Lower Limb

The Lower Limb
Pelvis, Thigh, Leg
and Foot
Surface Anatomy

• Gluteal region / posterior pelvis
• Iliac crest
• Gluteus maximus
• Cheeks
• Natal/gluteal cleft
• Vertical midline; “Crack”
• Gluteal folds
• Bottom of cheek; “prominence”

 
Surface Anatomy

• Anterior thigh and leg
• Palpate
• Patella
• Condyles of femur
• Femoral Triangle
• Boundaries:
• Sartorius (lateral)
• Adductor longus (medial)
• Inguinal ligament (superior)
• Contents:
• Femoral artery, vein and nerve, lymph nodes

Surface Anatomy

• Posterior leg
• Popliteal fossa
• Diamond-shape fossa behind knee
• Boundaries
• Biceps femoris (superior-lateral)
• Semitendinosis and semimembranosis (superior-medial)
• Gastrocnemius heads (inferior)
• Contents
• Popliteal artery and vein
• Calcaneal (Achilles) tendon
 Surface Anatomy

• Anterior leg bones
• Tibia
• Tibial tuberosity
• Anterior crest
• Medial surface
• Medial malleolus
• Fibula
• Lateral malleolus
Bones of the Lower Limb

• Function:
• Carry weight of entire erect body
• Support
• Locomotion
• Points for muscular attachments
• Components:
• Thigh
• Femur
• Knee
• Patella
• Leg
• Tibia (medial)
• Fibula (lateral)
• Foot
• Tarsals (7)
• Metatarsals (5)
• Phalanges (14)
Thigh

• Femur
• Largest, longest, strongest bone in the body!!
• Receives a lot of stress
• Courses medially
• More in women!
• Articulates with acetabulum proximally
• Articulates with tibia and patella distally
Knee

• Patella
• Triangular sesamoid bone
• Protects knee joint
• Improves leverage of thigh muscles acting across the knee
Leg

• Tibia
• Receives the weight of body from femur and transmits to foot
• Second to femur in size and weight
• Articulates with fibula proximally and distally
• Interosseous membrane
• Fibula
• Does NOT bear weight
• Muscle attachment
• Not part of knee joint
• Stabilize ankle joint
Foot

• Function:
• Supports the weight of the body
• Act as a lever to propel the body forward
• Parts:
• Tarsals
• Talus = ankle
• Between tibia and fibula
• Articulates with both
• Calcaneus = heel
• Attachment for Calcaneal tendon
• Carries talus
• Metatarsals
• Phalanges
 

• Function:
• Supports the weight of the body
• Act as a lever to propel the body forward
• Parts:
• Tarsals
• Talus = ankle
• Between tibia and fibula
• Articulates with both
• Calcaneus = heel
• Attachment for Calcaneal tendon
• Carries talus
• Metatarsals
• Phalanges
• 3 arches
• Medial
• Lateral
• Transverse
• Has tendons that run inferior to foot bones
• Help support arches of foot
Joints of Lower Limb

• Hip (femur + acetabulum)
• Ball + socket
• Multiaxial
• Synovial
• Knee (femur + tibia)
• Hinge (modified)
• Biaxial
• Synovial
• Contains menisci, bursa, many ligaments
• Knee (femur + patella)
• Plane
• Gliding of patella
• Synovial
Joints of Lower Limb

• Proximal Tibia + Fibula
• Plane, Gliding
• Synovial
• Distal Tibia + Fibula
• Slight “give” (synarthrosis)
• Fibrous (syndesmosis)
• Ankle (Tibia/Fibula + Talus)
• Hinge, Uniaxial
• Synovial
• Intertarsal & Tarsal-metatarsal
• Plane, synovial
• Metatarsal-phalanges
• Condyloid, synovial
• Interphalangeal
• Hinge, uniaxial
Muscles of Hip and Thigh

• Gluteals
• Posterior pelvis
• Extend thigh
• Rotate thigh
• Abducts thigh
• Anterior Compartment Thigh
• Flexes thigh at hip
• Extends leg at knee
• Medial/Adductor Compartment
• Adducts thigh
• Medially rotates thigh
• Posterior Compartment Thigh
• Extends thigh
• Flexes leg
Gluteals

• Gluteus maximus
• Origin - Ilium, sacrum and coccyx
• Insertion - Gluteal tuberosity of femur, iliotibial tract
• Action - Extends thigh, lateral rotation & abduction
• Innervation - Inferior gluteal nerve
• Gluteus medius & Gluteus minimus
• Origin – posterior Ilium
• Insertion - Greater trochanter of femur
• Action - Abduction, medial rotation
• Innervation - Superior gluteal nerve
• Lesser Gluteals help stabilize hip to allow fluent bipedal walking
• Tensor fasciae latae
• Origin – iliac crest and ASIS
• Insertion – iliotibial tract
• Action - Flex thigh, abduct thigh, medial rotation of thigh
• Innervation – Superior gluteal nerve
Anterior Compartment Thigh

• Quadriceps femoris
• Rectus femoris
• Origin – anterior inferior iliac spine, margin of acetabulum
• Insertion – patella and tibial tuberosity via the patellar ligament
• Action – extends knee, flexes thigh
• Vastus lateralis
• Origin-lateral proximal femur, linea aspera
• Vastus medialis
• Origin-medial proximal femur, linea aspera
• Vastus intermedius
• Origin – ant & lateral femur
• Insertion for all– patella and tibial tuberosity via the patellar ligament
• Action – extends knee
Anterior Compartment Thigh

• Quadriceps femoris
• Rectus femoris
• Origin – anterior inferior iliac spine, margin of acetabulum
• Insertion – patella and tibial tuberosity via the patellar ligament
• Action – extends knee, flexes thigh
• Vastus lateralis
• Origin-lateral proximal femur, linea aspera
• Vastus medialis
• Origin-medial proximal femur, linea aspera
• Vastus intermedius
• Origin – ant & lateral femur
• Insertion for all– patella and tibial tuberosity via the patellar ligament
• Action – extends knee
• All above innervated by the femoral nerve!!!
 
Anterior Compartment Thigh

• Sartorius
• Origin - anterior superior iliac spine
• Insertion – medial tibia
• Action - flex, abduct, lat rotate thigh; weak knee flexor
• Iliopsoas
• Origin - Ilia, sacrum, lumbar vertebrae
• Insertion – lesser trochanter of femur
• Action – flexor of thigh
• Innervation – femoral nerve
Adductors

• Adductor longus
• Adductor brevis
• Adductor magnus
• Origin – inferior pelvis (details on pg 564)
• Insertion – linea aspera of femur
• Action – adducts and medial rotates
• Innervation – Obturator nerve
• Pectineus
• Origin – pectineal line of pubis
• Insertion – lesser trochanter of femur
• Action – adducts, medial rotates
• Innervation – femoral, sometimes obturator
• Gracilis
• Origin – inferior pubic ramus
• Insertion – medial tibia
• Action – adducts thigh, flex, medial, rotates leg
• Innervation – Obturator nerve
Posterior Compartment - Hamstring

• Biceps femoris (2 heads)
• Origin – ischial tuberosity (long) linea aspera of femur (short)
• Insertion - lateral tibia, head fibula
• Action - thigh extension, knee flexion, lateral rotation
• Semitendinosus
• Semimembranosus
• Origin - ischial tuberosity
• Insertion –proximal, medial tibia
• Action - thigh extension, knee flexion, medial rotation
Sciatic nerve innervates all of the above muscles!!!

Muscles of the Leg

• Anterior Compartment
• Dorsiflex ankle, invert foot, extend toes
• Innervation: Deep fibular nerve
• Lateral Compartment
• Plantarflex, evert foot
• Innervation: Superficial Fibular nerve
• Posterior Compartment
• Superficial and deep layers
• Plantarflex foot, flex toes
• Innervation: Tibial nerve
Anterior Compartment

• Tibialis anterior
• Origin - tibia
• Insertion - tarsals
• Action - dorsiflexion, foot inversion
• Extensor digitorum longus
• Origin – tibia and fibula
• Insertion - phalanges
• Action – toe extension
• Extensor hallucis longus
• Origin – fibula, interosseous membrane
• Insertion – big toe
• Action - extend big toe, dorsiflex foot
• All innervated by deep fibular nerve
Lateral Compartment

• Fibularis (peroneus) longus
• Origin – lateral fibula
• Insertion – 5 th metatarsal, tarsal
• Action - plantarflex, evert foot
• Fibularis (peroneus) brevis
• Origin – distal fibula
• Insertion - proximal fifth metatarsal
• Action – same as above!!
All innervated by the superficial fibular nerve

Superficial Posterior Compartment

• Triceps surae
• Gastrocnemius (2 heads)
• Origin - medial and lateral condyles of femur
• Insertion - posterior calcaneus via calcaneal tendon
• Soleus
• Origin – tibia and fibula
• Insertion – same as above
• Action of both – plantarflex foot
• Plantaris
• Origin – posterior femur
• Insertion – same as above!
• Action – plantarflex foot, week knee flexion
All innervated by the tibial nerve
Deep Posterior Compartment

• Popliteus
• Origin - lateral condyle femur
and lateral meniscus

• Insertion – proximal tibia
• Action – flex and medially rotate leg
• Flexor digitorum longus
• Origin - tibia
• Insertion - distal phalanges of toe 2-5
• Action – plantarflex and invert foot, flex toe
• Flexor hallucis longus
• Origin - fibula
• Insertion - distal phalanx of hallux
• Action - plantarflex and invert foot, flex toe
• Tibialis posterior
• Origin – tibia, fibula, and interosseous membrane
• Insertion - tarsals and metatarsals
• Action - plantarflex and invert foot
All innervated by the tibial nerve
Muscles of the Foot

• Dorsum of Foot
• Extensor digitorum brevis
• O: calcaneus, I: prox phalanx of hallux
• Action: extend MT-P joint
• Innervation = Deep Peroneal (Fibular) n.
• Plantar Surface of Foot (= sole): 4 layers
• O: Tarsals and/or Metatarsals, I: Phalanges
• Action: Flex, Ext, ABduct, ADduct
• Innervation: Medial + Lateral Plantar n. (from Tibial n.)
Plexuses of the Lower Limb

• “Lumbosacral plexus”
• Lumbar Plexus
• Arises from L1-L4
• Lies within the psoas major muscle
• Sacral Plexus
• Arises from spinal nerve L4-S4
• Lies caudal to the lumbar plexus
Lumbar Plexus

• Femoral nerve
• Cutaneous branches
• Thigh, leg, foot (e.g. saphenous nerve)
• Motor branches
• Anterior thigh muscles (e.g. quadriceps, sartorius, iliopsoas)
• Obturator nerve
• Sensory
• Skin medial thigh; hip, knee joints
• Motor
• Adductor muscles
• Lateral femoral cutaneous
• Sensory
• Skin lateral thigh
• Genitofemoral
• Sensory
• Skin scrotum, labia major, anterior thigh
• Motor
• Cremaster muscle
Sacral Plexus

• Sciatic
• Motor:
• Hamstring
• Branches into:
• Tibial nerve
• Cutaneous
• Posterior leg and sole of foot
• Motor
• Posterior leg, foot
• Common fibular (peroneal) nerve
• Cutaneous
• Anterior and lateral leg, dorsum foot
• Motor
• Lateral compartment, tibialis anterior, toe extensors
• Superior gluteal nerve
• Motor
• Gluteus medius and minimus, tensor fasciae latae
Sacral Plexus

• Inferior gluteal nerve
• Motor
• Gluteus maximus
• Posterior femoral cutaneous nerve
• Sensory
• Inferior buttocks, posterior thigh, popliteal fossa
• Pudendal nerve
• Sensory
• External genitalia, anus
• Motor
• Muscles of perineum
Arteries

• Common iliac (from aorta) branches into:
• Internal iliac
• Supplies pelvic organs
• External iliac
• Supplies lower
Arteries

• Internal iliac branches into:
• Cranial and Caudal Gluteals
(Superior and Inferior)

• Gluteals
• Internal Pudendal
• Perineum, external genitalia
• Obturator
• Adductor muscles
• Other branches supply rectum, bladder, uterus, vagina, male reproductive glands
Arteries

• External iliac becomes…….
• Femoral
• Once passes the inguinal ligament
• Lower limb
• Branches into Deep femoral
• Adductors, hamstrings, quadriceps
• Branches into Medial/lateral femoral circumflex
• Head and neck of femur
• Femoral becomes……
• Popliteal (continuation of femoral)
• Branches into:
• Geniculars
• Knee
• Splits into:
• Anterior Tibial
• Anterior leg muscles, further branches to feet
• Posterior Tibial
• Flexor muscles, plantar arch, branches to toes
Veins

• Deep Veins: Mostly share names of arteries
• Ultimately empty into Inferior Vena Cava
• Plantar
• Tibial
• Fibular
• Popliteal
• Femoral
• External/internal iliac
• Common iliac
• Superficial Veins
• Dorsal venous arch (foot)
• Great saphenous (empties into femoral)
• Small saphenous (empties into popliteal)