12. POPLITEAL FOSSA & LEG

POPLITEAL FOSSA + BORDERS

• Diamond-shaped depression POST KNEE joint

• Borders:

  • Superomedial → Semimembranous & Semitendinous m.

  • Superolateral → Biceps Femoris m.

  • Inferomedial → Medial Head of Gastrocnemius

  • Inferolateral → Lateral head of Gastrocnemius

  • Posterior (roof) → Popliteal fascia

  • Floor → Supracondylar Lines of Femur, POST KNEE joint + Popliteus m.

POPLITEAL FASCIA

• Subcutaneous Fascia (of Skin) overlying popliteal fossa

  • Small saphenous vein

  • POST cutaneous Nerve of THIGH

  • Medial & Lateral Sural Cutaneous Nerves

• Popliteal Fascia

  • Strong,deep fascia continuous w/ FASCIA LATAE ABOVE + DEEP FASCIA of LEG below

POPLITEAL FOSSA: CONTENTS

• Popliteal A,

• Popliteal V.

  • Small Saphaneous drains into

• Tibial N.

• Common Fibular (Peroneal) N.

• POST Cutaneous N. of the THIGH

• Popliteal Lymph Nodes + Lymphatic Vessels

POPLITEAL FOSSA: NERVES

• Sciatic N. ends + divides into:

  • Tibial N.

    • Medial Sural N. → forms Sural N.

  • Common Fibular N.

    • Sural communicating branch → forms Sural N.

    • Deep Fibular N.

    • Superficial Fibular N.

• POSTERIOR Cutaneous N. Of the Thigh ends at Popliteal Fossa

Ignore

Ignore

POPLITEAL FOSSA: ARTERIES

• Popliteal Artery

  • Continuation of FEMORAL ARTERY as it passes through ADDUCTOR Hiatus

  • Ends as bifurcation → into ANT + POST Tibial Arteries

POPLITEAL FOSSA: BRANCHES

• Include (& contribute to the Genicular Anastomosis)

  • 5 GENICULAR BRANCHES

    • SUP Lateral → anastomoses w/ Descending Lateral Femoral Circumflex A.

    
    

    • SUP Medial → anastomoses w/ Descending Genicular A.

    
    

    • Middle → anastomoses w/ 4th Perforating A.

    
    

    • Inferior Lateral → anastomoses w/ ANT Tibial Recurrent (from ANT Tibial A.)

    
    

    • Inferior Medial

  
  

  • ANT Tibial A.

  • POST Tibial A.

GENICULAR ANASTOMOSIS

PICTURE

POPLITEAL FOSSA: VENOUS & LYMPH DRAINAGE

• Popliteal Vein

  • Begins at the distal border of the POPLITEUS as a continuation of the POST Tibial Vein

  • Ends as the FEMORAL vein as it passes through the ADDuctor Hiatus

  • Tributaries Include:

    • POST Tibial

    • ANT Tibial Vein Begins

    • Genicular Veins

• Lymph:

  • Superficial POPLITEAL lymph nodes lies → around Small Saphenous Vein

  • Deep Popliteal lymph nodes receive lymph from JOINT CAPSULE of knee + deep veins of leg

  • ALL lymph vessels go to DEEP INGUINAL lymph nodes

LEG: BONES + 3 FASCIAL COMPARTMENTS

• BONES:

  • Tibia + Fibula

  • Connected by an interosseous membrane

• 3 FASCIAL COMPARTMENTS:

  • ANT

  • LATERAL

  • POST (Superficial + Deep)

  • Separated by ANT + POST intermuscular septa

ANT COMPARTMENT OF LEG: DORSIFLEXOR (EXTENSOR) COMPARTMENT

• DORSIFLEXOR (EXTENSOR) COMPARTMENT

  • ANT to the INTEROSSEOUS Membrane btw lateral surface of tibial shaft + medial surface of the shaft of the fibula

    • Inferiorly → 2 band-like thickenings

      • Superior Extensor Retinaculum

      • Inferior Extensor Retinaculum

• Muscle Actions:

  • Dorsiflexion of ankle

  • Extension of toes

  • Inversion of ankle at subtalar joint

• Muscle Nerve: Deep Fibular Nerve (from → Common Fibular Nerve)

• Artery Supply: ANT Tibial Artery (from → Popliteal Artery)

ANTERIOR LEG MUSCLES- DORSIFLEXION OF ANKLE: TIBIALIS ANTERIOR

• PA: Lateral condyle + Lateral superiors surface of tibia & interosseous membrane

• DA: Medial cuneiform + base of 1st Metatarsal

• N: Deep Fibular Nerve

• A: Dorsiflexes ankle → Inverts subtalar joint

ANTERIOR LEG MUSCLES- DORSIFLEXION OF ANKLE: EXTENSOR DIGITORUM LONGUS

• PA: Lateral condyle tibia + Superior medial surface of fibula + Interosseous membrane

• DA: Middle & distal phalanges of lateral 4 digits (toes)

• N: Deep Fibular Nerve

• A: Extends lateral 4 toes + Dorsiflexes ankle → Inverts subtalar joint

ANTERIOR LEG MUSCLES- DORSIFLEXION OF ANKLE: EXTENSOR HALLUCIS LONGUS

• PA: Middle part of fibula & interosseous membrane

• DA: Base of distal phalanx of great toe (Hallux)

• N: Deep Fibular Nerve

• A: Extends great toe + Dorsiflexes ankle joint

ANTERIOR LEG MUSCLES- DORSIFLEXION OF ANKLE: FIBULARIS TERTIUS

• PA: Inferior third fibula & interosseous membrane

• DA: Dorsum of base of 5th metatarsal

• N: Deep Fibular Nerve

• A: Dorsiflexes ankle + Everts subtalar joint

LATERAL COMPARTMENT OF LEG: EVERTOR COMPARTMENT

• Bound by lateral surface of fibula + ANT & POST intermuscular septa + deep fascia of leg

• Ends Inferiorly at SUPERIOR Fibular Retinaculum

• 2 muscles innervated → Superficial Fibular Nerve

• Tendons pass POSTERIORLY to Lateral Malleolus

• Blood Supply:

  • Perforating Branches of ANT Tibial Artery

  • Perforating Branches of Fibular Artery

LATERAL LEG MUSCLES → EVERTORS: FIBULARIS (PERONEUS) LONGUS (FL)

• PA: Head & Superior 2/3 of fibula

• DA: Base of 1st Metatarsal

• N: Superficial Fibular Nerve

• A:

  • Everts Subtalar joint

  • Weakly plantar flexes ankle joint

LATERAL LEG MUSCLES → EVERTORS: FIBULARIS (PERONEUS) BREVIS (FB)

• PA: Head & Superior 2/3 of fibula

• DA: Base of 1st Metatarsal

• N: Superficial Fibular Nerve

• A: Everts Subtalar joint + weakly plantar flexes ankle joint

POSTERIOR COMPARTMENT OF LEG: PLANTARFLEXION COMPARTMENT

• POST compartment = Superficial & Deep subcompartments → separated by Transverse intermuscular septum)

• INFERIORLY, the Flexor Retinaculum (btw MEDIAL Malleolus & Calcaneus) hold deep muscle tendons + POsT Tibial Artery as they bend around Medial Malleolus

• ALL innervated by → TIBIAL NERVE

• Supplied by → POST TIBIAL & FIBULAR ARTERIES

• POSTERIOR Muscle Actions include:

  • Plantarflexioin & Inversion

• Calcaneal Tendon → MOST POWERFUL TENDON in body

“ You stroll with SOLEUS but win the long jump w/ GAESTROCNEMIUS” - per Dr. Mudnt

Ignore

Ignore

SUPERFICIAL POSTERIOR LEG MUSCLES- TRICEPS SURAE (PLANTARFLEXORS) : GASTROCNEMIUS

• PA:

  • Lateral Head = Lateral aspect of lateral femoral condyle

  • Medial Head = Popliteal surface of femur; superior to medial condyle

• DA: Calcaneus via Calcaneal Tendon

• N: Tibial Nerve

• A: Plantarflexes ankle joint when knee is extended + Raises heal during walking + Flexes knee joint

SUPERFICIAL POSTERIOR LEG MUSCLES- TRICEPS SURAE (PLANTARFLEXORS) : SOLEUS

• PA:

  • Superior Posterior Fibula + Soleal line & middle 1/3 tibia

• DA: Calcaneus via Calcaneal Tendon

• N: Tibial Nerve

• A: Plantarflexes ankle independent of knee position; stabilizes ankle joint

SUPERFICIAL POSTERIOR LEG MUSCLES- TRICEPS SURAE (PLANTARFLEXORS) : PLANTARIS

• ABSENT IN 5-10%

• PA:

  • Lateral Supracondylar line of femur = Oblique popliteal ligament

• DA: Calcaneus via Calcaneal Tendon

• N: Tibial Nerve

• A: Weakly assist in plantarflexing ankle

DEEP POSTERIOR LEG MUSCLES: POPLITEUS

• PA: Lateral Femoral condyle

• DA: Posterior surface of tibia (superior to soleal line)

• N: Tibial Nerve

• A: Weakly flexes KNEE joint to unlock knee by rotating femur 5° (on fixed TIBIA) + Medial rotates TIBIA unplanted limb

DEEP POSTERIOR LEG MUSCLES: FLEXOR HALLUCIS LONGUS

• PA: INFERIOR 2/3 Fibula + Inferior Interosseous Membrane

• DA: Base of Distal phalanx (great TOE = Hallux)

• N: Tibial Nerve

A: Flexes great toe at all joints; weakly plantarflexes ankle joint; supports

medial longitudinal arch of foot

DEEP POSTERIOR LEG MUSCLES: FLEXOR DIGITORUM LONGUS

• PA: POST SURFACE OF TIBIA + Fibula via broad Tendon

• DA: Bases of distal phalanges of Lateral 4 digits

• N: Tibial Nerve

• A: Flexes 4 toes + Plantarflexes ankle joint + supports longitudal arches of foot

DEEP POSTERIOR LEG MUSCLES: TIBIALIS POSTERIOR

• PA: Interosseus membrane + POST TIBIA & FIBULA

• DA: Tuberosity of Navicular + Cuneiform + cuboid + sustentaculum tali of calcaneus, bases of 2nd, 3rd & 4th metatarsals

• N: Tibial Nerve

A: Plantarflexes ankle; inverts foot + maintains medial longitudinal arch

NERVES OF LEG: SAPHENOUS NERVE

• ORIGIN: FEMORAL NERVE

• DISTRIBUTION: Supplies skin on Medial side of ANKLE + FOOT

NERVES OF LEG: SURAL NERVE

• ORIGIN: TIBIAL + COMMON FIBULAR NERVES

• DISTRIBUTION: Supplies skin on POST & Lateral Leg & Foot

NERVES OF LEG: TIBIAL NERVE

• ORIGIN: Sciatic

• DISTRIBUTION: Supplies POST Leg muscles & Knee joint

NERVES OF LEG: COMMON FIBULAR NERVE

• ORIGIN: Sciatic

• DISTRIBUTION:

  • Supplies skin on lateral POST Leg via Sural

  • Knee joint via Articular Branch

NERVES OF LEG: SUPERFICIAL FIBULAR NERVE

• ORIGIN: Common Fibular Nerve

• DISTRIBUTION: Supplies Fibularis Longus & Fibularis Brevis → Supplies Skin on distal 1/3 on ANTERIOR Leg & dorsum of Foot

NERVES OF LEG: DEEP FIBULAR NERVE

• ORIGIN: Common Fibular Nerve

• DISTRIBUTION: Supplies ANTERIOR Leg muscles → supplies SKIN between 1st & 2nd toes

ARTERIES OF LEG: POPLITEAL

• ORIGIN: Femoral (once it passes through ADDUCTOR Hiatus)

• DISTRIBUTION IN LEG: Superior, Middle & INF GENICULAR Arteries to Lateral + Medial aspects of Knee

ARTERIES OF LEG: ANTERIOR TIBIAL ARTERY

• ORIGIN: Popliteal

• DISTRIBUTION IN LEG: Anterior (ANT) leg compartment

ARTERIES OF LEG: DORSALIS PEDIS

• ORIGIN: Continuation of ANT tibial Artery distal to INF Retinaculum

• DISTRIBUTION IN LEG:

  • Muscles on dorsum of foot

  • pierces 1st dorsal Interosseous muscle as Deep Plantar Artery to help form Plantar Arch

ARTERIES OF LEG: POSTERIOR TIBIAL ARTERY

• ORIGIN: Popliteal

• DISTRIBUTION IN LEG:

  • POST & Lateral Leg compartments

  • Circumflex Fibular Branch joins anastomoses around Knee

  • Nutrient artery passes to → Tibia

ARTERIES OF LEG: FIBULAR ARTERY

• ORIGIN: Posterior Tibial

• DISTRIBUTION IN LEG:

  • POST Leg compartment

  • Perforating branches supply lateral compartment of Leg

LEG CLINICAL CONSIDERATIONS

• POPLITEAL pulse & POST Tibial pulse

• Popliteal Aneurysm = abnormal dilation of ALL or PART of popliteal artery

• Compartment Syndrome = infection of a compartment causes INCREASE in INTRA-COMPARTMENT pressure

• Shin Splints = TIBIALIS anterior sprain (tears in the periosteum covering shaft of tibia)

• Footdrop = Injury the COMMON FIBULAR NERVE (most injured nerve in lower limb)

• Ruptured calcaneal tendon

• Calcaneal tendon reflex

Ignore

• POPLITEAL pulse & POST Tibial pulse

• Popliteal Aneurysm = abnormal dilation of ALL or PART of popliteal artery

• Compartment Syndrome = infection of a compartment causes INCREASE in INTRA-COMPARTMENT pressure

• Shin Splints = TIBIALIS anterior sprain (tears in the periosteum covering shaft of tibia)

• Footdrop = Injury the COMMON FIBULAR NERVE (most injured nerve in lower limb)

• Ruptured calcaneal tendon

• Calcaneal tendon reflex