Anatomy
Elementary concepts on the
locomotion apparatus.
Skeleton :
Skeleton is divided into
several great parts.
- Head
- Trunk (scapulas,
clavicles, sternum, ribs, vertebrae, pelvis).
- Upper limbs (humerus, radius, ulna, carp, metacarpus, phalanges)
- Lower limbs (femur,
kneecap, tibia, fibula, anterior tarsal bones, metatarsals, phalanges).
- The two waists, scapular and pelvic (clavicle, scapula, spine,
sacrum, iliac bone).
Spinal
column and vertebrae :
It includes thirty three vertebrae
which are seven
cervical vertebrae (C1 - C7), twelve thoracic (T1 - T12), five lumbar
(L1 - L5) and nine fused for the sacrum and coccyx.
Vertebral column have four curvatures which enable
to increase its resistance and its statics.
Its structure may cause many
possibilities of traumatisms because there is a great number of joints (risks
of acute or overuse injuries, back muscle strain, back ligament sprain ... ); the presence of an intervertebral disc makes that it can be crushed, or moved by heavy charges
(herniated discs, chronic
lumbar backaches); weakness of the four curvatures changes areas; presence of spinal cord inside vertebral holes and the thirty one pairs of
nerves (compression of the sciatic nerve).
To avoid all these traumatisms, it's recommended to :
- don't make efforts with too heavy loads
if you do not control the technical movement, perfectly !
- preserve curvatures of the column without reversing them,
in particular always raising loads with your legs (flexing the legs) and not with
the back (bending the back).
- take the load the nearest as you can
from the body, don't move away the load from the axis of the body.
- maintain vertebrae lumbar flat on the ground
during abdominal exercises.
Balance of the pelvis :
A problem of imbalance of pelvis can be at origin of
bad curvatures of the spine (scoliosis, lordosis or
kyphosis) because pelvis influence the good position of vertebral column.
It's necessary to proscribe a bad placement
of pelvis during execution of housework or exercises or when children grew.
Joints :
They are used to connect bones between them. According to their mobility
we group together them in three
categories, synarthroses (immovable joints: cranium ...), amphiarthroses (not very mobile or
limited: vertebrae ...), diarthroses (great amplitude and mobility : bend ...).
Training exercises can increase articular amplitude and flexibility.
There are two types of articular accidents,
strains or sprains (traumatism without displacement of articular
surfaces) and dislocations or subluxations (traumatisms with bones out of their
sockets). To know more, please refer to our page " traumatisms ".
Muscles :
A skeletal muscle is
made of bundles of muscle cells, held together and surrounded by fibrous partitions. These
connective tissue partitions allow easy movement of muscles. Each cell of muscle contains functional units
called sarcomeres, divided by boundaries called Z lines. Each sarcomere contains thick filaments and thin filaments
(myosin and actin filaments). When the muscle is stimulated by a nerve, thin filaments slide along thick filaments. Muscle
becomes shorter.
We have three types of fibres,
training can improve quality of a fibre.
- Type I: slow contractions (aerobe - endurance)
- Type II a: powerful and with fast contraction (anaerobic alactic -
strength/speed)
- Type II b: used for resistance (anaerobic lactic -
resistance).
Synergetic muscles are muscles which produce the same action (biceps), the antagonist muscles are muscles
which produce an opposite action (biceps - triceps). It's the smoothness of these opposite actions which makes precision of a movement.
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