Ch7
The Axial Skeleton
• Consists of ________ bones
• Three major regions
• Skull
• ________ column
• ________ cage
The Skull
• Two sets of bones
1. ________ bones
• Enclose the brain in the cranial cavity
• Cranial ________ (calvaria)
• Cranial ________: anterior, middle, and posterior cranial
fossae
• Provide sites of attachment for head and neck muscles
The Skull
2. ________ bones
• Framework of face
• Cavities for special sense organs for sight, ________, and
smell
• Openings for ________ and ________ passage
• Sties of attachment for ________ and muscles of ________
expression
Cranial Bones
• ________ bone
• Parietal bones (2)
• ________ bone
• Temporal bones (2)
• ________ bone
• Ethmoid bone
Frontal Bone
• Anterior portion of ________
• Most of anterior cranial fossa
• Superior wall of ________
• Contains air-filled ________ sinus
Parietal Bones and Major Associated Sutures
• Superior and lateral aspects of cranial vault
• Four sutures mark the articulations of parietal bones with frontal,
occipital, and temporal bones:
1. ________ suture—between parietal bones and frontal bone
2. ________ suture—between right and left parietal bones
3. ________ suture—between parietal bones and occipital bone
4. ________ (squamosal) sutures—between ________ and temporal
bones on each side of skull
Occipital Bone
• Most of skull’s posterior wall and posterior cranial fossa
• ________ with 1st vertebra
• Sites of attachment for the ________ nuchae and many neck
and back muscles
Temporal Bones
• ________ aspects of skull and parts of ________ floor
• Four major regions
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Squamous
Tympanic
________
Petrous
Sphenoid Bone
• Complex, bat-shaped bone
• ________ bone
• Articulates with all other cranial bones
• Three pairs of processes
• Greater wings
• Lesser wings
• ________ processes
Ethmoid Bone
• ________ skull bone
• Superior part of nasal septum, roof of nasal cavities
• Contributes to medial wall of orbits
Sutural Bones
• Tiny irregularly shaped bones that appear within sutures
Facial Bones
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Mandible
________ bones (maxillae) (2)
________ bones (2)
Nasal bones (2)
________ bones (2)
________ bones (2)
Vomer
Inferior nasal ________ (2)
Mandible
• Lower jaw
• Largest, strongest bone of face
• _________________ joint: only freely movable joint in skull
Maxillary Bones
• Medially fused to form upper jaw and central portion of facial
skeleton
• ________ bones
• Articulate with all other facial bones except mandible
Zygomatic Bones
• Cheekbones
• ________ margins of orbits
Nasal Bones and Lacrimal Bones
• Nasal bones
• Form ________ of nose
• Lacrimal bones
• In medial walls of orbits
• ________ fossa houses ________ sac
Palatine Bones and Vomer
• Palatine bones
• Posterior one-third of hard palate
• ________ walls of the nasal cavity
• Small part of the orbits
• Vomer
• Plow shaped
• Lower part of ________ septum
Inferior Nasal Conchae
• Form part of lateral walls of nasal cavity
Orbits
• Encase eyes and ________ glands
• Sites of attachment for eye muscles
• Formed by parts of ________ bones (next slide)
Nasal Cavity
• Roof, lateral walls, and floor formed by parts of four bones
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Ethmoid
________ bones
Maxillary bones
Inferior nasal ________
• Nasal septum of bone and hyaline cartilage
• Ethmoid
• Vomer
• Anterior septal cartilage
Paranasal Sinuses
• ________ -lined, ________ -filled spaces
• Lighten the skull
• Enhance ________ of voice
• Found in frontal, sphenoid, ethmoid, and maxillary bones
Hyoid Bone
• Not a bone of the skull
• Does not articulate directly with another bone
• Site of attachment for muscles of swallowing and speech
Vertebral Column
• Transmits ________ of trunk to ________ limbs
• Surrounds and protects ________ cord
• Flexible curved structure containing 26 irregular bones (vertebrae)
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________ vertebrae (7)—vertebrae of the neck
________ vertebrae (12)—vertebrae of the thoracic cage
________ vertebrae (5)—vertebra of the lower back
________ —bone inferior to the lumbar vertebrae
________ —terminus of vertebral column
Vertebral Column: Curvatures
• Increase the resilience and flexibility of the spine
• Two posteriorly ________ curvatures
• Cervical and lumbar
• Two posteriorly ________ curvatures
• Thoracic and sacral
• Abnormal spine curvatures
• ________ (abnormal lateral curve)
• ________ (hunchback)
• ________ (swayback)
Ligaments
• ________ and ________ longitudinal ligaments
• From neck to sacrum
• ________ flavum
• Connects adjacent vertebrae
• ________ ligaments
• Connect each vertebra to those above and below
Intervertebral Discs
• Cushionlike pad composed of two parts
1. Nucleus pulposus
• Inner ________ nucleus that gives the disc its elasticity and
compressibility
2. ________ fibrosus
• Outer collar composed of collagen and fibrocartilage
General Structure of Vertebrae
• Body or ________
• Anterior weight-bearing region
• ________ arch
• Composed of pedicles and laminae that, along with centrum, enclose
vertebral foramen
• Vertebral foramina
• Together make up vertebral canal for spinal cord
• ________ foramina
• Lateral openings between adjacent vertebrae for spinal nerves
General Structure of Vertebrae
• Seven processes per vertebra:
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________ process—projects posteriorly
________ processes (2)—project laterally
Superior ________ processes (2)—protrude superiorly inferiorly
________ articular processes (2)—protrude inferiorly
Cervical Vertebrae
• C1 to C7: ________, ________ vertebrae
• C3 to C7 share the following features
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________ body
________ processes are bifid (except C7)
Large, triangular vertebral foramen
________ foramen in each transverse process
Cervical Vertebrae
• C1 (________) and C2 (________) have unique features
• Atlas (C1)
• No body or spinous process
• Consists of anterior and posterior arches, and two lateral masses
• Superior surfaces of lateral masses articulate with the occipital
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Cervical Vertebrae
• ________ (C2)
• Dens projects superiorly into the ________ arch of the atlas
• Dens is a pivot for the rotation of the atlas
Thoracic Vertebrae
• T1 to T12
• All articulate with ribs at facets and ________
• Long ________ process
• Location of ________ facets allows rotation of this area of
spine
Lumbar Vertebrae
• L1 to L5
• Short, thick pedicles and ________
• Flat hatchet-shaped ________ processes
• Orientation of ________ facets locks lumbar vertebrae together
so as to prevent rotation
Sacrum and Coccyx
• Sacrum
• 5 fused ________ (S1–S5)
• Forms posterior wall of pelvis
• ________ with L5 superiorly, and with auricular surfaces of the hip bones
laterally
• Coccyx
• Tailbone
• 3–5 fused vertebrae
• Articulates superiorly with sacrum
Thoracic Cage
• Composed of
• ________ vertebrae
• Sternum
• ________ and their costal cartilages
• Functions
• Protects vital ________ of thoracic cavity
• Supports ________ girdle and upper limbs
• Provides attachment sites for many muscles, including intercostal muscles
used during ________
Sternum (Breastbone)
• Three fused bones
• Manubrium
• Articulates with ________ and ribs 1 and 2
• Body
• Articulates with costal cartilages of ribs 2 through 7
• Xiphoid process
• Site of muscle attachment
• Not ________ until ~ age 40
Ribs and Their Attachments
• ________ pairs
• All attach posteriorly to thoracic vertebrae
• Pairs 1 through 7
• True (________) ribs
• Attach directly to the sternum by individual costal cartilages
Ribs and Their Attachments
• Pairs 8 through12
• ________ ribs
• Pairs 8–10 also called ________ ribs
• Attach indirectly to ________ by joining costal cartilage of rib
above
• Pairs 11–12 also called vertebral (floating) ribs
• No attachment to ________
Structure of a Typical Rib
• Main parts:
• Head
• Articulates posteriorly with facets (demifacets) on bodies of two adjacent
vertebrae
• Neck
• Tubercle
• Articulates posteriorly with transverse costal facet of same-numbered
thoracic vertebra
• Shaft
Appendicular Skeleton
• Bones of the limbs and their girdles
• ________ girdle attaches the upper limbs to the body trunk
• ________ girdle secures the lower limbs
Pectoral Girdle (Shoulder Girdle)
• ________ and the sca________ pulae
• Attach the upper limbs to the axial skeleton
• Provide attachment sites for muscles that move the upper limbs
Clavicles (Collarbones)
• ________ acromial (________) end articulates with the scapula
• Cone-shaped sternal (medial) end articulates with the sternum
• Act as braces to hold the scapulae and arms out laterally
Scapulae (________ Blades)
• Situated on the dorsal surface of rib cage, between ribs 2 and 7
• Flat and ________, with three borders and three angles
• Seven large ________, named according to location
The Upper Limb
• 30 bones form the skeletal framework of each upper limb
• Arm
• Humerus
• Forearm
• ________ and ulna
• Hand
• 8 ________ bones in the wrist
• 5 ________ bones in the palm
• 14 ________ in the fingers
Humerus
• Largest, longest bone of upper limb
• Articulates ________ with glenoid cavity of scapula
• Articulates ________ with radius and ulna
Bones of the Forearm
• Ulna
• ________ bone in forearm
• Forms the major portion of the elbow joint with the humerus
• Radius
• ________ bone in forearm
• Head articulates with ________ of ________ and with radial notch of
ulna
• Interosseous membrane connects the radius and ulna along their entire
length
Hand: Carpus
• ________ bones in two rows
• Proximal row
• Scaphoid, lunate, triquetrum, and pisiform proximally
• ________ row
• Trapezium, trapezoid, capitate, and hamate distally
• Only ________ and ________ articulate with radius to form
wrist joint
Hand: Metacarpus and Phalanges
• Metacarpus
• ________ metacarpal bones (#1 to #5) form the palm
• Phalanges
• Each finger (digit), except the thumb, has three phalanges—
distal, middle, and proximal
• Fingers are numbered 1–5, beginning with the thumb (________)
• Thumb has no middle phalanx
Pelvic (Hip) Girdle
• Two hip bones (each also called ________ bone or os coxae)
• Attach the lower limbs to the axial skeleton with strong ligaments
• Transmit weight of ________ body to ________ limbs
• Support pelvic organs
• Each hip bone consists of three fused bones: ilium, ischium, and pubis
• Together with the sacrum and the coccyx, these bones form the bony
pelvis
Hip Bone
• Three regions
1. Ilium
• ________ region of the ________ bone
• Auricular surface articulates with the sacrum (sacroiliac joint)
2. Ischium
• ________ part of hip bone
3. Pubis
• Anterior portion of hip bone
• Midline pubic ________ joint
Comparison of Male and Female Pelves
• Female pelvis
• Adapted for childbearing
• True ________ (inferior to pelvic brim) defines birth canal
• Cavity of the true pelvis is ________, ________, and has greater
capacity
Comparison of Male and Female Pelves
• Male pelvis
• Tilted ________ forward
• Adapted for support of male’s heavier build and stronger muscles
• Cavity of true pelvis is narrow and deep
Comparison of Male and Female Pelves
The Lower Limb
• Carries the weight of the body
• Subjected to exceptional forces
• Three segments of the lower limb
• ________: femur
• ________: tibia and fibula
• ________: 7 tarsal bones in the ankle, 5 metatarsal bones in the
metatarsus, and 14 phalanges in the toes
Femur
• Largest and strongest bone in the body
• Articulates proximally with the ________ of the hip and distally
with the tibia and patella
Bones of the Leg
• Tibia
• Medial leg bone
• Receives the weight of the body from the femur and transmits it to the foot
• Fibula
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Not weight bearing; no articulation with femur
Site of muscle attachment
Connected to tibia by ________ membrane
Articulates with tibia via proximal and distal ________ joints
Foot: Tarsals
• ________ tarsal bones form the posterior half of the foot
• ________ transfers most of the weight from the tibia to the
calcaneus
• Other tarsal bones: ________, ________, and the medial,
________, and lateral cuneiforms
Foot: Metatarsals and Phalanges
• Metatarsals:
• Five metatarsal bones (#1 to #5)
• Enlarged head of metatarsal 1 forms the “ball of the foot”
• Phalanges
• The 14 bones of the toes
• Each digit (except the hallux) has three phalanges
• Hallux has no middle phalanx
Arches of the Foot
• Arches are maintained by interlocking foot bones, ligaments,
and tendons
• Arches allow the foot to bear weight
• Three arches
• ________ longitudinal
• ________ longitudinal
• Transverse
Developmental Aspects: Fetal Skull
• Infant skull has more bones than the adult skull
• ________ bones such as the mandible and frontal bones are unfused
• At birth, skull bones are connected by ________
• Fontanelles
• Unossified remnants of fibrous membranes between fetal skull bones
• Four fontanelles
• Anterior, posterior, mastoid, and sphenoid
Developmental Aspects: Growth Rates
• At birth, the cranium is huge relative to the face
• At 9 months of age, cranium is _ adult size
• ________ and ________ are foreshortened but lengthen with
age
• The arms and legs grow at a faster rate than the head and
trunk, leading to adult proportions
Developmental Aspects: Spinal Curvature
• Thoracic and sacral curvatures are obvious at birth
• These primary curvatures give the spine a C shape
• ________ posteriorly
Developmental Aspects: Spinal Curvature
• Secondary curvatures
• ________ and lumbar—convex anteriorly
• Appear as child develops (e.g., lifts head, learns to walk)
Developmental Aspects: Old Age
• ________ discs become thin, less hydrated, and less elastic
• Risk of disc ________ increases
• Loss of stature by several centimeters is common by age 55
• Costal cartilages ossify, causing the thorax to become rigid
• All bones lose mass