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Skeletal system.

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Presentation on theme: "Skeletal system."— Presentation transcript:

1 Skeletal system

2 Divisions of Skeleton Axial Skeleton- 80 bones that make up the center axis of the skeleton. (green) Appendicular skeleton-126 bones that make up appendages to axial skeleton (legs, arms, etc.) (purple)

3 Axial Skeleton-Skull Made up of 28 irregularly shaped bones
2 major divisions Cranium (brain case)-8 bone Face-14

4 Cranial Bones Frontal 2 parietal 2 temporal Occipital Sphenoid Ethmoid

5 Cranial bone Frontal-forms forehead & anterior part of cranium.
Contains FRONTAL PARANASAL SINUSES. Forms orbit (eye space) and nasal cavity. Parietal bones- give shape to bulging topside of cranium.



8 Cranial Bones Temporal Bones-lower sides of cranium & part of its floor House middle & inner ear structures Mastoid sinuses Occipital bone- lower posterior part of skull Forms movable joint with first cervical vertebrae


10 Cranial Bones Sphenoid bones-resemble a bat with outstretched wings
Located in central portion of cranial floor. Lines orbit & nasal cavity. Sphenoid sinuses Protects the pituitary gland. Ethmoid bone- Irregular bone, lying anterior to sphenoid but posterior to nasal bones Fashions posterior nasal septum, nasal cavity sidewalls, nasal roof, & sides of orbit. Contains ethmoid sinuses . Functions in olfaction.



13 Sutures of the Cranium Sutures are immovable joints where two cranial bones meet. Coronal Lambdoidal Squamous Sagittal

14 Lateral View


16 Fontanels “Soft spots” in infants before ossification (bone formation). Allows compression of skull during birth.


18 Flash cards Using the pictures provided, create a set of flash cards for the cranial bones. On the front of the card, glue the picture provided, as well as a description of the bone On the back side, write the name of the bone.

19 Frontal Bone Contains muscosa lined, air filled spaces called sinuses
Connects with parietal bones in a suture (immovable joint) called coronal suture

20 Facial Bones 2 maxilla 2 zygomatic (malar) 2 nasal Mandible 2 lacrimal
2 palatine vomer 2 inferior nasal conchae (turbinates)

21 Facial Bones 2 Maxillae- form part of the floor with orbits, roof of mouth, floor and sidewall of nose. Maxillary sinuses Mandible-lower jaw & only movable joint in the skull



24 Facial Bones Zygomatic bone-forms outer margin of orbit.
2 nasal bones- form upper bride of nose and with septal cartilage, lower bridge of nose. Lacrimal bone-paper thin bone that is posterior and lateral to each nasal bone. Lines the orbit. Contains the foramen (hole) for the tear ducts. Lines the nasal cavity.



27 Facial Bones 2 palatine bones- join each other like 2 L’s facing each other. Form posterior portion of palate (roof of mouth). Form lateral wall of nasal cavity Inferior nasal conchae- scroll shaped bone projecting into nasal cavity. Important in the ventilation of lungs by warming & humidifying. Vomer bone- fashions posterior septum


29 Palatine

30 Vomer

31 Paranasal Sinuses Muscosa lined, air filled spaces
maxillary sinuses, the largest of the paranasal sinuses, are under the eyes, in the maxillary bones. frontal sinuses, superior to the eyes, in the frontal bone. ethmoid sinuses are within the ethmoid bone between the nose and the eyes. sphenoid sinuses, in the sphenoid bone at the center of the skull base.

32 Mastoid

33 External Auditory Meatus
Tube running from outer ear to middle ear. Extends from pinna (visible ear) to ear drum. Sound enters through here.

34 Foramen Holes in the bone.
Foramen magnum is the hole in the cranial floor that allows passage of spinal cord.

35 Axial skeleton- Hyoid Bone
A single bone in the neck. Part of axial skeleton U shape felt just above larynx and below mandible. Many muscles of the mouth floor attached to it (including tongue). Only bone in the body that does not articulate with any other.

36 Axial skeleton- Vertebral Column
Forms the longitudinal axis of the skeleton. Flexible because of segmentation. 24 vertebrae plus the sacrum and coccyx. 7 cervical vertebrae: framework of neck 12 thoracic vertebrae: posterior to thoracic region (chest) 5 lumbar vertebrae: small of the back.


38 Characteristics of vertebral Column
All but 1st cervical vertebrae have flat rounded body; sharp spinous markings at the anterior; & transverse process. All but the sacrum & coccyx have central opening (vertebral foramen). An upward projection (dens) on the 2nd cervical vertebrae provides an axis for rotating the head.

39 occipital condyles The occipital condyles on the skull are the articulation point for the skull to the vertebrae.

40 Ribs & Vertebrae The thoracic Vertebrae have articular facets for ribs. This is where ribs and vertebrae connect. There are also facets between vertebrae for other vertebrae as well.




44 Axial skeleton- Sternum
Medial portion of the anterior chest wall. 3 parts Upper- manubrium: articulates with clavicle and first rib. Middle- body: articulates with ribs 2-10 Lower- xiphoid process: cartilage that ossifies during adult life

45 Axial Skeleton- Ribs 12 ribs form thoracic cage or thorax along with sternum & vertebrae. Rib’s head articulate with body and ribs tubercle articulates with vertebrae True ribs: first 7 ribs joins a coastal cartilage that attaches to the sternum directly. False ribs do not attach directly to sternum. Floating ribs do not attach to sternum at all.

46 1 2 true 3 4 5 6 false 7 8 11 12 9 10 floating

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