Muscles Bundle Pairs and Attachment to BonesMuscles Bundle Pairs and Attachment to Bones

Skeletal MusclesSkeletal Muscles

MuscleMuscle in Latin means “little mouse” because of the in Latin means “little mouse” because of the fancied resemblance of the muscle body to a mouse fancied resemblance of the muscle body to a mouse contracting beneath the skincontracting beneath the skin

Attachments:Attachments:

TendonsTendons

Made up of bundles (fascicles) of collagen fibers, mainly Made up of bundles (fascicles) of collagen fibers, mainly parallel and often large enough to see with the naked parallel and often large enough to see with the naked eyeeye

Flexible and resists stretch; so it can turn corners Flexible and resists stretch; so it can turn corners

Appear white in life because it is vascularAppear white in life because it is vascular Heal very slowly: this is why damage to the large Heal very slowly: this is why damage to the large

tendon in the heel, the Achilles tendon is so tendon in the heel, the Achilles tendon is so crippling for a sportsman (as it was, incidentally, crippling for a sportsman (as it was, incidentally, for Achilles) for Achilles)

Take the form of cords or strips, circular in cross Take the form of cords or strips, circular in cross section, oval or flattenedsection, oval or flattened

Striated in appearanceStriated in appearance Around the outside is an epitendineum with Around the outside is an epitendineum with

elastic fibers, which obviously causes a little elastic fibers, which obviously causes a little drag as tendons run through connective tissuedrag as tendons run through connective tissue

AponeurosisAponeurosis A very flattened tendon A very flattened tendon White like nervous tissueWhite like nervous tissue Usually has the appearance of a flattened sheet of Usually has the appearance of a flattened sheet of

collagen fibers, or often several sheets running on each collagen fibers, or often several sheets running on each other in different directions like plywood.other in different directions like plywood.

FleshyFleshy

Muscle joined to bone without the intervention of a frank Muscle joined to bone without the intervention of a frank collagenous tendon or aponeurosiscollagenous tendon or aponeurosis

The collagen is still there, but in amongst the muscle The collagen is still there, but in amongst the muscle fibers, or forming a very short tendonfibers, or forming a very short tendon

Origin, Insertion, and BellyOrigin, Insertion, and Belly

OriginOrigin - attachment of the muscle tendon to the stationary bone - attachment of the muscle tendon to the stationary bone

InsertionInsertion - the bone that is moved - the bone that is moved

BellyBelly - fleshy portion between the origin and insertion - fleshy portion between the origin and insertion

Skeletal muscles produce movement by exerting force on tendons, which Skeletal muscles produce movement by exerting force on tendons, which then pull on bonesthen pull on bones

Most muscles cross a joint and attach to the articulating bone that forms a Most muscles cross a joint and attach to the articulating bone that forms a jointjoint

When the muscle contracts, it pulls one of the articulating bones toward When the muscle contracts, it pulls one of the articulating bones toward the otherthe other

The other muscle tendon attaches to the muscle's INSERTIONThe other muscle tendon attaches to the muscle's INSERTION In limbs, the origin is usually proximal and the insertion is usually distalIn limbs, the origin is usually proximal and the insertion is usually distal When a muscle contracts, it pulls its insertion toward its originWhen a muscle contracts, it pulls its insertion toward its origin The belly shortens and thickens during the contractionThe belly shortens and thickens during the contraction

Types of Muscles according to Movement of Body PartsTypes of Muscles according to Movement of Body Parts

Prime MoverPrime Mover - Muscles that assume the major - Muscles that assume the major responsibility for producing a responsibility for producing a specific movementspecific movement

AntagonistsAntagonists - Muscles that oppose, or reverse, a particular - Muscles that oppose, or reverse, a particular movement by a movement by a prime mover prime mover

SynergistsSynergists - Muscles that reduce undesirable or - Muscles that reduce undesirable or unnecessary extra movements unnecessary extra movements

that might result as the prime mover contractsthat might result as the prime mover contracts

FixatorsFixators - Are synergists which immobilize the origin of the - Are synergists which immobilize the origin of the prime mover so that prime mover so that

the prime mover can act more efficientlythe prime mover can act more efficiently

. .

The biceps brachii is the prime mover of elbow The biceps brachii is the prime mover of elbow flexion while the triceps brachii is the antagonistflexion while the triceps brachii is the antagonist

Quadriceps group muscle cause lower leg to Quadriceps group muscle cause lower leg to extend, leg moves away from thighextend, leg moves away from thigh

The deltoid muscle originates on the scapula, The deltoid muscle originates on the scapula, which is a moveable bone. The pectoralis minor, which is a moveable bone. The pectoralis minor, rhomboids, and trapezius muscles attach the rhomboids, and trapezius muscles attach the scapula to the axial skeleton. When the deltoid scapula to the axial skeleton. When the deltoid contracts to abduct the arm, these other muscles contracts to abduct the arm, these other muscles hold the scapula still and therefore act as hold the scapula still and therefore act as fixatorsfixators

Body Parts MovementBody Parts Movement

Muscle mechanicsMuscle mechanics::

a. swinga. swing - tending to move the mobile bone - tending to move the mobile boneb. shuntb. shunt - compressing the joint - compressing the jointc. spinc. spin - rotating the mobile bone - rotating the mobile bone

There are 3 different types of joints in the body:There are 3 different types of joints in the body:

Freely Movable JointsFreely Movable Joints (ball-and-socket, hinge, and (ball-and-socket, hinge, and pivot joints) which allow movement freely pivot joints) which allow movement freely

Slightly Movable JointsSlightly Movable Joints (gliding joints) which allow (gliding joints) which allow considerable movementconsiderable movement

Immovable JointsImmovable Joints (bones of the skull) which allow (bones of the skull) which allow little or no movement at alllittle or no movement at all

Toes, Elbows, knees and fingers- uses hinge Toes, Elbows, knees and fingers- uses hinge joints (back-and-forth movements like hinges on joints (back-and-forth movements like hinges on a door).a door).

Spinal vertebra- The joints between vertebrae Spinal vertebra- The joints between vertebrae are called gliding joints, where one part of a are called gliding joints, where one part of a bone slides over another bone bone slides over another bone