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Skeleton is divided into

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Presentation on theme: "Skeleton is divided into"— Presentation transcript:

1 Skeleton is divided into
Skeletal Organization Skeleton is divided into two divisions! Axial (the center or “axis”) Appendicular (legs and arms)


3 Axial skeleton 1. Skull (28 bones including auditory ossicles) 2. Hyoid bone (1 bone) 3. Vertebral column (26 bones) a. Cervical (7 vertebrae) b. Thoracic (12 vertebrae) c. Lumbar (5 vertebrae) d. Sacrum (1 – 5 fused vertebrae) e. Coccyx (1 -~4 fused vertebrae) 4. Thoracic Cage (25 bones) a. Ribs (24) b. Sternum (1 – 3 parts) 80 total bones in axial skeleton

4 The Skull – 28 bones Braincase – encloses cranial cavity
Surrounds & protects brain 6 bones, 8 when paired Facial bones – forms facial structure 8 bones, 14 when paired Auditory ossicles – form the middle ear These bones transmit vibration to eardrum Malleus, incus, & stapes

5 Braincase bones – 8 bones
2 parietals 2 temporals 1 frontal 1 occipital 1 sphenoid 1 ethmoid

6 Braincase Parietals (wall) Most of sides & roof of cranial cavity
Joined to temporal by squamous suture (scale-like) Joined to frontal by coronal suture (crown) Joined to occipital by lambdoid suture () Sagittal suture joins two parietals

7 Braincase Temporals (time)
Inferior part of cranium & part of cranial floor Joined to occipital and parietal by squamous suture External auditory meatus – sound waves travel through to eardrum Mastoid process – neck muscle attachment for head rotation Other landmarks: Zygomatic Process – articulates with zygomatic Mandibular Fossa – articulates with mandible Styloid Process – muscle attachment for tongue, hyoid, & pharynx movement

8 Braincase Occipital (back of head) Sphenoid (wedge-shaped)
Posterior part & prominent portion of the base of the cranium Joined to parietals by lambdoid suture Occipital bone landmarks: Foramen Magnum – passage of spinal cord (connects to brain) Occipital Condyles – articulate with vertebral column Sphenoid (wedge-shaped) Connects to all other cranial bones Sella turcica (next slide) – contains pituitary gland

9 Braincase Ethmoid Light, spongy bone that increases surface area of nasal cavity Moistens & warms inhaled air Anterior floor of the cranium between the orbits Composes much of nasal cavity & part of nasal septum Ethmoid bone landmarks: Crista Galli Perpendicular Plate – part of nasal septum (with vomer) Superior Nasal Conchae & Middle Nasal Conchae – form lateral walls of nasal cavity


11 Facial bones – 14 bones 2 maxillae 2 zygomatic 2 palatine 2 nasals
2 lacrimals 2 inferior nasal conchae 1 mandible 1 vomer

12 Facial Bones Zygomatic bones cheek bones
form the floor & outer walls of the orbits Zygomatic bone landmarks: Temporal processes Zygomatic arches (temporal & zygomatic) Muscle attachment for moving the mandible

13 Facial Bones Maxillae paired bones forming upper jaw (holds teeth)
articulate with every bone of the face except the mandible Maxillary bone landmark: Palatine Processes = horizontal projection forming the anterior 2/3 of the hard palate (palatines form the rest)

14 Facial Bones Mandible Mandible landmarks: Lower jaw (holds teeth)
Largest and strongest bone in the face the only moveable skull bone Articulates with the temporal bone to form the Temporal Mandibular Joint (TMJ) Mandible landmarks: Ramus = perpendicular portion of bone Angle Mandibular condyle = articulates with temporal Mandibular Notch

15 Facial Bones Nasal bones Lacrimals Palatines Bridge of nose
Forms part of tear duct Palatines Posterior 1/3 of hard palate

16 Facial Bones Inferior nasal conchae Vomer
Part of nasal septum (with perpendicular plate of ethmoid)

17 Other Skull Features Orbits Nasal cavity Made by 7 bones!
Orbit landmarks: Superior orbital fissures & Inferior orbital fissures Blood vessels & nerves Optic foramen (optic nerve) Nasolacrimal canal (tear duct) Nasal cavity Nasal septum = vomer + ethmoid (perpendicular plate) Nasal conchae Inferior nasal concha – individual bone Superior & middle nasal conchae – ethmoid bone Increase surface area

18 Paranasal sinuses Open into nasal cavity
Decrease skull weight & serve as resonating chambers during voice production Frontal, maxillary, ethmoidal, & sphenoidal

19 Hyoid bone U-shaped Not part of skull
No direct bony attachment to skull (attached by muscles & ligaments) Attachment site for tongue & larynx muscles (speech & swallowing)


21 Vertebral Column “Backbone” Central axis of skeleton 5 regions:
Cervical vertebrae (neck + to turn) (C1-C7) Thoracic vertebrae (T1-T12) Lumbar vertebrae (L1-L5) Sacral (S) Coccygeal bone (CO) 4 curves: Cervical curves anteriorly Thoracic curves posteriorly Lumbar curves anteriorly Sacral & coccygeal curve posteriorly

22 Functions of Vertebral Column
Supports weight of head & trunk Protects spinal cord Allows spinal nerves to exit spinal cord Site for muscle attachment Permits head & trunk movement

23 Vertebral Column Defects
Lordosis – abnormal anterior curvature Lumbar Swayback Kyphosis – abnormal posterior curvature Usually upper thoracic Hunchback Scoliosis – abnormal lateral curvature

24 Vertebral Column Damage
Herniated disk Compresses nerves “Broken Tailbone” Fractured coccyx Can occur during childbirth and from falls

25 Vertebral Anatomy Body – bears weight
Intervertebral disks – separate bodies; dense fibrous connective tissue Vertebral arch – forms vertebral foramen Vertebral foramen – houses spinal cord Vertebral canal – formed by all vertebral foramina; spinal cord passage/protection Pedicle – extend from body to transverse process (feet); forms part of vertebral arch Lamina – extend from transverse process to spinous process; forms part of vertebral arch

26 Vertebral Anatomy Transverse process – extend laterally from the arch between pedicle & lamina Spinous process- project dorsally from laminae; can feel externally Intervertebral foramina- notches formed by adjacent vertebrae; spinal nerves exit here Articular process – area of vertebral articulation Articular facet – smooth surface articulates with ribs

27 Differences in Vertebrae
Cervical small bodies (except atlas) Transverse foramen on transverse process for vertebral arteries going to brain Some have split spinous processes Atlas – 1st vertebra holds up head Axis – 2nd vertebra allows rotation (dens)

28 Differences in Vertebrae
Thoracic Long, think spinous processes directed inferiorly Lateral articular facets for rib articulation Lumbar Large, thick bodies Heavy, rectangular transverse & spinous processes Medially facing superior articular facets (“locks” vertebrae together for stability)

29 Differences in Vertebrae
Sacrum 5 fused vertebrae Median sacral crest – spinous processes on 1st 4 vertebrae Sacral hiatus- inferior end of sacrum without a crest Site of anesthetic injection prior to childbirth Sacral promontory- bulge in anterior edge of body of 1st vertebra in sacrum Palpated before childbirth to determine pelvic opening size Coccyx (“tailbone”) 4 fused vertebrae Reduced vertebral bodies No foramina or processes

30 Thoracic Cage “Rib cage” Functions: Consists of:
Protects vital organs in thorax Prevents collapse of thorax during respiration Consists of: Thoracic vertebrae Ribs + associated cartilages Sternum


32 Ribs & Costal Cartilages
12 pairs (24 total) Articulate with thoracic vertebrae True ribs – (1-7) superior 7 attach to sternum via cartilage False ribs – (8-12) inferior 5 do not directly attach to sternum Floating ribs – (11-12) inferior 2 not attached to sternum at all

33 Sternum “Breastbone” Three parts: Manubrium (handle) Body
Jugular notch – superior to manubrium; between clavicular articulations Body Sternal angle – at junction of manubrium & body; locates 2nd rib & used to find apex of heart Xiphoid process (sword) Used in CPR alignment

34 Appendicular Skeleton, Joints & Movement
Ch. 6 Appendicular = “to hang something on”

35 Appendicular Skeleton
Pectoral girdle (scapulae & clavicle) Upper limbs (arm, forearm, wrist, hand) Pelvic girdle (2 coxae) Lower limbs (thigh, leg, ankle, foot)



38 Pectoral Girdle 2 scapulae 2 clavicles Articulates with humerus
Articulates with sternum & scapula

39 Upper Limb Arm Forearm Wrist Hand

40 Upper Limb: Arm Humerus – region between shoulder and elbow

41 Upper Limb: Forearm Radius (lateral or thumb side) & Ulna (medial or little finger side)

42 Upper Limb: Wrist & Hand
Wrist – region between forearm and hand 8 carpals Hand – attached to carpals 5 metacarpals 5 digits 3 phalanges per finger (2 on thumb)

43 Pelvic Girdle 2 coxae Coxa formed by 3 fused bones: ilium, ischium, pubis Sex differences: larger pelvic inlet and outlet in females, broader pelvis in females, greater subpubic angle in females (childbirth)



46 Lower Limb Thigh Leg Ankle Foot

47 Lower Limb: Thigh Femur – region between hip and knee Patella
Articulates with coxa and tibia Patella

48 Lower Limb: Leg Tibia (shin) and fibula

49 Lower Limb: Foot & Ankle
Ankle = 7 tarsals; articulates with tibia & fibula; calcaneus forms heel Foot = 5 metatarsals; 3 phalanges per digit (except great toe – has 2)

50 Joints or “Articulations”
Articulation = place where two bones come together Classification methods: Function: Synarthrosis (non-movable) Amphiarthrosis (slightly movable) Diarthrosis (freely movable) Structure (connective tissue type): Fibrous (fibrous tissue) Cartilaginous (cartilage) Synovial (synovial fluid)

51 Fibrous joints Cartilaginous joints Synovial joints No movement
Sutures in fetal skull Cartilaginous joints Slight movements Epiphyseal plates, costal cartilage Synovial joints Free movements Most joints (wrist, knee, shoulder, hip, etc.)

52 Fibrous Joints



55 Synovial Joints

56 Types of Joint Movements
Flexion vs. extension Plantar flexion vs. dorsiflexion Abduction vs. adduction Pronation vs. supination Eversion vs. inversion Rotation Protraction vs. retraction Elevation vs. depression Circumduction Excursion (mandible moving side to side) Opposition vs. reposition (thumb & pinky together, then apart)




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