Anterior Thigh Muscles 3

Note: Arrows indicate

direction of action
of iliopsoas muscle

Adductors 1

A. Iliopsoas muscle
3

Quadriceps
femoris tendon
Patella

Sartorius
Patellar ligament Patella tendon
(cut)
Patellar ligament
Tibial tuberosity Tibial tuberosity

B. Anterior view C. Anterior view, deep dissection

Netter’s Anatomy Coloring Book Plate 3-27

3 Medial Thigh Muscles

The thigh is divided into three muscle compartments by con-

nective tissue intermuscular septae. The muscles of the medial COLOR the following muscles, using a different color for
compartment primarily adduct the lower limb at the hip. Several each muscle:
muscles cross both the hip and knee joints and act on both n 1. Pectineus
joints. These muscles are summarized in the table below. n 2. Adductor longus
n 3. Gracilis
n 4. Adductor brevis: lies deep to the adductor longus
(cut in illustration)
n 5. Obturator externus: lies very deep in the thigh
n 6. Adductor magnus: the most powerful adductor of
the hip

PROXIMAL ATTACH­ DISTAL ATTACHMENT

MUSCLE MENT (ORIGIN) (INSERTION) INNERVATION MAIN ACTIONS
Pectineus Superior ramus of pubis Pectineal line of femur, just infe- Femoral nerve; may receive Adducts and flexes thigh at hip;
rior to lesser trochanter a branch from obturator assists with medial rotation of
nerve (L2-L4) thigh
Adductor longus Body of pubis inferior Middle third of linea aspera Obturator nerve (L2-L4) Adducts and medially rotates
to pubic crest of femur thigh at hip
Adductor brevis Body and inferior ramus Pectineal line and proximal part Obturator nerve (L2-L4) Adducts thigh at hip and to some
of pubis of linea aspera of femur extent flexes it
Adductor magnus Inferior ramus of pubis, Gluteal tuberosity, linea aspera, Adductor part: obturator Adducts thigh at hip; A­ dductor
r­ amus of ischium, and medial supracondylar line nerve (L2-L4) part: also flexes thigh at hip;
ischial tuberosity (adductor part), and adductor Hamstring part: tibial part ­Hamstring part: extends thigh
tubercle of femur (hamstring of sciatic nerve
part)
Gracilis Body and inferior ramus Superior part of medial surface Obturator nerve (L2-L3) Adducts thigh at hip, flexes leg at
of pubis of tibia knee and helps rotate it medially
Obturator externus Margins of obturator Trochanteric fossa of femur Obturator nerve (L3-L4) Rotates thigh laterally at hip;
foramen and obturator steadies femoral head in
membrane ­acetabulum

Clinical Note:
A “groin pull” is a common athletic injury and is a stretching or
tearing of one or more of the adductor muscles in the medial
compartment of the thigh. The adductor longus and magnus are
especially vulnerable.

Plate 3-28 See Netter: Atlas of Human Anatomy, 6th Edition, Plates 479 and 480 Muscular System
 Medial Thigh Muscles 3
Iliopsoas

2
4

5
4

2 6

Patella

Patellar ligament

A. Anterior view B. Anterior view, deep dissection

Netter’s Anatomy Coloring Book Plate 3-28

3 Anterior and Lateral Leg Muscles

The leg is divided into three muscle compartments by connec-

tive tissue intermuscular septae. The muscles of the anterior COLOR the following muscles, using a different color for
compartment: each muscle:
• Dorsiflex the foot at the ankle joint n 1. Fibularis longus: the tendon crosses deep within
• Extend the toes the sole and inserts into the 1st metatarsal
• Invert (turn the sole inward) the foot n 2. Tibialis anterior

Realize that the muscles of the lower limb are just the reverse of
n 3. Fibularis brevis: the tendon inserts into the 5th
metatarsal
the upper limb. Lower limb flexors are in the posterior compart-
ments (anterior compartment in the upper limb) and extensors n 4. Extensor digitorum longus
are in the anterior compartments (posterior compartment in the n 5. Extensor hallucis longus (“hallucis” refers to the big
upper limb). This arrangement occurs because of the different toe)
way the limbs rotate during embryonic development. n 6. Fibularis tertius: tendon only; muscle deep
to extensor digitorum longus
The muscles of the lateral compartment primarily evert (turn the
sole outward) the foot. The muscles of these two compartments
are summarized in the table below.

PROXIMAL ATTACH­ DISTAL ATTACHMENT

MUSCLE MENT (ORIGIN) (INSERTION) INNERVATION MAIN ACTIONS
Tibialis anterior Lateral condyle and superior Medial and inferior surfaces Deep fibular (peroneal) Dorsiflexes foot at ankle
half of lateral surface of tibia of medial cuneiform and nerve (L4-L5) and inverts foot
base of first metatarsal
Extensor hallucis Middle part of anterior surface Dorsal aspect of base Deep fibular (peroneal) Extends great toe
longus of fibula and interosseous of distal phalanx of nerve (L5-S1) and dorsiflexes foot
­membrane great toe at ankle
Extensor digitorum Lateral condyle of tibia and Middle and distal phalanges Deep fibular (peroneal) Extends lateral four digits
longus s­ uperior three fourths of of lateral four digits nerve (L5-S1) and dorsiflexes foot
­anterior surface of interos­­ at ankle
seous ­membrane and fibula
Fibularis (peroneus) Inferior third of anterior ­ Dorsum of base of 5th Deep fibular (peroneal) Dorsiflexes foot at ankle
tertius surface of fibula and ­metatarsal nerve (L5-S1) and aids in eversion of foot
­interosseous ­membrane
Fibularis (peroneus) Head and superior two thirds Base of first metatarsal Superficial fibular Everts foot and weakly
longus of lateral surface of fibula and medial cuneiform (­peroneal) nerve ­ lantarflexes foot at ankle
p
(L5-S2)
Fibularis (peroneus) Inferior two thirds of lateral Dorsal aspect of tuberosity on Superficial fibular Everts foot and weakly
brevis surface of fibula lateral side of 5th metatarsal (­peroneal) nerve ­ lantarflexes foot at ankle
p
(L5-S2)

Clinical Note:
Anterior compartment syndrome (sometimes called anterior
shin splints) occurs from excessive contraction of anterior com-
partment muscles. The pain over these muscles radiates down
the ankle and onto the dorsum of the foot overlying the extensor
tendons. This condition is usually chronic and swelling of the
muscle in the tightly ensheathed muscular compartment may
lead to nerve and vascular compression. In the acute syndrome
(rapid, unrelenting swelling), the compartment may have to be
opened surgically (fasciotomy) to relieve the pressure.

Plate 3-29 See Netter: Atlas of Human Anatomy, 6th Edition, Plates 506, 507, and 515 Muscular System
 Anterior and Lateral Leg Muscles 3

1st
Head of Head of metatarsal
fibula fibula bone

1
Medial
2 2 cuneiform
bone
Fibularis
(peroneus)
1 longus tendon

3 4

4 Tibia

C. Plantar view

5 3

Fibula

Superior
extensor
retinaculum Fibula

Lateral Medial
malleolus malleolus
Lateral
6 malleolus

A. Superficial dissection 6
Fibularis (peroneus) longus
tendon passing to sole of foot
B. Lateral view Fibularis (peroneus)
brevis tendon

Netter’s Anatomy Coloring Book Plate 3-29

3 Posterior Leg Muscles

The leg is divided into three muscle compartments by connec-

tive tissue intermuscular septae. The muscles of the posterior COLOR the following muscles, using a different color for
compartment: each muscle:
• Plantarflex the foot at the ankle joint n 1. Plantaris (muscles 1-3 of this list comprise the
• Flex the toes superficial group)
• Invert (turn the sole inward) the foot n 2. Gastrocnemius: lateral and medial heads, the “calf”
muscle
The muscles of the posterior compartment are arranged into a
superficial and a deep group. The superficial group of muscles
n 3. Soleus

all merge their tendons of insertion into a strong calcaneal (Achil- n 4. Popliteus
les) tendon that attaches to the heel (calcaneal tuberosity). These n 5. Flexor digitorum longus
muscles are summarized in the table below. n 6. Tibialis posterior
n 7. Flexor hallucis longus (“hallucis” refers to the big toe)

PROXIMAL ATTACHMENT DISTAL ATTACHMENT

MUSCLE ­(ORIGIN) (INSERTION) INNERVATION MAIN ACTIONS
Gastrocnemius Lateral head: lateral aspect Posterior aspect of calcaneus Tibial nerve (S1-S2) Plantarflexes foot at ankle; raises
of lateral condyle of femur via calcaneal tendon heel during walking; flexes leg at
Medial head: popliteal surface knee joint
of femur, superior to medial condyle
Soleus Posterior aspect of head of fibula, superior Posterior aspect of calcaneus Tibial nerve (S1-S2) Plantarflexes foot at ankle;
fourth of posterior surface of fibula, soleal via calcaneal tendon steadies leg on foot
line, and medial border or tibia
Plantaris Inferior end of lateral supracondylar line Posterior aspect of calcaneus Tibial nerve (S1-S2) Weakly assists gastrocnemius in
of femur and oblique popliteal ligament via calcaneal tendon (tendo plantarflexing foot at ankle and
calcaneus) flexing knee
Popliteus Lateral epicondyle of femur and lateral Posterior surface of tibia, Tibial nerve (L4-S1) Weakly flexes leg at knee and
meniscus superior to soleal line unlocks it
Flexor hallucis Inferior two thirds of posterior surface of Base of distal phalanx Tibial nerve (S2-S3) Flexes great toe at all joints and
longus fibula and inferior interosseous membrane of great toe (big toe) weakly plantarflexes foot at ankle;
supports longitudinal arches of
foot
Flexor digitorum Medial part of posterior surface of Bases of distal phalanges Tibial nerve (S2-S3) Flexes lateral four digits and plan-
longus tibia ­inferior to soleal line, and from of lateral four digits tarflexes foot at ankle; supports
fascia ­covering tibialis posterior longitudinal arch of foot
Tibialis posterior Interosseous membrane, posterior surface Tuberosity of navicular, cunei- Tibial nerve (L4-L5) Plantarflexes foot at ankle and
of tibia inferior to soleal line, and posterior form, and cuboid and bases of inverts foot
surface of fibula metatarsals 2, 3, and 4

Clinical Note:
“Shin splints” refers to pain along the inner distal two thirds
of the tibial shaft and is a common syndrome in athletes. The
primary cause is repetitive pulling of the tibialis posterior tendon
as one pushes off the foot during running.
Tendinitis of the calcaneal (Achilles) tendon is a painful inflam-
mation that often occurs in runners who run on hills or uneven
surfaces. Repetitive stress on the tendon occurs as the heel
strikes the ground and when plantarflexion lifts the foot and
toes. This is the strongest muscle tendon in the body. Rupture
of the tendon is a serious injury, because the avascular tendon
heals slowly. In general, most tendon injuries heal more slowly
because of their avascular nature.

Plate 3-30 See Netter: Atlas of Human Anatomy, 6th Edition, Plates 503 to 505 Muscular System
 Posterior Leg Muscles 3

1
1

3
2

3 3

7
Calcaneal (Achilles) Calcaneal (Achilles)
tendon tendon
Hook

Calcaneal tuberosity
A. Posterior view, superficial dissection C. Posterior view, intermediate dissection

Flexor digitorum longus tendon

Flexor retinaculum

Tibialis posterior tendon

Flexor digitorum tendon
Flexor hallucis longus tendon

B. Posterior view

Netter’s Anatomy Coloring Book Plate 3-30