1. Muscles of the Body
Dr. Nichols Coronado HS

2. Attachments and Actions of Skeletal Muscles
Actions depend largely on what the muscles are attached to
Attachment sites
Origin – an attachment site for a less movable bone
Insertion – an attachment site for a more movable bone

3. Attachments and Actions (cont.)
Movement usually produced by a group of muscles
Prime mover (agonist) – muscle responsible for most of the movement
Synergists – muscles that help the prime mover by stabilizing joints
Antagonist – muscle that produces movement opposite to prime mover
Relaxes when prime mover contracts

4. Figure of Body Movements
Flexion – bending a body part
Extension – straightening a body part
Hyperextension – extending a body part past the normal anatomical position
Dorsiflexion – pointing the toes up
Plantar flexion – pointing the toes down
Abduction – moving a body part away from the anatomical position
Adduction – moving a body part toward the anatomical position
Figure of Body Movements

5. Body Movements (cont.)
Back

6. Body Movements (cont.) Circumduction – moving a body part in a circle
Pronation – turning the palm of the hand down
Supination – turning the palm of the hand up

7. Body Movements (cont.)
Inversion – turning the sole of the foot medially
Eversion – turning the sole of the foot laterally
Retraction – moving a body part posteriorly
Protraction – moving a body part anteriorly

8. Body Movements (cont.)
Elevation – lifting a body part; for example, elevating the shoulders as in a shrugging expression
Depression – lowering a body part; for example, lowering the shoulders

9. Correct! Apply Your Knowledge
The doctor has asked you to abduct the patient’s leg so he can see the patient’s wound. In order to position the patient correctly, what will you have to do?
ANSWER: Move the patient’s leg away from its position in the anatomical position.
Correct!

10. Major Skeletal Muscles
The muscle name indicates
Location
Size
Action
Shape OR
Number of attachments of the muscle
As you study muscles, you will find it easier to remember them if you think about what the name describes.

11. Muscles of the Head Sternocleidomastoid Frontalis Splenius capitis
Pulls the head to one side
Pulls the head to the chest
Frontalis
Raises the eyebrows
Splenius capitis
Rotates the head
Allows it to bend to the side
Orbicularis oris
Allows the lips to pucker

12. Muscles of the Head (cont.)
Orbicularis oculi
Allows the eyes to close
Zygomaticus
Pulls the corners of the mouth up
Platysma
Pulls the corners of the mouth down
Masseter and temporalis
Close the jaw

13. Arm Muscles Pectoralis major Latissimus dorsi
Pulls the arm across the chest
Rotates and adducts the arms
Latissimus dorsi
Extends and adducts the arm and rotates the arm inwardly

14. Arm Muscles (cont.) Deltoid Subscapularis Infraspinatus
Abducts and extends the arm at the shoulder
Subscapularis
Rotates the arm medially
Infraspinatus
Rotates the arm laterally

15. Arm Muscles (cont.) Biceps brachii Brachialis Brachioradialis
Flexes the arm at the elbow
Rotates the hand laterally
Brachialis
Brachioradialis
Flexes the forearm at the elbow

16. Arm Muscles (cont.) Triceps brachii Supinator Pronator teres
Extends the arm at the elbow
Supinator
Rotates the forearm laterally (supination)
Pronator teres
Rotates the forearm medially (pronation)

17. Wrist, Hand, and Finger Muscles
Flexor carpi radialis and flexor carpi ulnaris
Flex and abduct the wrist
Palmaris longus
Flexes the wrist
Flexor digitorum profundus
Flexes the distal joints of the fingers, but not the thumb

18. Wrist, Hand, and Finger Muscles (cont.)
Extensor carpi radialis longus and brevis
Extend the wrist and abduct the hand
Extensor carpi ulnaris
Extends the wrist
Extensor digitorum
Extends the fingers, but not the thumb

19. Respiratory Muscles Diaphragm External and internal intercostals
Separates the thoracic cavity from the abdominal cavity
Its contraction causes inspiration
External and internal intercostals
Expand and lower the ribs during breathing

20. Click for View of Abdominal Muscles
External and internal obliques
Compress the abdominal wall
Transverse abdominis
Also compresses the abdominal wall
Rectus abdominis
Flexes the vertebral column
Compresses the abdominal wall
Click for View of Abdominal Muscles

21. Click for View of Pectoral Girdle Muscles
Trapezius
Raises the arms
Pulls the shoulders downward
Pectoralis minor
Pulls the scapula downward
Raises the ribs
Click for View of Pectoral Girdle Muscles

22. Leg Muscles Iliopsoas major Gluteus maximus Gluteus medius and minimus
Flexes the thigh
Gluteus maximus
Extends the thigh
Gluteus medius and minimus
Abduct the thighs
Rotate them medially

23. Leg Muscles (cont.) Adductor longus and magnus
Adduct the thighs
Rotate them laterally
Biceps femoris, semitendinosus, and semimembranosus
Known as the hamstring group
Flex the leg at the knee
Extend the leg at the thigh

24. Leg Muscles (cont.)
Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius
Extend the leg at the knee
Sartorius
Flexes the leg at the knee and thigh
Abducts the thigh, rotating the thigh laterally but rotating the lower leg medially

25. Ankle, Foot, and Toe Muscles
Tibialis anterior
Inverts the foot and points the foot up (dorsiflexion)
Extensor digitorum longus
Extends the toes and points the foot up
Gastrocnemius
Flexes the foot and flexes the leg at the knee

26. Ankle, Foot, and Toe Muscles (cont.)
Soleus
Flexes the foot
Flexor digitorum longus
Flexes the foot and toes

27. Bravo! Apply Your Knowledge
Your patient complains of hurting his hamstring when running today. You would look at what part of the leg, and what muscles would be involved?
ANSWER: You would look at the back of his leg, and the muscles involved would be the biceps femoris, semitendinosus, and semimembranosus. These three muscles are known as the hamstring group.
Bravo!

28. Muscle Strains and Sprains
Strains – injuries due to over-stretched muscles or tendons
Sprains – more serious injuries that result in tears to tendons, ligaments, and/or cartilage of joints
RICE is recommended treatment for either
Rest
Ice
Compression
Elevation

29. Muscle Strains and Sprains (cont.)
Prevention
Warm up muscles
A few minutes before an intense activity raises muscle temperature and makes muscle more pliable
Stretching
Improves muscle performance and should always be done after the warm-up or after exercising
Cooling down or slowing down
Before completely stopping prevents pooling of blood in the legs and helps remove lactic acid from muscles

30. Aging and the Musculoskeletal System
Contractions become slower and not as strong
Dexterity and gripping ability decrease
Mobility may decrease
Assistive devices helpful
Routine exercise
Swimming
Physical therapy

31. Diseases and Disorders of the Muscular System
Description
Botulism
Affects the gastrointestinal tract and various muscle groups
Fibromyalgia
Fairly common condition that causes chronic pain primarily in joints, muscles, and tendons
Muscular dystrophy
Inherited disorder characterized by muscle weakness and a loss of muscle tissue
Myasthenia gravis
Autoimmune condition in which patients experience muscle weakness

32. Diseases and Disorders of the Muscular System (cont.)
Description
Rhabdomyolysis
A condition in which the kidneys become damaged after serious muscle injuries
Tetanus (lockjaw)
Painful inflammation of a tendon and the tendon-muscle attachment to a bone
Torticollis (wryneck)
Acquired or congenital; spasm or shortening of the sternocleidomastoid muscle; head bends to affected side and chin rotates to opposite side
Trichinosis
An infection caused by parasites (worms)

33. Apply Your Knowledge Good Job!
The doctor has told your patient that his son has muscular dystrophy disorder. What is muscular dystrophy?
ANSWER: Muscular dystrophy is an inherited disorder characterized by muscle weakness and a loss of muscle tissue.
Good Job!

34. In Summary
22.1 The functions of muscles include movement, stability, control of body openings and passages, and the production of heat.
22.2 The three types of muscle tissue are striated voluntary skeletal muscle, smooth involuntary visceral muscle, and specialized striated and involuntary cardiac muscle.
22.3 Peristalsis is the rhythmic contraction produced by smooth muscle to push substances through various tubes in the body.

35. In Summary (cont.)
22.4 Muscles create energy in three ways. Creatine phosphate is a rapid method for muscles to create energy, aerobic respiration uses stored glucose to produce ATP in the Krebs cycle, and lactic acid production occurs when a cell is low in oxygen and coverts pyruvic acid to lactic acid.
22.5 Skeletal muscle is composed of connective tissues, skeletal muscle tissue, blood vessels, and nerves. The coverings of skeletal muscles include fascia, tendon, aponeurosis, epimysium, perimysium, and endomysium.

36. In Summary (cont.)
22.6 The origin of a muscle is the attachment site of the muscle to the less movable bone during muscle contraction. The insertion of a muscle is the attachment site for the muscle to the more movable bone during muscle contraction.
22.7 The body movements produced by skeletal muscles include flexion, extension, hyperextension, dorsiflexion, plantar flexion, abduction, adduction, rotation, circumduction, pronation, supination, inversion, eversion, retraction, protraction, elevation, and depression.

37. In Summary (cont.)
22.8 The major muscles of the head are sternocleidomastoid, splenius capitis, frontalis, orbicularis oris and oculi, zygomaticus, platysma, masseter, and temporalis. The upper extremity muscles include pectoralis major, latissimus dorsi, deltoid, subscapularis, biceps brachii, brachialis, brachioradialis, triceps brachii, supinator and pronator teres, flexor carpi radialis and ulnaris, plamaris longus, flexor digitorum profundus, extensor carpi radialis longus and brevis, and extensor digitorum. The major respiratory muscles are the diaphragm and the external and internal intercostals.

38. In Summary (cont.)
22.8 (cont.) The abdominal muscles include external and internal obliques, transverse abdominis, and rectus abdominis. The pectoral girdle muscles include trapezius and pectoralis minor. The muscles of the lower extremity include iliopsoas major; gluteus maximus, medius, and minimus; adductor longus and magnus; biceps femoris; semitendinosus and semimembranosus; rectus femoris; vastus lateralis, medius, and intermedius; sartorius; tibialis anterior; extensor digitorum longus; gastrocnemius; soleus; and flexor digitorum longus.

39. In Summary (cont.)
22.9 Strain injuries involve injuries to muscles and/or tendons. Sprains are more serious injuries that result in tears to tendons, ligaments, and/or the cartilage of joints.
22.10 The common diseases of aging include arthritis, fractures, osteoporosis, and muscular decline. Aging causes a decline in strength and speed of muscle contractions. Dexterity and gripping abilities lessen and mobility often decreases related to skeletal and muscular decline.

40. In Summary (cont.)
22.11 The diseases of the muscular system, as well as their symptoms and treatments, vary widely and are discussed in the Pathophysiology section of this chapter. Some of the common diseases discussed include botulism, fibromyalgia, muscular dystrophy, myasthenia gravis, tendonitis, tetanus, and torticollis.

41. End of Chapter 22
Everyone has a ‘risk muscle.’ You keep it in shape by trying new things. If you don’t, it atrophies. Make a point of using it at least once a day.
~Roger von Oech