The major muscle groups

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The major muscle groups Axial muscles- position
head and spinal column move rib cage (about 60
of muscles) Appendicular muscles stabilize or
move the bones of the appendicular skeleton
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Superifical muscles (anterior view)
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Muscle names are descriptive Location (e.g.,
temporalis attaches to temporal bone in
skull) Action (flexor causes muscle
flexion) Shape (deltoid is shaped by the Greek
letter delta)
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Groups of axial muscles Head and neck- facial
expressions, chewing, swallowing Muscles of the
spine- flexors and extensors of the spinal
column Muscles of the trunk- walls of the
thoracic and abdominopelvic cavities floor of
the pelvic cavity
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Originate on skull Insert into the dermis
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Largest group of muscles associated
with mouth Orbicularis oris- opening Buccinator-
compresses cheeks Masseter and temporalis-
chewing Other, smaller groups control movements
of eyes, scalp, ears, movements of jaw, etc.
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Muscles of spine Covered by superficial
muscles erector spinae- extensors quadratus
lumborum- flexors Muscles of trunk-
intercostals, obliques, transversus abdominalis,
diaphragm, rectus abdominalis
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Perineum- floor of abdominal cavity
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Muscles associated with pelvic floor Broad sheet
of support muscles (levator ani) Muscles
associated with urination and defecation
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Appendicular muscles shoulders and upper
limbs pelvic girdle and lower limbs Trapezius
movements of scapula, clavicle, extension of
head and neck Flexors, rotators, abductors
(raise) adductor (lower) of arm Extensors of
wrist Flexors and extensors of fingers
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Muscles of hip and lower limb Movement of the
thigh flexors, extensors, abductors,
adductors Movement of the leg flexors,
extensors Movement of ankles and
feet dorsiflexor, eversion, plantar flexion
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Effects of aging on the muscular
system skeletal muscle fibers become
smaller in diameter muscles become smaller and
less elastic tolerance for exercise
decreases ability to recover from injury
decreases You cant start exercising too early!
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Disorders of the muscular system (often due to
nervous disorders) Trauma (tears, bruises,
damage to connective tissue). Pain may arise
from damage to skeleton Infection,
inflammation Weakness, atrophy (disease,
infection) Tremors, paralysis (nervous system)