Download VII. Muscles of the Lower Limb

VII. Muscles of the Lower Limb
1. 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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
VII. Muscles of the Lower Limb
2. 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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Image taken from www.google.com
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
VII. Muscles of the Lower Limb
4. 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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
VII. Muscles of the Lower Limb
6. 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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
VII. Muscles of the Lower Limb
8. 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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Review: Major
superficial muscles of
the anterior surface
of the body
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Review:
Major
superficial
muscles of the
posterior
surface of the
body
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
VIII. Developmental Aspects
A. 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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings