Week 4 Lower Limb Anatomy

Fascia Lata

• “lata” = broad

• outer layer of deep fascia that forms a “stocking-like” membrane

• from hip to knee

• continuous with the Deep fascia of the leg

• deep to superficial fascia

• Iliotibial Tract (ITB):

  Thickened lateral portion of the fascia lata, from the iliac tubercle to the lateral condyle of the tibia

• FASCIAL SEPTA: separates the limbs into compartments.

compartment syndrome

•  increase in interstitial pressure, resulting in peripheral nerve and muscle ischemia.

• Surgical emergency (acute)

thigh compartments

• medial

• posterior

• anterior

leg compartments

1. lateral

2. posterior

3. anterior

sacrotuberous ligament

• connects sacrum to ischial tuberosity

• forms greater sciatic foramen

• prevents sacrum from collapsing under body weight

sacrospinous ligament

• extends from sacrum to ischial spine

• forms the lesser sciatic foramen

• prevents sacrum from collapsing under body weight

iliolumbar ligament

• two bands (anterior and posterior) that extend from L5 to the iliac crest and iliac tuberosity

• stabilises lumbosacral spine on the pelvis

anterior sacroiliac ligament

• key for holding pelvic complex together

• supports upper body weight

iliofemoral ligament

• resists hyperextension

ischiofemoral ligament

• resists hyperflexion

pubofemoral ligament

• resists abduction

gluteus maximus

Origins:

• Ilium, post glut line, sacrum & coccyx

Insertions:

• ITB & gluteal tuberosity of femur

Actions:

• Hip extension

• Hip lateral/external rotation

Gluteus Medius

Origins:

• Ilium (external surface)

Insertions:

• Greater trochanter (lateral surface)

Actions:

• Hip abduction

• Hip medial/internal rotation

• weakness of these muscles causes drooping of the pelvis to the contralateral side while walking → trendelenburg gait

Gluteus Minimus

Origins:

• ilium (external surface)

Insertions:

• Greater trochanter

Actions:

• Hip abduction

• Hip medial/internal rotation

• Hip stabilisation

• weakness of these muscles causes drooping of the pelvis to the contralateral side while walking → trendelenburg gait

hip extension

• action of the gluteus maximus

• increasing the angle between your pelvis and thigh

  • squatting

  • climbing stairs

  • walking, running, jumping

gluteus maximus

gluteus medius

gluteus minimus (characteristic white, shiny bit)

trendelenburg test

• clinical exam used to assess the strength of the hip abductor muscles, particularly the gluteus medius and minimus

• patient stands on one leg

• A negative (normal) test: The pelvis remains level or slightly elevates on the side of the raised leg

• A positive Trendelenburg sign: The pelvis drops on the side of the lifted leg, indicating weakness of the hip abductors (gluteus medius and minimus) on the weight-bearing leg

middle and superficial muscles of the hip posterior compartment

gluteal muscles:

• gluteus maximus (extensor)

• gluteus medius (abductor)

• gluteus minimus (abductor)

deep muscles of the hip posterior compartment

• All lateral/external rotators

• all originate from the sacrum or pelvic bone

• all attach at greater trochanter

P GO GO Q (order)

• Piriformis

• Gemellus (“twin) superior

• Obturator internus

• Gemellus (“twin”) inferior

• Obturator externus

• Quadratus femoris

piriformis

• deep muscle of the hip posterior compartment

• lateral/external rotator

Origin:

• sacrum

Attachment:

• greater trochanter

Gemellus (“twin”) superior

• deep muscle of the hip posterior compartment

• lateral/external rotator

Origin:

• ischium

Attachment:

• greater trochanter

Gemellus (“twin”) inferior

• deep muscle of the hip posterior compartment

• lateral/external hip rotator

Origin:

• ischium

Attachment:

• greater trochanter

Obturator internus

• deep muscle of the hip posterior compartment

• lateral/external rotator

Origin:

• inner obturator membrane

Attachment:

• greater trochanter

Obturator externus

• deep muscle of the hip posterior compartment

• lateral/external rotator

Origin:

• outer obturator membrane

Attachment:

• greater trochanter

Quadratus femoris

• deep muscle of the hip posterior compartment

• lateral/external rotator

Origin:

• ischium

Attachment:

• greater trochanter (ish)

Tensor Fasciae Latae (TFL)

Actions:

• Most important: synergist: acts as a dynamic ligament

• contributes to knee extension

• resists varus

Origin:

• ASIS

Attachment:

• iliotibial tract → lateral epicondyle

Iliopsoas

• prime mover for hip flexion

• combination of two muscles - therefore a biceps

  • Psoas Major

  • Iliacus

• inserts at lesser trochanter

Psoas major

Actions:

• Hip flexion

• Lumbar (spine) flexion

Origin:

• T12-L5 vertebrae

Insertions:

• Lesser trochanter

Iliacus
Action:

• Hip flexion

Origin:

• iliac fossa + AIIS

Insertion:

• lesser trochanter

Psoas Minor

Actions:

• Synergist: assists in hip & spine flexions (unnecessary muscle, half of people don’t have it)

Origin:

• T12-L1 vertebrae

Insertion:

• pectineal line (pubic bone/ramus)

anterior thigh compartment

• hip flexors/knee extensors

• nerve supply: femoral nerve

• Muscles:

  • Quadriceps Femoris

    • Vastus Medialis

    • Vastus Intermedius

    • Vastus Lateralis

    • Rectus Femoris

    • Articularis Genu

  • Sartorius

  • Pectineus

femoral anterior (knee extensors), medial obturator (adductors), posterior sciatic (knee flexors)

think: females have vaginas, pecs and sass

medial thigh compartment

• hip adductors

• nerve supply: obturator nerve

• Muscles:

  • Adductor Longus

  • Adductor Brevis

  • Adductor Magnus

  • Gracilis

anterior femoral (knee flexors), medial obturator (adductors), posterior sciatic (knee extensors)

think: adductors are obtrusive and ungrateful, refuse to lift (help)

posterior thigh compartment

• hamstrings

• hip extensors/knee flexors

• nerve supply: sciatic nerve

• Muscles:

  • Biceps Femoris

  • Semitendinosus

  • Semimembranosus

think: femoral anterior (adductors), medial obturator (knee flexors), posterior sciatic (knee extensors)

ss = sciatic

pectineus

Origins:

• pectineal line (pubis bone/superior ramus)

Insertions:

• Femur - pectineal line

Actions:

• Hip flexion

• Hip adduction

Sartorius

Origins:

• ASIS

Insertions:

• tibia (medial surface)

Action:

• Knee flexion

• Hip flexion (weak)

• Hip abduction (weak)

femoral triangle

• triangle bordered by:

  • sartorius

  • adductor longus

  • inguinal ligament

• contains important vessels:

  • femoral nerve

  • femoral artery

  • femoral vein

• clinically relevant

quadriceps femoris muscles

• All knee extensors

• All originate from femur except Rectus Femoris

• All attach to quadriceps femoris tendon → tibial tuberosity

• Vastus Medialis

• Vastus Intermedius

• Vastus Lateralis

• Rectus Femoris

  • also a hip flexor

  • origin: ilium

• Articularis Genu (“fifth head”)

  • also attaches to patella

vastus medialis

Origins:

• Femur

Insertions:

• Quadriceps femoris tendon → tibial tuberosity

Action:

• Knee extension

Vastus intermedius

Origins:

• Femur

Insertions:

• Quadriceps femoris tendon → tibial tuberosity

Action:

• Knee extension

Vastus Lateralis

Origins:

• Femur

Insertions:

• Quadriceps femoris tendon → tibial tuberosity

Action:

• Knee extension

Rectus femoris

Origins:

• Anterior Inferior Iliac Spine (AIIS)

Insertions:

• Quadriceps femoris tendon → tibial tuberosity

Action:

• Knee extension

• Hip flexion

Articularis genu (“knee”)

Origins:

• Femur

Insertions:

• Quadriceps femoris tendon + patella

Action:

• reduces friction between femur and bursa (fluid-filled sac, cushions and reduces friction between bones and soft tissue)

Gracilis

Origins:

• Pubis

Insertions:

• tibia (medial surface)

Actions (not a very strong muscle):

• Hip adduction

• Knee flexion (weak)

Adductor longus

Origins:

• Pubis

Insertions:

• Femur (linea aspera)

Actions:

• Hip adduction

• Hip medial rotation

Adductor Brevis

Origins:

• Pubis

Insertions:

• Femur (linea aspera)

Actions:

• Hip adduction

• Hip medial/internal rotation

Adductor magnus

Two parts: hamstring and adductor

Forms a hiatus/canal/gap allowing femoral nerve and artery to pass through

Origins:

1. ischiopubic ramus

2. ischial tuberosity

Insertions:

1. Femur (linear aspera)

2. Femur (adductor tubercle)

Actions:

• Hip adduction

• Hip medial rotation

Biceps femoris

Origins:

• Long head: ischial tuberosity

• Short head: femur (linea aspera)

Insertions:

• Head of fibula

Actions:

• Hip extension

• Knee flexion

Semitendinosus (thinner and more superifical)

Origins:

• Ischium

Insertions:

• medial tibia (surface)

Actions:

• Hip extension

• Knee flexion

Semimembranosus (deeper and wider than semitendinosus)

Origins:

• Ischium

Insertions:

• medial tibia (condyle)

Actions:

• Hip extension

• Knee flexion

Popliteal Fossa

shallow depression in the back of the knee that contains many nerves, blood vessels, and lymph nodes

Clinical Significance:

An injury at the popliteal fossa affects the innervation of lower leg and foot.

Presentations:

Weakness in plantar flexion, inversion, and toe flexion of the foot, due to decreased innervation to the muscles in the deep compartments of the lower leg.

posterior compartment of leg: superficial group

• gastrocnemius

• soleus

• plantaris

gastrocnemius

Origins:

Insertions:

Actions:

soleus

Origins:

Insertions:

Actions:

plantaris

Origins:

Insertions:

Actions:

posterior compartment of the leg: deep group

• popliteus

• tibialis posterior

• flexor digitorum longus

• flexor hallucis longus

(Tiny Dick Harry, Harry is lazy and doesn’t move) (he’s posing with his leg like o->-/ bc he’s a popstar)

nerve supply: tibial nerve (bc it’s tiny and he’s not afraid to admit it)

popliteus

Origins:

• femur (lateral condyle)

Insertions:

• tibia (posterior surface)

Actions:

• unlocks the knee by laterally rotating femur 5º on fixed tibia

• Stabilises knee by resisting lat rotation of tibia on femur

tibialis posterior

Origins:

• tibia (posterior surface)

• fibula (posterior surface)

Insertions:

• Tuberosity of:

  • navicular

  • cuneiform

  • metatarsals

Actions:

• ankle plantar flexion

• foot inversion

flexor digitorum longus

Origins:

Insertions:

Actions:

flexor hallucis longus

Origins:

Insertions:

Actions:

anterior compartment of leg

• tibialis anterior

• extensor hallucis longus

• extensor digitorum longus

• fibularis tertius

nerve supply: deep fibular nerve

(tiny dick harry fibs bc he’s anti-small dicks)

tibialis anterior

Origins:

Insertions:

Actions:

extensor hallucis longus

Origins:

Insertions:

Actions:

extensor digitorum longus

Origins:

Insertions:

Actions:

fibularis tertius

Origins:

Insertions:

Actions:

lateral compartment of leg

• fibularis longus

• Fibularis Brevis

nerve supply: superficial fibular nerve

actions:

• foot eversion

• ankle plantarflexion

fibularis longus

Origins:

Insertions:

Actions:

Fibularis Brevis

Origins:

Insertions:

Actions:

fibularis vs tibularis actions

fibularis = EVERT

tibialis = INVERT

tarsal tunnel

houses essential structures:

• Tibialis posterior, flexor digitorum longus (FDL), and flexor hallucis longus (FHL) tendons.

• Posterior tibial artery and vein.

• Posterior tibial nerve

Clinical Significance

Tarsal Tunnel Syndrome: an entrapment neuropathy that is associated with the compression of the structures within the tarsal tunnel