Skeletal System

Skeletal System Functions Provides shape and support.

Video Notes Anatomy Skeletal System Support

Skeletal System Functions Enables you to

move. Skeletal muscles,

which are attached to bones by tendons, pull on the bones to produce movement.

Skeletal System Jobs Protects your internal organs. Your heart and lungs are shielded by

your ribs. Your brain is protected by your skull. Your spinal cord is protected by your

vertebral column.

Video Notes Anatomy Skeletal System Bones Protect

Skeletal System Jobs Produces blood cells. Some of your bones are filled with

special material that makes red and white blood cells.

Video Notes Anatomy Skeletal System Bones Make Blood

Skeletal System Jobs Stores minerals, fats, and other

substances.

Types of Bone Compact bone: has no visible

open spaces and provides most of the strength and support for a bone.

Types of Bone Spongy bone: has many open spaces

which makes the bone light, but strong.

Bone Marrow Bone marrow is a soft tissue found

inside the bones that makes red blood cells and stores fat.

Video Notes Anatomy Skeletal System Bone Types

Cartilage Cartilage- soft, flexible tissue that is

part of the skeletal system. Makes up the nose and ears, and helps cushion the area where two bones meet.

Video Notes Anatomy Skeletal System Cartilage

Joints Joints- the place where two or more

bones connect and allow for movement.

Video Notes Anatomy Skeletal System Types of Joints

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)

1. Fibrous joints• No movement• Sutures in fetal skull

2. Cartilaginous joints• Slight movements• Epiphyseal plates, costal cartilage

3. Synovial joints • Free movements• Most joints (wrist, knee, shoulder, hip, etc.)

Fibrous Joints

Synovial Joints

Ball and Socket Joint Ball and Socket Joint: allow the

greatest range of motion, like your shoulder and hip.

Hinge Joint Hinge Joint: like the hinge of a door,

allows forward or backward motion.

Knee Joint Elbow Joint

Pivot Joint Pivot Joint: allows one bone to rotate

around another, neck and head.

Sliding Joint Sliding Joint: allows one bone to slide

over another, wrist and ankles.

Types of Joint Movements1. Flexion vs. extension2. Plantar flexion vs. dorsiflexion3. Abduction vs. adduction4. Pronation vs. supination5. Eversion vs. inversion6. Rotation7. Protraction vs. retraction8. Elevation vs. depression9. Circumduction10.Excursion (mandible moving side to side)11.Opposition vs. reposition (thumb & pinky together,

then apart)

Bone to Bone Ligaments- connects bone to bone.

Bone to Muscle Tendons- connects muscle to bone.

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Divisions of the Skeleton Axial skeleton

Skull Hyoid bone Vertebral column Thoracic (rib) cage

Appendicular skeleton Limbs Girdles

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

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

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)

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

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

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

Vertebral Column Defects Lordosis –

abnormal anterior curvature Lumbar Swayback

Kyphosis – abnormal posterior curvature Usually upper thoracic Hunchback

Scoliosis – abnormal lateral curvature

Vertebral Column Damage

Herniated disk Compresses nerves

“Broken Tailbone” Fractured coccyx Can occur during

childbirth and from falls

Thoracic Cage “Rib cage” Functions:

Protects vital organs in thorax Prevents collapse of thorax during respiration

Consists of: Thoracic vertebrae Ribs + associated cartilages Sternum

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

Sternum “Breastbone” Three parts:

Manubrium (handle) 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

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Appendicular Skeleton

Girdles Pectoral or shoulder Pelvic

Upper Limbs Arm Forearm Wrist Hand

Lower Limbs Thigh Leg Foot

Pectoral Girdle

2 scapulae Articulates with

humerus 2 clavicles

Articulates with sternum & scapula

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)

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Comparison of the Male and Female Pelvis

Upper Limb

Arm Forearm Wrist Hand

Upper Limb: Arm Humerus –

region between shoulder and elbow

Upper Limb: Forearm

Radius (lateral or thumb side) & Ulna (medial or little finger side)

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)

Lower Limb

Thigh Leg Ankle Foot

Lower Limb: Thigh

Femur – region between hip and knee Articulates with

coxa and tibia Patella

Lower Limb: Leg

Tibia (shin) and fibula

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)