Unit 1 Lecture 8: Muscles of the Leg & Foot

Question 1

Crural Fascia

Answer 1

deep fascia that invest the leg

Question 2

Fascia

Answer 2

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

Question 3

Muscles of the Leg

Answer 3

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.

Question 4

Crural refers to ______ .

Answer 4

LEG

Question 5

Muscles of Anterior Leg

Answer 5

1. Tibialis Anterior: Dorsiflexor AND a minor invertor of the foot
2. Extensor Digitorum Longus:
   Extends the digits 2-5**. Dorsiflexor of foot.
3. Extensor hallucis longus:
   Extends the big toe (the halux).
   Dorsiflexor of foot.
4. 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!!!

Question 6

The MAIN fooT Evertors are in the ______ Compartment

Answer 6

Lateral crural

Question 7

The MAIN Foot Invertors are part of the ____ compartment

Answer 7

Deep Posterior Crural

Think “Dip”

Question 8

Muscles of the Leg – Anterior

Actions

Answer 8

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

Question 9

Muscles of the lateral compartment of the leg:

Answer 9

Fibularis (peroneus) longus
Fibularis (peroneus) brevis

Actions:
Plantar flexes foot (minorly)
Everts foot (majorly)

Innervation
Superficial fibular (peroneal) nerve

Question 10

Muscles of Posterior Leg

Answer 10

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

Question 11

Superficial Posterior Leg Muscles: VERY IMPORTANT as Foot _____

Answer 11

Superficial group: VERY IMPORTANT as Foot PLANTAR FLEXORS

Question 12

The muscles of the posterior compartment of the leg, superficial group:

Answer 12

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.

Question 13

triceps surae.

Answer 13

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…

Question 14

Muscles of Leg – Posterior (Superficial)

Actions

Answer 14

Gastrocnemius
Plantar flexes foot (ankle)
Flexes leg (knee)

Soleus
Plantar flexes foot (ankle)

Plantaris
Plantar flexes foot (ankle)
Flexes leg (knee)

Question 15

The muscles of the posterior compartment of the leg, deep group:

Answer 15

Popliteus
Flexor hallucis longus
Flexor digitorum longus
Tibialis posterior

All the posterior crural muscles are innervated by the tibial nerve.

Question 16

Muscles of Posterior Leg (Deep):

Actions

Answer 16

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

Question 17

Drop Foot

Answer 17

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.

Question 18

Muscles of the Foot

Answer 18

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

Question 19

Extensor digitorum brevis

Answer 19

Action: Extends digits 1-4 **

Innervation:
Deep fibular (peroneal) nerve

Question 20

Muscles of the Foot: Plantar

Answer 20

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

Question 21

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.

Answer 21

fibularis longus m.