 Approximately 40% of your body weight  Approximately 650 muscles  Muscles only pull (they can’t push)  You have over 30 facial muscles  Eye muscles move more than 100,000 times a day

1. Skeletal 2. Cardiac 3. Smooth

 Definition - organs that are composed mainly of skeletal muscle tissue, but they also contain connective tissues, nerves, and blood vessels.  Each cell is a single muscle fiber.  Muscle fibers form bundles called fascicles.  Directly or indirectly attached to the bones of the skeleton

Muscle plays six important roles in the body: 1. Produce skeletal movement 2. Maintains posture and body position 3. Support soft tissues (abdominal wall & pelvic cavity) 4. Guard entrances and exits (digestive and urinary tracts) 5. Maintain body temperature (energy is converted to heat) 6. Store nutrient reserves (proteins are broken down & amino acids are used)

 The muscle fibers in a single fascicle are parallel, but the organization of fascicles in skeletal muscles can vary  The arrangement is correlated with muscle power and range of motion (structure determines function)  Skeletal muscles are classified as: 1. Parallel muscles (most common) – fascicles are parallel to the long axis of the muscle 2. Convergent muscles – converge at a common attachment site; fibers spread out and pull in different directions 3. Pennate muscles – form a common angle with the tendon 4. Circular muscles – cocentrically arranged around an opening

Three layers of connective tissue are part of each muscle: 1. Epimysium – dense layer of collagen fibers that surround the entire muscle 2. Perimysium – divides the muscle into a series of compartments each containing a bundle of muscle fibers (fascicle); contains collagen & elastic fibers, blood vessels and nerves that maintain blood flow 3. Endomysium – flexible, elastic connective tissue layer; surrounds the individual skeletal muscle cells and interconnects adjacent muscle fibers

 At the end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium come together to form a tendon or aponeurosis  Tendons and aponeuroses attach muscles to bone  Origin – where the fixed end of the muscle attaches to the bone (cartilage or connective tissue)  Insertion – where the movable end of the muscle attaches to another structure

 Gastrocnemius – calf muscle that extends from the distal portion of the femur to the calcaneus  When it contracts it pulls the calcaneus toward the knee  Origin – femur  Insertion - calcaneus

Naming of Skeletal Muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Direction of muscle fibers Example: rectus (straight)  Relative size of the muscle Example: maximus (largest)

Naming of Skeletal Muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Location of the muscle Example: many muscles are named for bones (e.g., temporalis)  Number of origins Example: triceps (three heads)

Naming of Skeletal Muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Location of the muscles origin and insertion Example: sterno (on the sternum)  Shape of the muscle Example: deltoid (triangular)  Action of the muscle Example: flexor and extensor

 Axial muscles arise on the axial skeleton (60% of skeletal muscles) ; position the head and spinal column and move the rib cage  Appendicular muscles stabilize and move the appendicular skeleton (40% of skeletal muscles)

Head and Neck Muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.14

Trunk Muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.15

Deep Trunk and Arm Muscles Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.16

Muscles of the Pelvis, Hip, and Thigh Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.18c

Muscles of the Lower Leg Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.19

Superficial Muscles: Anterior Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.20

Superficial Muscles: Posterior Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.21

 Agonist (prime mover) – a muscle whose contraction is mostly responsible for producing a particular movement Example – biceps brachii  Antagonist – a muscle whose action opposes that of a particular agonist Example – triceps brachii  Agonists and antagonists are functional opposites  Synergists – help a larger agonist work efficiently

 Muscle Tone – resting tension in a skeletal muscle  Isotonic muscle contraction – tension rises and the skeletal muscle’s length changes (lifting)  Isometric muscle contraction – the muscle as a whole does not change length, and the tension produced never exceeds the load (holding)

Types of Ordinary Body Movements Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Flexion – bending at the joint  Extension - straightening at the joint  Hyperextension Hyperextension  Rotation – rotating on axis  Abduction – moving away from the midline  Adduction – moving toward the body  Circumduction – circular movement

Body Movements Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.13

 Dorsifelxion  Plantar flexion Special Movements

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Inversion  Eversion

 Opposition  Supination  Pronation

What is a strain? Strains are injuries that involve the stretching or tearing of a musculo-tendinous (muscle and tendon) structure What is a sprain? A sprain is an injury involving the stretching or tearing of a ligament (tissue that connects bone to bone) Strain vs. Sprain

Ankle Sprains

Examples of Strains

Grade I (mild) sprain or strain involves some stretching or minor tearing of a ligament or muscle. Grade II (moderate) sprain or strain is a ligament or muscle that is partially torn but still intact. Grade III (severe) sprain or strain means that the ligament or muscle is completely torn, resulting in joint instability.

 R – rest  I - immobilize (ice)  C - compression  E - elevation

 Most surgery for ACL injuries involves replacing the ACL with tissue called a graft  Usually an autograft (tendon taken from another part of the body) is used  The most common grafts used are the tendon of the kneecap or one of the hamstring tendons  Another choice is allograft tissue, which is taken from a deceased donor

 Repairs an injured elbow ligament (UCL construction)  A surgeon replaces the injured UCL with a tendon taken from somewhere else in the patient’s body

Duchenne Muscular Dystrophy (DMD) Definition - One of nine types of muscular dystrophy, a group of genetic, degenerative diseases primarily affecting voluntary muscles. Cause - An absence of dystrophin, a protein that helps keep muscle cells intact. Information obtained from:

Onset - Early childhood - about 2 to 6 years. Symptoms - Generalized weakness first affecting the muscles of the hips, pelvic area, thighs and shoulders. Calves are often enlarged. Progression - DMD eventually affects all voluntary muscles, and the heart and breathing muscles. Inheritance - X-linked recessive. DMD primarily affects boys, who inherit the disease through their mothers. Women can be carriers of DMD but usually exhibit no symptoms.  Hayy4I