Compartments of the Leg Flashcards
Describe the screw home mechanism of the knee.
When the knee is fully extended, the tibia rotates laterally (due to the medial condyle being longer) which locks the knee into a more stable position.
To flex the knee, the popliteus ________ rotates to ______ the knee and allow it to flex.
Medially
Unlock
Which muscle is the key to the knee?
Popliteus
Fascia that helps divide the leg into compartments, in correlation with the tibia, fibula, and interosseous membrane.
Intermuscular Septa
What are the 4 compartments of the leg?
1) Anterior Compartment
2) Lateral Compartment
3) Superficial Posterior Compartment
4) Deep Posterior Compartment
The muscles in a compartment of the leg share the same general ________, nerve supply, and _____ supply.
Function
Blood
What are the 4 muscles in the anterior compartment of the leg?
1) Tibialis Anterior
2) Extensor Hallucis Longus
3) Extensor Digitorum Longus
4) Peroneus Tertius
Proximal Attachment: anterior, lateral, superior 1/2 of tibia, interosseous membrane
Distal Attachment: base of 1st MT, 1st (medial) cuneiform on plantar surface
Tibialis Anterior
What are the 2 actions of tibialis anterior?
1) Dorsiflexion
2) Inversion
Proximal Attachment: anterior middle fibula and interosseous membrane
Distal Attachment: base of distal phalanx of 1st toe on dorsal surface
Extensor Hallucis Longus
What are the 3 actions of extensor hallucis longus?
1) Extension of MTP/IP of 1st digit
2) Assist in dorsiflexion
3) Assist in inversion
Proximal Attachment: proximal 3/4 of anterior fibula, interosseous membrane
Distal Attachment: middle and distal phalanges of lateral 4 toes on dorsal surface
Extensor Digitorum Longus
What are the 3 actions of extensor digitorum longus?
1) Extension of the MTPs/PIPs/DIPs of 2nd-5th digits
2) Dorsiflexion
3) Eversion
Proximal Attachment: anterior distal fibula
Distal Attachment: base of 5th MT on dorsal surface
Peroneus Tertius
What are the 2 actions of peroneus tertius?
1) Weak dorsiflexion
2) Weak eversion
What is the order of tendons from medial to lateral for the muscles of the anterior compartment of the leg?
1) Tibialis Anterior Tendon
2) Extensor Hallucis Longus Tendon
3) Extensor Digitorum Longus Tendon
A structure that prevents the tendons of the anterior compartment of the leg from bowing as the muscles contract.
Retinacula
A structure that surrounds the tendon where there is possibility of friction between the tendons and the retinacula. Consists of an outer layer of connective tissue for structure and protection with a synovial inner layer for lubrication as the tendon moves.
Tendon Sheath
What are the 2 muscles in the lateral compartment of the leg?
1) Peroneus Longus
2) Peroneus Brevis
Proximal Attachment: lateral proximal 2/3rds of fibula
Distal Attachment: base of 1st MT, 1st (medial) cuneiform on plantar surface
Peroneus Longus
What are the 2 actions of peroneus longus?
1) Plantar Flexion
2) Eversion
Which muscle passes through the tunnel formed by the extensions of the long plantar ligament?
Peroneus Longus
Peroneus longus forms a stirrup with ________ ________ at the base of the 1st MT to support the __________ arch.
Tibialis Anterior
Transverse
Proximal Attachment: lateral distal 2/3rds of fibula
Distal Attachment: tuberosity of 5th MT
Peroneus Brevis
What are the 2 actions of peroneus brevis?
1) Plantar Flexion
2) Eversion
The peroneal tendons pass behind the _______ _______ and underneath the peroneal ________.
Lateral Malleolus
Retinacula
What are the 3 muscles in the superficial posterior compartment of the leg?
1) Gastrocnemius
2) Soleus
3) Plantaris
Proximal Attachment: medial and lateral femoral condyles
Distal Attachment: calcaneus via achilles tendon
Gastrocnemius
What are the 2 actions of gastrocnemius?
1) Plantar Flexion
2) Weak Knee Flexion
Proximal Attachment: proximal posterior fibula, soleal line of tibia, middle 1/3rd of medial border of tibia
Distal Attachment: calcaneus via achilles tendon
Soleus
What is the action of soleus?
Plantar Flexion
What is the name used for gastrocnemius and soleus?
Triceps Surae
Proximal Attachment: distal lateral supracondylar ridge of femur
Distal Attachment: calcaneus not via achilles tendon
Plantaris
What are the 2 actions of plantaris?
1) Plantar Flexion
2) Weak Knee Flexion
Which weak muscle can cause significant pain if it ruptures, often with injury to the Achilles tendon?
Plantaris
The fascia of the calf is continuous with the plantar ___________.
Aponeurosis
What are the 3 muscles in the deep posterior compartment of the leg?
1) Tibialis Posterior
2) Flexor Hallucis Longus
3) Flexor Digitorum Longus
Proximal Attachment: posterior tibia, interosseous membrane, fibula
Distal Attachment: navicular tuberosity and surrounding bones (cuneiforms, cuboid, bases of 2nd-4th MTs)
Tibialis Posterior
What are the 2 actions of tibialis posterior?
1) Plantar Flexion
2) Inversion
Proximal Attachment: lower 2/3rds of posterior fibula, interosseous membrane
Distal Attachment: plantar surface of 1st distal phalanx
Flexor Hallucis Longus
What are the 2 actions of flexor hallucis longus?
1) Flexion of MTP/IP of 1st digit
2) Plantar Flexion
Proximal Attachment: posterior middle tibia
Distal Attachment: plantar surface of distal phalanges of lateral 4 toes
Flexor Digitorum Longus
What are the 2 actions of flexor digitorum longus?
1) Flexion of MTPs/PIPs/DIPs of 2nd-5th digits
2) Plantar Flexion
The tendons of the deep posterior compartment muscles of the leg pass behind the ______ _________.
Medial Malleolus
A structure that forms the tarsal tunnel, which is clinically relevant.
Flexor Retinaculum
Caused by prolonged eversion/pronation, chronic tendonitis, direct trauma, and/or rheumatoid arthritis.
Tarsal Tunnel Syndrome
What is the order of tendons from anterior to posterior for the
muscles of the deep posterior compartment of the leg?
1) Tibialis Posterior Tendon
2) Flexor Digitorum Longus
3) Flexor Hallucis Longus
