Skeletal System

A. Functions1. Structure & support2. Protection3. Levers for movement4. Mineral storage 5. Blood cell production

Skeletal System

B. Classification of Bones1. By Location

A) Axial skeleton (80 bones)1) includes the bones making up the skull, vertebral column, and rib cage

B) Appendicular skeleton (126 bones)1) includes the bones of the arms, legs, pectoral girdle, and pelvic girdle

Skeletal System2. By Shape

A) Long - longer than wide (arms & legs)B) Short - roughly cube-shaped (carpals & tarsals)C) Sesamoid (round) bones - develop within a tendon (patella)

Skeletal System

D) Flat - thin, flattened, and usually slightly curved (skull bones) E) Wormian – within a skull sutureF) Irregular - fit none of the previous categories (vertebrae & os coxa)

Skeletal SystemC. Structure

1. Long boneA) Diaphysis

1) Medullary (marrow) cavity

B) Epiphyses1) Epiphyseal

line – adult

Skeletal System

2) Epiphyseal plate – children

3) Covered with articular cartilage

C) Outer portion – compact bone tissue

D) Inner portion & Ends – spongy bone tissue

Skeletal SystemE) Periosteum

1) outer CT covering

2) Sharpey’s fibersa) connect the

periosteum to the underlying bone tissue

F) Endosteum1) inner CT lining

Skeletal System

2. Short, Flat & Irregular bonesA) Periosteum & endosteum are

presentB) Contains marrow but has no marrow

cavityC) No epiphyses or diaphysisD) Resembles a sandwich

1) Diploe – internal spongy bone layer of short, flat, & irregular bones

Skeletal System

D. Bone Markings*review outline*

E. Bones of the Axial Skeleton1. Cranial Bones (8)

A) frontal bone1) coronal suture

a) separates frontal from parietal bones

Skeletal System

B) parietal bones1) sagittal suture

a) separates right and left parietal bones

2) lambdoid suturea) separates parietal bones from occipital bone

3) squamous suture a) separates parietal bones from temporal bones

Skeletal System

C) temporal bones1) external acoustic meatus

a) external opening of auditory canal2) internal acoustic meatus

a) internal opening of auditory canalb) passageway for the facial (VII) and vestibulocochlear (VIII) nerves

Skeletal System

3) stylomastoid foramen a) passageway for the facial (VII) nerve

4) carotid canala) passageway for carotid artery

5) jugular foramena) passageway for internal jugular vein,

glossopharyngeal (IX), vagus (X), and accessory (XI) nerves

Skeletal System

6) styloid processa) attachment point for tongue and

neck muscles7) mastoid process

a) attachment point for neck muscles8) mandibular fossa

a) articulation point between the temporal bone and the mandible

Skeletal System

D) occipital bone1) foramen magnum

a) passageway for the brain stem and the accessory nerve (XI)

2) hypoglossal canal a) passageway for the hypoglossal (XII) nerve

Skeletal System

3) external occipital protuberance a) attachment point for neck and back

muscles4) occipital condyles

a) articulate with the atlas of the vertebral column

Skeletal System

E) sphenoid bone1) sella turcica

a) houses the pituitary gland2) optical canal

a) passageway for the optic (II) nerve

Skeletal System

3) superior orbital fissurea) passageway for occulomotor (III),

trochlear (IV), trigeminal (V), and abducens (VI) nerves

4) foramen rotunduma) passageway for the trigeminal (V)

nerve

Skeletal System

F) ethmoid bone1) crista galli

a) attaches to membranes of the brain and helps stabilize it within the cranial cavity

2) cribiform platesa) passageways for the olfactory (I) nerve

Skeletal System2. Facial Bones (14)

A) nasal bonesB) lacrimal bones

1) lacrimal fossaa) houses components of the

lacrimal (tear) apparatusC) zygomatic bonesD) palatine bones

1) forms part of the hard palate of the oral cavity

Skeletal System

E) vomer1) forms part of the nasal septum

F) inferior concha1) form part of the lateral walls of the

nasal cavityG) maxilla

1) alveolar margina) houses the upper teeth

Skeletal System

2) palatine processesa) compose the majority of the hard palate of the oral cavity

H) mandible1) only movable bone of the skull2) mandibular condyle

a) articulation point between the mandible and the temporal bone

Skeletal System3. Vertebral column

A) 5 regions1) cervical vertebrae (7; C1-C7)

a) atlas (C1)i) articulates with the skull

(occipital condyles)b) axis (C2)

i) dens (odontoid process) (a) projection around which the

atlas rotates

Skeletal System

c) transverse foraminai) passageways for vertebral arteries feeding the brain

2) thoracic vertebrae (12; T1-T12)3) lumbar vertebrae (5; L1-L5)

Skeletal System

4) sacrum (1)a) sacral

foraminai) passageway for sacral spinal nerves and blood vessels

Skeletal System

b) sacral canali) passageway for the distal spinal cord

5) coccyx (1)

Skeletal System

B) Main components of the vertebrae1) centrum (body)2) spinous process3) transverse

processes4) vertebral

foramena) passageway

for the spinal cord

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5) superior & inferior articulating surfacesa) articulation

points between successive vertebrae

b) create a movable joint

Skeletal System

6) intervertebral foraminaa) created by

notches between inferior and superior articulating surfaces of successive vertebrae

b) passageway for spinal nerves

Skeletal System

7) intervertebral discsa) composed of

fibrocartilage; found in cervical through lumbar regions

b) provide cushioning between successive vertebrae

Skeletal System

4. Thoracic (rib) cageA) sternum

1) manubriuma) jugular

notchb) clavicular

notch2) body3) xiphoid

process

Skeletal System

B) ribs (12 pair)1) true ribs (7)2) false ribs (5)

a) floating ribs (2; 11-12)

3) costal cartilage

Skeletal System

5. HyoidA) makes up

superior aspect of larynx

B) does not articulate with any other bone

Skeletal System

F. Bones of the Appendicular Skeleton

Skeletal System

1. Pectoral girdleA) scapula

1) glenoid cavitya) articulates with the head of the humerus

Skeletal System

2) acromion processa) articulates

with clavicle

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B) clavicle1) articulates

with the acromion process of scapula and the clavicular notch of the manubrium

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2. ArmA) humerus

1) head articulates with the glenoid cavity of scapula

2) deltoid tuberosity

Skeletal System

B) radius1) circular head

articulates with the capitulum of the humerus and radial notch of the ulna

Skeletal System

C) ulna1) olecranon

process & trochlear notch articulate with the trochlea of the humerus

Skeletal System

2) head articulates with the ulnar notch of the radiusa) only major long

bone whose head is located at the distal end

Skeletal System

D) carpals (8)1) hamate2) pisiform3) triquetral4) lunate5) trapezoid6) trapezium7) scaphoid8) capitate

Skeletal System

E) metacarpals (5)1) numbered 1-5

starting at the thumb (pollex)

Skeletal System

F) phalanges1) numbered 1-5

starting at the thumb

2) proximal (5)3) middle (4)4) distal (5)

Skeletal System3. Pelvic girdle

A) os coxa (ossa coxae)1) ilium

a) largest bone of the os coxab) sacroiliac joint

i) joint between the os coxa & the sacrum

c) greater sciatic notchi) passageway for the sciatic nerve

Skeletal System

2) ischiuma) lesser sciatic notch

i) passageway for numerous blood vessels & nerves (but not the sciatic)

3) pubisa) pubic symphysis

Skeletal System

4) acetabuluma) articulates with the head of the

femur5) obturator foramen

a) in spite of its large size, very few blood vessels & nerves pass through it

b) almost completely closed by a fibrous membrane

Skeletal System

4. LegA) femur

1) largest bone in the body

2) head articulates with the acetabulum

Skeletal System

3) linea asperaa) roughened

posterior ridge serving in muscle attachment

4) greater & lesser trochantersa) attachment site

for thigh and buttock muscles

Skeletal System

B) tibia1) its medial & lateral condyles

articulate with the medial and lateral condyles of the femura) separated by the medial and lateral meniscii) composed of fibrocartilageii) provide cushioning for the joint

Skeletal System

2) anterior crest3) medial malleolus

a) forms the medial bulge of the ankle

Skeletal System

C) fibula1) articulates at

both ends of the tibia via the head and lateral malleolus

2) lateral malleolusa) forms the

lateral bulge of the ankle

Skeletal System

D) tarsals (7)1) calcaneus2) talus3) navicular4) medial cuneiform5) intermediate

cuneiform6) lateral cuneiform7) cuboid

Skeletal System

E) metatarsals (5)1) numbered 1-5

starting at the great toe (hallux)

Skeletal System

F) phalanges1) numbered 1-5

starting at the great toe

2) proximal (5)3) middle (4)4) distal (5)