MSS 1 Exercise Science: Skeletal System and Anatomy

Flashcards reviewing key concepts, structure, bone counts, divisions, spinal regions, postural deviations, and bone characteristics of the human skeletal system based on Chapter 1 to Chapter 7 lecture transcript.

What are the five key functions of the human skeletal system?

Supporting and protecting soft tissues and organs, providing attachment sites for muscles to allow movement, storing minerals (calcium and phosphates), producing blood cells in red bone marrow, and storing energy in yellow bone marrow.

How many bones are present in the human body at birth compared to full skeletal maturation?

An infant is born with approximately 270 bones, which fuse into 206 bones by full skeletal maturation.

At what age range does full skeletal maturation typically occur in humans?

Approximately 21 to 25 years of age.

Which bone at the base of the vertebral column is one of the last to complete fusion up to age 25?

The sacrum.

Into what two major classifications is the human skeleton divided, and how many bones are in each?

The axial skeleton (80 bones) and the appendicular skeleton (126 bones).

What structures comprise the axial skeleton?

The skull (cranium), vertebral column, thorax (rib cage and sternum), and the clavicle.

What bone serves as the only bony connection between the torso and the upper arm?

The clavicle.

How many individual bones make up the skull in an infant prior to fusion?

Approximately 22 bones.

What is the primary function of the mandible?

Mastication (chewing) of food.

What are the three movable regions of the vertebral column and the number of bones in each?

Cervical vertebrae (7 bones, C1–C7), thoracic vertebrae (12 bones, T1–T12), and lumbar vertebrae (5 bones, L1–L5).

What anatomical biological variance can occur in the human lumbar spine?

Some individuals are born with a sixth lumbar vertebra (L6).

What structural change causes sacroiliac (SI) joint pain?

The sacroiliac joint, which should be very tight and secure, becomes abnormally movable and falls out of alignment.

How do C-shaped and S-shaped scoliosis differ in typical origin?

An S-shaped scoliosis is usually a biological or genetic trait, while a C-shaped scoliosis can be genetic or caused by environmental adaptations (such as carrying an overloaded bag on one shoulder).

In addition to a lateral curve, what three-dimensional deviation can occur in scoliosis?

Rotation of the spine.

What characterizes kyphosis of the thoracic spine?

A hunching or flexing forward of the thoracic region, often accompanied by a forward head posture where the earlobe sits in front of the midpoint of the shoulder.

What physical traits and muscle dysfunctions are associated with excessive lordosis?

A sharper lumbar curve, tight lower back, distended lower abdominal region, and tight hip flexors.

What type of normal curvature is present in the cervical spine?

Lordosis (a backward-facing curve).

Which two cervical vertebrae allow for head nodding and shaking movements?

C1 and C2.

How does rotational capability compare between the thoracic spine and the lumbar spine?

The thoracic spine provides around 40 or more degrees of rotation, whereas the lumbar spine provides approximately 15 degrees total (roughly 3 degrees per vertebra).

What is the primary functional role of the lumbar vertebrae?

Support and weight bearing, supported by large bone structures and taller intervertebral discs.

How are the 12 pairs of ribs in the thoracic cage categorized?

10 attached ribs (connected to the sternum via costal cartilage) and 2 floating (or false) ribs.

What muscle holds the two floating ribs in place?

Quadratus lumborum.

What three anatomical parts comprise the sternum?

The manubrium (top component where the clavicle articulates), the body of the sternum, and the xiphoid process.

Why is the scapulothoracic joint categorized as a pseudo joint?

Because the scapula has no direct bone-on-bone attachment to the vertebral column and is held in place purely by the muscular system of the mid-back.

What occurs when an individual suffers an AC joint injury?

The clavicle pushes through and stretches the ligaments that hold it in place at the acromion of the scapula.

How do the radius and ulna differ in structure at the elbow and wrist joints?

The radius has a small rounded head at the elbow (allowing rotation over the ulna for pronation/supination) and a large head at the wrist; the ulna has a large wrench-like head at the elbow and a small head at the wrist.

Which carpal bone is most commonly fractured during a fall onto an outstretched hand?

The scaphoid bone.

What three bones make up the pelvic girdle?

The ilium, ischium, and pubis (pubic bone).

What condition can develop when the pubic symphysis becomes unstable in athletes?

Osteitis pubis.

What is the longest and largest bone in the human body?

The femur.

How do the tibia and fibula differ in location and load-bearing function in the lower leg?

The tibia is the larger, medial, load-bearing shin bone; the fibula is the smaller, thinner, lateral bone that maintains structural symmetry.

What is the primary functional purpose of the patella?

It provides a mechanical advantage for the quadriceps muscle by increasing its line of pull and overall force production.

Which tarsal bone forms the heel and serves as the attachment point for the Achilles tendon?

The calcaneus.

Which tarsal bone sits directly under the space formed by the tibia and fibula at the top of the ankle complex?

The talus.