrotuberous ligament, ischial tuberosity
- Iliotibial tract
Fascia lata is continuous with
- Deep fascia of leg
- Attaches to tibia inferiorly
Iliotibial tract
- Lateral thickening of fascia lata
- Attaches to iliac tubercle and Gerdy’s tubercle (tibia)
3 intermuscular septa divide thigh into 3 compartments
- Posterior
- Lateral
- Medial
- Lateral extends from iliotibial trace, very strong
Anterior thigh compartment content
- Muscles are primarily leg (knee extensors)
- Some hip flexors and rotators
- Femoral nerve
Medial thigh compartment content
- Muscles are primarily adductors of thigh (hip)
- (There are others)
- Obturator nerve
Posterior thigh compartment content
- Muscles are primarily hip extensors and knee flexors
- Sciatic nerve
Aorta bifurcates into
- Common iliac arteries
- L4
Common iliacs arteries divide
- L5/S1
- Internal iliac
- External iliac
Internal iliac artery
- Travels into pelvis
External iliac artery
- Travels toward anterior thigh
- Becomes femoral artery as it passes inguinal ligament
External iliac artery branches
- Deep circumflex iliac artery
- Inferior epigastric
Deep circumflex iliac artery
- Branches just proximal to inguinal ligament
- Travels toward ASIS where it anastomoses with other vessels
Retro-inguinal space (sub-inguinal space)
- Deep to inguinal ligament
- Passageway between abdominal cavity and lower limb
Retro-inguinal space (sub-inguinal space) is divided into 2 compartments by
- The iliopectineal arch (interlacunar ligament)
Interlacunar ligament
- Thickening iliacus/psoas fascia
- Attaches to inguinal ligament
2 compartments of retro-inguinal space
- Muscular compartment (lacuna)
- Vascular compartment (lacuna)
Muscular compartment (lacuna) contents
- Iliacus muscle (lateral)
- Psoas major muscle (medial)
- Femoral nerve: between iliacus and psoas major muscles
- Lateral femoral cutaneous nerve (sometimes)
Vascular compartment (lacuna) contents are surrounded by
- Femoral sheath
Vascular compartment (lacuna) contents
- Femoral artery
- Femoral vein
- Femoral canal (empty space and lymphatics)
- Femoral branch of genitofemoral nerve
Lateral to medial arrangement of structures passing under ligament
- Nerve
- Artery
- Vein
- Empty space (femoral canal)
- Lymphatics
- (NAVEL)
Great saphenous vein arises from
- Dorsal venous arch (medial marginal vein)
- Dorsal vein of 1st digit
Great saphenous vein pathway
- Ascends medially
- Anterior to medial malleolus
- Posterior to medial femur condyle
- Passes through saphenous opening (fossa ovalis)
Great saphenous vein drains into
- Femoral vein
Tributaries of great saphenous vein
- Anterior and posterior accessory saphenous veins
- Superficial epigastric
- Superficial circumflex iliac
- External pudendal veins
- Small saphenous can also drain into the GSV
Inguinal lymph nodes
- Superficial inguinal
- Horizontal group
- Vertical group
- Deep inguinal
Superficial inguinal lymph nodes (in superficial fascia) drain into
- Deep inguinal nodes
- External iliac nodes
Horizontal group
- 5-6 nodes
- Located right below inguinal ligament
Horizontal group receives lymph from
- Superficial gluteal region and proximal thigh
- Trunk below the umbilicus
- Perineum
Vertical group
- 4-5 nodes
- Located along terminal end of saphenous vein
Vertical group drains
- Most regions superficial to deep fascia (except posterior/lateral leg and foot)
Deep inguinal lymph nodes
- 1-3 nodes
- Located deep to fascia lata
- Within the femoral triangle
- Medial to femoral vein
Cloquets node
- Most cephalad node
- Llocated at femoral ring
Cloquets node drains
- Deep tissue/structures of thigh
Cloquets node receives lymph from
- Popliteal nodes (tissues deep to deep fascia)
- Superficial inguinal nodes