The lateral compartment of the leg, also known as the fibular or peroneal compartment, contains two muscles - the peroneus longus and brevis. These muscles evert the foot and plantarflex the ankle joint. The peroneus longus originates on the head of the fibula and upper lateral fibular shaft and inserts on the medial cuneiform and base of the first metatarsal. The peroneus brevis originates on the lower lateral fibular shaft and inserts on the base of the fifth metatarsal. Both muscles are supplied by the superficial peroneal nerve.

1. Lateral Compartment of the Leg

2. The lateral compartment of the leg also known as
•Fibular compartment
or
•Peroneal compartment

3. The lateral compartment of the leg also known as
•Fibular compartment
or
•Peroneal compartment
It is the smallest of the 4 compartments in the leg
It contains 2 muscles that
•evert the foot
•plantarflex the ankle joint

4. The lateral compartment of the leg also known as
•Fibular compartment
•Peroneal compartment
It is the smallest of the 4 compartments of the leg
It contains 2 muscles that
•evert the foot
•plantarflex the ankle joint
1. Fibularis or Peroneus Longus
2. Fibularis or Peroneus Brevis

5. Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L

6. Tibi
a
Fibula
Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L

7. Septum
Septum
Interosseous
membrane
Tibi
a
Fibula
Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L

8. Tibi
a
Fibula
Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L
Deep Posterior
Compartment

9. Tibi
a
Fibula
Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L
Deep Posterior
Compartment

10. Tibi
a
Fibula
Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L
Superficial Posterior
Compartment
Deep Posterior
Compartment

11. Tibi
a
Fibula
Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L
Deep Posterior
Compartment
Superficial Posterior
Compartment
Anterior Compartment

12. Tibi
a
Fibula
Cross Section through middle of right leg looking up from foot
anterioranterior
posteriorposterior
L
A
T
E
R
A
L
M
E
D
I
A
L
Superficial Posterior
Compartment
Deep Posterior
Compartment
Lateral
Compartment
Anterior Compartment

13. Fibularis or Peroneus Longus
Arises from
-Head of the Fibula
-Upper 2/3rds of the lateral surface
of the Fibula

14. Arises from
-head of the fibula and the
-upper 2/3rds of the lateral surface
of the fibula
The tendon runs obliquely in
the sole of the foot and inserts
onto the
-Medial cuneiform
-base of 1st
metatarsal
Fibularis or Peroneus Longus

15. Fibularis or Peroneus Brevis
Arises from the lower 2/3rds of the
lateral surface of the shaft of the Fibula
Where the muscles
overlap, Peroneus Brevis
is the anterior one and
Peroneus Longus is the
posterior one.

16. Arises from the lower 2/3rds of the lateral
surface of the shaft of the fibula
Inserts onto the styloid process
at the base of the 5th
metatarsal
Fibularis or Peroneus Brevis
Where these muscles
overlap, Peroneus Brevis
is the anterior one and
Peroneus Longus is the
posterior one.

17. Where the two tendons overlap
behind the lateral malleolus
Peroneus Brevis lies anterior to
Peroneus Longus
To help you remember,
think of Peroneus Longus as
‘Lounging Behind’!

18. Peroneus Brevis
lies anterior to
Peroneus Longus
Peroneus LongusPeroneus Longus
tendontendon
Peroneus Brevis tendonPeroneus Brevis tendon
Lateral MalleolusLateral Malleolus
(distal end of Fibula)(distal end of Fibula)

19. Both muscles are supplied by the
Superficial Peroneal Nerve
a terminal branch of the
Common Peroneal Nerve

20. Both muscles are supplied by the
Superficial Peroneal Nerve
a terminal branch of the
Common Peroneal Nerve
It has an extensive sensory distribution to the
•anterolateral aspect of distal part of the leg
•dorsum of the foot

21. Both muscles are supplied by the
Superficial Peroneal Nerve
a terminal branch of the
Common Peroneal Nerve
It is sometimes referred to as the
Musculocutaneous Nerve of the Leg
It has an extensive sensory distribution to the
•anterolateral aspect of distal part of the leg
•dorsum of the foot

22. Summary of Muscles

23. Peroneus or Fibularis Longus
Origin Head of fibula, upper 2/3rds of
lateral fibular shaft surface
Insertion Plantar posterolateral aspect of
medial cuneiform and lateral side
of 1st metatarsal base
Action Everts foot and plantar flexes
ankle, supports the transverse
arch of the foot
Nerve Supply Superficial peroneal nerve (L5, S1,
S2)
Blood Supply Anterior tibial and peroneal
arteries
Lateral Leg

24. Peroneus or Fibularis Brevis
Origin Lower 2/3rds of lateral fibular
surface;
Insertion Lateral surface of styloid process
of 5th metatarsal base
Action Everts foot and plantar flexes
ankle
Nerve Supply Superficial peroneal nerve (L5, S1,
S2)
Blood Supply Muscular branches of peroneal
artery
Lateral Leg