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Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 7Anatomy of Bones
and Joints
Bone Trabeculae
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General Considerations of Bones
Average adult skeleton has 206 bones (Figure 7.1)
Bones are paired or unpaired
Most anatomical terms used to describe the featuresof bones are based on the relationship between thebones and associated ligaments, muscles, joints,nerves, and blood vessels (Table 7.1) Processes
Surfaces
Holes The skeleton is divided into the axial and
appendicularskeletons
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Fig 7.1
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Tab. 7.1
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Axial Skeleton
The axial skeleton forms the upright axis of thebody
Consists of
Skull Auditory ossicles
Hyoid bone
Vertebral column
Thoracic cage (rib cage)
Protects the brain, the spinal cord, and the vital
organs housed within the thorax
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Axial Skeleton
Skull Composed of 22 bones
The braincase protects the brain Paired parietal and temporal bones, and the unpaired
frontal, occipital, sphenoid, and ethmoid bones The facial bones protect the sensory organs of the
head and serve as muscle attachment sites The 14 facial bones are the maxilla (2), zygomatic (2),
palatine (2), lacrimal (2), nasal (2), inferior nasal concha
(2), mandible (1), and vomer (1) bones The mandible and maxillae hold the teeth, and the
auditory ossicles that function in hearing, arelocated inside the temporal bones
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Axial Skeleton
Skull (External view) Parietal bones
Joined at the midline by the sagittal suture
Joined to the frontal bone by the coronal suture
Joined to the occipital bone by the lambdoid suture
Joined to the temporal bone by the squamoussuture
The external occipital protuberance is an
attachment site for an elastic ligament
Nuchal lines are the points of attachment forneck muscles
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Fig 7.2
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Fig 7.3
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Axial Skeleton
Skull (Lateral view) The external acoustic meatus transmits sound
waves toward the eardrum
Neck muscles attach to the mastoid process,which contains mastoid air cells
The temporal lines are attachment points ofthe temporalis muscle
The zygomatic arch, from the temporal andzygomatic bones forms a bridge across theside of the skull
The mandible articulates with the temporal
bone
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Fig 7.4
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Fig 7.5
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Axial Skeleton
Skull (Anterior view) The orbits contain the eyes
The nasal cavity is divided by the nasalseptum
Sinuses within bone are air-filled cavities The paranasal sinuses, which connect to the nasal
cavity, are the Frontal sinus
Sphenoidal sinus
Maxillary sinuses
Ethmoidal labyrinth
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Fig 7.6
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Fig 7.7
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Fig 7.8
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Fig 7.9
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Fig 7.10
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Axial Skeleton
Skull (Inferior surface) Spinal cord and brain are connected through
the foramen magnum
Occipital condyles are points of articulationbetween the skull and the vertebral column
Blood reaches the brain through the internal
carotid arteries, which pass through the
carotid canals, and the vertebral arteries,which pass through the foramen magnum
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Axial Skeleton
Skull (Inferior surface) Most blood leaves the brain through the
internal jugular veins, which exit through the
jugular foramina Styloid processes provide attachment points
for three muscles involved in movement of the
tongue, hyoid bone, and pharynx
The hard palate separates the oral cavity fromthe nasal cavity
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Fig 7.11
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Axial Skeleton
Skull (Superior view inside the cranialcavity)
The crista galli is a point of attachment for one
of the meninges The olfactory nerves extend into the roof of
the nasal cavity through the olfactory foramina
of the cribriform plate
The sella turcica is occupied by the pituitary
gland
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Tab. 7.2
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Tab. 7.3
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Fig 7.12
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Axial Skeleton
The hyoid bone,which floats in
the neck, is the
attachment sitefor throat and
tongue muscles
Fig 7.13
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Axial Skeleton
Vertebral Column Provides flexible support and protects the spinal
cord
The vertebral column has four major curvatures: Cervical
Thoracic
Lumbar
Sacral/CoccygealAbnormal curvatures are
lordosis (lumbar)
kyphosis (thoracic)
scoliosis (lateral)
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Fig 7.14
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Fig 7.15
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Axial Skeleton
Vertebral Column (Vertebra) Consists of a body, a vertebral arch, and various
processes Part of the body and vertebral arch (pedicle and lamina) form
the vertebral foramen, which contains and protects the spinal
cord The transverse and spinous processes are points of muscle
and ligament attachment
Vertebrae articulate with one another through the superiorand inferior articular processes
Spinal nerves exit through the intervertebral foramina Adjacent bodies are separated by intervertebral disks
Fibrous outer covering (annulus fibrosus)
Gelatinous interior (nucleus pulposus)
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Fig 7.16
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Tab. 7.4
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Axial Skeleton
Vertebral Column Components All seven cervical vertebrae have transverse
foramina, and most have bifid spinous processes
The 12 thoracic vertebrae have attachment sites forribs and are characterized by long, downward-pointing spinous processes
The five lumbar vertebrae have thick, heavy bodiesand processes. Their superior articular facets facemedially and their inferior articular facets face laterally
The sacrum consists of five fused vertebrae andattaches to the coxal bones to form the pelvis
The coccyx consists of four fused vertebrae attachedto the sacrum
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Fig 7.17
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Fig 7.18
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Tab.
7.4(Contd.)
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Tab. 7.5
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Page
160.a
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Page
160.b
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Axial Skeleton
Thoracic Cage The thoracic cage (consisting of the ribs, their
associated costal cartilages, and the sternum)protects the thoracic organs and changes volumeduring respiration
Twelve pairs of ribs attach to the thoracic vertebrae Seven pairs oftrue ribs
Five pairs offalse ribs
Two pairs of false ribs are floating
The sternum is composed of the Manubrium
Body
Xiphoid process
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Fig 7.19
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Fig 7.20
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Appendicular Skeleton
Consists of the bones of the upperandlower limbs and the girdles by which they
are attached to the body
Pectoral girdle: upper limbs Pelvic girdle: lower limbs
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Appendicular Skeleton
Pectoral Girdle Consists of the scapulae and clavicles
Scapula Articulates with the humerus (at the glenoid cavity)
and the clavicle (at the acromion) Attachment site for shoulder, back and arm
muscles
Clavicle
Holds the shoulder away from the body and allowsmovement of the scapula, resulting in freemovement of the arm
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Fig 7.21
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Fig 7.22
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Fig 7.23
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Appendicular Skeleton
Upper Limb The arm bone is the humerus
Articulates with the scapula (head), the radius(capitulum), and the ulna (trochlea)
Sites of muscle attachment are the greater andlesser tubercles, the deltoid tuberosity, and theepicondyles
The forearm contains the ulna and radius
The ulna and radius articulate with each other andwith the humerus and wrist bones
The wrist ligaments attach to the styloid processesof the radius and ulna
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Fig 7.24
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Fig 7 25