Download Lab 21

Muscles to know
Lab 21
Muscles of the Pelvis, Leg and
Foot
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Muscles of the Pelvis
and Lower Limbs
• Pelvic girdle is tightly bound to axial
skeleton:
– permits little movement
– has few muscles
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
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tibialis anterior
ext hallucis longus
ext digitorum longus
fibularis (peroneus)
longus
gastrocnemius
soleus
flexor hallucis longus
flexor digitorum longus
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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psoas major
iliacus
gluteus maximus
gluteus medius
sartorius
quadriceps femoris (4)
gracilus
adductor longus
biceps femoris
semitendinosis
semimembranosus
Muscles that Move the Thigh
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Gluteal muscles
Lateral rotators
Adductors
Iliopsoas group
Note: in legs and feet, look at each joint
individually (cf. arms)
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Muscles of hip and thigh
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Gluteal Muscles (1 of 2)
psoas major
iliacus
gluteus maximus
gluteus medius
adductor longus
• 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)
Muscles that Move the Thigh
• Gluteus medius and [gluteus minimus]:
– originate anterior to gluteus maximus
– insert on trochanter of femur
Figure 11–19a, b
Muscles that Move the Thigh
Adductors
• Adductor longus:
– hip flexion and adduction
• Gracilis (UPPER LEG):
– hip flexion and adduction
Figure 11–19c, d
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Summary: Muscles that
Move the Thigh
Iliopsoas group
• 2 hip flexors insert on the same tendon:
– psoas major
• originates on lumbar vetebrae, inserts on femur
– iliacus
• originates on illium/fossa
Table 11–16 (1 of 2)
Summary: Muscles that
Move the Thigh
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
Table 11–16 (2 of 2)
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
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Muscles that Move the Leg
Extensors of the Knee
• 4 muscles of the quadriceps femoris:
– 3 vastus muscles:
• vastus lateralis
• vastus medialis
• vastus intermedius
– rectus femoris muscle
Figure 11–20a
Muscles that Move the Leg
Summary: Muscles that
Move the Leg
Figure 11–20b, c
Summary: Muscles that
Move the Leg
Table 11–17 (1 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
Table 11–17 (2 of 2)
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Muscles that Produce Extension
at the Ankle (Plantar flexion)
Muscles that Move
the Foot and Toes
Calf muscles
Large posterior calf muscles, both insert on
Achilles):
• Gastrocnemius
• Soleus
• Fibularis longus
Figure 11–21a, b
Muscles that Move
the Foot and Toes
The Achilles Tendon
• The calcaneal tendon (Achilles tendon):
– shared by the gastrocnemius and soleus
Figure 11–21c, d
Muscles that Produce
Flexion at the Ankle
Muscles that Move
the Foot and Toes
• Tibialis anterior:
– opposes the gastrocnemius
Figure 11–21a, b
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Muscles that Move
the Foot and Toes
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)
Figure 11–21c, d
The Intrinsic Muscles of the
Foot
Muscles that Produce
Flexion at the Toes
• Flexor digitorum longus
• Flexor hallucis longus:
– oppose the extensors
Toe flexors are on bottom of foot
Figure 11–22a
The Intrinsic Muscles of the
Foot
Figure 11–22b, c
Summary: Muscles that
Move the Foot and Toes
Table 11–18
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Today
• Lab 21
– Ignore muscles that are not on the list
Due Next Week
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