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Chapter 06
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1
Skeletal Structure and Function
• Skeletal system
– Composed of bones, cartilages, and ligaments
• joined tightly
• form strong flexible framework for the body
– Cartilage
• forerunner of bone in embryonic development
• covers many joint surfaces
2
Skeletal Structure and Function
• Skeletal system (cont)
– Ligaments
• collagenous bands
• hold bones together at joints
– Tendons
• structurally similar to ligaments
• attach muscle to bone
– Bone marrow
• soft material enclosed in bones
3
Skeletal Structure and Function:
Functions of the Skeletal System
• Principal functions
– Support
• bones of limbs and vertebral column support body
• mandible and maxilla support teeth
• some viscera supported by bones
4
Skeletal Structure and Function:
Functions of the Skeletal System
• Principal functions (cont)
– Protection
• brain and spinal cord
• lungs, heart, and pelvic viscera
– Movement
• provide attachment and leverage for muscles
• allow for limb movement and ventilation
5
Skeletal Structure and Function:
Functions of the Skeletal System
• Principal functions (cont)
– Blood formation
• the major producer of blood cells
– Storage
• body’s main reservoir of calcium and phosphorus
• released when needed for other functions
• bone marrow, reserve of stored fuel
6
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Osseous tissue
– Hard, calcified tissue of bone
– Compact bone
• solidly filled with opaque matrix
• encloses spongy bone
– Spongy bone
• porous lattice with spaces
• found on interior of bone
7
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Bone cells
– Osteogenic cells
• stem cells capable of making more cells
• give rise to osteoblasts
– Osteoblasts
• synthesize organic matter of bone
– Osteocytes
• former osteoblasts
• trapped in deposited matrix
– Osteoclasts
• bone-dissolving cells
8
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Bone matrix
– Surrounds osteocytes and lacunae
– One-third organic by weight
• include collagen and protein–carbohydrate complexes
– Two-thirds inorganic by weight
• 85% calcium phosphate
• calcium carbonate, magnesium, potassium, and fluoride
9
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Minerals in matrix
– Resist compression
– Enable bones to support the body
– E.g., in rickets and osteomalacia
• bones mineral-deficient and easily deformed
10
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Collagen in matrix
– Gives bones ability to resist tension
– Bones can bend without breaking
11
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Spongy (cancellous) bone
–
–
–
–
–
Porous lattice of rods and plates, trabeculae
Calcified and hard
Spongelike appearance
Spaces filled with bone marrow and blood vessels
Imparts strength, while adding minimum of weight
12
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Compact (dense) bone
– Forms outer shell surrounding spongy bone
– Prevents bone marrow from seeping out
– Provides solid attachments
• for muscles, tendons, and ligaments
– At surface, organized in parallel layers
13
Skeletal Structure and Function:
Osseous (Bone) Tissue
• Compact (dense) bone (cont)
– Deeper, organized into osteons
– Layers called lamellae arranged concentrically
• around central canal
• contains small blood vessels and nerves
– Osteocytes in lacunae between lamellae
14
Histology
of Osseous
Tissue:
Compact
Bone
(Figure
6.3a, c)
15
Skeletal Structure and Function:
Gross Anatomy of Bones
• Long bones
– Most bones of the limbs
• specialized for leverage and movement
– Shaft, or diaphysis
• elongated midsection provides leverage
– Head, or epiphysis
• expanded end strengthens joints
• provide area for tendon and ligament attachment
• filled with spongy bone (and in nearby shaft)
16
Skeletal Structure and Function:
Gross Anatomy of Bones
• Long bone features
– Articular cartilage
• hyaline cartilage covers ends where bones meet
• eases joint movements
– Medullary cavity
• long cavity inside diaphysis
• contains bone marrow
– Epiphyseal lines
• in adults, mark former growth zones
17
General
Anatomy
of a Long
Bone
(Figure
6.4)
Skeletal Structure and Function:
Gross Anatomy of Bones
• Flat bone features
– Protective plates covering organs
• e.g., sternum and heart
• e.g., cranial bones and brain
– May provide attachment surfaces for muscles
• e.g., scapula
– Two layers of compact bone
– Middle layer of spongy bone
19
Skeletal Structure and Function:
Gross Anatomy of Bones
• Other categories of bones
– Short bones
• e.g., wrist bones
– Irregular bones
• e.g., vertebrae
20
Skeletal Structure and Function:
Gross Anatomy of Bones
• Periosteum
– Fibrous sheath covering the bone
– Collagen fibers continuous with tendons
• penetrate into bone itself
– None over articular cartilage
– Covers both sides of flat bone
21
Skeletal Structure and Function:
Gross Anatomy of Bones
• Endosteum
– Covers internal surface of bone
– Covers spongy bone in middle of flat bone
22
Skeletal Structure and Function:
Gross Anatomy of Bones
• Red bone marrow
– Produces blood cells and platelets
– Fills nearly every bone of a child’s skeleton
• more limited distribution in adults
– Soft network of delicate blood vessels
• surrounded by reticular tissue and blood-forming cells
23
Skeletal Structure and Function:
Gross Anatomy of Bones
• Yellow bone marrow
– Replaces much of red bone marrow in maturity
– Fatty marrow
24
Distribution
of Red and
Yellow Bone
Marrow
(Figure 6.6)
25
Skeletal Structure and Function
What are the four types of cells in bone tissue?
Which type dissolves bone? Which type are
trapped in lacunae?
Osteogenic cells, osteoblasts, osteocytes, osteoclasts
Osteoclasts
Osteocytes
26
Bone Development and
Metabolism: Ossification
• Ossification
– Formation of bone
– Mesenchyme
• soft embryonic connective tissue
• forerunner of adult bone, muscle, blood, and others
• starting point of ossification
27
Bone Development and
Metabolism: Ossification
• Intramembranous ossification
– Produces flat bones of the skull and clavicle
– Plays role in thickening, strengthening, and remodeling bone
• continues past age bones can no longer grow in length
28
Bone Development and
Metabolism: Ossification
• Steps of intramembranous ossification
1) Osteoid tissue deposited into embryonic mesenchyme
• deposited by mesenchymal cells
• tissue like bone but not hardened
2) Crystallization of minerals on collagen fibers of osteoid
• calcium phosphate and others
• harden matrix into spongy bone trabeculae
• osteocytes trapped in space between bones
29
Bone Development and
Metabolism: Ossification
• Steps of intramembranous ossification (cont)
3) Condensation of mesenchyme adjacent to bone
• form fibrous periosteum
• spongy bone becoming calcified trabeculae
4) Compact bone formed at surfaces
• done by osteoblasts
• spongy bone left in middle
30
Bone Development and
Metabolism: Ossification
• Endochondral ossification
– Produces most other bones
• e.g., vertebra, ribs, and pelvic bones
• e.g., limbs and parts of skull
– Mesenchyme first transformed into hyaline cartilage
– Cartilage broken down, replaced by osseous tissue
31
Bone Development and
Metabolism: Ossification
• Steps of endochondral ossification
1) Early hyaline cartilage
• approximates shape of future bone
• covered with perichondrium
2) Formation of primary ossification center
• near cartilage middle
• osteoblasts depositing layer of bone around cartilage
• fibrous sheath now periosteum
32
Bone Development and
Metabolism: Ossification
• Steps of endochondral ossification (cont)
3) Blood vessels invading ossification center
• primary marrow cavity formed
• secondary ossification center at one end of bone
4) Enlargement of marrow cavity at epiphysis (by birth)
• second marrow cavity hollowed out
• development of another ossification center at other end
• metaphysis, transitional zone
– where cartilage being replaced by bone
33
Bone Development and
Metabolism: Ossification
• Steps of endochondral ossification (cont)
5) Primary and secondary cavities separated by wall
•
•
•
•
•
termed epiphyseal plate
growth zone
middle layer of hyaline cartilage
metaphysis on each side
active throughout childhood and adolescence
34
Bone Development and
Metabolism: Ossification
• Steps of endochondral ossification (cont)
6) Reserve cartilage in epiphyseal plate depleted
• attain maximum adult height
• by late teens to early twenties
35
Endochondral Ossification (Figure 6.8)
Bone Development and Metabolism:
Growth and Remodeling
• Changes in bone
–
–
–
–
Continue throughout life
E.g., limbs becoming longer in kids
E.g., changing curvature of cranium in kids
E.g., from increased tension of the bone
• athletes with greater bone mass than sedentary people
37
Bone Development and Metabolism:
Growth and Remodeling
• Interstitial growth
–
–
–
–
–
One method of bone growth
Chondrocytes multiply, enlarge, and secrete new matrix
Occurs in epiphyseal plate
Adds length until plate depleted
Osseous tissue
• deposited in channels created by chondrocytes
38
Bone Development and Metabolism:
Growth and Remodeling
• Epiphyseal plate
– Transparent line across end of bone
• appears on kids’ X-rays
• appearance of gap between epiphysis and diaphysis
– Plates “close” when cartilage depleted
• no longer a gap between epiphysis and diaphysis
– Epiphyseal line
• mark left behind by epiphyseal plate
39
Bone Development and Metabolism:
Growth and Remodeling
• Appositional growth
–
–
–
–
Other means of cartilage and bone growth
Only type in mature bone
New matrix deposited on tissue surface
Occurs by intramembranous ossification
40
Bone Development and Metabolism:
Growth and Remodeling
• Appositional growth (cont)
–
–
–
–
Osteoid deposited by osteoblasts in periosteum
Calcify tissue and become trapped as osteocytes
Tissue laid down in layers parallel to surface
Medullary cavity enlarged
• osteoclasts dissolving bone on inner surface
41
Bone Development and Metabolism:
Mineral Homeostasis
• Bone exchange of minerals
– Skeleton the primary reservoir of calcium and phosphate
• phosphate roles
– component of DNA, RNA, ATP, phospholipids, and others
• calcium roles
– muscle contraction and blood clotting
– exocytosis and nervous communication
– response to hormones
42
Bone Development and Metabolism:
Mineral Homeostasis
• Mineral deposition by osteoblasts
– Extract calcium phosphate and other ions from blood
– Deposit in osseous tissue
• Mineral resorption by osteoclasts
– Dissolve bone
– Release minerals into blood
– Requires critical balance with deposition
• can cause bone abnormalities if either unbalanced
43
Bone Development and Metabolism
Which type of ossification produces the flat
bones of the skull and most of the clavicle?
Which type produces most other bones,
including the bones of limbs?
Intramembranous ossification
Endochondral ossification
44
The Axial Skeleton
Learning Outcomes: (cont)
e. Describe the general features of the vertebral column, general
structure of a vertebra and intervertebral disc, and regional
differences between the vertebrae.
f. Describe the anatomy of the ribs and sternum, regional
differences between the ribs, and the articulation of the ribs
with the vertebral column and sternum.
45
The Axial Skeleton
• Bone markings
– Ridges, spines, and bumps
– Depressions, holes, and joint surfaces
– Canal
• tubular passage in a bone
– Condyle
• rounded knob
46
The Axial Skeleton
• Bone markings (cont)
– Crest
• narrow ridge
– Epicondyle
• flare superior to condyle
– Facet
• smooth mostly flat joint surface
– Fissure
• slit through bone
47
The Axial Skeleton
• Bone markings (cont)
– Foramen
• hole through a bone
– Fossa
• basin
– Process
• bony prominence
– Sinus
• cavity within a bone
48
The Axial Skeleton
• Bone markings (cont)
– Spine
• sharp, slender, or narrow process
– Tubercle
• small rounded process
– Tuberosity
• rough surface
49
The Axial Skeleton
• Two skeletal regions
– Axial skeleton
• central supporting axis of body
• includes skull, vertebral column, ribs, and sternum
– Appendicular skeleton
• includes bones of upper limb and pectoral girdle
• includes bones of lower limb and pelvic girdle
50
The Adult
Skeleton
(Figure
6.11)
The Axial Skeleton: The Skull
• Skull
– Most complex part of skeleton
– One freely movable bone, mandible
– 21 relatively immobile bones
• connected by sutures
• joints appearing as seams on skull
– With many foramina
• holes for passage of nerves and blood vessels
52
The Axial Skeleton: The Skull
• Skull cavities
– Cranial cavity
• encloses the brain
– Orbits
• eye sockets
– Nasal cavity
– Oral (buccal) cavity
53
The Axial Skeleton: The Skull
• Skull cavities (cont)
– Middle- and inner-ear cavities
– Paranasal sinuses
• air-filled spaces connected to nasal cavity
• named for bones in which they occur
– frontal, sphenoid, ethmoid, and maxillary
54
The Paranasal Sinuses (Figure 6.13)
The Axial Skeleton: The Skull
• Bones of skull
– 8 cranial bones
•
•
•
•
form cranium
in direct contact with membranes enclosing brain
2 parietal and temporal bones
1 frontal, occipital, sphenoid, and ethmoid bone
– 14 facial bones
56
The Skull,
Anterior
View
(Figure
6.12)
The Axial Skeleton: The Skull
• Frontal bone
– Forms
• forehead
• roof of orbit
• anterior third of roof of cranial cavity
– Has supraorbital foramen
• ridge with small hole in eyebrow region
• for passage of a nerve, artery, and vein
58
The Axial Skeleton: The Skull
• Frontal bone (cont)
– Has frontal sinus
– Infant with separate right and left
• normally fuse into single bone
59
The Axial Skeleton: The Skull
• Parietal bones
– Form most of cranial roof and part of walls
– Begin at the coronal suture
• separates them from frontal bone
– Extend to lambdoid suture at rear
– Separated by longitudinal sagittal suture
60
The Axial Skeleton: The Skull
• Temporal bones
– Form
• region around ears
• part of lower wall and floor of cranial cavity
61
The Axial Skeleton: The Skull
• Temporal bone features
– Zygomatic process
• spine from temple
• forms part of zygomatic arch
– completed by zygomatic bone and part of the maxilla
– External acoustic meatus
• auditory canal
62
The Axial Skeleton: The Skull
• Temporal bone features (cont)
– Mastoid process
• lump behind earlobe
– Styloid process
• provides attachment for muscle of throat
– Mandibular fossa
• depression on inferior surface
• where mandible articulates with cranium
63
The Axial Skeleton: The Skull
• Temporal bone features (cont)
– Carotid canal
• passage for internal carotid artery
– Jugular foramen
• passage for internal jugular vein
– Contains middle- and inner-ear cavities
64
The Axial Skeleton: The Skull
• Occipital bone
– Forms rear of skull and much of its base
– Contains foramen magnum
• opening admitting spinal cord to cranial cavity
– Occipital condyles
• knobs on both sides of foramen magnum
• where skull rests on vertebral column
65
The Axial Skeleton: The Skull
• Sphenoid bone
– Thick median body with outstretched wings
– Pair of sphenoid sinuses
– Sella turcica
• saddlelike structure housing pituitary gland
– Part of lateral cranium
– Part of wall of the orbit
66
The Axial Skeleton: The Skull
• Sphenoid bone (cont)
– Optic canal
• permits passage of optic nerve
– Superior orbital fissure
• allows passage of nerves supplying eye muscles
– Posterior nasal apertures
• paired openings of nasal cavity
67
The Axial Skeleton: The Skull
• Ethmoid bone
–
–
–
–
Located between orbits
Forms roof of nasal cavity
Honeycombed with air cells of ethmoid sinus
Vertical perpendicular plate
• forms superior part of nasal septum
• divides nasal cavity into right and left spaces
– nasal fossae
68
The Axial Skeleton: The Skull
• Ethmoid bone (cont)
– Nasal conchae
• project into fossa from lateral wall
• superior and middle conchae, extensions of ethmoid bone
– Cribriform plates
• perforations for nerve fibers for smell
• separated by median ridge, crista galli
69
The Axial Skeleton: The Skull
• Facial bones
–
–
–
–
–
Shape the face
Support internal structures of oral and nasal cavities
2 maxillae, palatine, zygomatic, and lacrimal bones
2 nasal bones and inferior nasal conchae
1 vomer and mandible
70
The Axial Skeleton: The Skull
• Maxillae
– Form upper jaw and support teeth
– Form the floor and medial walls of the orbit
– Inferior orbital fissure
• passage within orbit for blood vessels and nerve
– Forms four-fifths of hard palate
• anterior part of roof of mouth
71
The Axial Skeleton: The Skull
• Palatine bones
– L-shaped bones
– Form
• posterior one-fifth of hard palate
• part of nasal cavity wall
• part of floor of orbit
72
The Axial Skeleton: The Skull
• Zygomatic bones
– Form
• angles of cheeks inferolateral to eyes
• part of lateral wall of orbit
– Each with inverted T shape
– Prominent zygomatic arch
• from zygomatic, temporal bones, and maxilla
73
The Axial Skeleton: The Skull
• Lacrimal bones
– Form part of medial wall of each orbit
– House membranous sacs
• collect tears from eyes
• drain into nasal cavity
74
The Axial Skeleton: The Skull
• Nasal bones
– Form bridge of nose
– Support cartilages that shape lower nose
• Inferior nasal conchae
– Separate bone
– Largest of three choncha
75
The Axial Skeleton: The Skull
• Vomer
– Forms lower part of nasal septum
– Joins perpendicular plate of ethmoid bone
76
The Axial Skeleton: The Skull
• Mandible
– Supports lower teeth
– Provides attachment for muscles of mastication
– Horizontal portion, body
• contains teeth
– Posterior part, ramus
• meets with body at the angle
• anterior coronoid process, and posterior condylar process
77
The Axial Skeleton: The Skull
• Mandible (cont)
– Mandibular condyle
• caps condylar process
• meets temporal bone to form hinge of jaw
– termed temporomandibular joint (TMJ)
– Mental foramen
• on anterolateral surface of body
• hole for passage of nerves and blood vessels of chin
78
The Skull, Lateral View (Figure 6.14a)
79
The Base of the Skull (Figure 6.15a)
80
The Base of the Skull (Figure 6.15b)
81
The Orbital (Eye) Region (Figure 6.17)
82
The Axial Skeleton: The Skull
• Bones associated with skull
– Three auditory ossicles
• in each middle ear
– Hyoid
• beneath chin
• attachment site
– for muscles controlling mandible, tongue, and larynx
83
The Axial Skeleton: The Vertebral Column
• Vertebral column
–
–
–
–
Physically supports skull and trunk
Protects spinal cord
Absorbs stresses of walking and lifting
Provides attachments
• for limbs, thoracic cage, and postural muscles
84
The Axial Skeleton: The Vertebral Column
• Parts of vertebral column
–
–
–
–
–
Flexible chain of 33 vertebrae
23 cartilaginous intervertebral discs
7 cervical vertebrae in neck
12 thoracic vertebrae in chest
5 lumbar vertebrae in lower back
85
The Axial Skeleton: The Vertebral Column
• Parts of vertebral column (cont)
– 5 sacral vertebrae at base of spine
• fused as single bone, sacrum
– 4 tiny coccygeal vertebrae
• fused as single bone, coccyx
86
The Axial Skeleton: The Vertebral Column
• Curves of vertebral column
– Column C-shaped at birth
– Beyond age 3, slightly S-shaped
• four bends
– cervical, thoracic, lumbar, pelvic curvatures
• makes bipedal walking possible
– Abnormal spinal curvatures
• scoliosis, kyphosis, and lordosis
87
The
Vertebral
Column
(Figure
6.18)
88
Adult Spinal Curvatures (Figure 6.19)
89
The Axial Skeleton: The Vertebral Column
• Structure of vertebra
– Body (centrum), weight-bearing portion
• rough surfaces with attachments to intervertebral discs
– Vertebral foramen
• opening posterior to body
90
The Axial Skeleton: The Vertebral Column
• Structure of vertebra (cont)
– Vertebral arch
• encloses vertebral foramen
• consists of pair of flat of plates, laminae
• supported on pair of pillars, pedicles
– collectively form vertebral canal
– passage for the spinal cord
91
The Axial Skeleton: The Vertebral Column
• Structure of vertebra (cont)
– Spinous process
• extends from apex of arch
• directed toward rear and downward
– Transverse processes
• extend laterally from arch
– Both processes
• provide attachment for ligaments and muscles
92
The Axial Skeleton: The Vertebral Column
• Structure of vertebra (cont)
– Superior articular processes
• project upward from one vertebra
– Inferior articular processes
• meet superior articular processes
• resists twisting of vertebral column
• gap between, intervertebral foramen
– allows for passage of spinal nerves
93
Lumbar
Vertebra
(Figure
6.20a)
94
The Axial Skeleton: The Vertebral Column
• Cervical vertebrae
– Smallest vertebrae
– C1, Atlas
• ring surrounding large vertebral foramen
• supports head
• has superior articular facets
– meet occipital condyles of skull
– rock back and forth when nodding
95
The Axial Skeleton: The Vertebral Column
• Cervical vertebrae (cont)
– C2, Axis
• allows rotation of head
• prominent knob, dens or odontoid process
– projects into vertebral foramen of atlas
• first vertebra with spinous process
96
The Atlas and Axis, Vertebrae C1 and C2 (Figure 6.21)
The Axial Skeleton: The Vertebral Column
• Cervical vertebrae (cont)
– C2 to C6
• spinous process forked
– C1 to C7
• round transverse foramen in transverse process
– provide passage for vertebral arteries and veins
98
The Axial Skeleton: The Vertebral Column
• Thoracic vertebrae
– Support ribs
• have depressions for rib attachment
• costal facets, on bodies of vertebrae
• transverse costal facets at ends of transverse processes
– Pointed spinous processes angled downward
99
The Axial Skeleton: The Vertebral Column
• Lumbar vertebrae
–
–
–
–
Thick body
Squarish spinous process
Superior articular processes facing medially
Inferior processes facing laterally
• enables region to resist twisting
100
Typical Cervical, Thoracic, and Lumbar Vertebrae (Figure 6.22)
101
The Axial Skeleton: The Vertebral Column
• Sacral vertebrae
– Fully fused into sacrum by age 26
– Form posterior wall of pelvic cavity
– Four pairs of sacral foramina
• for emergence of spinal nerves
– Median sacral crest
• fused spinous processes of vertebrae
102
The Axial Skeleton: The Vertebral Column
• Sacral vertebrae (cont)
– Lateral sacral crest
• fused transverse processes
– Sacroiliac (SI) joint
• where sacrum articulates with hip bones
– Sacral canal
• contains spinal nerve roots
103
The Axial Skeleton: The Vertebral Column
• Coccygeal vertebrae
– Fuse into small single bone, coccyx
– Provide attachment for pelvic floor muscles
– Vestige of tail bones in other animals
104
The Sacrum and Coccyx (Figure 6.23)
105
The Axial Skeleton: The Vertebral Column
• Intervertebral discs
–
–
–
–
Bind adjacent vertebrae together
Enhance spinal flexibility
Support weight of body
Absorb shock
106
The Axial Skeleton: The Vertebral Column
• Intervertebral discs (cont)
– Consist of
• inner gelatinous nucleus pulposus
• outer fibrocartilage, anulus fibrosus
– if pulposus oozes out, termed herniated disc
107
The Axial Skeleton: The Thoracic Cage
• Thoracic cage
–
–
–
–
–
Thoracic vertebrae, sternum, and ribs
Encloses heart and lungs
Provides attachment for pectoral girdle and upper limbs
Protects thoracic organs, spleen, part of liver, and kidneys
Rhythmically expanded by respiratory muscles
108
The Axial Skeleton: The Thoracic Cage
• Sternum
– Bony plate anterior to heart
– Short superior manubrium
• articulation site of 1st pair of ribs
• clavicles articulating with clavicular notches here
109
The Axial Skeleton: The Thoracic Cage
• Sternum (cont)
– Swordlike body
• articulation site of second pair of ribs
– Daggerlike xiphoid process at inferior end
• articulation site of remaining ribs
110
The Axial Skeleton: The Thoracic Cage
• Ribs
–
–
–
–
12 pairs
Attach posteriorly to vertebral column
All but last two attaching to sternum
Most curved, flattened blades
111
The Axial Skeleton: The Thoracic Cage
• Types of ribs
– Ribs 1 to 7, true ribs
• each with own costal cartilage
• cartilaginous strip attaching to sternum
– Ribs 8 to 12, false ribs
• 8 to10 attach to costal cartilage of rib 7
• 11 to 12 with no costal cartilages
– Ribs 11 to 12, floating ribs
• lack any connection to sternum
112
Thoracic
Cage and
Pectoral
Girdle,
Anterior
View
(Figure
6.24)
113
The Axial Skeleton
Are the following bones cranial or facial
bones: parietal, zygomatic, sphenoid, and
lacrimal bones?
Cranial, facial, cranial, facial
114
The Appendicular Skeleton
Learning Outcomes:
a. Describe the bones of the pectoral girdle and upper limb, and
the major features of the individual bones.
b. Do the same for the bones of the pelvic girdle and lower limb.
115
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Pectoral girdle
– Supports the arm
– Consists of clavicle and scapula on both sides
116
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Clavicle
– S-shaped bone
– Medial sternal end with hammerlike head
• articulates with manubrium
– Lateral flattened acromial end
• articulations with acromion of scapula
– Braces the shoulders
117
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Scapula
– Triangular plate overlying 2 to 7 ribs on upper back
– Superior, medial, and lateral borders
– Subscapular fossa
• broad anterior surface
– Spine
• prominent transverse ridge on posterior surface
118
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Scapula (cont)
– Supraspinous fossa
• indentation superior to spine
– Infraspinous fossa
• surface inferior to spine
• both fossa occupied by rotator cuff muscles
119
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Shoulder region of scapula
– Acromion
• extension of scapular spine
• articulates with clavicle
– Coracoid process
• shaped like bent finger
• provides attachment for biceps and other arm muscles
– Glenoid cavity
• shallow socket
• articulates with head of humerus
120
The Right Scapula (Figure 6.26)
121
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Bones in the upper limbs
–
–
–
–
–
Humerus in the arum
Radius and ulna in the forearm
8 carpal bones in the wrist
5 metacarpal bones in the hand
14 phalanges in the hand
122
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Humerus
– Only bone from shoulder to elbow
– Hemispherical head
• inserts into glenoid cavity of scapula
– Greater and lesser tubercles
• sites of muscle attachments lateral to head
• intertubercular groove between for tendon of biceps
123
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Humerus (cont)
– Deltoid tuberosity
• rough area on lateral shaft
• insertion for deltoid muscle
– Capitulum and trochlea
• two condyles on distal end
• capitulum on lateral side
• pulleylike trochlea on medial side
124
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Humerus (cont)
– Lateral and medial epicondyles
• bony prominences proximal to condyles
– Olecranon fossa
• distal fossa on posterior side
• for ulna when elbow extended
125
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Humerus (cont)
– Coronoid fossa
• distal fossa on anterior side
• for ulna head when elbow flexed
– Radial fossa
• distal fossa on lateral side
• for radius head when elbow flexed
126
The Right
Humerus
(Figure
6.27)
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Radius
– Extends from elbow to wrist laterally
– Ends just proximal to base of thumb
– Proximal head
• rotates on capitulum when palm forward and back
128
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Radius (cont)
– Radial tuberosity
• process just distal to head
• attachment for tendon of biceps muscle
– Flared distal end
• articulates with three carpal bones
• small point, styloid process
129
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Ulna
– Medial bone of the forearm
– Proximal end with C-shaped trochlear notch
• wraps around trochlea of humerus
• posterior wall formed by bony point, olecranon
• anterior wall formed by coronoid process
– Radial notch
• for head of radius on medial head
130
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Ulna (cont)
– Styloid process
• point on distal medial end
– Interosseous membrane
• loosely joins radius and ulna
• helps with weight distribution across elbow
131
The Right
Radius and
Ulna
(Figure
6.28)
132
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Carpal bones
– In the base of the hand
– Arranged in two rows of four bones
– Allow movements of hand
• from side to side
• anterior to posterior
133
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Carpal bones (cont)
– Proximal row starting laterally
• scaphoid, lunate, triquetral, and pisiform
– Distal row starting laterally
• trapezium, trapezoid, capitate, and hamate
• hamate with prominent hook on palmar side
134
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Metacarpal bones
– Occupy palmar region
– Numbered I through V
• metacarpal I at base of thumb
• metacarpal V at base of little finger
– Divided into a base, body, and head
• head forming knuckles
135
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Phalanges
– Bones of the fingers
– Each with a base, body, and head
– Identified by
• metacarpal number
• proximal, middle, or distal
136
The Appendicular Skeleton:
The Pectoral Girdle and Upper Limb
• Phalanges (cont)
– Digits II through IV
• have three bones
– Digit I, pollex
• only proximal and distal bones
137
The Right
Hand
(Figure
6.29a)
138
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Pelvic girdle
– Right and left hip bones and sacrum
– Sacroiliac joint
• where hip bones joined to sacrum
– Pubic symphysis
• where hip bones joined to each other
• just superior to genitalia
• median pad of fibrocartilage, interpubic disc
139
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Regions of pelvis
– Pelvis, girdle plus muscles and ligaments
– Greater (false) pelvis
• superior region between flare of hips
• contains and supports lower intestines
– Pelvic inlet
• opening leading to lesser (true) pelvis
140
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Regions of pelvis (cont)
– Lesser (true) pelvis
• narrower inferior space
• contains rectum, urinary bladder, and uterus
– Pelvic brim
• edge of pelvic inlet
– Pelvic outlet
• lower opening of lesser pelvis
141
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Sexual dimorphism of pelvis
– Male pelvis
• heavier and thicker
– Female pelvis
• adapted to needs of pregnancy and childbirth
• wider, shallower
• larger, rounder pelvic inlet and outlet for infant passage
142
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Hip bone
– Formed by fusion of three childhood bones
• ilium, ischium, and pubis
– Acetabulum
• deep socket for head of femur
143
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Ilium
– Largest hip bone
– Iliac crest, upper margin of ilium
– Greater sciatic notch
• notch for sciatic nerve
– Iliac fossa, anteromedial surface
144
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Ischium
–
–
–
–
Inferoposterior part of hip bone
C-shaped bone
Most of posterior wall of acetabulum
Ischial tuberosity
• lowermost part
145
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Pubis
– Most anterior part of hip bone
– Anterior part of acetabulum
– Pubic symphysis
• where anterior pubic bones jointed by interpubic disc
– Obturator foramen
• encircled by ischium and pubis
• large hole below acetabulum
146
The Pelvic Girdle (Figure 6.30a)
147
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Bones of lower limb
–
–
–
–
–
–
Femur in thigh, patella (kneecap)
Tibia and fibula in leg
7 tarsal bones in ankle
5 metatarsal bones in foot
14 phalanges in foot
Adapted for weight bearing and locomotion
148
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Femur
–
–
–
–
Longest and strongest bone in body
Hemispherical head inserting into acetabulum
Constricted neck distal to head
Greater and lesser trochanters
• processes of upper femur
• insertions for hip muscles
149
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Femur (cont)
– Linea aspera
• ridge on posterior surface
• attachment side for adductor muscles of thigh
– Medial and lateral epicondyles
• on distal end of femur
• sites of muscle and ligament attachment
150
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Femur (cont)
– Medial and lateral condyles
• surfaces of knee joint
– Patellar surface
• on anterior femur
• depression for patella
151
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Patella (kneecap)
– Roughly triangular bone
– Cartilaginous at birth
• ossifies between ages 3 to 6
– Broad superior base
152
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Patella (kneecap) (cont)
– Pointed inferior apex
– Shallow articular facets on posterior surface
• where articulates with femur
• glides on patellar surface when knee flexed and extended
153
The Right
Femur and
Patella
(Figure
6.31)
154
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Tibia
–
–
–
–
On medial side of leg (between knee and ankle)
Thick, strong bone
Only weight-bearing bone of region
Medial and lateral condyles
• flat surfaces on superior head
• meet condyles of femur
155
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Tibia (cont)
– Tibial tuberosity
• anterior surface of tibia just below patella
• where patellar ligament inserts
– Anterior border
• sharply angular
– Medial malleolus
• medial knob of tibia
156
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Fibula
–
–
–
–
Slender lateral strut
Helps stabilize the ankle
Broader at proximal end, the head
Lateral malleolus
• knob and distal end of fibula
– Connected to tibia through interosseous membrane
157
The Right
Tibia and
Fibula
(Figure
6.32)
158
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Tarsal bones
– Arranged in proximal and distal groups
– Integrated into arches of the foot
– Proximal group
• calcaneus of heel
• talus, articulates with tibia
• navicular bone anterior to talus
159
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Tarsal bones (cont)
– Distal group medial to lateral
• first, second, and third cuneiforms
• cuboid, the largest
• Metatarsal bones
– Numbered I to V from medial to lateral
– I proximal to great toe
160
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Phalanges
– Bones of the toes
– 1st toe, hallux
• contains only proximal and distal phalanges
– Other toes with proximal, middle, and distal phalanges
161
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Arches of foot
– Absorb shock and body jostles
– Medial longitudinal arch
• extends from heel to great toe
– Lateral longitudinal arch
• extends from heel to little toe
162
The Appendicular Skeleton:
The Pelvic Girdle and Lower Limb
• Arches of foot (cont)
– Transverse arch
• extends from side to side
– Arches held together by short ligaments
• can be weakened or stretched causing fallen arches
163
The Right Foot (Figure 6.33a-b)
164
The Appendicular Skeleton
What are the bones of the pelvic girdle?
Which three bones fuse to form the hip
bone? What opening divides the greater
and lesser pelvis?
The sacrum and two hip bones
Ilium, ischium, pubis
Pelvic inlet
165