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The Skeleton.

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Presentation on theme: "The Skeleton."— Presentation transcript:

1 The Skeleton

2 Skeleton The word skeleton comes from a Greek work meaning “dried up”
Infants are born with about 350 bones which fuse resulting in 206 bones that provide the framework for our structure 177/206 is for voluntary movement

3 Functions Protection: Blood Production: Storage: Movement:
Soft tissues and vital organs i.e. brain, heart lungs, and spinal cord Blood Production: Red blood cells (manufactured by red marrow) Storage: - Calcium and phosphorous Movement: Act as levers for muscle activity

4 Skeleton Organization
Two Divisions: Axial Skeleton: protection of internal organs Appendicular Skeleton: movement

5 Axial Skeleton 80 bones Forms the vertical axis of the body: Skull
Vertebral Column Thoracic Cage: Ribs Sternum

6 Appendicular Skeleton
126 bones Forms the appendages and their attachments to the appendicular skeleton: Upper Limbs Lower Limbs Shoulder Girdle Pelvic Girdle

7 Skull Bones that support the head, neck, and trunk, and protects the brain and spinal cord: - Cranial bones, facial bones, auditory ossicles, and hyoid bone Cranial Bones: enclose and protect the brain Facial Bones: forms the framework of the face

8 Skull Hyoid bone: Only bone that does not articulate with any other bone Suspended above the larynx (voice box) where it is anchored by ligaments to the styloid process of the temporal bone Helps to support the tongue Serves as an attachment point for muscles to help elevate the larynx during swallowing

9 Skull Auditory Ossicles:
Stapes (stirrup), Incus (anvil), Malleus (hammer) Named for their shape Three smallest bones in the human body Located in the middle ear Transmit sound

10 Thoracic Cage 25 bones (page 4): Sternum and 24 Ribs Ribs:
Encases heart, lungs, and organs Attached posteriorly to T1-T12 Ribs 1-7 are True Ribs and attach anteriorly to manubrium and body of sternum Ribs 8-10 are False Ribs, their cartilage joins the 7th rib anteriorly Ribs 11 and 12 are Floating Ribs and do not attach to the sternum


12 Coccyx: Tailbone 26 Bones (pg. 3) 7 cervical vertebrae
Vertebral Column 26 Bones (pg. 3) 7 cervical vertebrae 12 Thoracic Vertebrae 5 Lumbar Vertebrae Sacrum 5 fused vertebrae Coccyx: Tailbone

13 Cervical Vertebrae Begins at the base of the skull Seven cervical vertebrae-C1-C7 Smaller in size than rest of vertebrae Most moveable vertebrae Protect the spinal cord, support the skull, and provide movement (i.e., rotation) Eight pairs of cervical nerves which control breathing and upper body muscles (C3 controls diaphragm) C1 is called the Atlas (ring shaped; no body and spinous process) C2 is called the Axis (has a body, spinous process, and dens)


15 Thoracic Vertebrae 12 Thoracic Vertebrae-T1-T12 Located in the chest
Very little movement due to attachment to Ribs and Sternum Protect internal organs 1 Vertebral Body 2 Spinous Process 3 Transverse Process 4 Pedicle 5 Foramen 6 Lamina 7 Superior Facet

16 Lumbar Vertebrae 5 Lumbar Vertebrae-L1-L5
Designed to carry most of the body’s weight Largest vertebrae More range of motion than thoracic vertebrae, but less than cervical vertebrae

17 Sacrum Located behind the pelvis Connects the spine to the pelvis
Five fused bones-S1-S5 Below the sacrum are five additional fused bones which form the coccyx (tailbone)

18 Curvature of the Spine Acts like a spring to absorb shock, maintain balance, and allow range of motion Cervical Spine: Curves slightly inward Inward curve of the spine is called Lordosis Thoracic Spine: Curves outward Outward curve of the spine is called Kyphosis Lumbar Spine: Curves slightly inward-Lordosis

19 Intervertebral Disks In between the vertebrae are intervertebral discs made of fibrous cartilage that act as shock absorbers and allow the back to move. As a person ages, these discs compress and shrink, resulting in a distinct loss of height (generally between 0.5 and 2.0cm) between the ages of 50 and 55.

20 Axial Skeleton Summary
Vertebral column 7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae Sacrum Coccyx Skull Cranial bones Facial bones Auditory ossicles Hyoid bone Thoracic Cage 24 ribs Sternum

21 Shoulder Girdle (pages 4-5)
Pectoral or Shoulder Girdle Clavicle (2): collarbone Scapula (2): shoulder blade

22 Upper Extremities (pages 5-7)
Humerus (2): arm bone Radius (2): forearm (thumb side) Ulna (2): forearm (pinky side) Carpals (16): wrist bones 8 in each wrist Metacarpals (10): hand bones Phalanges (28): Fingers 2 in each thumb and 3 in each finger

23 Pelvic Girdle (pg. 80) Attaches the lower limbs and transmits the weight of the upper body to the lower limbs Ilium: upper portion of the pelvis Ischium: what we sit on (butt bones) Pubis: Lower most anterior part of pelvis

24 Lower Extremities (pages 81-83)
Femur (2): largest, longest and strongest bone (Thigh bone) Patella (2): Kneecap Tibia (2): Large shin bone Fibula (2): Thin shin bone Tarsals (14): ankle bones Metatarsals (10): foot bones Phalanges (28): Toes 2 in big toe and 3 in all other toes

25 Appendicular Skeleton Summary
Shoulder Girdle Clavicle Scapula Upper Extremities Humerus Radius Ulna Metacarpals Carpals Phalanges Pelvic Girdle Ilium Ischium Pubis Lower Extremities Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges

26 Bone Markings Passageways, joint formations, and attachment points for muscles, tendons, and ligaments Foramen: rounded hole or opening Foramen Magnum is the large hole in the skull

27 Bone Markings Process: projection Spinous Process of Vertebrae
Fossa: shallow or hollow surface Iliac Fossa of Pelvis Crest: a prominent ridge Iliac Crest of Pelvis

28 Bone Markings Condyle: smooth or rounded projection
Lateral and Medial Condyles of the Femur Epicondyle: projection located above a condyle Medial and Lateral Epicondyles of the Humerus

29 Bone Markings Trochanter: a large rough projection
Greater Trochanter of Femur Tuberosity: a small rounded projection Tibial Tuberosity


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