Classification and Structure of Bones

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Questions and Answers

What is the primary function of the articular cartilage on the epiphysis of long bones?

To serve as a site for muscle attachment

To provide rigidity to the bone structure

To decrease friction at joint surfaces (correct)

To assist in the formation of red marrow

What component of the long bone is responsible for the lengthwise growth during youth?

Epiphyseal plate (correct)

Articular cartilage

Medullary cavity

Epiphyseal line

Which structure indicates the area of previous growth in adult long bones?

Endosteum

Epiphyseal plate

Epiphyseal line (correct)

Medullary cavity

What is contained within the medullary cavity of long bones in adults?

Yellow marrow primarily composed of fat Signup and view all the answers

What type of bone marking refers to an outgrowth from the bone surface?

Process Signup and view all the answers

Which component of a long bone is specifically responsible for lining the inner surface of the shaft?

Endosteum Signup and view all the answers

What type of cartilage primarily composes the articular cartilage covering the epiphyses?

Hyaline cartilage Signup and view all the answers

What are bone markings primarily used for?

Muscle and ligament attachment Signup and view all the answers

Which bones are classified as flat bones?

Ribs and sternum Signup and view all the answers

What shape are short bones generally classified as?

Cube-shaped Signup and view all the answers

Which of the following statements is true regarding irregular bones?

They do not fit into other bone classification categories. Signup and view all the answers

What is primarily found in the diaphysis of long bones?

Compact bone Signup and view all the answers

What type of bone contains mostly spongy bone with an outer layer of compact bone?

Short bones Signup and view all the answers

What is the purpose of the periosteum?

To cover the bone and provide attachment for fibers Signup and view all the answers

Sesamoid bones are classified as which type of bone?

Short bones Signup and view all the answers

Which examples represent irregular bones?

Vertebrae and hip bones Signup and view all the answers

Which of the following is NOT considered a part of the skeletal system?

Muscles Signup and view all the answers

What are the two subdivisions of the skeleton?

Axial and appendicular skeletons Signup and view all the answers

Which of the following functions is NOT performed by bones?

Hormone production Signup and view all the answers

Which type of osseous tissue is characterized as dense, smooth, and homogeneous?

Compact bone Signup and view all the answers

Long bones are typically distinguished by which of the following traits?

A shaft with enlarged ends Signup and view all the answers

Which of the following is an example of a long bone?

Humerus Signup and view all the answers

Which type of bone is primarily found at the ends of long bones?

Spongy bone Signup and view all the answers

Which group of bones is classified based on their shape as irregular bones?

Vertebrae Signup and view all the answers

What are the two bones that compose the shoulder girdle?

Clavicle and Scapula Signup and view all the answers

How many total bones are included in the appendicular skeleton?

126 Signup and view all the answers

Which bone of the upper arm articulates proximally with the glenoid cavity of the scapula?

Humerus Signup and view all the answers

What is the primary function of the shoulder girdle?

To connect the upper limb to the axial skeleton Signup and view all the answers

Which of the following statements best describes the ulna?

It articulates with the humerus at the coronoid process. Signup and view all the answers

What is the primary structural characteristic of the shoulder girdle?

It is a light, poorly reinforced girdle. Signup and view all the answers

Which articulation is found at the distal end of the humerus?

Both B and C Signup and view all the answers

Which bone in the forearm is considered the lateral bone in the anatomical position?

Radius Signup and view all the answers

What is the primary function of the thoracic cage?

Protect organs of the thoracic cavity Signup and view all the answers

Which type of vertebrae is specifically located in the neck region?

Cervical vertebrae Signup and view all the answers

Which part of the vertebra protects the spinal cord?

Vertebral foramen Signup and view all the answers

How many total vertebral bones are present in the vertebral column?

26 Signup and view all the answers

Which of the following statements accurately describes the ribs?

True ribs are pairs 1-7 Signup and view all the answers

Which of the following is NOT a feature commonly associated with vertebrae?

Pelvic girdle Signup and view all the answers

What is the term for the vertebrae formed by the fusion of 5 bones?

Sacrum Signup and view all the answers

Which types of ribs are known as floating ribs?

Pairs 11-12 Signup and view all the answers

Study Notes

Classification of Bones

Bones are classified into four groups based on shape: long, flat, short, and irregular.
Long bones: Longer than they are wide, mostly compact bone with spongy bone at the ends, examples include femur and humerus.
Flat bones: Thin, flattened, and curved, two thin layers of compact bone sandwiching a layer of spongy bone, examples include most skull bones, ribs, and sternum.
Short bones: Generally cube-shaped, mostly spongy bone with an outer layer of compact bone, examples include carpals and tarsals.
Irregular bones: Do not fit into other bone classification categories, made up of unique shapes, examples include vertebrae and hip bones.

' Structure of a Long Bone

Diaphysis: The shaft of the bone, made of compact bone.
Periosteum: Fibrous connective tissue membrane covering the diaphysis, secures to the underlying bone using perforating (Sharpey’s) fibers.
Epiphyses: The ends of the bone, composed of spongy bone enclosed by a thin layer of compact bone.
Articular cartilage: Covers the external surfaces of the epiphyses, made of hyali ne cartilage, reduces friction at joint surfaces.
Epiphyseal Plate: Flat plate of hyaline cartilage found in young, growing bone, responsible for lengthwise growth of the bone. Epiphyseal line is the remnant of this plate in adults.
Endosteum: Connective tissue lining the inner surface of the shaft of the bone.
Medullary cavity: Space inside the shaft, contains yellow marrow (mostly fat) in adults. Contains red marrow for blood cell formation until age 6 or 7.

Bone Markings

Sites of attachment for muscles, tendons, and ligaments.
Passages for nerves and blood vessels.
Projections or processes: Grow out from the bone surface (all projections start with "T").
Depressions or cavities: Indentations in the bone (All depressions start with "F" except facet).

Vertebral Column (Spine)

Axial support extending from skull to pelvis.
Composed of 26 vertebral bones separated by intervertebral discs.
7 cervical vertebrae: Neck region.
12 thoracic vertebrae: Chest region.
5 lumbar vertebrae: Lower back region.
Sacrum: Fusion of 5 vertebrae.
Coccyx: Fusion of 3-5 vertebrae.

Common Features of Vertebrae

Body (centrum): The main part of the vertebra.
Vertebral arch: Forms the posterior opening for the spinal cord.
- Pedicle: Connects the body to the lamina.
- Lamina: Forms the posterior part of the arch.
Vertebral foramen: Opening for the spinal cord.
Transverse processes: Project laterally from the arch.
Spinous process: Projects posteriorly from the arch.
Superior and inferior articular processes: Articulate with adjacent vertebrae.

Thoracic Cage

Bony thorax, or thoracic cage, protects organs of the thoracic cavity.
Consists of:
- Sternum: Breastbone.
- Ribs:
  - True ribs (pairs 1-7): Directly attach to the sternum.
  - False ribs (pairs 8-12): Attach indirectly to the sternum through cartilage.
  - Floating ribs (pairs 11-12): Do not connect to the sternum.
- Thoracic vertebrae: The 12 vertebrae of the chest region.

Appendicular Skeleton

Composed of 126 bones, including:
- Limbs (appendages): Arms and legs.
- Pectoral girdle: Attaches the upper limbs to the axial skeleton (clavicle and scapula).
- Pelvic girdle: Attaches the lower limbs to the axial skeleton (hip bones).

Bones of the Shoulder Girdle (Pectoral Girdle)

Composed of two bones:
- Clavicle: Collarbone.
- Scapula: Shoulder blade.
Light and poorly reinforced girdle, allowing for exceptional upper limb flexibility. L

Bones of the Upper Limbs

Humerus: Upper arm bone.
- Proximal end articulates with the scapula at the glenoid cavity.
- Distal end articulates with the forearm bones (ulna and radius) at the trochlea and capitulum.
Ulna: Medial bone of the forearm in anatomical position.
- Proximal end articulates with the humerus.
Radius: Lateral bone of the forearm in anatomical position.
- Proximal end articulates with the humerus.

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Description

Explore the different classifications of bones based on shape, including long, flat, short, and irregular bones. Learn about the structure of a long bone, including key components such as the diaphysis, periosteum, and epiphyses. This quiz will help reinforce your understanding of skeletal anatomy.