The Leg

Presented by Dr. Maryna Kornieieva Asst. of Anatomy

• Orthopedic anatomy• Clinical anatomy• Radiologic anatomy

Leg: Orthopedic Anatomy

Proximal leg: bones

Anterior view: tibia(T) and fibula(F)

Posterior view: tibia(T) and fibula(F)

Medial tibial condyleMedial tibial condyle

Lateral tibial condyle

Tibial tuberosity(patellar ligament)

Intercondilar eminenceFibular Articular facet

Soleal line

Medial surface(subcutaneous)

Anterior border

Medial borderLateral border(interosseous)

Lateral surface Posterior surface

Head

Styloid process

Neck

TT

F

Proximal Tibiofibular Joint

The proximal TF joint is synovial and of little clinical consequence (opposed to the fibrous distal TF joint which is vital to ankle stability)

Proximal Tibiofibular Joint

Distal Tibiofibular Joint

Interosseous membrane

Type: synovial, plane, gliding joint

Type: fibrous joint

Movements: small amount

Movements: small amount

Articulation: lateral condyle of the tibia and the head of the fibula

Articulation: fibular notch at the lower end of the tibia and the lower end of the fibula.

Ligaments:

Anterior and posterior ligaments

Clinical notes

The fibular neck has the common peroneal (fibular) nerve running around it that may be injured by fracture, oedema or compression.

Tibial plateau fractures occur due to a fall from a height, direct trauma, valgus or varus injuries (usually valgus due to lateral trauma causing lateral condyle injury) and minor falls in an osteoporotic patient.

Anterior Intercondilar area

Posterior Intercondylar area

Tibial plateau

Intercondilar eminence

CT (MIP)

Clinical notes

The tuberosity may avulse anteriorly or fragment. It usually responds to conservative treatment.

Osgood-Schlatter’s disease -(epiphysitis) is due to avulsion and inflammation of the soft young tibial tuberosity epiphysis subject to the pull of the powerful quadriceps muscle.

Tibial shaft fractures

1) It is a weight-bearing bone with little surrounding muscle anteromedially (that would improve blood supply for healing).2) There are only skin and periosteum over the bone increasing the chance of an open fracture.3) The fibula may hold the ends of a tibial fracture apart, making healing less likely.

Transverse(hit by a car)

Spiral (torsion injury)

Oblique(direct trauma plus indirect

torsion)

Clinical notes: peripheral pulses must be checked early. If the foot is pale and pulseless, immediate temporary reduction is required.

Treatment: Conservative treatment may be used for stable fractures but otherwise, internal fixation by intramedullary nail or plate is used. Isolated tibial fractures may require fibular osteotomy.

Difficulties:

Distal leg: bones

Eversion injuries to the ankle may cause high fibula fractures (even at the fibular neck) due to sprining of the bone around the distal TF joint as the fulcrum.

Medial malleolus

PosteriorAnterior

Malleolar fossa

Tibialis posterior groove

Flexor hallucis longus groove

Distal TF joint

Peroneus longus groove

Add X-ray Ankle mortise

Lateral malleolus

Distal Tibiofibular JointThe bony mortise keeps the ankle joint very solid but depends on an intact distal tibiofibular joint (if it is not intact then there can be lateral shift of the talus).

Ligaments of the Distal TF joint:

Interosseous ligaments

Anterior inferior tibiofibular lig.

Posterior inferior tibiofibular lig.

Posterior talo-fibular ligament Anterior talo-

fibular ligamentCalcaneo-fibular lig

Clinical notes

Rotational ankle injuries do often cause malleolar fractures: medial one is stressed in hyperinversion, while lateral one – in hypereversion.

Cross-sectional computed tomography scan showing measurement of the anterior, central, and posterior width of the distal tibiofibular joint (normal).

Diastasis is complete disruption of the strong fibrous distal tibiofibular joint. It indicates significant trauma and unstable ankle (a serious injury). This allows lateral shift of the talus and needs fixation.

Leg: Clinical Anatomy

The Leg: regionsis the part of the lower limb between the knee and ankle joint

Anterior region of the leg Posterior region of the leg

Surface Anatomy of the LegAnterior region Posterior region

Superficial veinsLong (greater) saphenous vein forms in front of the medial malleolus and ascends up along the medial side of the lower limb till it opens into the femoral vein 3-4 cm below the inguinal ligament (saphenous hiatus).

Short (lesser) saphenous vein forms behind the lateral malleolus and goes toward the popliteal fossa, there it tributes into the popliteal vein.

There are numerous perforating veins (30-40) connecting superficial veins with the deep along their way. The valves inside the perforating veins allow one-directed blood flow (from superficial veins to the deep).

The vascular wall of the superficial veins is thin and is able to resist only the minimal blood pressure. In case of development of venous hypertension, the wall dilates and become tortures. This state is known as varices, or varicose disease.

Compartments of the legDeep fascia attaches to the periosteum of the anterior and medial borders of the tibia

Anterior Crural Intermuscular Septum

Posterior Crural Intermuscular Septum

Investing Deep Fascia

Transverse Intermuscular Septum

Transverse intermuscular septum separates superficial and deep muscles of the posterior compartment and gives rise to retinacula around the ankle.

Leg: compartments

Muscles:

1. tibialis anterior,

2. extensor digitorum longus,

3. extensor hallucis longus,

4. peroneus tertius;

Blood supply: Anterior tibial artery

Nerve supply: Deep peroneal nerve

Superficial muscles:

1. gastrocnemius,

2. plantaris, and

3. soleus

Deep muscles:

Popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior.

Blood supply: Posterior tibial artery

Nerve supply: Tibial nerve

Anterior Compartment (AC) Posterior Compartment (PC) Lateral Compartment (LC)

Muscles: 1. Peroneus longus, 2. Peroneus brevis;

Blood supply: Perforating branches from the fibular (peroneal) artery

Nerve supply: Superficial fibular (peroneal) nerve

AC muscles: Tibialis AnteriorOrigin:Lateral surface ofshaft of tibia andinterosseousmembrane.

Insertion:Medial cuneiform and base of 1st metatarsal bone.

Nerve Supply:Deep peronealnerve

Action:Extends foot at ankle joint; inverts foot at subtalar and transverse tarsal joints; holds up medial longitudinal arch of foot.

Extensor Digitorum Longus

Action:Extends toes; extends footat ankle joint

Insertion:Extensor expansion of lateralfour toes

Origin: Anterior surface ofshaft of fibula

Nerve Supply:Deep peroneal nerve

Extensor Hallucis Longus

Action:Extends big toe; extendsfoot at ankle joint; invertsfoot at subtalar andtransverse tarsal joints

Insertion:Base of distal phalanx ofgreat toe

Origin:Anterior surface of shaft of fibula

Nerve Supply: Deep peronealnerve

Peroneus (Fibularis) TertiusOrigin:Anterior surface ofshaft of fibula

Insertion:Base of 5th metatarsal bone

Nerve Supply:Deep peronealnerve

Action: Extends foot at ankle joint; everts foot at subtalar and transverse tarsal joints.

Anterior compartment: vessels

Anterior Tibial Artery arises from the popliteal artery within the cruropopliteal canal.

It quits the canal via the anterior outlet (the opening in interosseous membrane) and descends to the foot with the deep fibular nerve.

Branches:1) Anterior tibial

recurrent artery (ascends to the genicular anastomosis);

2) Muscular branches;

3) Anterior (medial and lateral) malleolar arteries (descend to the ankle).

It continues with the dorsal artery of foot.

Anterior compartment: nervesDeep fibular nerve

It one of the two divisions of the common fibular nerve.

Course: It passes through the anterior crural intermuscular septum and descends toward the ankle deep to the extensor digitorum longus.Supplies:

On the leg - all muscles of the anterior compartment;On the foot - extensor digitorum brevis, first two dorsal interossei muscles, + the skin between the great and second toes.

Deep Fibular Nerve Injury

The deep fibular nerve could be damaged as a part of the common peroneal nerve, because last one is extremely vulnerable to injury as it winds around the neck of the fibula.

Injury to the common peroneal nerve (as well as the deep fibular itself) causes foot drop.

Anterior Compartment of the Leg Syndrome

Compartment syndrome occurs with a rise in pressure within a compartment due to many causes but often unrecognized trauma. Symptoms: • Progressive ischemic pain;• Numbness and

paraesthesia;• Swelling and induration in

the leg;• Pale foot.

It is required urgent fasciotomy to avoid muscle necrosis and distal ischemia.

PC musclesSuperficial Deep

Gastrocnemius

Soleus

Plantaris

Tibialis Posterior

Popliteus

Flexor Digitorum LongusFlexor Hallucis Longus

GastrocnemiusOrigin:Lateral head fromlateral condyle offemur and medialhead from abovemedial condyle

Insertion:Via tendo calcaneus into posterior surface of calcaneum.

Nerve Supply: Tibial nerve

Action:

• Plantar flexes foot at ankle joint;

• flexes knee joint.

Soleus

Insertion:Via tendo calcaneusinto posterior surface of calcaneum

Action: Together with gastrocnemius andplantaris is powerful plantar flexor of ankle joint; providesmain propulsive force in walking and running

Nerve Supply: Tibial nerve

Origin:Shafts of tibia and fibula

Ruptured Tendo CalcaneusCommon in middle-aged tennis players

The rupture occurs at its narrowest part, about 5 cm above its insertion.

Symptoms:• Acute pain;• Impossible plantar flexion;• Palpable gape above calcaneus

N

The tendon should be sutured as soon as possible and the leg immobilized with the ankle joint plantar flexed and the knee joint flexed.

Plantaris

Nerve Supply:Tibial nerve

Action:Plantar flexes foot at ankle joint;flexes knee joint Origin:

Lateralsupracondylarridge of femur

Insertion:Posterior surface ofcalcaneum

Plantaris

PopliteusThe popliteus muscle arises inside the capsule of theknee joint and is inserted into the upper part of the posteriorsurface of the tibia.

The tendon separates the lateral ligament of the knee joint from the lateral meniscus so that the meniscus is not tethered to the ligament and is freer to move and adapt to the surfaces of the condyle of the femur and the tibia.

The popliteus muscle is responsible for “unlocking” the knee joint.

Tibialis Posterior

Nerve Supply:Tibial nerve

Origin: Posterior surfaceof shafts of tibiaand fibula andinterosseousmembrane

Action:Plantar flexes foot at anklejoint; inverts foot at subtalarand transverse tarsal joints;supports medial longitudinalarch of foot

Tibialis posterior groove

Flexor retinaculum

Insertion:Tuberosity of navicular boneand other neighboring bones

Tarsal TunnelBoundaries: Contents:

• Tibialis posterior tendon

• Flexor digitorum longus tendon

• Posterior tibial artery• Posterior tibial vein• Tibial nerve• Flexor hallucis longus

tendon

• roof: flexor retinaculum• floor: medial surfaces of the talus and calcaneus

Flexor Digitorum Longus

Nerve Supply:Tibial nerve

Action:

Flexes distal phalanges of lateral four toes; plantar flexes foot at ankle joint;

supports medialand lateral longitudinal arches of foot.

Origin: Posterior surface ofshaft of tibia

Insertion:Bases of distalphalanges oflateral four toes

L R

Flexor Hallucis LongusOrigin: Posterior surface ofshaft of fibula Nerve Supply:

Tibial nerve

Action:Flexes distal phalanx of big toe; plantar flexes foot at ankle joint; supports medial longitudinal arch of foot.

Insertion:

Base of distalphalanx of big toe.

L R

Posterior compartment: vesselsTibialis Posterior artery Peroneal (fibular) artery

Passes downward along the posterior surface of the tibialis posterior, accompanied by deep veins and the tibial nerve.Branches:• Peroneal artery• Muscular branches• Nutrient artery to the

tibia.• Anastomotic branches• Medial and lateral

plantar arteries

It descends behind the fibula, either within the substance of the flexor hallucis longus muscle or posterior to it.

• Muscular branches • Nutrient artery to the fibula• Anastomotic branches (ankle

joint)• Perforating branch (pierces

the interosseous membrane to reach the muscles of the lateral compartment of the leg).

Branches:

1 - a. poplitea; 2 - a. genu sup. lateralis; 3 - a. genu inf. lateralis; 4 - a. peronea (fibularis); 5 - rami malleolares tat.; 6 - rami calcanei (lat.); 7 - rami calcanei (med.); 8 - rami malleolares mediales; 9 - a. tibialis post.; 10 - a. genu inf. medialis; 11 - a. genu sup. medialis.

Palpation of the posterior tibial artery

The point: posterior and inferior to the medial malleolus.

Goal: assessing a patient for peripheral vascular disease.

Deep Veins: Thrombosis

It passes rapidly to the heart and lungs, causing pulmonary embolism, which is often fatal.

DVT - is the formation of a blood clot (thrombus) within a deep vein, predominantly in the legs.

Non-specific signs may include pain, swelling, redness, warmness, and engorged superficial veins.

• Older age;• Major surgery and orthopedic surgery;• Inactivity and immobilization, as with orthopedic

casts, sitting, travel, bed rest, and hospitalization;• Trauma, minor leg injury, and lower limb amputation;• Blood disorders; and others.

Risk factors:

Tibial nerve

• Muscular branches: soleus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior.

• Cutaneous: The medial calcaneal branch supplies the skin over the medial surface of the heel.

• Articular branch to the ankle joint.• Medial and lateral plantar nerves

Branches on the leg:

The cutaneous innervation of the terminal branches of the sciatic nerve.

Tarsal Tunnel SyndromeSymptoms:• Pain and tingling in and around ankles and

sometimes the toes• Swelling of the feet• Painful burning, tingling, or numb sensations

in the lower legs. Pain worsens and spreads after standing for long periods; pain is worse with activity and is relieved by rest.

• Pain radiating up into the leg, and down into the arch, heel, and toes

• Pain along the Posterior Tibial nerve path• Burning sensation on the bottom of foot that

radiates upward reaching the knee• "Pins and needles"-type feeling and

increased sensation on the feet.

TT -  is a compression neuropathy and painful foot condition in which the tibial nerve is compressed as it travels through the tarsal tunnel.

Definition:

Peroneus LongusOrigin: Lateral surface of shaft of fibula

Insertion:Base of 1stmetatarsaland the medialcuneiform

Nerve Supply: Superficialperoneal nerve

Action:Plantar flexes foot at ankle joint; everts foot at subtalar and transverse tarsal joints; supports lateral longitudinal and transverse arches of foot.

Peroneus Brevis

Action:Plantar flexes foot at ankle joint; everts foot at subtalar and transverse tarsal joint; supportslateral longitudinal arch of foot.

Origin:Lateral surface ofshaft of fibula

Nerve Supply:Superficialperoneal nerve

Insertion:Base of 5thmetatarsal bone

Tenosynovitis and Dislocation of the Peroneus Longus and Brevis Tendons

Tenosynovitis can affect the tendon sheaths of the peroneus longus and brevis muscles as they pass posterior to the lateral malleolus.

Tendons of peroneus longus and brevis may dislocate forward. For this condition to occur, the superior peroneal retinaculum must be torn.

PL – peroneus longus; PB – peroneus brevis; SPR – superior peroneal retinaculum; IPR – inferior peroneal retinaculum.

Lateral compartment: vesselsNumerous branches from the peroneal (fibular) artery, which passes through posterior compartment of the leg, pierce the posterior fascial septum, and supply the peroneal muscles.

 NC-MRA (inflow inversion recovery) shows normal arterial vasculature of the lower extremities. PA, popliteal artery; AT, anterior tibial arteries; PT, posterior tibial arteries; and PER, peroneal arteries.

Nerves The superficial peroneal nerve is one of the terminal branches of the common peroneal nerve

Muscular: to the peroneus longus and brevis

Branches

Cutaneous: • lower part of the

front of the leg;• dorsum of the

foot;• dorsal surfaces of

the skin of all the toes (except the adjacent sides of the first and second toes and the lateral side of the little toe).

It arises in the substance of the peroneus longus muscle on the lateral side of the neck of the fibula, and then descends between the peroneus longus and brevis muscles.

Leg: Radiologic Anatomy

Sectional Anatomy of the Leg

T1-weighted axial image through the upper leg 

(fatty tissues bright, fluids dark)

MRI

T2W axial MR image through the upper leg

Note increased signal of all the muscles, in all the compartments. This is edema. There is also some edema of the subcutaneous tissues. It is very unusual for a trauma, for example, to present with edema in all compartments. There are no fluid collections within the muscles, but notice the perifascial fluid collections.(fatty tissues dark, fluids bright)