9/17 Anterolateral Leg Flashcards
Tibia and fibula orientation
where is the lateral and anterior compartments located?
lateral compartment is on the fibula side
anterior compartment in front of the interosseous membrane
osteology of the foot
fibular trochlea
Cuboid
- MOST LATERAL BONE IN DISTAL ROW OF TARSUS
- ARTICULATES WITH:
– POSTERIORLY= CALCANEUS
– ANTERIORLY= 4TH AND 5TH METATARSALS
– MEDIALLY= NAVICULAR AND LATERAL CUNEIFORM
• CUBOID SULCUS: – GROOVE (FIBULARIS LONGUS)
Crural (Leg) Fascia
- Deep fascia of leg – Continuous with fascia lata
- Covers leg muscles
- Part of proximal attachment of underlying muscles
- Thickens distally to form extensor retinaculum (L., band or halter)
- Prevents bowstringing during dorsiflexion
Crural Fascia does what?
encloses the 4 different compartments in the leg
Crural Fascia
- Thick septa 1. anterior 2. lateral 3. posterior
- Structures in compartments share…
– Same general function – Nerve – Artery and vein
KNOW THIS !!!
what function does the anterior compartment
Anterior (dorsiflexor/extensor) Compartment Muscles
Anterior (dorsiflexor/extensor) Compartment Muscles
• Location:
– Anterior to interosseous membrane
• Muscles:
1. Tibialis anterior
2. Extensor hallucis longus
3. Extensor digitorum longus
4. Fibularis tertius (NOT SHOWN)
• Primary functions: – Dorsiflexion – Toe extension
Tibialis Anterior
- Long thick muscle on anterolateral surface of tibia
- Proximal attachment: – Lateral tibial condyle and superolateral ½ of tibia
- Distal attachment: – Medial surface of first (medial) cuneiform and first metatarsal base
- Functions: – dorsiflexion and inversion of
Extensor Digitorum Longus
- Proximal attachment: – Lateral tibial condyle – Anterior fibular surface – Interosseous membrane
- Distal attachment: – Each of the four tendons forms an extensor expansion over dorsum of lateral four proximal phalanges that divide into
– Two lateral slips (distal phalanx)
– One central slip (middle phalanx)
• Functions: – Extends lateral four digits – Dorsiflexion
Fibularis Tertius
- Fuse with digitorum longus proximally
- Tendon does not attach to a digit
- Variably present
- Do not confuse with other “fibularis” muscles
- Attachments:
– Proximal: Anteroinferior fibular surface – Distal: Dorsum of fifth metatarsal base
• Functions: – Dorsiflexion – Eversion
Extensor Hallucis Longus
- Lateral to tibialis anterior
- Proximal attachment:
– Anteromedial fibular surface and interosseous membrane. Medial to distal half of the proximal attachment of extensor digitorum longus
- Distal attachment: – Base of distal phalanx of hallux
- Functions: – Extend hallux – Dorsiflex ankle
Anterior Compartment:
Deep Fibular Nerve
- One of two terminal branches of the common fibular nerve: – Begins between fibula and fibularis longus muscle. – Runs inferomedially with anterior tibial vessels between tibialis anterior and extensor hallucis longus. Ends in medial and lateral terminal branches on dorsum of foot.
- Supplies: – Anterior compartment muscles – Ankle joint and metacarpal phalangeal joints – Dorsal intrinsic foot muscles – Skin between first and second digits
Anterior Compartment:
Anterior Tibial Artery
- Arises from popliteal artery
- Begins near inferior border of popliteus muscle – Tibial tuberosity demarcates approximate point of division of anterior and posterior tibial arteries.
- Passes anteriorly over interosseous membrane
- Descends on anterior surface of interosseus membrane between EHL and TA muscles with deep fibular nerve.
- Ends at ankle between malleoli to become dorsalis pedis artery.
Lateral Compartment contains?
fibularis longus and brevis
superficial fibular nerve
Fibularis Longus Muscle
- Extends from fibular head to sole of foot
- Superficual to fibularis brevis
- Attachments:
– Proximal: Head and superolateral 2/3 of fibula – Passes inferior just posterior to lateral malleolus – Runs obliquely and distally across sole of foot to attach distally to first metatarsal and medial cuneiform bone.
• Functions: – Eversion and plantar flexion
cuboid sulcus is for?
groove for fibularis longus
Fibularis Brevis Muscle
- Deep to fibularis longus
- Attachments:
– Proximal: Inferolateral 2/3 of tibia – Descends posterior to lateral malleolus
– Distal: dorsal surface of tuberosity on lateral side of fifth metatarsal
• Functions:
– Eversion – Plantarflexion
Superficial Fibular Nerve
- One of the two terminal branches of the common fibular nerve.
- Begins between fibularis longus and fibula.
- Descends between fibular muscles and lateral to extensor digitorum longus
- Becomes superficial in distal third of leg to supply: – Anteroinferior leg – Nearly the entire dorsal surface of the foot – Most of the dorsal aspect of the digits
Clinical Anatomy: Common Fibular Nerve
- Common fibular nerve winds superficially around fibular head – most commonly injured lower extremity nerve
- Injury results in paralysis of all anterior and lateral crural muscles
- Loss of dorsiflexion and eversion causes “foot-drop:” – Difficult to achieve heel strike – Patient has high stepping gait, waddling gait, or a swing-out gait – If leg swung strongly forward the foot strikes with a “clop” – Loss of sensation along anterolateral leg and dorsum of foot
Lateral Compartment: Arterial Supply
• Branches that pass anteriorly from the fibular artery. The one compartment without a distinct arterial branch accompanying the compartment nerve.
– Fibular artery = largest branch of posterior tibial artery
Clincial Anatomy: Crural Fascia
Leg compartmental syndromes
– Septa are very tough
– Trauma may lead to hemorage, edema, & inflammation
– Intracompartmental pressure may lead to ischemia and permanent injury
– Incising fascia (Fasciotomy) may be performed to relieve pressure.
Shin Splints
- Due to repetitive microtrauma to tibialis anterior
- Inducing small tears to periosteum over tibia
- and/or tears to overlying deep fascia
- Is a mild form of compartmental syndrome (swelling of tibialis anterior due to repetitive ground reaction force).
summary of all leg compartments
