lab 21 muscles of the pelvis, leg and foot. muscles to know psoas major iliacus gluteus maximus...
TRANSCRIPT
Muscles to know
• psoas major• iliacus• gluteus maximus• gluteus medius• sartorius• quadriceps femoris (4)• gracilus• adductor longus• biceps femoris• semitendinosis• semimembranosus
• 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…
• 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 of hip and thigh
• 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
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
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
• 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
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 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
The Achilles Tendon
• The calcaneal tendon (Achilles tendon):– shared by the gastrocnemius and soleus
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)
Muscles that Produce Flexion at the Toes
• Flexor digitorum longus
• Flexor hallucis longus:– oppose the extensors
Toe flexors are on bottom of foot