Lab 21
Muscles of the Pelvis, Leg and
Foot
Muscles to know
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psoas major
iliacus
gluteus maximus
gluteus medius
sartorius
quadriceps femoris (4)
gracilus
adductor longus
biceps femoris
semitendinosis
semimembranosus
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tibialis anterior
ext hallucis longus
ext digitorum longus
fibularis (peroneus)
longus
gastrocnemius
soleus
flexor hallucis longus
flexor digitorum longus
Muscles of the Pelvis
and Lower Limbs
• Pelvic girdle is tightly bound to axial
skeleton:
– permits little movement
– has few muscles
Muscles that Position
the Lower Limbs
1. Muscles that move the thigh
2. Muscles that move the leg
3. Muscles that move the foot and toes
Generally…
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Muscles that are lateral are abductors
Muscles that are medial are adductors
flexors are on inner surface of joint
extensors are on outer surface of joint
Note: in legs and feet, look at each joint
individually (cf. arms)
Muscles that Move the Thigh
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Gluteal muscles
Lateral rotators
Adductors
Iliopsoas group
Muscles of hip and thigh
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psoas major
iliacus
gluteus maximus
gluteus medius
adductor longus
Gluteal Muscles (1 of 2)
• Cover lateral surfaces of ilia
• Gluteus maximus:
– largest, most posterior gluteal muscle
– produces extension and lateral rotation at
hip
– Originates on illiac crest, etc., inserts on
illiotibial tract and femur
Gluteal Muscles (2 of 2)
• Gluteus medius and [gluteus minimus]:
– originate anterior to gluteus maximus
– insert on trochanter of femur
Muscles that Move the Thigh
Figure 11–19a, b
Muscles that Move the Thigh
Figure 11–19c, d
Adductors
• Adductor longus:
– hip flexion and adduction
• Gracilis (UPPER LEG):
– hip flexion and adduction
Iliopsoas group
• 2 hip flexors insert on the same tendon:
– psoas major
• originates on lumbar vetebrae, inserts on femur
– iliacus
• originates on illium/fossa
Summary: Muscles that
Move the Thigh
Table 11–16 (1 of 2)
Summary: Muscles that
Move the Thigh
Table 11–16 (2 of 2)
Muscles that Move the Leg
• Flexors of the knee:
– originate on the pelvic girdle
– generally: hamstrings
• Extensors of the knee:
– originate on the femoral surface
– insert on the patella
– generally: quads
Flexors of the Knee
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Biceps femoris
Semimembranosus
Semitendinosus
Sartorius:
– originates superior to the acetabulum
– long, ribbon-like muscle
– traverses the quads and wraps around to the
back of the knee
Hamstrings
• Made up of:
– biceps femoris (long and short heads)
– semimembranosus
– semitendinosus
• All are knee flexors
Muscles that Move the Leg
Figure 11–20a
Extensors of the Knee
• 4 muscles of the quadriceps femoris:
– 3 vastus muscles:
• vastus lateralis
• vastus medialis
• vastus intermedius
– rectus femoris muscle
Muscles that Move the Leg
Figure 11–20b, c
Summary: Muscles that
Move the Leg
Table 11–17 (1 of 2)
Summary: Muscles that
Move the Leg
Table 11–17 (2 of 2)
Muscles that Move
the Foot and Toes
• Extrinsic muscles that move the foot and
toes include:
– muscles that produce extension at the ankle
(Plantar flexion)
– muscles that produce flexion at the ankle
– muscles that produce extension at the toes
– muscles that produce flexion at the toes
Muscles that Produce Extension
at the Ankle (Plantar flexion)
Calf muscles
Large posterior calf muscles, both insert on
Achilles):
• Gastrocnemius
• Soleus
• Fibularis longus
Muscles that Move
the Foot and Toes
Figure 11–21a, b
Muscles that Move
the Foot and Toes
Figure 11–21c, d
The Achilles Tendon
• The calcaneal tendon (Achilles tendon):
– shared by the gastrocnemius and soleus
Muscles that Produce
Flexion at the Ankle
• Tibialis anterior:
– opposes the gastrocnemius
Muscles that Move
the Foot and Toes
Figure 11–21a, b
Muscles that Move
the Foot and Toes
Figure 11–21c, d
Muscles that Produce
Extension at the Toes
• Extensor digitorum longus
• Extensor hallucis longus
Toe extensors are on top of foot
Note: there are no muscles in toes
themselves (only tendons)
The Intrinsic Muscles of the
Foot
Figure 11–22a
Muscles that Produce
Flexion at the Toes
• Flexor digitorum longus
• Flexor hallucis longus:
– oppose the extensors
Toe flexors are on bottom of foot
The Intrinsic Muscles of the
Foot
Figure 11–22b, c
Summary: Muscles that
Move the Foot and Toes
Table 11–18
Today
• Lab 21
– Ignore muscles that are not on the list
Due Next Week