The Skeletal System

Axial skeleton• Skull• Vertebral column• Rib cage

– Ribs

– Sternum

Skull: cranium + face

• Cranial bones:– Frontal

– Parietal

– Temporal

– Occipital

– Sphenoid

– Ethmoid

• Frontal bone

• Parietal bone

• Occipital bone– Foramen magnum

– Occipital condyle

Temporal bone• Squama temporalis

– Zygomatic proces

– Mandibular fossa

• Mastoid part– Mastoid process

• Petrous bone– Contains the middle/inner

ear structures

• Tympanic part– External acoustic meatus

– Styloid process

Sphenoid

• Base of the cranium• Body

– Sinuses

– Sella turcica

– Pterygoid processes

• Greater and lesser wings• Many foramen

– Optic canal

– Superior orbital fissure

– Foramen ovale

– Foramen lacerum

– Foramen rotundum

Ethmoid• Back and upper nose• Perpendicular plate• Ethmoid sinuses• Crista gali• Cribriform plate and

foramina• Superior and middle

nasal conchae

Facial bones

• Maxilla• Palatine bones• Zygomatic bones• Lacrimal bones• Nasal bones• Inferior nasal concha• Vomer• Mandible

Maxilla Palatine bones• Alveolar processes• Palatine process

Zygomatic and lacrimal bones

• Zygomatic bone– zygomatic arch

– Lower ocular orbit

• Lacrimal bones– nasolacrimal canal

Nasal bone, Vomer and Inferior nasal conchae

Other skull bones

• Hyoid bone

• Auditory ossicles– Three of the smallest bones

in your body– Middle ear cavity of the

petrous part of the temporal bone (paired or unpaired?)

– From lateral – medial• Malleus, incus & stapes

Other skull bones

Bones with sinuses

• Frontal• Maxillary• Sphenoid• Ethmoid

• Sinus: cavity with the bone of the skull make it lighter + resonance box for the voice

Bones forming the orbit of the eye

• Frontal bone• Zygomatic• Maxilla• Lacrimal• Sphenoid• Ethmoid

Bones forming the nasal cavity

• Ethmoid• Vomer• Palatine• Maxilla• Nasal bone• Inferior nasal

conchae

Various “hardcore” bones• Remember that many of the cranial & facial

bones are “paired”– Paired = left & right

• Left & right parietal bones

• Left & right temporal bones

• Left & right lacrimal bones

• Nasal bones

• Zygomatic bones

• Maxilla bones

• Palatine bones

• Inferior nasal concha

Various “hardcore” bones• Remember that many of the cranial & facial

bones are “paired”– UN-paired (single)

• Frontal bone

• Occipital bone

• Sphenoid bone

• Ethmoid bone

• Vomer bone

• Mandible

• Hyoid bone

Skull foramen

• http://www.studystack.com/studytable-2333

Vertebral column• 31 vertebra divided into

regions• Forming various curves

– Cervical

– Thoracic

– Lumbar

– Pelvic

Typical vertebra• Vertebral body : support

• Vertebral canal (foramen): for spinal cord

• Processes: for muscle attachment– Spinous process

– Transverse processes

– Superior articular process

– Inferior articular process

• Facet: articulation with other vertebrae and ribs

• Intervertebral foramen: formed by 2 adjacent vertebra spinal nerves exit through it

• Intervertebral discs: made of an envelope of fibrocartilagenous tissues (interanulus fibrosus) and in the center of a gelatinous substance (nucleus pulposus)

What happens when a disc ruptures?

7 Cervical vertebrae

• Typical features: • Small body• Bifid spinous process• Transverse foramen

• Special vertebrae: Atlas and Axis:

• Atlas = C1 round, occipital condyles

• Axis: Dens of axis• C7: longer spinous process

prominence

• Note C7: prominent vertebra (landmark on the vertebral column

12 Thoracic vertebrae• NO transverse foramen• Body larger then cervical

vertebra• Spinous processes longer,

tend to slent downward• Facets of articulation with

ribs

5 Lumbar vertebrae• Large wide body• Short spinous prcesses

5 sacral vertebrae sacrum

• 5 sacral vertebrae fuse to form the sacrum

• Features:– Auricular surface

– Median sacral crest

– Sacral canal

– Sacral foramina

– Apex

– Sacral promontory

• Coccyx– 4 fused vertebrae tailbone

Sternum - Ribs

- 7 pairs true ribs

- 3 pairs – false ribs

- 2 pairs – floating ribs

Appendicular skeleton: upper extremity• Pectoral girdle:

– Scapula

– Clavicle

• Upper arm:– Humerus

• Lower arm:– Ulna

– Radius

• Wrist:– Matacarpals bones

• Hand– Metacarpals

– Phalanges

Pectoral girdle• Scapula

– Left or right?

– The smooth side (subscapular fossa) is against the rib cage

– The glenoid fossa is lateral (it is where the humerus attaches)

• Clavicle– Left or right:

– Sternal end (square end) against sternum, acromial end (flatter end) against acromiom

• Clavicle– The curvature near the

sternal end sticks out

– See previous drawing

• Humerus– Left or right?

– The head of the humerus

must face medially

– The olecranon fossa

(the largest fossa at the elbow)

is posterior

Wrist and Hand

• See book

Appendicular skeleton: lower extremity• Pelvic girdle

– Coxal bones

• Thigh– Femur

• Lower leg:– Tibia

– Fibula

• Ankle– Tarsal bones

• Foot– Metatarsal

– Phalanges

Coxal bone

• Left or right?– The acetabulum must face

externally

– The symphysis pubis is anterior

Femur• Left or right?

– The head of the femur must face internally

– The smooth surface in the lower femur is anterior while the deep groove is posterior

Tibia - Fibula• Tibia:

– Left or right?

– The styloid process, at the base is the exernal malleolus or internal ankle

– The tibial tuberosity is anterior

• Fibula:– The hed of the fibula is against the

lateral condyle

– The styloid process is the lateral malleolus or external ankle

– Slented side of styloid process is posterior

Ankle - Foot

Scoliosis

Lordosis Kyphosis

Kyphosis