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Muscles of lower limb


The muscles of lower limb are divided into:

Hip
Thigh
Leg
foot

Anterior group

Iliopsoas

Psoas major: arise from the transverse processes of the lumbar vertebrae laterally

Iliacus: arise from the iliac fossa
insert in the lesser trochanter of the femur

Action:the most powerful flexor of the thigh. If the lower limb is fixed, it bends the vertebral column forward (e.g., when sitting up from supine position) and flexes the lumbar region laterally. It also can rotate the thigh laterally.

tensor fasciae latae

Actions: Flexes and abducts the hip joint. Helps to keep the knee extending in erect posture and steadies the trunk on the thigh.



Posterior group

Gluteus Maximus

Action: a powerful extensor of the thigh, the most powerful lateral rotator, and an important postural muscle.

Gluteus Medius and gluteus minimus

Action : Gluteus Medius Abducts and rotates the thigh. gluteus minimus Abducts and its anterior fibers can medial rotate the thigh.

Piriformis

Action : rotate and abduct the thigh laterally


The muscles of thigh

Anterior group

Sartorius

Origin: anterior superior iliac spine
Insertion: the upper part of the medial surface of the tibia

Action: flexes the thigh and the leg, when the knee is flexed, it medially rotates the leg.

Quadriceps Femoris
Rectus femoris
Vastus lateralis
Vastus medialis
Vastus intermedius


Quadriceps Femoris

Origin:
Rectus femoris: anterior inferior iliac spine
Vastus medialis: medial lip of linea aspera
Vastus lateralis: lateral lip of linea aspera
Vastus intermedius: anterior surface of femur

Insertion: tibial tuberosity via patellar ligament

Action : extend the leg. rectus femoris also flexes the thigh.


Medial group

gracilis
pectineus  
adductor longus
adductor brevis
adductor magnus


Actions: Adduct, flex and laterally rotate the thigh. The gracilis can adduct the hip joint and flex the knee.



posterior group


biceps femoris
semitendinosus
Semimembranosus



Actions: They are the main extensors of the thigh and flexors of the leg. When the knee joint is semi-flexed, they also can rotate the leg.



The muscles of leg

Anterior group

tibialis anterior

extensor digitorum longus
extensor hallucis longus


Actions: All the muscles of this group can dorsiflex the ankle joint. In addition, the tibialis anterior can invert the foot (the sole of the foot faces medially), the extensor hallucis longus extends the big toe, and the extensor digitorum longus extends the other toes.


lateral group

peroneus longus

peroneus brevis


Actions: Acting together, they plantar flex and exert the ankle joint.


The posterior group

Superficial layer

Triceps surae

Gastrocnemius

Soleus

Actions: Plantar flexes the ankle joint (e.g., in walking and dancing) and steadies leg on foot during standing. The gastrocnemius also can flex the knee joint.


deep layer

popliteus
flexor digitorum longus

Actions: Plantar flexes the ankle joint as well as all joints of the lateral four toes.

tibialis posterior

Actions: Flexes the ankle joint, inverts the foot.

flexor hallucis longus
Actions: plantar flexes the ankle joint and the big toe at all joints.



Muscles of the foot

extensor digitorum brevis

The muscles of the foot can be grouped into four layers, but these are difficult to dissociate, even in dissection. The muscles function either to move the toes or to support the arches of the foot through their contraction