ANATOMY OF THE MUSCULAR SYSTEM

ANATOMY OF THE MUSCULAR SYSTEM

Anatomy of the Muscular SystemOriginMuscle attachment that remains fixedInsertionMuscle attachment that movesActionWhat joint movement a muscle producesi.e. flexion, extension, abduction, etc.Organization of Muscle FibersFour patterns of fascicle organization:(1) Parallel muscle (2) Convergent muscle(3) Pennate muscle(4) Circular muscleParallel MuscleMuscle fibers arranged parallel to the long axis of the muscleEX: most of the skeletal muscles, like bicepsWhen parallel muscle contracts, it gets shorter in length and larger in diameter

Convergent MuscleThe muscle fibers are spread over a broad area, but all the fascicles converge at one common attachment siteMuscle fibers spread out like a fan or broad triangle EX: pectoralis muscles

Pennate MuscleFascicles form a common angle with the tendon, and contain more muscle fibers than parallel muscles, so more tension is produced during contractionEX: unipennate all fibers on the same side of the tendon: extensor digitorum Bipennate fibers on both sides of the tendon: rectus femoris

Circular MuscleFibers are concentrically arranged around an opening or a recessWhen the muscle contracts, the diameter of the opening closesEX: orbicularis oculis

For muscles to create a movement, they can only pull, not push Muscles in the body rarely work alone, & are usually arranged in groups surrounding a joint A muscle that contracts to create the desired action is known as an agonist or prime mover (EX: biceps contracts) A muscle that helps the agonist is a synergist A muscle that opposes the action of the agonist, therefore undoing the desired action is an antagonist (EX: triceps extends the elbow)How Muscles are Named1. Orientation of muscle fibers 2. Location3. Relative Position4. Structure, Shape, and Size5. Origin and Insertion 6. ActionHow Muscles are Named1. Orientation of fibersRectus = straightTransversus = fibers run across the long axis of the bodyOblique = fibers run at an oblique angle to the long axisHow Muscles are Named2. LocationMuscles are named for their location or body regionEX: temporalis, frontalis, femorisHow Muscles are Named3. Relative PositionMuscles visible at the surface of the body are called externus or superficialisDeeper muscles are called internus or profundisHow Muscles are Named4. Structure, Shape, and SizeSome muscles named for the number of tendons of origin (EX: biceps or triceps brachii)Shape: deltoid, rhomboidLong muscles called longus (long) or longissimus (longest)Short muscles called brevisHow Muscles are Named5. Origin and Insertion First name will indicate origin, second name the insertionEX: genioglossus muscle Origin = chin (genio)Insertion = tongue (glossusHow Muscles are Named6. ActionSome muscles are named for the action they produce when contracted.EX: extensor, flexor, retractor, abductor, adductor, levator, pronator, etcHow Muscles are Named: ActionFlexion = decreasing the angle between 2 bones (dorsiflexion = decrease angle between foot and the shin; plantar flexion = pointing toesExtension = increasing the angle between 2 bonesAbduction = moving a body part away from the midlineAdduction = moving a body part toward the midlineCircumduction = movement in a circular motionHow Muscles are Named: ActionRotation = turning movement of a bone around its long axisSupination = thumbs upPronation = thumbs downInversion = turning sole of foot inEversion = turning sole of foot outElevation = lifting a body partDepression = returning body part to its pre-elevated position

An Overview of the Major Skeletal MusclesFigure 7-11(a)18

An Overview of the Major Skeletal MusclesFigure 7-11(b)19Anatomy of the Muscular SystemMuscles of the Head and Neck

Figure 7-12(a)20Anatomy of the Muscular SystemMuscles of the Head and Neck

Figure 7-12(c)21Anatomy of the Muscular SystemMuscles of the Spine

Figure 7-1422Anatomy of the Muscular SystemFigure 7-15(a)

Oblique and Rectus Muscles and the Diaphragm23Anatomy of the Muscular SystemMuscles of the Shoulder

Figure 7-17(a)Anatomy of the Muscular SystemMuscles of the Shoulder

Figure 7-17(b)Anatomy of the Muscular SystemMuscles that Move the Arm

Figure 7-18(a)Anatomy of the Muscular SystemMuscles that Move the Arm

Figure 7-18(b)Anatomy of the Muscular SystemMuscles That Move the Forearm and Wrist

Figure 7-19Anatomy of the Muscular SystemMuscles That Move the Thigh

Figure 7-20(a)Anatomy of the Muscular SystemMuscles That Move the ThighFigure 7-20(b)

Anatomy of the Muscular SystemMuscles That Move the LegFigure 7-21

Anatomy of the Muscular SystemMuscles That Move the Foot and ToesFigure 7-22(a)

Anatomy of the Muscular SystemMuscles That Move the Foot and ToesFigure 7-22(b)

Anatomy of the Muscular SystemMuscles That Move the Foot and ToesFigure 7-22(c)

Anatomy of the Muscular SystemMuscles That Move the Foot and ToesFigure 7-22(d)