FACTS & HINTS

HIGH-YIELD FACTS

Clinical Points

Baker's Cyst

Posterior herniation of the synovial membrane through the joint capsule into the popliteal fossa

Swelling appears below joint line and mayextend as far as the midcalf

Large swellings mayinterfere with knee movements but otherwise asymptomatic

Bursitis

Inflammation of the bursa surrounding the knee because of repeated frictional forces In chronic inflammation, bursae become distended and filled with fluid

Prepatellar bursitis (housemaid's knee) and infrapatellar bursitis (clergyman's knee) are most recognized variants

Knee Injury

Knee injuries common, as the knee joint has little external supportive tissue Ligament sprains usuallyself-limiting, but maycause secondarydamage to menisci Tearing of the ligaments often needs surgical correction

Rupture of anterior cruciate ligament occurs when force is directed anteriorlyto the semi-flexed knee, typicallyoccurring in skiers and footballers

Posterior cruciate ligament is more resilient to injury, but mayrupture when force is applied to the tibial tuberositywhile the knee is flexed Collateral ligaments are vulnerable to lateral stresses

MNEMONICS

Memory Aids

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52 Leg

STUDYAIMS

At the end of your study, you should be able to:

Describe the fascial compartments of the leg and understand their importance

Identifythe different parts and surface markings of the tibia and fibula

Know the origins, insertions, and actions of the muscles of the leg

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GUIDE

Lower Limb: Leg

[Plate 503, Attachments of Muscles of Leg]

Bones

Tibia

Large, weightbearing

Osteological features

Medial and lateral condyles-medial and lateral protuberances at proximal end articulate with femur

Intercondylar eminence-together with condyles forms tibial plateau, fits into intercondylar fossa of femur

Tibial tuberosity-proximal end of anterior border, broad bump for attachment of patellar ligament

Gerdy's tubercle-Protrusion from lateral condyle to which iliotibial tract attaches

Shaft-or body, with rough diagonal ridge on posterior proximal end: soleal line

Medial malleolus-inferomedial projection at distal end, articulates with talus

Fibula

Slender, nonweightbearing

Osteological features

Head-proximal end with pointed apex, articulates with tibia

Shaft-or body, has three borders (anterior, interosseous, and posterior) and surfaces (anterior, posterior and lateral) for muscle attachments

Lateral malleolus-distal enlargement, articulates with tibia, contributes to ankle joint Interosseous membrane uniting tibia and fibula

Fascial Compartments

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Crural fascia

Deep fascia surrounding leg

Distal continuation of fascia lata

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Attaches to anterior and medial borders of tibia

Thicker in proximal leg

Continues as extensor retinaculum distally

Extensions from deep surface-anterior and posterior intermuscular septa-attach to anterior and posterior margins of fibula Intermuscular septa and interosseous membrane divide leg into three fascial compartments: anterior, lateral, and posterior Muscles in posterior compartment are subdivided into superficial and deep compartments bytransverse intermuscular septum

Joints

Proximal tibiofibular joint

Plane-type synovial joint

Nonweightbearing

Between head of fibular and lateral condyle of tibia

Fibrous capsule reinforced byanterior and posterior ligaments of the head of the fibula Distal tibiofibular

Fibrous joint (syndesmosis)

Medial surface of distal fibula articulates with facet on inferior end of tibia

Reinforced byanterior and posterior tibiafibular ligaments and interosseous ligament (extension of interosseous membrane)

Muscles

[Plate 507, Muscles of Leg (Superficial Dissection): Anterior View]

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[Plate 509, Muscles of Leg: Lateral View]

Anterior (= extensor) compartment

Primarilydorsiflexors of ankle

Include

Tibialis anterior (also inverts foot and holds up medial longitudinal arch of foot)

Extensor hallucis longus (also dorsiflexes halluxand inverts foot)

Extensor digitorum longus (also dorsiflexes toes)

Peroneus tertius (also everts foot)

Muscles of the Anterior Leg

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Lateral (= everter) compartment

Primarilyeverters of the foot

Include

Peroneus longus

Peroneus brevis

Both plantarflexankle, evert foot, and hold up lateral longitudinal arch of foot

Muscles of the Lateral Leg

Posterior compartment

Comprised of superficial and deep groups

Separated bytransverse intermuscular septum

Superficial group = plantar flexors of the foot

Gastrocnemius

Soleus

Plantaris

Gastrocnemius and plantaris cross the knee joint and thus also flexknee

All three contribute to calcaneal tendon

Deep group = plantar flexors of the foot

Tibialis posterior (also inverts foot and supports medial longitudinal arch of foot)

Flexor hallucis longus (also plantarflexes interphalangeal joint of halluxand supports medial longitudinal arch of foot)

Flexor digitorum longus (also plantarflexes DIP joints of lateral four toes and supports medial and lateral longitudinal arches of foot)

Popliteus

Forms inferior floor of popliteal fossa

Tendon lies between fibrous capsule and synovial membrane of knee joint

Flexes knee

Rotates femur five degrees laterallyon tibial plateau to unlock knee so flexion can occur

Muscles of the Posterior Leg

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