Gross Anatomy-Muscles of Anterior Compartment Flashcards
Describe the Muscles of Anterior Compartment
- Consists of 4 muscles
- Elevate foot and depress heel (dorsiflexion)
What are the **4 muscles of Anterior Compartment **
- Tibialis Anterior (TA)
- Extensor Digitorum Longus (EDL)
- Fibularis Tertius
- Extensor Hallucis Longus (EHL)
Describe the Tibialis Anterior (TA)
of the Anterior Compartment
- Most medial and superficial dorsiflexor
- Lies against lateral surface of tibia
- Tendon has its own synovial sheath
- Strongest dorsiflexor
- O: Lateral condyle and superior ½ of lateral surface of tibia and interosseous membrane
- I: Medial and inferior surfaces of medial cuneiform and base of 1st metatarsal
- A: Dorsiflexion and inversion
- N: Deep fibular (peroneal) n. (L4, L5)
- B: Anterior tibial a.
- TA and TP are synergists for inversion
- To test TA:
- Stand on heels or dorsiflex against resistance
- Normally, tendon can be seen and palpated
- Tests integrity of deep fibular n.
Describe the** Extensor Digitorum Longus (EDL) **
of the Muscles of Anterior Compartment
- Most lateral of anterior leg muscles
- Forms 4 tt. that attach to phalanges
- Has common synovial sheath with FT
- Each tendon forms extensor expansion
- Over proximal phalanx of toe
- Each extensor tendon divides into a median band and two lateral bands
- Median band passes to base of proximal phalanx
- Lateral bands pass to base of distal phalanx
O: Lateral condyle of tibia and superior ¾ of medial surface of fibula and interosseous
membrane
I: Middle and distal phalanges of lateral 4 digits
A: Extension of lateral 4 digits and dorsiflexion
N: Deep fibular n. (L4, L5)
B: Anterior tibial a.
How do you Test the EDL
• To test EDL:
- Four toes dorsiflexed against resistance
- Normally, tendons can be seen and palpated
- Tests integrity of deep fibular n.
Describe the Fibularis Tertius
of the Muscles of Anterior Compartment
• Separated part of EDL
- Continuous proximally
- Separate tendon distally
• Not always present
- **O: ** Inferior 1/3 of anterior surface of fibula and interosseous membrane
- **I: ** Dorsum of base of 5th metatarsal
- **A: ** Dorsiflexion and aids in eversion
- N: Deep fibular n. (L4, L5)
- **B: ** Anterior tibial a.
Describe the Extensor Hallucis Longus (EHL)
of the Muscles of Anterior Compartment
- Thin muscle
- Lies deep between TA and EDL at its superior attachment
- Rises to surface in distal 1/3 of leg
- Deep fibular n. and anterior tibial a. found between EHL and TA
- O: Middle part of anterior surface of fibula and interosseous membrane
- I: Dorsal aspect of base of distal phalanx of great toe (hallux)
- A: Extension of great toe and dorsiflexion
- N: Deep fibular n. (L4, L5)
- B: Anterior tibial a.
Vasculature of Anterior Compartment
Describe the Arteries
• Arteries –
o Anterior tibial a. – from popliteal a.
- Passes from posterior to anterior via gap in interosseous membrane
- Runs with deep fibular n.
- Anterior tibial recurrent a. –
• To genicular anastomosis
- Perforating branches –
• Help supply lateral compartment
- Descends between TA and EHL, then EDL
- Supplies anterior compartment
- Medial and lateral malleolar branches –
• Supply ankle
- Terminates as dorsalis pedis a.
Vasculature of the Anterior Compartment
Describe the Veins
• Veins –
o Anterior tibial v. –
- Drains into posterior tibial v.
Innervation of Anterior Compartment
name 2
Deep fibular n.
Saphenous n.
Describe the Deep fibular n.
of the Innervation of Anterior compartment
• Deep fibular n. – terminal branch of common fibular n.
- Also known as deep peroneal n.
- Runs with anterior tibial a.
- Supplies anterior compartment mm.
- Terminates as:
- Lateral branch of deep fibular n.
- Medial branch of deep fibular n.
Describe the Saphenous n.
of the Innervation of Anterior compartment
o Runs with great saphenous v.
o Supplies skin of anteromedial and posteromedial leg
What is a Tibialis Anterior Strain
(Shin Splints)
• Mild form of anterior compartment syndrome
• Result from repetitive microtrauma to tibialis anterior m.
- Causes small tears in periosteum of tibia and/or fleshy attachments to overlying deep fascia
- Due to overexertion of muscles by untrained person
- Edema and pain usually in the distal 2/3 of tibia
- Can decrease blood flow to area
*little note:Teresa had these one year very badly trained too hard too fast!!!! They are not not not fun ;[ they hurt =[
Discribe the Injury to Deep Fibular n.
• Can be injured by lacerations, tight fitting ski boots or anterior compartment syndrome
- Often called “ski boot syndrome”
- Causes pain in anterior compartment
- High lesion (proximal) would affect:
- Dorsiflexion
- Inversion
- Sensory loss to area between 1st and 2nd toes
• Low lesion (distal) would affect:
- Pain in dorsum of foot
- Sensory loss between 1st and 2nd toes
* note Don’t tie your shoes or boots so tight maybe retie them part way through the day =p
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dont forget to BREATHE!!!
DEEP BREATHS
**IN AND OUT **
YEP YOUR DOING GREAT!!
