Transcript lecture seven – skeletal system

HUMAN ANATOMY
LECTURE SEVEN
SKELETAL SYSTEM
ANATOMIC BONE
FEATURES
General Terms
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Head - enlarged end
Neck - constriction (narrowing) between head and body
Margin or border - edge
Angle - bend
Body - main part
Condyle - smooth rounded articular surface
Epicondyle - near or above condyle
Facet - small flattened atricular surface
Ridges
• Line or linea - low ridge
• Crest or cristae - prominent ridge
• Spine - very high ridge
Projections
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Process - prominent projection
Tubercle - small rounded bump
Tuberosity - knob
Trochanter - tuberosities on proximal femur
Openings
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Foramen - hole
Canal or meatus - tunnel
Fissure - cleft
Sinus or labyrinthe – cavity
Depressions
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Fossa - depression
Notch - depression in bone margin
Fovea - little pit
Groove or sulcus - deeper, narrow depression
DIVISIONS OF THE SKELETAL
SYSTEM
Axial Skeleton
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Skull
Hyoid bone
Vertebral column
Thoracic (rib) cage
Appendicular Skeleton
• Limbs
• Girdles
THE COMPLETE SKELETON
THE SKULL/CRANIUM
Functions
• Protects brain
• Supports special sense organs
• Provides foundation for structures
that take air, food, water into body
Superior View
• Parietal bone - sides
• Frontal bone - forehead
• Occipital bone - back
BONES OF THE SKULL
• 22 bones plus 6 auditory ossicles (bones of ear)
• Divided into 2 sections:
(1) Neurocranium (braincase)
- surround and protect brain
- parietals, temporals, frontal, occipital, sphenoid, ethmoid bones
(2) Viscerocranium (facial bones)
- protect major sensory organs: eyes, ears, nose, tongue
- provide attachment sites for muscles of mastication, facial expression,
eye movement
- maxillae, zygomatics, lacrimals, nasals, inferior nasal conchae, mandible
POSTERIOR VIEW OF THE SKULL
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Parietal bones – sides of head
Occipital bone – back of head
Temporal bone - near ears
Mastoid process - bump behind ear
Occipital condyles – points of
articulation between skull and
vertebral column
• Zygomatic arch - cheekbones
LATERAL VIEW OF THE SKULL
• Parietal bones
• Frontal bone - forehead
• Temporal bone
- external auditory meatus
into eardrum
- mastoid process
- zygomatic process of
zygomatic arch
• Maxilla - upper jaw
• Mandible - lower jaw
- coronoid process
FRONTAL VIEW OF THE SKULL
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Frontal bone
Zygomatic bones
Maxillae
Mandible
- tooth sockets
• Nasal bones
• Orbits - eye sockets
THE ORBIT
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Sphenoid bone - behind eye
Frontal bone
Maxilla
Zygomatic bone
Ethmoid bone - inner eye
Lacrimal bone - next to nose
NASAL CAVITY
• Nasal Septum - divides cavity
into right and left halves
- perpendicular plate of
ethmoid
- anterior is hyaline cartilage
• Nasal conchae - lateral walls
that increase surface area
(warm and moisten air)
- inferior is separate bone
- middle and superior are
projections from ethmoid bone
PARANASAL SINUSES
• Associated with bones of nasal
cavity
• Function:
- decrease skull weight
- resonating chambers for voice
- secrete mucous to clean out
nasal cavity
• Named for bones in which they
are found:
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Frontal
Maxillary
Ethmoidal
Sphenoidal
INTERIOR OF CRANIAL CAVITY
• Cribriform plate of ethnoid
bone - forms floor of olfactory
fossa (olfactory nerves pass through
foramina of cribriform plate)
• Sphenoid bone – floor of
cranium (joins cranium and facial
bones)
• Sella turcica of sphenoid bone
- houses the pituitary gland
• Foramen Magnum - opening for
spinal cord
INFERIOR VIEW OF THE SKULL
• Foramen magnum
• Occipital condyles
• Styloid processes – processes off
temporal bone for attachment of
muscles
• Occipital bone
• Temporal bone
• Zygomatic bone
• Maxilla
• Spheniod bones
BONES OF THE EAR
• Malleus
• Incus
• Stapes
HYOID BONE
• No direct bony attachment to skull
• Attachment point for some tongue
muscles
• Attachment point for neck muscles
that elevate larynx during speech
and swallowing
VERTEBRAL COLUMN
Functions
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Supports weight of head and trunk
Protects spinal cord
Allows spinal nerves to exit spinal cord
Provides site of muscle attachment
Permits movement of head and trunk
26 bones in adults, 34 in fetus
• 5 fuse to form sacrum
• 4 or 5 coccygeal fuse to form the coccyx
Regions
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Cervical (7 vertebrae)
Thoracic (12 vertebrae)
Lumbar (5 vertebrae)
Sacral bone (1)
Coccygeal bone (1)
Four major curvatures
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Cervical - anterior
Thoracic - posterior
Lumbar - anterior
Sacral and coccygeal - posterior
VERTEBRAE
4 basic parts:
1) body - weight bearing portion
2) arch - surrounds vertebral foramen
(spinal cord runs through)
- sides are pedicles
- lamina make up the roof
3) processes
- transverse processes extend
laterally from sides of arch
- spinous process projects dorsally
- articular processes are smooth
surfaces where vertebrae meet
4) foramen
- vertebral foramen
- intervertebral foramen where
nerves run through to spinal cord
CERVICAL VERTEBRAE
• Superior 7 vertebrae
• Very small bodies with bifid
spinous process and transverse
foramina
• Atlas - first cervical vertebra
- articulates with skull and
allows “yes” movement and
tilting side to side
- no body and no spinous
process
• Axis - second cervical vertebra
- considerable rotation
- dens extends into vertebral
foramen of atlas - lends to
rotation of atlas for “no”
THORACIC VERTEBRAE
• 12 middle vertebrae
• Long, thin spinous processes
directed inferiorly
• Long transverse processes
• Articular facets on transverse
processed for connection with
ribs (on 1st 10)
• Facets on body for articulation
with ribs
LUMBAR VERTEBRAE
• Large, thick bodies
• Heavy, rectangular transverse and
spinous processes
• Superior articular facets face
medially and inferior facets face
laterally - allows for locking to
adjacent vertebrae
- limits rotation
- adds strength
SACRUM AND COCCYX
Sacrum - attaches pelvic girdle to
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axial skeleton
Fusion of 5 sacral vertebrae
Median sacral crest - fusion of
spinous processes of 1st 4
Sacral hiatus - spinous process of
5th vertebrae
Sacroiliac articulating surface articulates with last lumbar
Sacral foramina - intervertebral
foramina
Coccyx - tailbone
• 4 vertebrae fused into a single bone
THORACIC OR RIB CAGE
Functions
• Protects vital organs
• Forms semi-rigid structure for
respiration
Parts
• Thoracic vertebrae
• Ribs (12 pairs)
- superior 7 “true” ribs attach directly
to sternum via costal cartilages
- inferior 5 “false” ribs
- 3 attach to sternum via common
cartilage
- 2 floating do not attach to
sternum
- head articulates with transverse
facets of thoracic vertebrae
STERNUM
Divided into
1) Manubrium - articulates with 1st
rib and clavicle at jugular notch
2) Body - ribs 3 – 7 articulate
3) Xiphoid process - attachment of
diaphragm and rectus abdominus
muscles
APPENDICULAR SKELETON
126 supporting bones and girdles
Girdles
• Pectoral/shoulder
• Pelvic
Upper Limbs
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Arm
Forearm
Wrist
Hand
Lower Limbs
• Thigh
• Leg
• foot
PECTORAL GIRDLE
• Scapula (shoulder blade)
- acromion process
- coracoid process
- glenoid fossa
-spine
- supra spinous fossa
• Clavicle (collarbone) - articulates
with acromion and manubrium of
sternum
- acromial (lateral end)
- sternal (medial end)
HUMERUS (Upper arm)
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Head - articulates with scapula
Greater tubercle - lateral bump
Lesser tubercle - medial bump
Intertubercular groove
Deltoid tuberosity
Capitulum - articulates with
radius
• Trochlea - articulates with ulna
RADIUS (Forearm)
Lateral bone of forearm
• Head - articulates with capitulum of
humerus
• Neck
• Radial tuberosity
• Styloid process
ULNA (Forearm)
Medial bone of forearm
• Olecranon process
• Trochlear notch - articulates with
capitulum of humerus
• Head - articulates with carpals of wrist
• Styloid process
WRIST AND HAND
• Wrist
- 8 carpals arranged in 2 rows of 4
- all are concave anteriorly
• Hand
- 5 metacarpals (palm) articulate
with distal carpals of wrist
- 3 phalanges on each digit
(proximal, middle, distal positions)
- thumb only has 2 phalanges
PELVIC GIRDLE
Main features:
• Coxal (pelvic) bones and
sacrum form a sturdy ring
• Pelvis - pelvic girdle and
coccyx
• Sacrum
• Coxae - right and left
- ilium
- pubis
- ischium
• Acetabulum - articulates
with head of femur
• Obturator foramen
COXAE
• Formed by the fusion of the:
1) ilium - articulates with the
sacrum
- iliac crest
- anterior superior iliac spine
2) pubis
- pubic symphysis
- superior and inferior pubic
ramis
3) ischium
- ischial spine
MALE AND FEMALE PELVIS
FEMUR AND PATELLA
Femur (thigh bone)
• Head - articulates with pelvis at
acetabulum
• Neck
• Greater and lesser trochanters
• Medial and lateral condyles –
articulate with tibia
Patella (knee cap)
• Located within quadricep tendon of
anterior thigh muscle (quadricep
femoris) also patellar ligament
TIBIA AND FIBULA (lower leg)
Tibia (shin)
• Medial and lateral condyles articulate with condyles of femur
• Tibial tuberosity
• Medial malleolus (inner ankle)
Fibula
• Head - articulates with tibia
• Lateral malleolus (outer ankle)
ANKLE AND FOOT
Ankle
• 7 tarsals make up ankle and
heel
• Talus - articulates with tibia
• Calcaneus (heel)
Foot
• 5 metatarsals (sole)
• Phalanges (toes)
ARCH OF FOOT
Distributes weight of body between
heel and ball of foot
• weight is transferred from the
tibia and fibula to the talus
• through to the calcaneus
• through arch system along lateral
side of foot to the ball (head of
metatarsals)
ie/ footprint in wet sand - imprint of
heel, lateral margin, ball and toes