PNB 2264 Muscle and Bone Basics

Functions of bones

Support, protection, allowing for movement, calcium and potassium storage, hematopoesis

Classes of bone

Long, short, flat, irregular, sesamoid

Periosteum

“Wrapping” around a long bone; has fibrous cellular layer

Endosteum

Active layer of osteoblasts and osteoclasts

Medullary cavity stores…

Yellow bone marrow

The medullary cavity is located in the…

Diaphysis

What bone marrow is in the epiphysis?

Red bone marrow

Articular cartilage

Hyaline cartilage that lines the epiphysis

Appositional growth

Increase in width by adding layers and remodeling the marrow cavity

Endochondral ossification

Bone replaces hyaline cartilage and forms most of the bones in the body by 6-8 weeks after conception

Intramembranous ossification

Bone forms from mesenchyme. Occurs mostly in flat bones and portions of other bones

Fontanelle

Space where the bones of a baby’s skull have not completely fused; allows for easier delivery of the baby

Low blood calcium leads to the release of..

PTH from the parathyroid

High blood calcium leads to the release of…

Calcitonin from the thyroid gland

Range of motion

Normal extent of mobility for a certain joint

Degrees of freedom

# of axes at which movement in a joint occurs

Functional joint classifications

Synarthrotic; amphiarthrotic; diarthrotic

Synarthrosis

Immovable

Amphiarthrosis

Slightly moveable

Diarthrosis

Freely movable

Structural classification of joints

Fibrous, cartilaginous, synovial

Fibrous joint

Made of fibrous connective tissue

Cartilaginous

Made of cartilage connective tissue

Synovial joint

Synovial fluid in a membrane wraps the joint

An example of a synarthrotic joint

Skull sutures

An example of a amphiarthrotic joint

Pubic symphysis

An example of a diarthrotic joint

Elbow

Movements occurring along the sagittal plane

Flexion and extension

Movements occurring along the frontal plane

Abduction and adduction

Abduction

Movement away from the midline

Adduction

Movement towards the midline

Circumduction

A combination of frontal and sagittal movements into a cone-like shape

Movements occurring on the longitudinal axis of the moving segment

Rotation

Specialized rotation at proximal and distal radioulnar joints

Pronation & supination

Pronation

Rotating the hand downwards or backwards

Supination

Rotating the hand so it faces back up

Inversion/eversion

Special movement of the intertarsal joints

Inversion

Sole of the foot turns inward, toward the midline

Eversion

Sole of the foot faces outward, away from the midline

Movements occurring only in the jaw and shoulder

Retraction / protraction; elevation/depression

Retraction

Pushing backwards

Protraction

Pushing forward

Opposition

Special argument of hand where the thumb touches any finger; “pincer grasp”

6 major types of synovial joints

Hinge, pivot, condyloid, saddle, gliding, ball & socket

Pivot joint

Allows for rotational movement around a single axis

Condyloid joint

A round condyle of one bone articulates with a very shallow cavity on the other

Saddle joint

Two saddle shaped bones articulate with one another (concave and convex ends)

Uniaxial joints

1 axis of rotation; hinge/pivot

Biaxial joints

2 axes of rotation; condyloid/saddle

Nonaxial joints

No axes of rotation, nearly flat surfaces; gliding joints