Part 2 Exercise Science: Bones and Joints of the Human Body

Flashcards testing knowledge of skeletal system structure, joint types, structural anatomy, bony landmarks, bone categories, and physiological factors of bone health from Chapter 1 to Chapter 7.

How many fused bones are in an adult skeletal structure, and by what birth age do they typically finish fusing?

An adult skeleton has approximately $206$ fused bones, which typically finish fusing by around $25$ years of birth age (occurring across $21\text{ to }25$ years of chronological age).

Roughly how many bones is an infant born with prior to ossification and fusing?

An infant is born with roughly $270$ bones.

What are the three main classifications of joints in the human body?

The three main joint classifications are fibrous joints, cartilaginous joints, and synovial joints.

What are the primary structural characteristics and movement capabilities of a fibrous joint?

Fibrous joints consist of very dense fibrous connective tissue forming a thin joint base that allows effectively no movement.

How many bones make up an infant skull, and what do they fuse into in an adult?

An infant skull is made up of approximately $20\text{ to }22$ bones, which fuse in adulthood (outside of the mandible or jaw) into a single structure called the cranium or skull.

What hormone is released during pregnancy that allows the pubic symphysis cartilaginous joint to open for birthing?

The natural hormone relaxin.

How long can relaxin take to leave the body and return to normal levels post-pregnancy?

Relaxin can take up to $2\text{ years}$ to return to normal levels and leave the body.

What condition involves movement or inflammation of the pubic symphysis leading to pelvic instability?

Osteitis pubis.

Which ribs form cartilaginous joint connections with the sternum?

Ribs $T1\text{ through }T10$ form cartilaginous joints with the sternum.

What structural role does a ligament play in a joint?

A ligament connects bone to bone, providing structural integrity and strength to the joint.

What is the function of a bursa within or around a joint?

A bursa is a gel-like sac that functions as a shock-absorbing pad to reduce friction between moving structures such as bones, tendons, and ligaments.

What is the functional difference between a tendon and a ligament?

A tendon connects muscle to bone, whereas a ligament connects bone to bone.

What is the function of articular cartilage in a synovial joint?

Articular cartilage provides a thick, dense, smooth protective surface over the ends of articulating bones to prevent friction and bone-on-bone wear.

What is the role of synovial fluid inside the joint cavity?

Synovial fluid acts as a nutrient-bearing lubricant to keep the internal working surfaces of the joint healthy and functioning smoothly.

How does the meniscus structure assist the knee joint?

The meniscus forms two flattened bowl-like craters on top of the tibia that allow the rounded bottom ends of the femur to sit congruently, aiding knee joint stabilization.

Which specific synovial joint type is situated between cervical vertebrae $C1$ and $C2$?

A pivot joint.

How much ground reaction force passes through the heel and ankle tarsal plane joints during running?

Running generates $1.5\text{ to }3\times$ body weight in force through the heel.

Why is the scapulothoracic joint classified as a pseudo joint rather than a true synovial joint?

It is a pseudo joint because it lacks a joint capsule, joint cavity, synovial fluid, synovial membrane, and articulating cartilage, and is supported purely by the muscular system.

Which mid-back muscles support the scapulothoracic pseudo joint?

The middle trapezius, rhomboids, pectoralis minor, and latissimus dorsi.

Which pelvic bony landmark is used to locate testing sites for skinfold measurements?

The anterior superior iliac spine.

Which bony landmark is used as a landmark in first aid to locate proper CPR compression position?

The xiphoid process.

Which bony landmark on the scapula is used to evaluate forward head posture and neutral spine alignment?

The acromion process.

What are the four primary structural categories of bone shape, along with the fifth specialized category?

Long bones, short bones, flat bones, irregular bones, and sesamoid bones.

Where does longitudinal growth occur within a long bone?

Growth occurs at the epiphyseal growth plates (or lines) located at either end of the long bone.

What substance is stored in the medullary cavity of long bones?

Yellow bone marrow.

What are the two major functional benefits of the patella as a sesamoid bone?

It protects the internal structures of the knee joint and increases the mechanical advantage of the quadriceps muscle.

Why do tendons recover faster from minor injuries than ligaments?

Tendons have a high blood supply, whereas ligaments have a very poor blood supply.

At what birth age does bone mass naturally peak in humans?

Bone mass peaks around the birth age of $35$ years.

How much force was recorded passing through cricketer Brett Lee's heel during his delivery stride impact?

Between $7\text{ and }11\times$ his body weight.

Which hormone decline in post-menopausal women accelerates bone mineral density loss?

Estrogen.

Which Western Australian researcher is noted for studying 'anabolic aging' and heavy load training in older adults?

Professor Rob Newton.