Chapter 10 Lecture Outline

Transcription

1 Chapter 10 Lecture Outline See separate PowerPoint slides for all figures and tables preinserted into PowerPoint without notes. Copyright McGraw-Hill Education. Permission required for reproduction or display. 1

2 Introduction Copyright The McGraw-Hill Education. Permission required for reproduction or display. Muscles constitute nearly half of the body s weight and are of central interest in several fields of health care and fitness Figure 10.5a 10-2

3 The Structural and Functional Organization of Muscles Expected Learning Outcomes Describe the varied functions of muscles. Describe the connective tissue components of a muscle and their relationship to the bundling of muscle fibers. Describe the various shapes of skeletal muscles and relate this to their functions. Explain what is meant by the origin, insertion, belly, action, and innervation of a muscle. 10-3

4 The Structural and Functional (Continued) Organization of Muscles Describe the ways that muscles work in groups to aid, oppose, or moderate each other s actions. Distinguish between intrinsic and extrinsic muscles. Describe, in general terms, the nerve supply to the muscles and where these nerves originate. Explain how the Latin names of muscles can aid in visualizing and remembering them. 10-4

5 The Structural and Functional Organization of Muscles About 600 human skeletal muscles Constitute about half of our body weight Three kinds of muscle tissue Skeletal, cardiac, smooth Specialized for one major purpose Converting the chemical energy in ATP into the mechanical energy of motion Myology the study of the muscular system 10-5

6 The Functions of Muscles Muscle functions include: movement, stability, control of openings, heat production, and glycemic control Movement Move from place to place; move body parts; move body contents in breathing, circulation, and digestion In communication: speech, writing, facial expressions and other nonverbal communications Stability Maintain posture by preventing unwanted movements Antigravity muscles: prevent us from falling over Stabilize joints by maintaining tension 10-6

7 The Functions of Muscles Control of openings and passageways Sphincters: internal muscular rings that control the movement of food, blood, and other materials within body Heat production by skeletal muscles As much as 85% of our body heat Glycemic control Muscles absorb and store glucose which helps regulate blood sugar concentration within normal range 10-7

8 Connective Tissues of a Muscle Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tendon Fascia Skeletal muscle Muscle fascicle Nerve Blood vessels Epimysium Perimysium Endomysium Muscle fiber Muscle fascicle Figure 10.1a Perimysium Muscle fiber (a) 10-8

9 Connective Tissues and Fascicles Endomysium Thin sleeve of loose connective tissue around each fiber Allows room for capillaries and nerve fibers Provides chemical environment for muscle fiber Perimysium Thicker layer of connective tissue that wraps fascicles Fascicles: bundles of muscle fibers wrapped together Carries nerves, blood vessels, and stretch receptors Epimysium Fibrous sheath surrounding entire muscle Outer surface grades into fascia; inner surface projections form perimysium Fascia Sheet of connective tissue that separates neighboring muscles or muscle groups from each other and the subcutaneous tissue 10-9

10 Connective Tissues and Fascicles Figure 10.1c 10-10

11 Fascicles and Muscle Shapes Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fusiform Parallel Triangular Unipennate Bipennate Multipennate Tendon Circular Belly Tendon Biceps brachii Rectus abdominis Pectoralis major Palmar interosseous Rectus femoris Figure 10.2 Deltoid Orbicularis oculi Strength of a muscle and the direction of its pull are determined partly by the orientation of its fascicles 10-11

12 Fascicles and Muscle Shapes Fusiform muscles thick in the middle and tapered at each end Parallel muscles uniform width and parallel fascicles Triangular (convergent) muscles broad at one end and narrow at the other Pennate muscles feather shaped - Unipennate fasciles approach tendon from one side - Bipennate fascicles approach tendon from both sides - Multipennate bunches of feathers converge to single point Circular muscles (sphincters) form rings around body openings 10-12

13 Muscle Compartments Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Key Lateral Anterior Posterior Anterior compartment Medial Lateral compartment Posterior compartment, deep layer Posterior compartment, superficial layer Tibia Fibula Interosseous membrane Artery, veins, and nerve Intermuscular septa Fasciae Subcutaneous fat Figure 10.3 Muscle compartment a group of functionally related muscles enclosed by fascia Also contains nerves and blood vessels that supply the muscle group Intermuscular septa are very thick fascia that separate one compartment from another 10-13

14 Muscle Attachments Indirect attachment to bone Tendons connect muscle to bone Collagen fibers of the endo-, peri-, and epimysium continue into the tendon and from there into periosteum and matrix of bone Aponeurosis tendon is a broad, flat sheet (palmar aponeurosis) Retinaculum connective tissue band that tendons from separate muscles pass under Direct (fleshy) attachment to bone Little separation between muscle and bone Muscle seems to emerge directly from bone 10-14

15 Muscle Origins and Insertions Origin Bony attachment at stationary end of muscle Belly Thicker, middle region of muscle between origin and insertion Origins Scapula Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extensors: Triceps brachii Long head Lateral head Origins Humerus Bellies Flexors: Biceps brachii Brachialis Insertion Bony attachment to mobile end of muscle Insertion Figure 10.4 Insertion Radius Ulna 10-15

16 Muscle Origins and Insertions Some anatomists prefer nontraditional descriptions of attachments by proximal vs. distal or superior vs. inferior Some muscles insert not on bone but on the fascia or tendon of another muscle or on collagen fibers of the dermis Example: many facial muscles insert in the skin 10-16

17 Functional Groups of Muscles Action effect produced by a muscle to produce or prevent movement Four categories of muscle action: prime mover, synergist, antagonist, and fixator Prime mover (agonist) Muscle that produces most of force during a particular joint action Synergist: muscle that aids the prime mover May contribute additional force, modify the direction of movement, or stabilize a nearby joint 10-17

18 Functional Groups of Muscles (Continued) Antagonist: opposes the prime mover Prevents excessive movement Sometimes relaxes to give prime mover control over an action Antagonistic pairs muscles that act on opposite sides of a joint Fixator: muscle that prevents movement of bone 10-18

19 Functional Groups of Muscles Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Origins Scapula Extensors: Triceps brachii Long head Lateral head Insertion Origins Humerus Bellies Flexors: Biceps brachii Brachialis Insertion Radius Ulna For elbow flexion: Prime mover brachialis Synergist biceps brachii Antagonist triceps brachii Fixator muscle that holds scapula firmly in place Rhomboids Figure

20 Intrinsic and Extrinsic Muscles Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (b) Intermediate flexor Figure 10.28b Flexor digitorum superficialis tendons Flexor digitorum profundus tendons Common flexor tendon Flexor digitorum superficialis Flexor pollicis longus Intrinsic muscle entirely contained within a region, such as the hand Both origin and insertion there Extrinsic muscle acts on a designated region, but has its origin elsewhere Fingers: extrinsic muscles in the forearm Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tendon sheath Tendon of flexor digitorum profundus Tendon of flexor digitorum superficialis Lumbricals Opponens digiti minimi Flexor digiti Abductor digiti minimi Flexor retinaculum Tendons of: Flexor carpi ulnaris Flexor digitorum superficialis Palmaris longus (a) Palmar aspect, superficial Figure 10.31a First dorsal interosseous Adductor pollicis Tendon of flexor pollicis longus Flexor pollicis brevis Abductor pollicis brevis Opponens pollicis Tendons of: Abductor pollicis longus Flexor carpi radialis Flexor pollicis longus 10-20

21 Muscle Innervation Innervation of a muscle refers to the identity of the nerve that stimulates it Knowing innervation enables diagnosis of nerve, spinal cord, and brainstem injuries from muscle tests Spinal nerves arise from the spinal cord Emerge through intervertebral foramina Immediately branch into posterior and anterior rami Innervate muscles below the neck Plexus: web-like network of spinal nerves adjacent to the vertebral column 10-21

22 Muscle Innervation Cranial nerves arise from the base of the brain Emerge through skull foramina Innervate the muscles of the head and neck Numbered CN I to CN XII 10-22

23 Blood Supply Muscular system receives about 1.24 L of blood per minute at rest (one-quarter of the blood pumped by the heart) During heavy exercise, total cardiac output rises and the muscular system s share is more than three-quarters (11.6 L/min) Capillaries branch extensively through the endomysium to reach every muscle fiber 10-23

24 How Muscles Are Named Latin names Depressor labii inferioris, flexor digiti minimi brevis Describes distinctive aspects of the structure, location, or action of a muscle Footnotes throughout chapters show interpreted names of muscles Pronunciation of muscles available online at

25 The Muscular System Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superficial Deep Frontalis Platysma Deltoid Pectoralis major Biceps brachii Brachioradialis Flexor carpi radialis External abdominal oblique Tensor fasciae latae Orbicularis oculi Zygomaticus major Masseter Orbicularis oris Sternocleidomastoid Trapezius Pectoralis minor Coracobrachialis Serratus anterior Brachialis Rectus abdominis Supinator Flexor digitorum profundus Flexor pollicis longus Transverse abdominal Internal abdominal oblique Pronator quadratus Adductor longus Sartorius Rectus femoris Vastus lateralis Vastus medialis Adductors Vastus lateralis Vastus intermedius Gracilis Fibularis longus Tibialis anterior Extensor digitorum longus (a) Anterior view Gastrocnemius Soleus Extensor digitorum longus Figure 10.5a Figure 10.5b 10-25

26 A Learning Strategy Examine models, cadavers, dissected animals, or a photographic atlas Palpate muscles on yourself if possible Locate origins and insertions of muscles on an articulated skeleton Study derivation of each muscle name Usually describes the muscle s location, appearance, origin, insertion, or action Say the names aloud to yourself or study partner, and spell them correctly 10-26

27 Muscles of the Head and Neck Expected Learning Outcomes Name and locate the muscles that produce facial expression. Name and locate the muscles used for chewing and swallowing. Name and locate the neck muscles that move the head. Identify the origin, insertion, action, and innervation of any of these muscles

28 Muscles of Facial Expression Muscles that insert in the dermis and subcutaneous tissues Tense the skin and produce facial expressions Innervated by facial nerve (CN VII) Paralysis causes face to sag Found in scalp, forehead, around the eyes, nose, and mouth, and in the neck 10-28

29 Muscles of Facial Expression Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superficial Deep Galea aponeurotica Frontalis Corrugator supercilii Orbicularis oculi Nasalis Levator labii superioris Zygomaticus minor Zygomaticus major Risorius Modiolus Depressor anguli oris Depressor labii inferioris Levator anguli oris Masseter Buccinator Orbicularis oris Mentalis (cut) Platysma (a) Anterior view Figure 10.8a 10-29

30 Muscles of Facial Expression Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Galea aponeurotica Temporalis Frontalis (cut) Corrugator supercilii Orbicularis oculi Occipitalis Zygomatic arch Nasalis Levator labii superioris Zygomaticus minor Zygomaticus major Masseter Sternocleidomastoid Levator scapulae Inferior pharyngeal constrictor Thyrohyoid Sternothyroid Omohyoid Sternohyoid (b) Lateral view Figure 10.8b Orbicularis oris Modiolus Risorius (cut) Mentalis Depressor labii inferioris Depressor anguli oris Buccinator 10-30

31 Muscles of Chewing and Swallowing Extrinsic muscles of the tongue Tongue is very agile organ Pushes food between molars for chewing (mastication) Forces food into the pharynx for swallowing (deglutition) Crucial importance to speech Intrinsic muscles of tongue Vertical, transverse, and longitudinal fascicles Palatoglossus Styloglossus Inferior longitudinal muscle of tongue Genioglossus Mylohyoid (cut) Geniohyoid Styloid process Mastoid process Posterior belly of digastric (cut) Superior pharyngeal constrictor (cut) Stylohyoid Middle pharyngeal constrictor Hyoglossus Hyoid bone Larynx Inferior pharyngeal constrictor Trachea Esophagus Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure

32 Muscles of Chewing and Swallowing Four pairs of muscles produce biting and chewing movements of the mandible Depression: to open mouth Elevation: biting and grinding Protraction: incisors can cut Retraction: make rear teeth meet Lateral and medial excursion: grind food Temporalis, masseter, medial pterygoid, and lateral pterygoid Innervated by mandibular nerve, a branch of the trigeminal (CN V) Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Temporalis Orbicularis oris Buccinator Masseter (cut) (a) Lateral view Lateral pterygoid plate Medial pterygoid plate Lateral pterygoid muscle Medial pterygoid muscle Interior of oral cavity (b) Posterior view Figure 10.10a,b 10-32

33 Muscles of Chewing and Swallowing Hyoid muscles suprahyoid group Aspects of chewing, swallowing, and vocalizing Eight pairs of hyoid muscles associated with hyoid bone Digastric opens mouth widely Geniohyoid depresses mandible Mylohyoid elevates floor of mouth at beginning of swallowing Stylohyoid elevates hyoid Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superficial Deep Suprahyoid group Levator scapulae Digastric: Anterior belly Posterior belly Stylohyoid Mylohyoid Hyoid bone Common carotid artery Internal jugular vein Infrahyoid group Sternocleidomastoid Sternohyoid Omohyoid: Superior belly Inferior belly Thyrohyoid Sternothyroid Clavicle Infrahyoid group (a) Anterior view Figure 10.11a 10-33

34 Muscles of Chewing and Swallowing Hyoid muscles infrahyoid group Fix hyoid bone from below, allowing suprahyoid muscles to open mouth Omohyoid depresses hyoid after elevation Sternohyoid depresses hyoid after elevation Thyrohyoid depresses hyoid and elevates larynx Sternothyroid depresses larynx after elevation Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stylohyoid Hyoglossus Mylohyoid Digastric (anterior belly) Hyoid bone Thyrohyoid Omohyoid (superior belly) Sternothyroid Sternohyoid (b) Lateral view Digastric (posterior belly) Splenius capitis Inferior pharyngeal constrictor Sternocleidomastoid Trapezius Levator scapulae Scalenes Omohyoid (inferior belly) Figure 10.11b 10-34

35 Muscles of Chewing and Swallowing Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Styloid process Palatoglossus Styloglossus Mastoid process Posterior belly of digastric (cut) Superior pharyngeal constrictor (cut) Inferior longitudinal muscle of tongue Genioglossus Stylohyoid Middle pharyngeal constrictor Hyoglossus Mylohyoid (cut) Hyoid bone Geniohyoid Larynx Inferior pharyngeal constrictor Trachea Esophagus Figure 10.9 Pharynx: three pairs pharyngeal constrictors Encircle pharynx forming a muscular funnel During swallowing, drive food into the esophagus 10-35

36 Muscles Acting on the Head Originate on vertebral column, thoracic cage, and pectoral girdle Insert on the cranial bones Actions Flexion (tipping head forward) Extension (holding the head erect) Lateral flexion (tipping head to one side) Rotation (turning the head to the left and right) 10-36

37 Muscles Acting on the Head Neck flexors Sternocleidomastoid Scalenes Neck extensors Trapezius Splenius capitis Semispinalis capitis Figure

38 Muscles Acting on the Head May cause contralateral movement: movement of the head toward the opposite side May cause ipsilateral movement: movement of the head toward the same side 10-38

39 Muscles of the Trunk Expected Learning Outcomes Name and locate the muscles of respiration and explain how they affect airflow and abdominal pressure. Name and locate the muscles of the abdominal wall, back, and pelvic floor. Identify the origin, insertion, action, and innervation of any of these muscles

40 Muscles of the Trunk Three functional groups Muscles of respiration Muscles that support abdominal wall and pelvic floor Movement of vertebral column 10-40

41 Muscles of Respiration Breathing requires the use of muscles enclosing thoracic cavity Diaphragm, external intercostal, internal intercostal, and innermost intercostal muscles Inspiration air intake Expiration expelling air 10-41

42 Muscles of Respiration Other muscles of chest and abdomen that contribute to breathing Sternocleidomastoid, scalenes of neck Pectoralis major and serratus anterior of chest Latissimus dorsi of back Abdominal muscles: internal and external obliques, and transverse abdominis Even some anal muscles 10-42

43 Muscles of Respiration Diaphragm muscular dome between thoracic and abdominal cavities Muscle fascicles extend to a fibrous central tendon Contraction flattens diaphragm Enlarges thoracic cavity (inspiration) In relaxation of diaphragm it rises Shrinks the thoracic cavity (expiration) Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (b) Inferior view of diaphragm Figure 10.13b Xiphoid process of sternum Inferior vena cava Ribs Esophagus Central tendon of diaphragm Aorta Vertebral column 10-43

44 Muscles of Respiration External intercostals Elevate ribs Expand thoracic cavity Create partial vacuum causing inflow of air Internal intercostals Depresses and retracts ribs Compresses thoracic cavity Expelling air Innermost intercostals Same action as internal intercostals Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Internal intercostals (a) Lateral view of intercostal muscles Figure 10.13a External intercostals 10-44

45 Muscles of the Anterior Abdominal Wall Internal abdominal oblique Intermediate layer of lateral abdominal muscles Unilateral contraction causes ipsilateral rotation of waist Aponeurosis Tendons of oblique and transverse muscles Broad, fibrous sheets Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Subclavius Pectoralis minor (cut) Pectoralis minor Internal intercostals Serratus anterior External intercostals Rectus abdominis (cut) Rectus sheath External abdominal oblique (cut) Internal abdominal oblique Inguinal ligament Internal abdominal oblique (cut) Posterior wall of rectus sheath (rectus abdominis removed) Transverse abdominal (cut) (b) Deep Figure 10.15b 10-45

46 Muscles of the Anterior Abdominal Wall Transverse abdominal Deepest of lateral abdominal muscles Horizontal fibers Compresses abdominal contents Contributes to movements of vertebral column Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Subclavius Pectoralis minor (cut) Pectoralis minor Internal intercostals Serratus anterior External intercostals Rectus abdominis (cut) Rectus sheath External abdominal oblique (cut) Internal abdominal oblique Inguinal ligament Internal abdominal oblique (cut) Posterior wall of rectus sheath (rectus abdominis removed) Transverse abdominal (cut) (b) Deep Figure 10.15b 10-46

47 Muscles of the Anterior Abdominal Wall Rectus abdominis Flexes lumbar region of vertebral column Produces forward bending at the waist Extends from sternum to pubis Rectus sheath encloses muscle Three transverse tendinous intersections divide rectus abdominis into segments, sometimes called a six pack Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pectoralis major Latissimus dorsi Serratus anterior Tendinous intersections Rectus sheath (cut edges) Rectus sheath Umbilicus Linea semilunaris Linea alba Aponeurosis of external abdominal oblique (a) Superficial Transverse abdominal Internal abdominal oblique (cut) External abdominal oblique (cut) Rectus abdominis Inguinal ligament Figure 10.15a 10-47

48 Muscles of Back Back muscles extend, rotate, and laterally flex vertebral column Most prominent superficial back muscles: latissimus dorsi and trapezius Upper limb movement Figure

49 Muscles of the Back Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Deep muscles Erector spinae Iliocostalis, longissimus, spinalis From cranium to sacrum Extension and lateral flexion of vertebral column Semispinalis thoracis Extension and contralateral rotation of vertebral column Superior nuchal line Longissimus capitis Splenius capitis Serratus posterior superior Splenius cervicis Erector spinae: Iliocostalis Longissimus Spinalis Serratus posterior inferior Internal abdominal oblique External abdominal oblique (cut) Semispinalis capitis Semispinalis cervicis Semispinalis thoracis Multifidus Quadratus lumborum Figure

50 Muscles of the Back (Continued) Quadratus lumborum Aids respiration Ipsilateral flexion of lumbar vertebral column Multifidus Stabilizes adjacent vertebrae Maintains posture 10-50

51 Muscles of the Pelvic Floor Layers of muscles and fasciae that span pelvic outlet Penetrated by anal canal, urethra, and vagina Perineum diamond-shaped region between the thighs Bordered by four bony landmarks Pubic symphysis anteriorly Coccyx posteriorly Ischial tuberosities laterally Urogenital triangle: anterior half of perineum Anal triangle: posterior half of perineum 10-51

52 Muscles of the Pelvic Floor Layers or compartments of the perineum Superficial perineal space Ischiocavernosus, bulbospongiosus Deep perineal space Deep transverse perineal, compressor urethrae Anal triangle External anal sphincter Pelvic diaphragm: deepest (most superior) layer Levator ani 10-52

53 Muscles of the Pelvic Floor Figure 10.20a Superficial perineal space Ischiocavernosus maintains erection Bulbospongiosus aids in erection, expels remaining urine 10-53

54 Muscles of the Pelvic Floor Figure 10.20b Deep perineal space Urogenital triangle contains deep transverse perineal muscle and compressor urethrae in females Anal triangle external anal sphincter 10-54

55 Muscles of the Pelvic Floor Figure 10.20c Pelvic diaphragm: deepest compartment of the perineum Levator ani: supports viscera and defecation Coccygeus muscle(s) 10-55

56 Hernias Hernia any condition in which the viscera protrudes through a weak point in the muscular wall of the abdominopelvic cavity Inguinal hernia Most common type of hernia (rare in women) Viscera enter inguinal canal or even the scrotum Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Aponeurosis of external abdominal oblique muscle Inguinal canal External inguinal ring Herniated loop of small intestine Upper scrotum Hiatal hernia Stomach protrudes through diaphragm into thorax Overweight people over 40 Figure Umbilical hernia Viscera protrude through the navel 10-56

57 Muscles Acting on the Shoulder and Upper Limb Expected Learning Outcomes Name and locate the muscles that act on the pectoral girdle, shoulder, elbow, wrist, and hand. Relate the actions of these muscles to the joint movements described in chapter 9. Describe the origin, insertion, and innervation of each muscle

58 Muscles Acting on the Shoulder and Upper Limb Compartments spaces where muscles are separated by fibrous connective tissue sheets (fasciae) Each compartment contains one or more functionally related muscles along with their nerve and blood supplies Muscles of upper limbs divided into anterior and posterior compartments Intermuscular septa (thick fascia) separates compartments Compartment syndrome one of the muscles or blood vessels in a compartment is injured 10-58

59 Compartment Syndrome If a blood vessel in a compartment is damaged, blood and tissue fluid accumulate Fasciae enclose muscle compartments snugly and prevent expansion Compartment syndrome mounting pressure triggers a sequence of degenerative events Blood flow to compartment is obstructed by pressure If ischemia (poor blood flow) persists for more than 2 to 4 hours, nerves begin to die After 6 hours, muscles begin to die Nerves can regenerate after pressure relieved, but muscle damage is permanent Myoglobin in urine indicates compartment syndrome Treatment: immobilization of limb and fasciotomy (incision to relieve compartment pressure) 10-59

60 Muscles Acting on the Shoulder and Upper Limb Upper limb is used for a broad range of powerful and subtle actions Climbing, grasping, throwing, writing, playing musical instruments, and manipulating small objects Muscles that act on the scapula Muscles that act on the humerus and shoulder joint Muscles that act on the forearm and elbow joint Muscles that act on the wrist, hand, and fingers 10-60

61 Muscles Acting on the Shoulder A group of muscles originate on the axial skeleton and insert on clavicle or scapula Scapula loosely attached to thoracic cage Capable of great movement Rotation, elevation, depression, protraction, retraction Clavicle braces the shoulder and moderates movements 10-61

62 Muscles Acting on the Scapula Figure

63 Muscles Acting on the Shoulder Anterior group of muscles of pectoral girdle Pectoralis minor Ribs 3 5 to coracoid process of scapula Draws scapula laterally Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Subclavius Pectoralis minor (cut) Serratus anterior All ribs to medial border of scapula Draws scapula laterally and forward; prime mover for reaching and pushing Pectoralis minor Internal intercostals Serratus anterior External intercostals Rectus abdominis (cut) Rectus sheath External abdominal oblique (cut) Internal abdominal oblique Inguinal ligament Internal abdominal oblique (cut) Posterior wall of rectus sheath (rectus abdominis removed) Transverse abdominal (cut) (b) Deep Figure 10.15b 10-63

64 Muscles Acting on the Shoulder Posterior group of muscles of pectoral girdle Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superficial Deep Four muscles of posterior group Trapezius: superficial Levator scapulae, Rhomboid minor, and Rhomboid major: deep Trapezius Stabilizes scapula and shoulder Elevates and depresses shoulder apex Sternocleidomastoid Trapezius Deltoid Erector spinae Latissimus dorsi External abdominal oblique Thoracolumbar fascia Gluteus medius Gluteus maximus Semispinalis capitis Splenius capitis Levator scapulae Rhomboid minor Rhomboid major Supraspinatus Infraspinatus Teres minor Teres major Serratus anterior Serratus posterior inferior External abdominal oblique Internal abdominal oblique Gluteus minimus Lateral rotators Figure

65 Muscles Acting on the Shoulder (Continued from slide 170) Levator scapulae Elevates scapula Flexes neck laterally Rhomboid minor Retracts scapula and braces shoulder Rhomboid major Same as Rhomboid minor 10-65

66 Muscles Acting on the Shoulder Posterior scapular muscles Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superficial Deep Sternocleidomastoid Trapezius Deltoid Semispinalis capitis Splenius capitis Levator scapulae Rhomboid minor Rhomboid major Supraspinatus Infraspinatus Teres minor Teres major Erector spinae Serratus anterior Serratus posterior inferior Latissimus dorsi External abdominal oblique External abdominal oblique Thoracolumbar fascia Gluteus medius Internal abdominal oblique Gluteus minimus Gluteus maximus Lateral rotators Figure

67 Muscles Acting on the Arm Nine muscles cross the shoulder joint and insert on humerus Two are axial muscles originating on axial skeleton Pectoralis major: flexes, adducts, and medially rotates humerus Latissimus dorsi: adducts and medially rotates humerus Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Deltoid Clavicle Sternum Pectoralis major Supraspinatus Spine of scapula Greater tubercle of humerus Infraspinatus Humerus Teres minor Teres major Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis Coracobrachialis Triceps brachii: Lateral head Long head Latissimus dorsi (a) Anterior view (b) Posterior view Figure 10.23a Figure 10.23b 10-67

68 Anterior View of Cadaver Chest Figure 10.24a 10-68

69 Back Muscles of Cadaver Figure 10.24b 10-69

70 Muscles Acting on the Arm Seven muscles with scapular origin Deltoid Rotates and abducts arm Intramuscular injection site Teres major Extension and medial rotation of humerus Coracobrachialis Flexes and medially rotates arm Remaining four form the rotator cuff that reinforce the shoulder joint Deltoid Figure 10.23a Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Clavicle Sternum Pectoralis major Coracobrachialis Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supraspinatus Spine of scapula Greater tubercle of humerus Infraspinatus Humerus Teres minor Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Figure 10.23b (b) Posterior view 10-70

71 Muscles Acting on the Arm Rotator cuff muscles Tendons of the remaining four scapular muscles form the rotator cuff Acronym SITS muscles Supraspinatus Infraspinatus Teres minor Subscapularis Tendons of these muscles merge with the joint capsule of the shoulder as they cross it in route to the humerus Holds head of humerus into glenoid cavity Supraspinatus tendon easily damaged 10-71

72 Rotator Cuff Muscles Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior Posterior Rotator cuff (SITS) muscles: Supraspinatus Infraspinatus Teres minor Subscapularis Clavicle Acromion Coracoid process Glenoid cavity Inferior angle Figure

73 Muscles Acting on the Forearm Elbow and forearm capable of flexion, extension, pronation, and supination Carried out by muscles in both brachium (arm) and antebrachium (forearm) Muscles with bellies in the arm (brachium) Principal elbow flexors: anterior compartment Brachialis and biceps brachii Brachialis produces 50% more power than biceps brachii Brachialis is prime mover of elbow flexion Principal elbow extensor: posterior compartment Triceps brachii Prime mover of elbow extension 10-73

74 Muscles Acting on the Forearm Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Principal flexor Brachialis Figure 10.23c Biceps brachii: Long head Short head Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Synergistic flexors Biceps brachii Brachioradialis Principal extensor Triceps brachii Deltoid Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Figure 10.23a Clavicle Sternum Pectoralis major Coracobrachialis Figure 10.23b (c) Anterior view Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supraspinatus Spine of scapula Greater tubercle of humerus Infraspinatus Humerus Teres minor Teres major Triceps brachii: Lateral head Long head Latissimus dorsi (b) Posterior view 10-74

75 Muscles Acting on the Forearm Muscles with bellies in the forearm (antebrachium) Brachioradialis: flexes elbow Anconeus: extends elbow Pronator quadratus: prime mover in forearm pronation Pronator teres: assists pronator quadratus in pronation Supinator: supinates the forearm 10-75

76 Muscles Acting on the Forearm Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lateral epicondyle Medial epicondyle Supinator Pronator teres Lateral epicondyle Medial epicondyle Supinator Pronator teres Ulna Radius Pronator quadratus Biceps brachii Ulna Radius Pronator quadratus Biceps brachii Radius Supinator Bursa Ulna Radius Supinator Bursa Ulna (b) Muscle actions in supination (b) Muscle actions in supination (a) Supination Figure 10.26a Figure 10.26c Supination Supinator muscle Palm facing anteriorly or superiorly (c) Pronation Pronation Pronator quadratus and pronator teres Palm faces posteriorly or inferiorly 10-76

77 Muscles Acting on the Wrist and Hand Anterior group Extrinsic muscles of the forearm Intrinsic muscles in the hand itself Extrinsic muscle actions Flexion and extension of wrist and digits Radial and ulnar flexion Finger abduction and adduction Thumb opposition Anterior view Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Biceps brachii Triceps brachii Brachialis Common flexor tendon Pronator teres Aponeurosis of biceps brachii Brachioradialis Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Extensor carpi radialis longus and brevis Flexor digitorum superficialis Flexor digitorum superficialis Common flexor tendon Flexor pollicis longus Supinator Interosseous membrane Flexor digitorum profundus Flexor pollicis longus Figure 10.28a,b,c (a) Superficial flexors Flexor retinaculum Palmar aponeurosis (b) Intermediate flexor Flexor digitorum superficialis tendons Flexor digitorum profundus tendons (c) Deep flexors Flexor digitorum superficialis tendons Flexor digitorum profundus tendons 10-77

78 Muscles Acting on the Wrist and Hand Anterior (flexor) compartment superficial layer Flexor carpi radialis Flexor carpi ulnaris Flexor digitorum superficialis Palmaris longus Anterior (flexor) compartment deep layer Flexor digitorum profundus Flexor pollicis longus 10-78

79 Cross Section of Upper Limb Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Deltoid Pectoralis major Biceps brachii: Short head Long head (a) (b) (c) Coracobrachialis Humerus Latissimus dorsi tendon Teres major Triceps brachii: Lateral head Long head (a) Anterior Lateral Medial Biceps brachii Brachialis Key Posterior Anterior (flexor) compartment, superficial Anterior (flexor) compartment, deep Posterior (extensor) compartment Other muscles (b) Triceps brachii: Medial head Long head Lateral head Figure 10.27a,b,c Brachioradialis Supinator Radius Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris (c) Pronator teres Flexor carpi radialis Palmaris longus Flexor digitorum superficialis Flexor pollicis longus Flexor carpi ulnaris Flexor digitorum profundus Ulna Anconeus 10-79

80 Muscles Acting on the Wrist and Hand Posterior group Extension of wrist and fingers, adduct/abduct wrist Extension and abduction of thumb (pollicis) Brevis means short, ulnaris indicates on ulna side of forearm Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Triceps brachii Posterior view Anconeus Flexor carpi ulnaris Extensor carpi ulnaris Extensor digiti minimi Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Abductor pollicis longus Extensor pollicis brevis Olecranon Extensor pollicis longus Extensor indicis Anconeus Supinator Abductor pollicis longus Extensor pollicis brevis Tendon of extensor indicis Tendons of extensor digitorum Extensor pollicis longus Tendons of extensor carpi radialis longus and brevis Figure 10.29a,b (a) Superficial extensors (b) Deep extensors 10-80

81 Muscles Acting on the Wrist and Hand Posterior (extensor) compartment superficial layer Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Posterior (extensor) compartment deep layer Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis 10-81

82 Carpal Tunnel Syndrome Flexor retinaculum bracelet-like fibrous sheet, passed under by flexor tendons crossing the wrist Carpal tunnel tight space between the flexor retinaculum and the carpal bones Flexor tendons passing through the tunnel are enclosed in tendon sheaths Enable tendons to slide back and forth quite easily 10-82

83 Carpal Tunnel Syndrome Carpal tunnel syndrome prolonged, repetitive motions of wrist and fingers cause tissues in the carpal tunnel to become inflamed, swollen, or fibrotic Puts pressure on median nerve of wrist that passes through the carpal tunnel along with flexor tendons Tingling and muscular weakness in the palm and medial side of the hand Pain may radiate to arm and shoulder Treatment: anti-inflammatory drugs, immobilization of the wrist, and sometimes surgery to remove part or all of flexor retinaculum 10-83

84 Carpal Tunnel Syndrome Repetitive motions cause inflammation and pressure on median nerve Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 10.31b Tendon sheath Tendon of flexor digitorum profundus Tendon of flexor digitorum superficialis Lumbricals Opponens digiti minimi Flexor digiti minimi brevis Abductor digiti minimi Flexor retinaculum Tendons of: Flexor carpi ulnaris Flexor digitorum superficialis Palmaris longus First dorsal interosseous Adductor pollicis Tendon of flexor pollicis longus Flexor pollicis brevis Abductor pollicis brevis Opponens pollicis Tendons of: Abductor pollicis longus Flexor carpi radialis Flexor pollicis longus (a) Palmar aspect, superficial Figure 10.31a 10-84

85 Intrinsic Muscles of the Hand Thenar group form thick, fleshy mass at base of thumb Adductor pollicis Abductor pollicis brevis Flexor pollicis brevis Opponens pollicis Hypothenar group fleshy base of the little finger Abductor digiti minimi Flexor digiti minimi brevis Opponens digiti minimi Midpalmar group hollow of palm Dorsal interosseous muscles (4) Palmar interosseous muscles (3) Lumbricals (4 muscles) 10-85

86 Muscles Acting on the Hip and Lower Limb Expected Learning Outcomes Name and locate the muscles that act on the hip, knee, ankle, and toe joints. Relate the actions of these muscles to the joint movements described in chapter 9. Describe the origin, insertion, and innervation of each muscle

87 Muscles Acting on the Hip and Lower Limb Body s largest muscles found in lower limb Less for precision, more for strength needed to stand, maintain balance, walk, and run Several cross and act on two or more joints Leg the part of the limb between the knee and ankle Foot includes tarsal region (ankle), metatarsal region, and the toes 10-87

88 Muscles Acting on the Hip and Femur Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior muscles of the hip Iliacus Flexes thigh at hip Iliacus portion arises from iliac crest and fossa Psoas major Flexes thigh at hip Arises from lumbar vertebrae They share a common tendon on the femur Iliopsoas: Iliacus Psoas major Pectineus Adductor magnus Adductor brevis Adductor longus Gracilis Piriformis Obturator externus Insertion of gracilis on tibia Figure

89 Muscles Acting on the Hip and Femur Lateral and posterior muscles of the hip Tensor fasciae latae Extends knee, laterally rotates knee Gluteus maximus Forms mass of the buttock Prime hip extensor Provides most of lift when you climb stairs Gluteus medius and minimus Abduct and medially rotate thigh Figure

90 Muscles Acting on the Hip and Femur Posterior group Lateral rotators six muscles inferior to gluteus minimus Deep to the two other gluteal muscles Gemellus superior Gemellus inferior Obturator externus Obturator internus Piriformis Quadratus femoris 10-90

91 Muscles Acting on the Hip and Femur Medial (adductor) compartment of thigh Five muscles act as primary adductors of the thigh Adductor brevis Adductor longus Adductor magnus Gracilis Pectineus Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Iliopsoas: Iliacus Psoas major Pectineus Adductor magnus Adductor brevis Adductor longus Gracilis Insertion of gracilis on tibia Figure Piriformis Obturator externus 10-91

92 Muscles Acting on the Knee and Leg Anterior (extensor) compartment of the thigh Contains large quadriceps femoris muscle Prime mover of knee extension Most powerful muscle in the body Has four heads rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius All converge on single quadriceps (patellar) tendon Extends to patella Then continues as patellar ligament Inserts on tibial tuberosity Sartorius: longest muscle in the body Tailor s muscle 10-92

93 Anterior Thigh Cadaver Muscles Figure

94 Muscles Acting on the Knee and Leg Figure 10.35a,b 10-94

95 Muscles Acting on the Knee and Leg Posterior (flexor) compartment of the thigh Contains hamstring muscles From lateral to medial: Biceps femoris Semitendinosus Semimembranosus Figure

96 Muscles Acting on the Foot Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (a) Posterior (b) Lateral Medial Figure 10.40b Key b Anterior (extensor) compartment Lateral (fibular) compartment Posterior (flexor) compartment, superficial Posterior (flexor compartment, deep) Anterior Gastrocnemius (lateral head) Fibularis longus (b) Fibula Fibularis brevis Extensor hallucis longus Extensor digitorum longus Gastrocnemius (medial head) Soleus Flexor hallucis longus Flexor digitorum longus Tibialis posterior Tibia Tibialis anterior Crural muscles, acting on the foot, are separated into three compartments Anterior compartment (red) Fibular (lateral) compartment (green) Posterior compartments (superficial = pink) (deep = purple) 10-96

97 Muscles Acting on the Foot Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Patella Patellar ligament Fibularis longus Tibia Gastrocnemius Fibularis brevis Extensor digitorum longus Extensor retinacula Soleus Tibialis anterior Tibialis anterior Extensor hallucis brevis Extensor digitorum brevis Extensor hallucis longus Fibularis tertius (a) (b) (c) (d) Extensor digitorum longus Anterior (extensor) compartment of the leg Dorsiflex the ankle Prevent toes from scuffing ground when walking Fibularis (peroneus) tertius Extensor digitorum longus Extensor hallucis longus Tibialis anterior Figure 10.38a d 10-97

98 Muscles Acting on the Foot Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plantaris Popliteus Heads of gastrocnemius (cut) Fibularis longus Gastrocnemius: Medial head Lateral head Tendon of plantaris Soleus Tendon of gastrocnemius Flexor digitorum longus Gastrocnemius (cut) Fibularis longus Fibularis brevis Flexor hallucis longus Figure 10.38a,b Calcaneal tendon (a) Calcaneus (b) Posterior compartment three muscles of the superficial group Gastrocnemius: plantar flexes foot, flexes knee Soleus: plantar flexes foot Plantaris: weak synergist of triceps surae Triceps surae collective name for gastrocnemius and soleus Inserts on calcaneus by way of the calcaneal (Achilles) tendon Strongest tendon in the body 10-98

99 Muscles Acting on the Foot Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plantaris (cut) Tibialis posterior Flexor digitorum longus Popliteus Gastrocne -mius (cut) Soleus (cut) Fibula (b) (c) Tibialis posterior Flexor digitorum longus Fibularis longus Popliteus Flexor hallucis longus Fibularis brevis Flexor hallucis longus Calcaneal tendon (cut) (a) Calcaneus (d) Plantar surface of the foot Figure Posterior compartment four muscles in the deep group Flexor digitorum longus: flexes phalanges Flexor hallucis longus: flexes great toe Tibialis posterior: inverts foot Popliteus: acts on knee 10-99

100 Muscles Acting on the Foot Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plantaris (cut) Gastrocnemius (cut) Popliteus Lateral (fibular) compartment two muscles Fibularis longus Fibularis brevis Soleus (cut) Flexor digitorum longus Fibula Tibialis posterior Fibularis longus Flexor hallucis longus Fibularis brevis Both plantar flex and evert the foot Provide lift and forward thrust Calcaneal tendon (cut) Calcaneus Figure 10.39a (a)

101 Intrinsic Muscles of Foot One dorsal muscle Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extensor digitorum brevis extends toes Flexor digiti minimi brevis Abductor digiti minimi Abductor hallucis Flexor digitorum brevis Plantar aponeurosis (cut) Quadratus plantae Flexor digitorum brevis (cut) Lumbricals Flexor hallucis longus tendon Flexor digitorum longus tendon Abductor hallucis (cut) Calcaneus Four ventral muscle layers (a) Layer 1, plantar view (b) Layer 2, plantar view Figure 10.41a e Support arches Abduct and adduct the toes Flexor digiti minimi brevis Adductor hallucis Flexor hallucis brevis Flexor hallucis longus tendon (cut) Plantar interosseous Dorsal interosseous Flex the toes Quadratus plantae (cut) Abductor hallucis (cut) Flexor digitorum longus tendon (cut) Dorsal view (c) Layer 3, plantar view (d) Layer 4, plantar view (e) Layer 4, dorsal view

102 Common Athletic Injuries Muscles and tendons are vulnerable to sudden and intense stress Proper conditioning and warm-up needed Common injuries include: Compartment syndrome Shin splints Pulled hamstrings Tennis elbow Pulled groin Rotator cuff injury Treat with rest, ice, compression, and elevation No pain, no gain is a dangerous misconception