Knee and Leg Muscles Flashcards
Posterior Leg Muscles - name the two compartments
- Superficial:
1. Gastrocnemius
2. Soleus
3. Plantaris - Deep Muscles:
1. Popliteus
2. Tibialis Posterior
3. Flexor Hallucis Longus
4. Flexor Digitorum
Gastrocnemius Muscle Origin
2 heads: Medial head is larger and more extensive
Medial head: Posterior surface of distal femur just superior to medial condyle
Lateral Head: Upper posterolateral surface of lateral femoral condyle
Two heads merge at inferior margin of popliteal fossa
Gastrocnemius Muscle Insertion
Posterior surface of calcaneus via calcaneal tendon
Gastrocnemius Muscle Innervation
Tibial Nerve (S1, S2)
Gastrocnemius Muscle Action
- Foot plantar flexion
- Knee flexion
Soleus Muscle Origin
- Upper 1/4 posterior surface of fibula and posterior aspect of head of fibula
- Soleal line of tibia and middle 1/3 medial border of tibia
- Tendinous arch formed between tibial and fibular attachments
Soleus Muscle Insertion
Posterior surface of calcaneus via calcaneal tendon
Soleus Muscle Innervation
Tibial Nerve (S1/S2)
Soleus Muscle Action
Floot Plantar Flexion
Plantaris Muscle Origin
Inferior aspect lateral supracondylar line of femur and oblique popliteal ligament
Plantaris Muscle Insertion
Medial border of calcaneal tendon at insertion to calcaneus
Plantaris Muscle Innervation
Tibial Nerve (S1/S2)
Plantaris Muscle Action
- Foot Plantar flexion
- Knee Flexion
Popliteus Muscle Origin
Lateral surface of lateral condyle of femur by cord like tendon that penetrates the fibrous membrane of the knee joint
Popliteus Muscle Insertion
Posterior surface of tibia, proximal to soleal line
Popliteus Muscle Innervation
Tibial Nerve (L4-S1)
Popliteus Muscle Action
- Knee Flexion
- Unlocks the knee joint as it begins to flex. (Lateral rotation of femur when foot is fixed)
Flexor Hallucis Longus Muscle Origin
Inferior 2/3rds posterior surface of fibula and interosseous membrane
Flexor Hallucis Longus Muscle Insertion
Plantar surface of distal phalanx of great toe; tendon travels through groove on posterior talus and runs underneath sustentaculum tali.
Flexor Hallucis Longus Muscle Innervation
Tibial Nerve (S2/S3)
Flexor Hallucis Longus Muscle Action
- Great toe flexion
- Assists with foot plantar flexion
- Foot inversion.
Flexor Digitorum Longus Muscle Origin
Medial - Posterior surface tibia, distal to soleal line (about middle 1/3rd)
Flexor Digitorum Longus Muscle Insertion
Base of distal phalanges, toes 2-5, plantar surface
Flexor Digitorum Longus Muscle Innervation
Tibial Nerve (S2/S3)
Flexor Digitorum Longus Muscle Action
- Toes 2-5 flexion
- Assists with foot plantar flexion
- Foot inversion.
What are the muscles of the anterior compartment of the leg?
- Tibialis Anterior
- Extensor Hallusic Longus
- Extensor Digitorum
- Fibularis (Peroneus) tertius
Tibialis Anterior Muscle Origin
Lateral condyle, proximal 2/3s lateral surface of tibia and interosseous membrane
Tibialis Anterior Muscle Insertion
Medial and inferior surface of medial cuneiform and plantar base of 1st metatarsal bone
Tibialis Anterior Muscle Innervation
Deep Peroneal Nerve (L4/L5)
Tibialis Anterior Muscle Action
- Foot Dorsiflexion
- Foot Inversion
- Helps support medial arch of foot during walking
Extensor Hallucis Longus Muscle Origin
Middle 1/2 medial surface of fibula and interosseous membrance
Extensor Hallucis Longus Muscle Insertion
Dorsal Base, distal phalanx of great toe
Extensor Hallucis Longus Muscle Innervation
Deep Peroneal Nerve (L5/S1)
Extensor Hallucis Longus Muscle Action
- Great toe extension
- Foot dorsiflexion