The small intrinsic muscles that move the toes originate on the bones of the tarsus and foot (Figure 11.21and Table 11.9). Some of the flexor muscles originate at the anterior border of the calcaneus; their muscle tone con-tributes to maintenance of the longitudinal arch of the foot.
As in the hand, the small interossei muscles (singular, interosseus) originate on the lateral and medial surfaces of the metatarsal bones. The four dorsal interossei muscles abduct the metatarsophalangeal joints of toes 3 and 4, while the three plantar interossei muscles adduct the metatarsophalangeal joints of toes 3–5.
Three intrinsic muscles of the foot move the great toe. The flexor hallucis brevis muscle flexes the great toe, while the adductor hallucis muscle adducts and the abductor hallucis muscle abducts the great toe.
Popliteus Semitendinosus
Semimembranosus
Popliteal fossa
Lateral head of gastrocnemius Gluteus maximus
Vastus lateralis covered by iliotibial tract
Biceps femoris, long head
Tendon of biceps femoris, short head
Medial head of gastrocnemius Adductor magnus
(d) Posterior view
(f) Origins and insertions, posterior view (e) Posterior view
Sartorius
Gracilis
Hamstrings
Hamstrings
Biceps femoris, short head
Biceps femoris, short head
Semimembranosus
Semimembranosus Adductor magnus
Semimembranosus Adductor
magnus
Semitendinosus
Semitendinosus
Biceps femoris, long head
Biceps femoris, long head
Adductor longus
Sartorius
Popliteus
Sartorius Rectus femoris
Psoas major Pectineus Iliacus
Vastus medialis
Vastus intermedius Vastus lateralis
Tensor fasciae latae
Origin Insertion
Figure 11.17 (continued)
Soleus Popliteus
Calcaneal tendon
Calcaneus Soleus Gastrocnemius, medial head
Gastrocnemius, lateral head
(a) Superficial muscles, posterior view
Tendon of biceps femoris Common fibular nerve
Gastrocnemius, lateral head Tendon of gracilis Tendon of semitendinosus
Gastrocnemius, medial head
Soleus Tendon of
semimembranosus
Tibial nerve
Fibularis longus
Flexor hallucis longus
Fibularis brevis
Calcaneus Calcaneal
tendon Flexor digitorum longus Tendon of tibialis posterior Gastrocnemius
(cut and removed)
(b) Posterior view Plantaris
Plantaris (cut)
Figure 11.18 Extrinsic Muscles That Move the Foot and Toes, Part I
(a) Superficial muscles of the posterior surface of the legs; these large muscles are primarily responsible for plantar flexion.
(b) Posterior view of a dissection of the superficial muscles of the right leg. (c) Posterior view of deeper muscles of the leg.
(d) A posterior view of the bones of the right leg and foot, showing the origins and insertions of selected muscles. For sectional views of the leg, see Figure 11.24c,d.
Tendon of fibularis longus
Tendon of fibularis brevis
Fibularis brevis
Head of fibula
Gastrocnemius,
medial head Gastrocnemius,
lateral head Plantaris
Soleus
Tibialis posterior Popliteus
Flexor digitorum longus
Flexor hallucis longus
Fibularis brevis
Calcaneal tendon (for gastrocnemius and soleus) Tibialis
posterior
Fibularis longus
Flexor hallucis longus
Flexor digitorum longus
(c) Deep muscles, posterior view (d) Origins and insertions, posterior view
Origin Insertion
Figure 11.18 (continued)
Inferior extensor retinaculum Superior extensor retinaculum Lateral malleolus
Tendon of extensor hallucis longus Extensor
digitorum longus Soleus
Tibialis anterior Lateral head of gastrocnemius Head of fibula
(b) Lateral view Tendon of
tibialis anterior
Abductor hallucis
Medial malleolus Calcaneal tendon
Inferior extensor retinaculum Superior extensor
retinaculum
Flexor retinaculum Soleus
Tibialis posterior Tibialis anterior Medial head of gastrocnemius Medial surface of tibial shaft Patellar ligament
Patella Iliotibial tract
(a) Medial view
Iliotibial tract
Patella
Head of fibula
Tibialis anterior
Superficial fibular nerve
Extensor digitorum longus
Lateral malleolus
Calcaneus
(c) Right lateral view, superficial muscles Inferior extensor retinaculum Calcaneal tendon Soleus Lateral head of gastrocnemius Patellar ligament Vastus lateralis
Biceps femoris, short head
Fibularis brevis Fibularis longus
Fibularis brevis Fibularis longus
Figure 11.19 Extrinsic Muscles That Move the Foot and Toes, Part II
(a) Medial view of the superficial muscles of the left leg. (b) Lateral view of the superficial muscles of the right leg. (c) Lateral view of a dissection of the superficial muscles of the right leg.
More intrinsic muscles participate in flexion of joints at the toes than participate in extension. The flexor digitorum brevis muscle, the quadratus plantae muscles, and the four lumbrical muscles are responsi-ble for flexion at joints of toes 2–5. The flexor digiti minimi brevis muscle is responsible for flexion of toe 5. Extension of the toes is accomplished by the extensor digitorum brevis muscle. This muscle assists the extensor hallucis longus muscle in extension of the great toe, and also assists the ex-tensor digitorum longus muscle (see Table 11.8) in extension of toes 2–4. It is the only intrinsic muscle found on the dorsum of the foot.
1. What leg movement would be impaired by injury to the obturator muscles?
2. Often one hears of athletes suffering a “pulled hamstring.” Describe the muscles in such an injury.
3. To which group of muscles do the pectineus and gracilis belong?
4. What is the collective name for the knee extensors?
See blue “Answers” tab at back of book.
Patella
Patellar ligament Tibial tuberosity
Tibia
Extensor digitorum longus
Extensor hallucis longus Tibialis anterior Fibularis
longus Patellar ligament
Medial condyle of femur Iliotibial tract Quadriceps tendon
Gastrocnemius
Soleus Vastus medialis
Vastus lateralis Sartorius Rectus femoris
(c) Anterior view (b) Origins and insertions,
anterior view Inferior extensor
retinaculum Lateral malleolus Superior extensor retinaculum
Extensor hallucis
longus Extensor digitorum longus
Tibia Tibialis anterior Fibularis longus Patella Iliotibial tract Patellar ligament
Tibial tuberosity
(a) Anterior view Fibula
Lateral malleolus Fibularis brevis Origin
Insertion SUPERFICIAL DEEP
Figure 11.20 Extrinsic Muscles That Move the Foot and Toes, Part III
(a) Anterior views showing superficial and deep muscles of the right leg. (b) Anterior view of the bones of the right leg, showing the origins and insertions of selected muscles. (c) Anterior view of a dissection of the superficial muscles of the right leg.
Fibularis brevis
Superior extensor retinaculum
Lateral malleolus of fibula
Inferior extensor retinaculum
Tendons of extensor digitorum longus
Dorsal interossei Tendons of extensor digitorum brevis
Medial malleolus of tibia
Tendon of tibialis anterior
Calcaneal tendon (for attachment of gastrocnemius and soleus)
Extensor digitorum brevis
Fibularis brevis
Dorsal interossei
Extensor digitorum brevis
Extensor digitorum longus
Extensor hallucis longus
Extensor hallucis brevis
Tendon of extensor hallucis longus Abductor hallucis
Extensor expansion Tendon of extensor hallucis brevis
Dorsal view Superior extensor
retinaculum Tendon of fibularis brevis
Lateral malleolus of fibula Inferior extensor retinaculum
Medial malleolus of tibia
Tendon of tibialis anterior
Extensor hallucis brevis
Tendon of extensor hallucis longus
Tendons of extensor digitorum brevis Tendons of extensor digitorum longus
Dorsal interossei
Abductor hallucis
Extensor expansion
Abductor hallucis Flexor digitorum brevis
Abductor digiti minimi Quadratus plantae Flexor hallucis brevis Flexor digiti minimi brevis Adductor hallucis Plantar interossei Abductor digiti minimi Flexor digitorum brevis Flexor digitorum longus
Flexor hallucis longus
Abductor hallucis and flexor hallucis brevis
Tibialis posterior Tibialis anterior Fibularis longus (a) Dorsal view
Plantar view (b) Origins and insertions
Tendon of extensor hallucis brevis
Origin Insertion
Figure 11.21 Intrinsic Muscles That Move the Foot and Toes
(a) Dorsal views of the right foot. (b) Dorsal (superior) and plantar (inferior) views of the bones of the right foot, showing the origins and insertions of selected muscles. (c) Right foot, sectional view through the metatarsal bones. (d) Plantar (inferior) view, superficial layer of the right foot. (e) Plantar (inferior) view, deep layer of the right foot. (f) Plantar (inferior) view, deepest layer of the right foot.
Tendon of
hallucis (cut and retracted) Tendon of tibialis
posterior
(e) Plantar view, deep layer (f) Plantar view, deepest layer
Tendon of flexor hallucis longus
Flexor digiti
minimi brevis Flexor digiti
minimi brevis
(d) Plantar view, superficial layer (c) Right foot, sectional view through the metatarsal bones
Tendon of
Tendon of flexor hallucis longus First metatarsal bone Tendons of flexor digitorum longus Abductor hallucis
Flexor hallucis brevis
Tendons of flexor digitorum brevis Tendons of extensor
digitorum longus
Tendons of extensor digitorum brevis tendons of flexor digitorum longus I
II III
IV V
Figure 11.21 (continued)
TABLE 11.9 Intrinsic Muscles of the Foot
Muscle Origin Insertion Action Innervation
Extensor digitorum brevis Calcaneus (superior and lateral surfaces)
Dorsal surface of toes 1–4 Extension at metatarsophalangeal joints of toes 1–4
Deep fibular nerve (S1, S2)
Abductor hallucis Calcaneus (tuberosity on inferior surface)
Medial side of proximal phalanx of great toe
Abduction at metatarsophalangeal joint of great toe
Medial plantar nerve (S2, S3)
Flexor digitorum brevis As above Sides of middle phalanges, toes 2–5
Flexion of proximal interphalangeal joints of toes 2–5
As above
Abductor digiti minimi As above Lateral side of proximal phalanx, toe 5
Abduction and flexion at metatarsophalangeal joint of toe 5
Lateral plantar nerve (S2, S3)
Quadratus plantae Calcaneus (medial, inferior surfaces)
Tendon of flexor digitorum longus
Flexion at joints of toes 2–5 As above
Lumbricals (4) Tendons of flexor digitorum longus
Insertions of extensor digitorum longus
Flexion at metatarsophalangeal joints; extension at interphalangeal joints of toes 2–5
Medial plantar nerve (1), lateral plantar nerve (2–4)
Flexor hallucis brevis Cuboid and lateral cuneiform
Proximal phalanx of great toe Flexion at metatarsophalangeal joint of great toe
Medial plantar nerve (L4–S5)
Adductor hallucis Bases of metatarsal bones II–IV and plantar ligaments
As above Adduction and flexion at
metatarsophalangeal joint of great toe
Lateral plantar nerve (S1–S2)
Flexor digiti minimi brevis Base of metatarsal bone V Lateral side of proximal phalanx of toe 5
Flexion at metatarsophalangeal joint of toe 5
As above
Dorsal interossei (4) Sides of metatarsal bones Medial and lateral sides of toe 2; lateral sides of toes 3 and 4
Abduction at metatarsophalangeal joints of toes 3 and 4; flexion of metatarsophalangeal joints and extension at the interphalangeal joints of toes 2 through 4
As above
Plantar interossei (3) Bases and medial sides of metatarsal bones
Medial sides of toes 3–5 Adduction of metatarsophalangeal joints of toes 3–5; flexion of metatarsophalangeal joints and extension at interphalangeal joints
As above