Unit 1 Lecture 8: Muscles of the Leg & Foot Flashcards
Crural Fascia
deep fascia that invest the leg
Fascia
Fascia helps to hold in the muscles, acting sort of like an elastic stocking, so that when the muscles contract, they don’t bulge too much outward.
The inward pressure of the fascia compresses deep veins, helping their blood to return to the heart
Muscles of the Leg
The muscles of the leg are divided into 3 muscles groups by connective tissue septa.
The 3 muscles groups of the leg are the anterior, lateral, and posterior crural (leg) muscles.
The posterior compartment is divided into a superficial and deep compartments.
Crural refers to ______ .
LEG
Muscles of Anterior Leg
- Tibialis Anterior: Dorsiflexor AND a minor invertor of the foot
- Extensor Digitorum Longus:
Extends the digits 2-5**. Dorsiflexor of foot. - Extensor hallucis longus:
Extends the big toe (the halux).
Dorsiflexor of foot. - Fibularis (peroneus) tertius: Dorsiflexor of foot. Minor eversion
ALL the anterior crural muscles are innervated by the deep fibular (peroneal) nerve!!!
ALL Dorsiflex the Foot!!!
The MAIN fooT Evertors are in the ______ Compartment
Lateral crural
The MAIN Foot Invertors are part of the ____ compartment
Deep Posterior Crural
Think “Dip”
Muscles of the Leg – Anterior
Actions
Tibialis anterior
Dorsiflexes foot
Inverts foot
Extensor digitorum longus
Extends digits 2-5
Dorsiflexes foot
Extensor hallucis longus
Extends hallux
Dorsiflexes foot
Fibularis (peroneus) tertius
Dorsiflexes foot
Everts foot
Dont Fib Another Lie
Muscles of the lateral compartment of the leg:
Fibularis (peroneus) longus
Fibularis (peroneus) brevis
Actions:
Plantar flexes foot (minorly)
Everts foot (majorly)
Innervation Superficial fibular (peroneal) nerve
Muscles of Posterior Leg
The muscles of the posterior compartment of the leg are divided into 2 groups by a fascial sheet:
Superficial group
Deep group
All the posterior crural muscles (i.e. superficial & deep) are innervated by the tibial nerve
Superficial Posterior Leg Muscles: VERY IMPORTANT as Foot _____
Superficial group: VERY IMPORTANT as Foot PLANTAR FLEXORS
The muscles of the posterior compartment of the leg, superficial group:
Gastrocnemius (has 2 heads).
Soleus: Does not pass the knee joint. Foot plantar flexor.
Plantaris: short muscle that crosses over the knee joint with a very long tendon
All the posterior crural muscles are innervated by the tibial nerve.
Collectively, the soleus and the 2 heads (i.e. medial & lateral) of the gastrocnemius compose the triceps surae.
triceps surae.
The soleus and the 2 heads (i.e. medial & lateral) of the gastrocnemius compose the triceps sure.
The triceps surae produces 94% of the power needed for Plantar Flexion, which is very important for Walking…
Muscles of Leg – Posterior (Superficial)
Actions
Gastrocnemius
Plantar flexes foot (ankle)
Flexes leg (knee)
Soleus
Plantar flexes foot (ankle)
Plantaris
Plantar flexes foot (ankle)
Flexes leg (knee)
The muscles of the posterior compartment of the leg, deep group:
Popliteus
Flexor hallucis longus
Flexor digitorum longus
Tibialis posterior
All the posterior crural muscles are innervated by the tibial nerve.
Muscles of Posterior Leg (Deep):
Actions
Popliteus:
Flexes leg (knee)
Unlocks knee by medially rotating the tibia
Medially rotates tibia
Flexor hallucis longus:
Flexes hallux
Plantar flexes foot
Flexor digitorum longus:
Flexes digits 2-5
Plantar flexes foot
Inverts foot
Tibialis posterior:
Plantar flexes foot
Inverts foot
Drop Foot
Foot Dorsiflexion and Foot Eversion are mostly lost if the common fibular nerve is damaged.
This leads to a condition called Drop Foot, they will have a high gait to keep from dragging toes or tripping.
Muscles of the Foot
The intrinsic muscles of the foot are divided into those found on the dorsum of the foot and those found on the plantar aspect of the foot.
They originate and insert into the foot
Extensor digitorum brevis
Action: Extends digits 1-4 **
Innervation: Deep fibular (peroneal) nerve
Muscles of the Foot: Plantar
Intrinsic muscles of the plantar aspect of the foot:
Abductor hallucis:
Action: Abducts hallux
Innervation: Medial plantar nerve
Flexor digitorum brevis:
Action: Flexes digits 2-5
Innervation: Medial plantar nerve
Abductor digiti minimi:
Action: Abducts 5th digit (pinki toe)
Innervation: Lateral plantar nerve
All of the following muscles are innervated by the deep fibular nerve EXCEPT _______.
A) extensor hallucis longus m. B)extensor digitorum longus m. C)tibialis anterior m. D)fibularis tertius m. E)fibularis longus m.
fibularis longus m.
