vii. muscles of the lower limb - tracy unified school … physiology...copyright © 2006 pearson...

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

VII. Muscles of the Lower Limb1. Gluteus maximus: forms most of the flesh of the

posterior buttock

-function: a powerful hip extensor that acts to bring the thigh in a straight line with the pelvis

-NOT a good site for intramuscular injections because its medial section overlies the large sciatic nerve, which must be avoided


VII. Muscles of the Lower Limb2. Adductor muscles: form the muscle mass at the

medial side of each thigh (refer to anterior diagram)

-function: to adduct or press the thighs together

3. Tensor fasciae latae: runs laterally along thigh

-function: steadies the femur on the tibia when standing; flexes the hip; and it medially rotates and abducts the thigh


Image taken from www.google.com


VII. Muscles of the Lower Limb4. Hamstring group: the muscles forming the muscle mass

of the posterior thigh

-functions: they flex the knee, rotate the leg medially and laterally, and extend the hip

5. Sartorius: thin, straplike, superficial muscles that run obliquely across the thigh

-function: a weak thigh flexor; allows us to sit in the cross-legged position


VII. Muscles of the Lower Limb6. Quadriceps group: consists of 4 muscles that form the

flesh of the anterior thigh

-function: the group as a whole acts to extend the knee powerfully, like when kicking a football

7. Tibialis anterior: a superficial muscle on the anterior leg

-function: to dorsiflex and invert the foot


VII. Muscles of the Lower Limb8. Gastrocnemius: a two-bellied muscle that forms

the curved calf of the posterior leg

-inserts through the large calcaneal (Achille’s) tendon into the heel of the foot

-function: a prime mover for plantar flexion of the foot

9. Soleus: fleshy muscle that is deep to the gastrocnemius

-function: a strong plantar flexor of the foot


Review: Major superficial muscles of the anterior surface of the body


Review: Major superficial muscles of the posterior surface of the body


VIII. Developmental AspectsA. Myasthenia gravis: a rare disease that can affect

muscles during adulthood (SUMMARIZE THIS)

-characterized by drooping of upper eyelids, difficulty in swallowing and talking, & generalized muscle weakness & fatigability

-involves a shortage of acetylcholine receptors, suggesting autoimmune disorder

-muscle cells are not stimulated properly & get progressively weaker

-death usually occurs as a result of inability of respiratory muscles to function, called respiratory failure

vii. muscles of the lower limb - tracy unified school … physiology...copyright © 2006 pearson...

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