Chapter 08 Lecture Outline

Transcription

1 Chapter 08 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 8.0 Skeletal System: Axial and Appendicular Skeleton Bones of the skeleton Support soft tissues Protect vital organs Bear body s weight Help us move 206 named bones in adult Differ in size, shape, and weight Can provide information about an individual 2

3 Axial and Appendicular Skeleton Figure 8.1 3

4 8.1b Bone Markings Bone markings Surface features that characterize each bone Projections o Where muscles, tendons, and ligaments attach Smooth areas o Sites of articulation between bones Depressions, grooves, and openings o Where blood vessels and nerves travel 4

5 Bone Markings Figure 8.2 5

6 8.2a General Anatomy of the Skull Skull Most complex structure in skeleton 22 bones Composed of o8 Cranial bones o14 Facial bones 6

7 8.2a General Anatomy of the Skull Cavities of the skull Largest, cranial cavity (endocranium) o Encloses, protects and supports brain Orbits (eye sockets) Oral cavity Nasal cavity Paranasal sinuses 7

8 Major Cavities of the Skull Figure 8.3 8

9 Frontal Bone glabella supraorbital margin superciliary arch 9

10 Parietal Bones attached to all four sutures 10

11 Temporal Bones external acoustic meatus internal acoustic meatus styloid process mastoid process zygomatic process carotid canal stylomastoid foramen jugular foramen* 11

12 Occipital Bone External occipital protuberance Occipital condyles Foramen magnum Hypoglossal canal Jugular foramen* 12

13 Sphenoid Bone greater/lesser wing medial/lateral pterygoid plates superior orbital fissure optic canal foramen ovale foramen rotundum foramen spinosum sella turcica 13

14 Ethmoid Bone crista galli cribiform plate superior/middle nasal conchae perpendicular plate 14

15 Zygomatic Bone (Table 8.3a) 15

16 Lacrimal Bone (Table 8.3b) 16

17 Vomer (Table 8.3c) 17

18 Inferior Nasal Concha (Table 8.3d) 18

19 Palatine Bone (Table 8.3e) 19

20 Maxilla (Table 8.3f) 20

21 Mandible (Table 8.3g) 21

22 8.2c Sutures Sutures Immovable joints Form boundaries between cranial bones Connected by dense regular CT Often with intricate interlocking forms Numerous in skull, each with specific name Named for bones or features they interconnect o E.g. occcipitomastoid suture connects occipital bone with mastoid process 22

23 8.2c Sutures Coronal suture Extends laterally across superior surface of skull Articulation between anterior frontal and posterior parietal bones Lambdoid suture Extends across posterior skull surface Articulates with parietal bones and occipital bone Named for resembling Greek letter lambda 23

24 8.2c Sutures Sagittal suture Extends between coronal and lambdoid sutures Articulates right and left parietal bones Squamous suture Articulates temporal bone and parietal bone on each side of skull Sutural bones Wormian bones Represent independent bone ossification centers Most common and numerous in lambdoid suture 24

25 8.4b Aging of the Skull Fontanelles Cranial bones interconnected by dense regular CT Soft spots on baby s head Enable some flexion in body plates during birth Ease baby s passage through birth canal Some close relatively quickly after birth o Small mastoid and sphenoidal fontanelles Posterior fontanelle closes at around 9 months Anterior fontanelle closes at around 15 months 25

26 Fetal Skull Figure

27 8.2c Sutures Sutures during the lifespan Typically closed as adjoining bones fuse Coronal usually in late 20s to early 30s Sagittal suture in 30s or later Lambdoid suture in 40s Squamous suture in 60+ years, or not at all Approximate age at death can be estimated from the extent of an individual s suture closure 27

28 Craniosynostosis Premature fusion of one or more cranial sutures If not surgically treated, individual grows up with unusual craniofacial shape Shape varies, according to which suture closed prematurely Plagiocephaly Clinical View: Craniosynostosis and Plagiocephaly Asymmetric head shape Caused by unilateral craniosynostosis or normal deformational factors 28

29 Anterior View of the Skull Figure 8.4 (top) 29

30 Superior View of the Skull Figure 8.5a 30

31 Posterior View of the Skull Figure 8.5b 31

32 Lateral View of the Skull Figure 8.6 (top) 32

33 Sagittal Section of the Skull Figure 8.7a 33

34 Inferior View of the Skull Figure 8.7b 34

35 Internal View of the Cranial Base Figure

36 What did you learn? What bones articulate at the lambdoid suture? Squamous suture? What are the 8 cranial bones? What are the 14 facial bones? Which bones form the nasal septum? Which bones form the hard palate? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 36

37 Orbital complex Orbits enclose and protect the eyes and muscles that move them Consists of multiple bones that form each orbit Figure

38 Paranasal Sinuses Figure

39 What did you learn? Which bones form the orbit? Where are the 4 paranasal sinuses located? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 39

40 8.3 Bones Associated with the Skull Auditory ossicles 3 tiny ear bones Housed within petrous part of each temporal bone Malleus, incus, and stapes Hyoid bone Inferior to skull between the mandible and the larynx Does not articulate with any other bone Sign of strangulation 40

41 Hyoid Bone Figure

42 8.5a Types of Vertebrae Vertebral column 24 individual vertebrae and fused the sacrum and coccyx Each articulates with one superior and one inferior vertebra Provides vertical support for body Supports weight of head Helps maintain an upright body position Houses and protects spinal cord 42

43 Cervical vertebrae Form bones of neck 7 vertebrae, C 1 C 7 C 1 articulates with occipital condyles C 7 articulates with first thoracic vertebra Support only the weight of the head Relatively small and light Distinguished by transverse foramina in transverse processes o 8.5a Types of Vertebrae House vertebral artery and vein 43

44 Cervical Vertebrae (Table 8.5a) 44

45 8.5c Vertebral Anatomy Cervical vertebrae (continued) Atlas (C 1 ) o Supports the head o Articulates with occipital condyles at the atlanto-occipital joint Permits nodding yes o Lacks body and spinous process o Lateral masses connected by anterior and posterior arches o Slight protuberances, anterior and posterior tubercles o Superior and inferior articular facets Articulate with occipital condyles and the axis o Articular facet for dens on its anterior arch 45

46 Atlas, Superior View Figure 8.18a 46

47 8.5c Vertebral Anatomy Cervical vertebrae (continued) Axis (C 2 ) o o o Body of axis fused here Produces dens Acts as a pivot for lateral rotation between atlas and skull Atlantoaxial joint between atlas and axis Permits shaking the head no 47

48 Atlas and Axis Figure 8.18 b-c 48

49 8.5a Types of Vertebrae Thoracic vertebrae Form superior region of the back Each articulates laterally with one or two pairs of ribs 12 vertebrae, T 1 T 12 T 12 articulates with first lumbar vertebra Heart-shaped bodies Costal facets or demifacets o On lateral side of body and on sides of transverse processes 49

50 Thoracic Vertebrae (Table 8.5b) 50

51 8.5a Types of Vertebrae Lumbar vertebrae Form inferior concave region ( small ) of the back 5 vertebrae, L 1 L 5 L 5 articulates inferiorly with first sacral vertebra Largest vertebrae Thicker, oval body Bear most of the weight of the body 51

52 Lumbar Vertebrae (Table 8.5c) 52

53 8.5c Vertebral Anatomy Sacrum Anteriorly curved, triangular bone Forms posterior wall of pelvic cavity Apex o Base o Narrow, pointed portion of the bone projecting inferiorly Broad superior surface 53

54 8.5c Vertebral Anatomy Sacrum (continued) 5 fused vertebrae Completely fused by age Transverse ridges o Horizontal lines of fusion remaining Articulates with L 5 superiorly o Via pair of superior articular processes 54

55 Sacrum (continued) Sacral canal o Continuation of vertebral canal Anterior and posterior sacral foramina o Permit passage of nerves to pelvic organs and gluteals Median sacral crest o Dorsal ridge formed by fusion of spinous processes Auricular surface 8.5c Vertebral Anatomy o Site of articulation with os coxae of pelvic girdle o Forms strong sacroiliac joint 55

56 8.5c Vertebral Anatomy Coccyx Fusion of 4 coccygeal vertebrae o Begins about age 25 Attachment site for several ligaments and muscles Co 1 Co 4 Start to unite during puberty In elderly, may ultimately fuse with the sacrum 56

57 Sacrum and Coccyx Figure

58 Clinical View: Coccyx (Tailbone) Injury Prone to bruising or fracture Injurious activities: falling on buttocks, sitting abruptly, hit during contact sports, cycling frequently, or childbirth Severe pain, coccydynia Slow to heal Treatment: rest, ice, and non-steroidal anti-inflammatory drugs 58

59 Vertebral Column Figure

60 Primary curves Thoracic and sacral curvatures Present at birth Result C-shape of column Secondary curves Appear after birth Help shift trunk weight over the legs Cervical curve o Appears when child is able to hold up head (3 4 months) Lumbar curve o 8.5b Spinal Curvatures Appears when child is learning to stand and walk (by first year of life) 60

61 Clinical View: Spinal Curvature Abnormalities Kyphosis Exaggerated thoracic curvature Produces hunchback look May result from osteoporosis Lordosis Exaggerated lumbar curvature, swayback May result from added abdominal weight Scoliosis Abnormal lateral curvature May require back brace or surgery 61

62 What did you learn? What are the secondary curves? How many Cervical vertebrae are there? Thoracic? Lumbar? What type of abnormal curve may result from pregnancy? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 62

63 8.5c Vertebral Anatomy Common structural features Body, thick anterior weight-bearing structure Vertebral arch posterior to body Vertebral foramen o Opening enclosed by body with vertebral arch Vertebral canal o Formed by stacked vertebral foramina o Contains the spinal cord 63

64 8.5c Vertebral Anatomy Common structural features (continued) Intervertebral foramina o o Lateral openings between adjacent vertebrae Passageways for spinal nerves extending to body Vertebral arch composed of 2 pedicles and 2 laminae Pedicles originate from posterolateral margins of body Laminae extend posteromedially from posterior edge of pedicle 64

65 8.5c Vertebral Anatomy Common structural features (continued) Spinous process projects posteriorly from laminae junction Transverse processes o Lateral projections on both sides of vertebral arch Superior and inferior articular processes o o o Originate at junction between pedicles and laminae Each with a smooth surface, articular facet Inferior facet articulates with superior facet of next inferior vertebra 65

66 8.5c Vertebral Anatomy Common structural features (continued) Stack of vertebral bodies stabilized by ligaments Intervertebral discs o Pads of fibrocartilage separating vertebral bodies o Outer ring of fibrocartilage, anulus fibrosus o Inner gelatinous region, nucleus pulposus o Shock absorbers between vertebral bodies o Allows vertebral column to bend 66

67 Vertebral Anatomy Superior View Figure 8.17a 67

68 Vertebral Anatomy Posterior and Lateral Views Figure 8.17b,c 68

69 Clinical View: Herniated Discs Nucleus pulposus protruding into or through the anulus fibrosus Produces a bulging of disc contents into vertebral canal Pinches the spinal cord or nerves Cervical and lumbar discs most commonly injured Cervical herniated discs Neck pain and pain down the upper limb Lumbar herniated discs Low back pain Pain down the entire lower limb, sciatica 69

70 8.6 Bones of the Thoracic Cage Thoracic cage Bony framework for the chest Consists of o Thoracic vertebrae posteriorly o Ribs laterally o Sternum anteriorly Protective enclosure around thoracic organs Attachment sites for many muscles 70

71 8.6a Sternum Sternum Breastbone Flat bone forming anterior midline of thoracic wall Manubrium Widest and most superior portion of sternum Two clavicular notches o Articulate sternum with left and right clavicles Suprasternal notch o Shallow superior indentation between the clavicular notches Costal notches o Articulations for first ribs costal cartilages 71

72 8.6a Sternum Sternum body Longest part of sternum Costal cartilages from ribs 2 7 attached here Articulates with manubrium at sternal angle o Costal cartilages of second ribs attach here o Important landmark for palpation and counting ribs Xiphoid process At tip of sternum Doesn t ossify until age 40 72

73 Thoracic Cage Figure

74 Ribs 12 pairs of ribs True ribs (ribs 1 7) 8.6b Ribs o Connect individually to the sternum by cartilaginous extensions Termed costal cartilages False ribs (ribs 8 12) o Costal cartilages not attached directly to the sternum Costal cartilage of ribs 8 10 o Fused to costal cartilage of rib 7 o Indirectly attached to sternum Ribs of without a connection to sternum o Called floating ribs 74

75 Figure 8.21 Rib Anatomy and Articulation with Thoracic Vertebrae 75

76 Clinical View: Variations in Rib Development Rudimentary cervical rib May form from seventh cervical vertebra May compress artery and nerves extending toward upper limb May produce tingling or pain Some individuals lacking a pair of 12th ribs Fused ribs Bifid ribs Splits into two portions when it reaches the sternum 76

77 8.7 The Upper and Lower Limbs: A Comparison Upper and lower limbs Share common features based on evolutionary history One bone attached to two bones; short bones and phalanges Exhibit differences based on primary limb functions Upper limb not weight bearing; more mobile Lower limb weight bearing Proximal part supported by a girdle of bones o Pectoral girdle holding upper limbs in place o Pelvic girdle articulating with lower limb 77

78 Similarities Between the Upper Limb and Lower Limb Skeletons: Proximal Limb Figure 8.22a 78

79 8.8 The Pectoral Girdle and Its Functions Pectoral girdle Articulates with the trunk Supports the upper limbs Consists of the clavicles and the scapulae Clavicle Collarbone Elongated S-shaped bone Extends between the manubrium of the sternum and the acromion of the scapula 79

80 Clavicle Figure 8.23a,b 80

81 8.8b Scapula Scapula Broad, flat, triangular bone Forms the shoulder blade Easily palpated on superolateral back region 81

82 8.8b Scapula Parts of the scapula Spine o Ridge of bone on posterior aspect Acromion o Large posterior process forming shoulder s bony tip o Continuous with spine Coracoid process o Smaller, more anterior projection o Site for muscle attachment 82

83 8.8b Scapula Scapula landmarks Subscapular fossa o Broad anterior surface of the scapula o Subscapularis muscle overlies this fossa Supraspinous fossa o Depression superior to spine o Supraspinatus muscle Infraspinous fossa o Inferior to the spine o Infraspinatus muscle 83

84 Scapula Figure

85 8.9 Bones of the Upper Limb Components of the upper limb Brachium (arm) Antebrachium (forearm) Hand Bones of the upper limb 1 humerus 1 radius and 1 ulna 8 carpal bones 5 metacarpal bones 14 phalanges 85

86 8.9a Humerus Components of the humerus Longest and largest upper limb bone Proximal end with a hemispherical head o Articulates with glenoid cavity of scapula Greater tubercle positioned lateral to head o Helps form rounded contour of shoulder Lesser tubercle smaller and more medial to head Intertubercular sulcus o o Between two tubercles Depression containing tendon of long head of biceps brachii muscle 86

87 8.9a Humerus Components of the humerus (continued) Anatomical neck o Between tubercles and head o Groove marking location of former epiphyseal plate Surgical neck o Narrowing of the bone o Immediately distal to the tubercles o Common fracture site 87

88 Components of the humerus (continued) Shaft with a roughened area o Deltoid tuberosity o Extends along lateral surface for half the length of the humerus o Deltoid muscle attachment Medial and lateral epicondyles o o o Bony side projections on distal humerus Provide surfaces for muscle attachment Ulnar nerve travels posterior to medial epicondyle 8.9a Humerus Funny bone 88

89 8.9a Humerus Components of the humerus (continued) Distal end with 2 curved surfaces o Articulation with bones of forearm o Capitulum located laterally Articulates with radius o Trochlea located medially Articulates with trochlear notch of ulna 89

90 8.9a Humerus Components of the humerus (continued) Distal end with 3 depressions 2 on anterior surface, 1 on posterior surface o Radial fossa anterolaterally placed Accommodates radial head o Coronoid fossa anteromedially placed Accommodates coronoid process of ulna o Olecranon fossa posteriorly placed Accommodates olecranon of ulna when elbow is extended 90

91 Humerus and Elbow Joint Figure

92 What did you learn? What is the difference between the anatomical neck and the surgical neck of the humerus? What portion of the humerus articulates with the radial head? What portion articulates with the trochlear notch of the ulna? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 92

93 8.9b Radius and Ulna Radius and ulna form forearm Bones are parallel Radius located laterally Components of the radius Articulates with capitulum of humerus Assists in rotation Components of the ulna trochlear notch at proximal end o Interlocks with trochlea of the humerus o Extension Olecranon process moves into fossa o Flexion Coronoid process moves into fossa 93

94 8.9b Radius and Ulna Borders between radius and ulna Interosseous borders, facing each other Connected by an interosseous membrane o Dense regular CT o Keeps radius and ulna a fixed distance apart o Pivot of rotation for the forearm 94

95 Radius and Ulna Figure 8.26a,b 95

96 8.9b Radius and Ulna Supination In anatomic position, palm of hand facing anteriorly Radius and ulna parallel Radius on lateral side of forearm Ulna on medial side Radius Thumb Ulna Little finger Figure 8.26c (c) Supination of right forearm The McGraw-Hill Companies, Inc./Christine Eckel, photographer 96

97 8.9b Radius and Ulna The McGraw-Hill Companies, Inc./Christine Eckel, photographer Pronation Radius and ulna pivoting along interosseous membrane Palm of hand facing posteriorly Head of radius still on lateral side of elbow Distal end of radius has crossed over More medial structure Ulna Little finger Radius Thumb Figure 8.26d (d) Pronation of right forearm 97

98 What did you learn? Describe how the radius and ulna are positioned when the forearm is pronated. Which process of the ulna joins with the humerus when the elbow is extended? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 98

99 8.9c Carpals, Metacarpals, and Phalanges Carpals Wrist bones Allow multiple movements at wrist Arranged in 2 rows of 4 bones each Proximal row from lateral to medial o Scaphoid, lunate, triquetrum, pisiform Distal row from lateral to medial o Trapezium, trapezoid, capitate, hamate 99

100 8.9c Carpals, Metacarpals, and Phalanges Metacarpals Bones in palm of hand Articulate with distal carpal bones Support the palm Roman numerals I V denote metacarpal bones Metacarpal I at base of the thumb, V at base of little finger 100

101 8.9c Carpals, Metacarpals, and Phalanges Phalanges 3 in 2nd through 5th fingers 2 phalanges in thumb (pollex) Proximal phalanx articulate with head of metacarpal Distal phalanx at tip of finger Middle phalanx between proximal and distal phalanges 101

102 Bones of the Carpals, Metacarpals, and Phalanges Figure

103 Clinical View: Scaphoid Fractures Scaphoid bone a more commonly fractured bone May fracture from fall from outstretched hand Blood vessels torn, resulting in avascular necrosis Death of bone tissue due to inadequate blood supply Takes a long time to heal 103

104 What did you learn? List the eight carpal bones, proximal row and distal row? What is the most commonly fractured carpal bone? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 104

105 8.10 Pelvis Girdle and Its Functions Pelvis 4 bones o Sacrum, coccyx, right and left ossa coxae Supports viscera in inferior part of ventral body cavity Pelvic girdle Left and right ossa coxae only Articulates anteriorly at pubic symphysis Articulates posteriorly with sacrum at auricular surface Provides attachment point for lower limbs 105

106 8.10a Os Coxae Os coxae Hip bone 3 bones o Ilium o Ischium o Pubis Fuse between ages 13 to 15 years Femur articulation with acetabulum o Deep, curved depression on lateral os coxae o Region where 3 bones have fused 106

107 Ilium 8.10a Os Coxae Largest of 3 coxal bones Forms superior region of the os coxae Iliac crest, superiormost ridge of ilium Ischium Triangular ischial spine, posterior to acetabulum Greater and Lesser sciatic notch Ischial tuberosity o Roughened projection on posterolateral border of ischium o Sitz bones o Bear weight of body in sitting position Pubis Pubic tubercle and symphyseal space Site of articulation of the two os coxae bones 107

108 Pelvis Figure

109 Os Coxae, Lateral View Figure 8.29a 109

110 Os Coxae, Medial View Figure 8.29b 110

111 What did you learn? What three bones fuse to form the os coxae? Where are the ischial tuberosities located, and what is their function? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 111

112 8.10b True and False Pelves Pelvic brim Continuous oval ridge Extends to inferior edges of sacral ala and promontory Divides pelvis into true and false pelves True pelvis o Inferior to pelvic brim o Encloses pelvic cavity and contains pelvic organs False pelvis o Superior to pelvic brim o Houses inferior abdominal organs 112

113 8.10b True and False Pelves Pelvic inlet Superiorly positioned space enclosed by pelvic brim Marks boundary between true and false pelves Pelvic outlet Inferiorly placed opening Bounded by coccyx, ischial tuberosities, inferior border of symphysial surface Covered with muscles and skin, forming perineum Width and size important in females o Must be wide enough to accommodate fetal head 113

114 Features of the Pelvis Figure

115 8.10c Sex Differences in the Pelvis Determing sex of the skeleton Ossa coxae the most sexually dimorphic bones Due to demands of pregnancy and childbirth Female pelvis shallower and wider Females with wider hips o Due to female ilium flares more laterally Female acetabulum projects more laterally Subpubic angle o Angle when pubic bones aligned at symphysial surfaces o Wider and more convex in females o Greater than 90 degrees 115

116 Features of the Pelvis Figure 8.30c 116

117 8.11 Bones of the Lower Limb Components of the lower limb Thigh, leg, foot Bones of the upper limb (30) 1 femur 1 patella 1 tibia and 1 fibula 7 tarsal bones 5 metatarsal bones 14 phalanges 117

118 8.11a Femur and Patella Femur Longest, heaviest, strongest bone in body Spherical head o Articulates with os coxae at acetabulum Fovea or fovea capitis o Small depression within head of the femur o Round ligament connects head to acetabulum Elongated neck joins shaft of femur at an angle o Results in medial angling of the femur 118

119 8.11a Femur and Patella Femur (continued) Greater trochanter o Projects laterally from junction of neck and shaft Lesser trochanter o o On femur s posteromedial surface Both trochanters are insertion sites for gluteal and thigh muscles Intertrochanteric crest o Thick oblique ridge of bone connecting trochanters 119

120 8.11a Femur and Patella Femur (continued) Medial and lateral condyles o Oval articulating surfaces on inferior femur surface o Separated by deep intercondylar fossa Medial and lateral epicondyle o Superior to each condyle Patellar surface o Smooth depression on anterior surface o Where patella articulates with the femur 120

121 Femur Figure

122 8.11a Femur and Patella Patella Kneecap Large, triangular sesamoid bone Housed within tendon of quadriceps femoris muscle Allows tendon to glide more smoothly Protects knee joint Superior broad base Inferior pointed apex Articular surface on posterior aspect o Articulates with patella surface of the femur 122

123 Patella Figure

124 8.11b Tibia and Fibula Tibia components Medial and lateral condyles o o o Relatively flat surfaces on superior head Articulate with medial and lateral condyles of the femur Separated by a prominent ridge, intercondylar eminence Tibial tuberosity o o Anterior surface near proximal condyles Attachment site for patellar ligament Medial malleolus o o Large process on medial distal border Palpated on medial side of the ankle 124

125 8.11b Tibia and Fibula Fibula Long, lateral, non-weight-bearing bone Knoblike head inferior and posterior to tibia s lateral condyle Neck and shaft distal to head Distal tip, lateral malleolus o o o o Extends laterally to the ankle joint Provides lateral stability Palpate on lateral side of the ankle Non weight bearing 125

126 Tibia and Fibula Figure

127 What did you learn? What is the primary function of the tibia? Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 127

128 8.11c Tarsals, Metatarsals, and Phalanges Tarsals 7 bones of the ankle and proximal foot Similar to the eight carpal bones Talus, superiormost and second largest o Articulates with the tibia Calcaneus, largest, forms heel o Posterior end with projection for attachment of calcaneal tendon Navicular bone, on medial side of ankle 128

129 8.11c Tarsals, Metatarsals, and Phalanges Tarsals (continued) Medial, intermediate, and lateral cuneiform bones o Wedge-shaped, positioned anterior to navicular bone Cuboid bone laterally placed o Articulates with lateral cuneiform medially and calcaneus posteriorly 129

130 8.11c Tarsals, Metatarsals, and Phalanges Metatarsals Form arched sole of foot Identified with Roman numerals I V, medially to laterally Articulate proximally with cuneiform bones or cuboid bone Each articulates distally with a proximal phalanx Two tiny sesamoid bones at head of first metatarsal o o Insert on the tendons of flexor hallucis brevis muscle Help tendons move more freely 130

131 8.11c Tarsals, Metatarsals, and Phalanges Phalanges Bones of the toes Total of 14 Great toe, hallux o Only 2 phalanges Other toes, 3 phalanges o Proximal, middle, distal 131

132 Bones of the Tarsals, Metatarsals, and Phalanges Figure

133 What did you learn? What are the seven tarsal bones? The weight of the body moves from the hips to to the to the. Copyright 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 133

134 8.11d Arches of the Foot Arches Help support weight of the body Ensure blood vessels on sole of foot not pinched when standing Shape maintained primarily by foot bones themselves Bones shaped so they can support their weight in an arch Strong ligaments and tendons also helping maintain arches shapes 134

135 8.11d Arches of the Foot Medial longitudinal arch (Figure 8.35a) Highest of the three arches Extends from heel to great toe Formed from calcaneus, talus, navicular, cuneiform bones, metatarsals I III Prevents medial side of foot from touching the ground 135

136 8.11d Arches of the Foot Lateral longitudinal arch (Figure 8.35b) Not as high as medial arch Extends between little toe and the heel Formed from calcaneus, cuboid bones, metatarsals IV and V 136

137 8.11d Arches of the Foot Transverse arch (Figure 8.35c,d) Runs perpendicular to longitudinal arches Formed from distal row of tarsals and bases of all metatarsals Footprint illustrates position of longitudinal arches 137

138 Clinical View: Pathologies of the Foot Bunion Localized swelling at first metatarsophalangeal joint Causes toe to point toward second toe Pes cavus Excessively high longitudinal arches Talipes equinovarus Congenital clubfoot Occurs when not enough room in the womb Feet permanently inverted Ankles plantar flexed 138

139 Clinical View: Pathologies of the Foot (continued) Pes planus Flat feet Medial longitudinal arch flattened Caused by excess weight, posture abnormalities, weak supporting tissue Metatarsal stress fracture Results from repetitive pressure Runners especially prone 139