LE Posterior Leg Flashcards
Posterior Compartment of Leg
- Largest of the 3 leg compartments
- Calf muscles are divided into superficial & deep groups by the transverse intermuscular septum
- Innervated by the tibial nerve (L4-S3)
- Blood supply - posterior tibial artery/vein
- Superficial Group - Gastrocnemius, Soleus, & Plantaris muscles
- Deep Group - Popliteus, FDL, FHL, & Tibialis Posterior muscles
**gastroc/soleus on top of these deep ms in pic**
Gastrocnemius
FROM: proximal (2 heads); biarticular
LATERAL HEAD: from the lateral aspect of the lateral condyle of femur
MEDIAL HEAD: from the popliteal surface of the femur, superior to the medial condyle
TO: the posterior surface of calcaneus via calcaneal tendon(pretty wide)
AXN: PF ankle; flex the knee joint. Eversion/inversion almost in neutral ankle position (depends on start position how it functions)
*IS A 2 JOINT MS*
INNERVATION: Tibial Nerve (L4-S3)
Triceps Surae – gastroc and soleus combined; have a common calcaneal tendon (aka Achilles)
*superficial group
Soleus
FROM: post aspect head of fibula, sup 1/4 of post surface of fibula, and soleal line of tibia & medial border of tibia
*below the knee!!!*
TO: the post surface of calcaneus via calcaneal tendon
INNERVATION: Tibial n. (S1, S2)
AXN: PF ankle (regardless of knee position), inversion, no influence on knee
**Proximal attachment is below knee; therefore, no knee action influence** so when want to stretch it, must isolate from gastroc by bending knee
*superficial group
Plantaris
- “Fools Nerve”
FROM: inferior end of lateral supracondylar line of femur & oblique popliteal ligament
TO: posterior surface of calcaneus via calcaneal tendon
AXN: weak assist in PF of ankle, & weak flexion of knee, very small influence
INNERVATION: Tibial N. (S1, S2)
*is 2 joint ms: knee and ankle jts*
-Often absent in 10-15%; is used commonly for grafting during reconstructive surgery (thats how insignificant it is)
*superficial group, superficial to soleus, deep to gastroc!*
Popliteus
- thin, triangular muscle forms the inferior part of floor of popliteal fossa
FROM: lateral surface of lateral condyle of femur and lateral meniscus
TO: posterior surface of tibia, superior to soleal line
AXN: weakly flexes the knee; with foot free off ground can help with IR tibia on femur (unlocks knee)
INNERVATION: Tibial N. (L4,5, S1)
*1 jt muscle*
*deep group*
Flexor Digitorum Longus (FDL)
FROM: medial part of the posterior surface of tibia, inferior to soleal line
TO: base of distal phalanges of lateral 4 toes
AXN: flexes lateral 4 digits (digits 2-5); PF ankle, inversion of foot; supports longitudinal arch of foot
INNERVATION: Tibial N. (S2, S3)
- Intrinsic foot muscles attach(extrinsic (crosses joints) vs intrinsic (starts and stops in same area):
- Quadratus plantae inserts on FDL
- Lumbricales arise from it
Flexor Hallicus Longus (FHL)
FROM: inferior 2/3 of post surface of fibula, & inf part of interosseous membrane
TO: plantar surface, base of distal phalanx of great toe
AXN: flexes great toe; PF ankle; inversion of foot; supports medial long arch
-Powerful “push-off” muscle during walking
INNERVATION: Tibial N. (S2, S3)
-tendon runs between 2 sesamoid bones in the tendons of the flexor hallicus brevis; sesamoid bones protect FHL tendon from repeated pressure of weight bearing at the 1st MT
Tibialis Posterior
FROM: interosseous membrane, post surface of tibia inferior to soleal line, & post surface of fibula
TO: tuberosity of navicular, all cuneiform bones, sustentaculum tali, cuboid, & base of 2nd, 3rd, & 4th MT
*All of the tarsal bones except the talus
AXN: main invertor of foot, PF of ankle; resists the collapse of the arch main supporter
INNERVATION: Tibial Nerve (L4, L5)
Posterior medial mallolus tendons
*Ant to Post at level of medial malleolus*
Tom - tibialis posterior
Dick – FDL
A Very Naughty – Posterior tibial a/v, tibial n
Harry - FHL
*anterior to malleolus on medial side is Ant tib and EHL (ant tib is more medial)*
Extensor Digitorum Brevis
FROM: the floor of the sinus tarsi of the calcaneous and the ext retinaculum
TO: Divides to the lateral 4 toes
AXN:: aids EDL in extending 4 medial toes at the MTP joints
INNERVATION: Deep peroneal n.
*on dorsum of foot*
Extensor Hallicus Brevis
FROM (Same as EDB): the floor of the sinus tarsi of the calcaneous and the ext retinaculum
TO: dorsal aspect of base of prox phalanx of great toe/hallux
AXN: aids the EHL in extending great toe at the MTP(bc of insertion)
INNERVATION: Deep peroneal n.
*dorsum of foot*
Pedal Pulse
- Just distal to med/lat malleoli
- Between 1st and 2nd metatarsal
*anterior tibial artery (ends as dorsalis pedis artery)
-travels with the deep peroneal n. which becomes cutaneous and provides sensation to webspace between great toe and 2nd toe
Plantar fascia
- Deep fascia of the plantar foot
- Has a thick central part (plantar aponeurosis) and weaker medial/lateral part (entire foot, everywhere arrows are going)
- Role of plantar fascia:
- Holds foot together
- Protects plantar surface from injury
- Supports longitudinal arches of foot
- Plantar Aponeurosis- fascia gets thick in the center
FROM: calcaneous
TO: divides into five bands and becomes continuous with tendon sheath of each toe
Plantar Layer #1
ABD Sammich
•Abductor Hallucis - med plantar n.
- Flexor Digitorum Brevis - med plantar n.
- Abductor Digiti Minimi - lateral plantar n.
Plantar Layer #2
Quadratus Plantae -Lateral plantar n.
AXN: Assists in flexing lateral 4 digits
(4) Lumbricals – axn same as hand (flex MTP, ext IPs)
- 1st lumbrical* – medial plantar n.
- lateral 3* - lateral plantar n.
*Attach to the FDL and FHL*
Medial vs Lateral Plantar n.
Medial Plantar NN
- Larger and more anterior of two terminal branches of the tibial nerve
**Digits 1,2,3, half of 4th is medial plantar nerve**
Lateral Plantar NN
- Smaller and more posterior of the two terminal branches of the tibial nerve
*Border between med/lat plantar nn is along the 4th metatarsal*
Quadtraus PLantae and lumbrical attachments
Quadratus Plantae and Lumbricals insert onto FHL tendon and FDL tendons
Layer # 3
Flexor Hallucis Brevis - med plantar n. (2 heads)
Adductor Hallucis - lat plantar n. (2 heads)
Flexor Digiti Minimi Brevis - lat plantar n.
Plantar Layer # 4-Dorsal interossei
Four dorsal Interossei - lat plantar n.
Plantar Layer #4-Plantar Interossei
Three Plantar Interossei - lat plantar n.
