Connective tissue components 1.Endomysium - Muscle fibers are covered with a delicate connective tissue membrane2.Perimysium - Groups of skeletal muscle fibers (fascicles) are bound together by a tougher connective tissue3.Epimysium - the muscle as a whole is covered by a coarse sheath4.Tendon - fibrous structures that attach muscles to bones5.Aponeurosis - 6.Tendon sheath -

Parallel Convergent Pennate Bipennate Sphincter

Size, shape, and fiber arrangement

Attachment of muscles

- point of attachment that does not move when the muscle contracts

-point of attachment that does move when the muscle contracts

Muscle actions

• Functional classification of muscle groups – always function in groups/pairs; some contract as some relax– Prime mover (agonist) – Muscle most responsible for

movement; “action” or “function” of that muscle– Antagonist – Muscle responsible for the movement

opposite of the prime mover; provides precision and control during contraction of prime mover; relaxes while prime mover contracts

– Synergist – Muscles that aid the prime mover; contract at same time as prime mover

– Fixator – joint stabilizer; maintains posture or balance during contraction of prime mover

1st Class Levers2nd Class Levers

3rd Class Levers

Bone = leverJoint = Fulcrum (F)Contracting Muscle = Force (P)Load (L)

How Muscles Are Named Features used in naming muscles

1. Location – gluteus, brachii2. Function3. Shape - deltoid4. Direction of fibers – rectus abdominus5. Number of heads or divisions – points of

origin-cep = head

6. Points of attachment -sternocleidomastoid7. Size of muscle – relative size, maximus,

minimus

Hints on how to deduce muscle actions 1. Be familiar with name, shape, and location 2. From shape and location, deduce name of origin and insertion bone 3. Determine which bone moves when muscle contracts 4. Deduce action—insertion moves toward origin 5. Deduce which muscle gives a specific action

Muscles Named According To: Overall Shape

Deltoid Shaped like delta Δ

Orbicularis Circular

Platy Flattened; platelike

Quadratus Square

Rhomboideus Diamond-shaped

Trapezius Trapezoidal

Triangularis Triangular

Muscles Named According To: Relative Size

Brevis Short

Longus Long

Magnus Large

Maximus Largest

Medius Moderately sized

Minimus Small

Muscles Named According To: Direction of Fibers

Oblique Diagonal to body’s midline

Rectus Parallel to midline

Sphincter Circling an opening

Transversus Right angle to midline

Muscles Named According To: Actions Produced

Abductor Abducts a part

Adductor Adducts a part

Depressor Depresses a part

Extensor Extends a part

Flexor Flexes a part

Levator Elevates a part

Rotator Rotates a part

Muscles Named According To: Regions Found

Brachialis Arm

Frontalis Frontal (bone)

Femoris Femur

Gluteus Posterior of hip/thigh

Oculi Eye

Radialis Radius

Ulnaris Ulna

Muscles of Facial Expression 1. occipitofrontalis – raise eyebrows2. corrugator supercilii – frowning forehead3. orbicularis oculi – blinking4. zygomaticus major – laughing5. orbicularis oris – puckering6. buccinator

Muscles of Mastication (chewing)1. masseter2. temporalis3. pterygoids

Muscles that Move the Head1. sternocleidomastoid2. semispinalis capitis3. splenius capitus4. longissimus capitus

Posture• Good posture

– body alignment that favors function, with least work– Standing position: head and chest held high; chin,

abdomen and buttocks pulled in; knees bent slightly; feet firmly on ground 6 in. apart.

• Poor posture

– puts abnormal strain on ligaments and bones• How Maintained

– Muscle Tone (Tonicity) – when muscles exert a pull against gravity

Cycle of Life

• During infancy and childhood, muscle coordination and control allows developmental sequences to occur

• Degeneration of muscles with age includes replacement with connective tissue