Lumbar plexus, Thigh and Legs😍

• Mnemonic
• Kidney - Always look for nerves with areas like subcostal, Hypogastric, inguinal
• Ovary - Obturator
• If u dont pass stools ( colon injury ) - Genitalide (Genitofemoral) laterally cut (Lateral cutaneous) cheyth female (Femoral) aakum.

• Origin: Ventral rami of L1–L4

• Divided based on Psoas Major

1. Piercing

• Genitofemoral N

• L1-L2

• Genitalia -pierce cheyyum



• Two branches:
• Femoral branch
• Skin of Femoral triangle
• Genital branch
• Motor: Cremaster muscle
• Content of inguinal canal
• Cremasteric Reflex
• Afferent → Femoral branch of GFN
• Efferent → Genital branch of GFN

2. Medial

• Obturator N

• L2-L4

• Medially ovary

• Motor supply
• Adductor longus
• Adductor brevis
• Adductor magnus (adductor part)
• Obturator externus
• Medial half of pectineus

• Sensory supply
• Hip joint
• Knee joint

• Referred pain
• Hip pathology → medial thigh pain

Other Nerves

• T12
• Subcostal N

• L1
• Iliohypogastric Nerve
• Skin over lateral gluteal and hypogastric regions
• Ilioinguinal Nerve
• Anterior scrotum/labia majora, root of penis/mons pubis, medial thigh
• Content of inguinal canal

• L2-L3
• Lateral Cutaneous N of thigh
• Compression deep to inguinal ligament → Meralgia paresthetica
• Positions
• Lithotomy
• Heavy Squatting

• L2-L4
• Femoral N
• Passes behind inguinal ligament
• Lies outside femoral sheath in triangle
• Femoral nerve supplies:
• Iliacus
• Sartorius
• Quadriceps femoris
• Hip joint
• Lateral half of pectineus
• Medial half of pectineus → Obturator nerve
• Divides into:
• Anterior division
• Motor: Sartorius
• Sensory: Medial & Intermediate cutaneous nerves of thigh
• Cute () Sar ()
• Posterior division
• Motor: Quadriceps femoris (RF, VL, VI, VM), hip joint
• Sensory: Saphenous nerve
• Longest cutaneous branch
• Accompanies great saphenous vein
• Medial leg & foot up to great toe
• Safe () sQuad ()

Applied Points

• Femoral vein cannulation:
• Anesthetizes femoral branch of genitofemoral nerve

• Referred hip pain:
• Felt on medial thigh, leg, or foot
• Due to common innervation by femoral nerve
• femoral nerve continues as saphenous nerve in medial aspect

Sacral plexus

• Sciatic nerve
• Largest branch
• Doesn’t innervate gluteal muscles

Greater Sciatic Foramen

• Above piriformis
• Superior gluteal nerve, artery, and vein

• Below piriformis
• Inferior gluteal nerve, artery, and vein
• Nerve to quadratus femoris
• Sciatic nerve
• Pudendal nerve
• Internal pudendal artery and vein
• Nerve to obturator internus

Lesser Sciatic Foramen

• Pudendal nerve

• Internal pudendal artery and vein

• Nerve to obturator internus

• Obturator internus muscle tendon

• Pudendal nerve
• Wind around the Ischial spine
• Site of pudendal nerve block

Gluteal Region & Posterior Thigh

Superior gluteal nerve

 

• L4, L5, S1

• Motor:
• Gluteus medius
• minimus
• Tensor fascia lata

• Injury
• Trendelenburg sign

Inferior gluteal nerve

• L5, S1, S2

• Motor:
• Gluteus maximus

Joint Nerve Supply

Hip joint:

• Femoral nerve

• Obturator nerve

• Superior gluteal nerve

• Nerve to quadratus femoris

Knee joint:

• Branches of:
• Femoral (saphenous)
• Obturator nerve
• Tibial nerve
• Common peroneal

Veins of LL

• Great Saphenous Vein:
• Longest vein in the body
• Drains into femoral vein → Runs medially
• Often used in surgeries like coronary artery bypass grafting
• Saphenous Nerve is affected while stripping for graft

• Short Saphenous Vein:
• Smaller in length.
• Drains the posterior part of the leg
• Drains into popliteal vein →Runs Laterally
• Sural Nerve is affected while stripping for graft

Fascia Lata and Modifications

1. Iliotibial Band (ITB)

Muscle Insertions

• Tensor fascia lata

• Gluteus maximus

• Max (glu maximus) tension (tensor fascia lata) when in IT Branch with LATHA (), but fabulous (FABER, FER) salary

Ober Test

• ITB contracture is common in polio.

• Leads to deformities:
• Hip Joint:
• FABER position
• Flexion
• Abduction
• External rotation
• Knee Joint:
• FER
• Flexion
• External rotation of tibia

INTERMUSCULAR SEPTUM

Pectineus

• Nerve Supply:
• Femoral nerve
• Obturator nerve

• Pet is supplied by both Father and mother

Adductor Magnus

• Nerve Supply:
• Obturator nerve
• Sciatic nerve
• Magnetic os

Linea Aspera of femur

• Roughened ridge on posterior surface of femoral shaft

• Formed of medial and lateral edges

Attachments of Linea aspera

• Adductor longus

• Intermuscular septa

• Short head of biceps femoris

• Mnemonic: ASPera
• A → Adductor longus
• S → Septa
• SP → SB → Short head Biceps Femoris

• Medial edge
• continuous as spiral line

• Lateral edge
• continuous as gluteal tuberosity

• Medial border
• continuous as medial supracondylar line

• Lateral border
• continuous as lateral supracondylar line

• Area in b/w
• popliteal surface

Saphenous Opening (Fossa Ovalis)

• Position:
• Located 3–4 cm inferolateral to the pubic tubercle

• Found in the fascia lata

Margins

• Lateral margin:
• Falciform margin
• Sharp, crescent-shaped edge

• Covered by:
• Cribriform fascia

Clinical Relevance

• Great saphenous vein enter & drain into femoral vein
• Site of Varicose veins ligation

• Important landmark for femoral hernias

• Present in anterior compartment

Femoral Triangle

Boundaries:

• Base: Inguinal ligament

• Medial: Medial border of Adductor longus

• Lateral: Medial border of Sartorius

• Femoral triangle () ariyahtond Sar (Sartorius) long Addichu (Adductor longus)

• Floor:
• Iliacus
• Psoas major
• Pectineus
• Adductor longus

Contents:

• Femoral artery

• Femoral vein

• Femoral nerve
• Outside femoral sheath

• Lymphatics

Femoral Sheath

• Formed by
• fascia transversalis → anterior
• fascia iliaca → posterior

• Encloses the femoral vessels below the inguinal ligament.

• Does not enclose femoral nerve.

• Smallest compartment

• Allows vein expansion

• Site for femoral hernia

• Contains Deep inguinal lymph nodes 
• also called Femoral ring nodes or Cloquet's node

• Contents (from lateral to medial):
1. Femoral artery
2. Femoral vein
3. Femoral ring 
• Lymph node of Cloquet
• Lymphatics
• Fat and loose connective tissue

Femoral Canal

• Most medial compartment of the femoral sheath

• Bounded by:
• Superiorly: Inguinal ligament
• Medially: Lacunar ligament
• Inferiorly: Pectineal ligament (Cooper’s ligament)

• Mnemonic:
• Superiorly → inferior → inguinal
• Medial → lateral → lacunar
• Inf → pokkathil → pectineal

Adductor Canal

• Subsartorial / Hunter's Canal

Transverse Section

• Roof: Sartorius

• Medial wall: Vastus medialis

• Floor: Adductor longus

• Fibrous septum separates Sartorius from deeper structures

Contents

1. Femoral Artery

2. Femoral Vein

3. Nerve to Vastus Medialis
• Present only in upper 1/3rd of canal

4. Saphenous Nerve

Popliteal aneurysm

• Ligation of Popliteal Artery in Adductor canal

• Reason to Avoid Femoral Artery Ligation:
• Presence of Profunda Brachii Artery.
• Ligation can affect blood supply

Muscles

• Gluteus maximus, medius, minimus + Piriformis, TFL and Sartorius
• Involved in Abduction

Fracture of greater trochanter

• Gluteus medius and minimus

• TFL

• Piriformis

Trendelenburg Test:

• Purpose: To assess the abductor mechanism of the hip.

• Mnemonic: Sound side sinks

Principle Abductors of Hip:

• Gluteus medius

• Gluteus minimus

• Supplied by the superior gluteal nerve.

Function of Abductors:

• Maintain gait by stabilizing the pelvis.

• Ipsilateral (I/L) abductors help swing the contralateral (C/L) limb.

Abductor Failure (Causes):

• Gluteus medius weakness.

• Gluteus minimus weakness.

• Superior gluteal nerve palsy.

• Coxa vara

Test Procedure:

• Ask the patient to stand on each limb for 30 seconds.

• Observe the ASIS

• Positive Test:
• When the patient stands on the pathological side (affected limb),
• the sound (unaffected) side sinks.
• ASIS/PSIS of the other side goes down.

• Note:
• Bilateral (B/L) abductor
• waddling gait.
• Mnemonic: No abductor → add(uctor) → wadd → waddling gait

Sartorius and Rectus Femoris

Sartorius

• Function similar to ITB contraction in polio

• Divides thigh into:
• Medial region → Femoral triangle
• Lateral region → Quadriceps area

Hip Region – Important Muscles & Structures

Flexors of Hip

• Iliopsoas
• Chief flexor
• Flexes hip beyond 90°

• Sartorius

• Rectus femoris

• Tensor fascia lata

Extensors of Hip

• Gluteus maximus
• Chief extensor
• Strong in resisted extension

• Hamstrings
• Extension in walking → non-resisted
• Long head of biceps femoris
• Semitendinosus
• Semimembranosus

Abductors of Hip

• Gluteus medius

• Gluteus minimus

• Tensor fascia lata

Adductors of Hip

• Adductor longus

• Adductor brevis

• Adductor magnus
• strongest

• Gracilis

• Pectineus

Medial Rotators

• Important in stance phase of gait
• Gluteus medius (anterior fibers)
• Gluteus minimus (anterior fibers)
• Tensor fascia lata

Hip Ligaments

• Iliofemoral
• Y-ligament of Bigelow
• Strongest
• Prevents hyperextension

• Pubofemoral
• Limits abduction

• Ischiofemoral
• Limits internal rotation

• Ligamentum teres
• Carries artery to femoral head

Bursae

• Largest: Iliopsoas bursa

• Trochanteric bursa
• Trochanteric bursitis → Lateral hip pain

• Ischial bursa

Nerve Supply

Thigh

• Anterior → Femoral nerve

• Medial → Obturator nerve

• Posterior → Tibial nerve

Leg

• Deep peroneal nerve

• Dorsiflexors: EHL, EDL, Tibialis anterior, Peroneus tertius

• Superficial peroneal nerve

• Evertors: Peroneus longus, brevis

• Tibial nerve

• Plantar flexors
• Superficial: Gastrocnemius, Soleus, Plantaris
• Superficial posterior compartment of leg → no neurovascular bundle
• Deep: Popliteus, FHL, FDL, Tibialis posterior

Foot

• Medial plantar nerve

• Lateral plantar nerve
• Supplies
• Flexor digitorum accessorius.
• First interosseous muscle.
• Sensory supply
• Lateral aspect of the sole

Invertors:

• Tibialis anterior

• Tibialis posterior

• FDL