Skeletal System I

Skeletal System I

• The skeletal system is comprised of bones, cartilages, and ligaments, forming a strong and flexible framework for the body.
• Cartilage is an embryonic precursor to most bones, covering articular surfaces.
• Ligaments connect bones, while tendons connect muscles to bones.
• Bones are living organs with nerves and blood vessels, indicating sensitivity and metabolic activity.
• Bones and teeth are lasting remnants of a living organism, embodying the transience of life.
• Nothing symbolizes death more than a skull in art and history.

Functions of the Skeletal System

• Support: Bones of the legs, pelvis, and vertebral column hold the body upright.
• Movement: Skeletal muscles' attachment to bones enables movement.
• Protection: Bones shield internal organs like the brain and spinal cord.
• Blood formation: Red bone marrow produces blood cells.
• Electrolyte balance: Bones store and release calcium and phosphate, balancing electrolyte levels in the blood.
• Acid-base balance: Bone buffers the blood against excessive pH changes.
• Detoxification: Bone tissue absorbs foreign elements, mitigating their toxic effects.

Bones and Osseous Tissue

• Bone is a connective tissue with a hardened matrix composed of calcium phosphate and other minerals.
• Mineralization or calcification is the process hardening bone.
• Osteology is the study of bone tissue.
• Bone tissue is not solely of osseous tissue, but also contains blood, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue.

General Features of Bones

• The outer shell of a bone is dense, white osseous tissue called compact bone.
• Bone marrow resides within the marrow cavity (medullary cavity).
• Spongy (cancellous) bone is found at the ends of bones, with a more loosely organized structure.

Long Bones

• Long bones are crucial for body movement; examples include the humerus, radius, ulna, femur, tibia, and fibula.
• Short bones comprise the wrist and ankle (carpals and tarsals).
• Irregular bones, such as vertebrae, sphenoid, and ethmoid, have diverse shapes and functions.
• Flat bones, like many bones of the cranium, sternum, scapula, and ribs, are thin and curved.

Bone Structure/Features

• Diaphysis: The bone shaft.
• Epiphysis: The enlarged bone ends.
• Epiphyseal plate: A transparent cartilage line in growing bones, where growth occurs.
• Periosteum: A fibrous and cellular membrane covering bones, for muscle attachment, blood supply, and bone repair.
• Foramina nutricium: Holes through which periosteal vessels penetrate bones.

Bone Materials

• Bone tissue is approximately one-third organic and two-thirds inorganic material.
• Organic matter includes collagen, glycosaminoglycans, proteoglycans, and glycoproteins.
• Inorganic material is primarily hydroxyapatite (a calcium phosphate salt).

Skeletal System

• Skeletal anatomy provides a basis for understanding location of structures.
• Bones also serve as a reference for other anatomical locations, such as for injections, pulse points, or X-ray comparisons.

The Bones (Types of Bones)

• Adult humans have 206 bones, while newborns have about 270.
• Sesamoid bones: Formed within tendons, such as the patella.
• Sutural bones (Wormian bones): Small bones found within the sutures of the skull.

Anatomical Structures in Bones

• A knowledge of bone-related terms, such as protrusions, cavities, and holes, is essential for anatomical study.
• Palpating bones (feeling them through the skin) allows for an understanding of their shapes and locations.

Anatomical Structure of Bones (terms)

• This section provides a detailed list of terms describing various bone structures in different locations, with examples..

Appendicular Skeleton

• This section details the division into appendicular and axial skeletons, further dividing into component parts such as pectoral girdle and upper limbs.

Pectoral Girdle

• The pectoral girdle (shoulder girdle) supports the arm and links it to the axial skeleton.
• This girdle is composed of the clavicle and scapula.
• The clavicle articulates with the sternum and scapula, and the scapula with the humerus.

Upper Limb (bones)

• Upper limb includes the humerus, radius and ulna, carpals, metacarpals, and phalanges (in decreasing order of size.)
• The bones of the upper limbs articulate as described.

Humerus (bone features)

• This section details features of the humerus bone, including the head, anatomical neck, greater and lesser tubercles, intertubercular groove (sulcus), surgical neck, and main shaft of the bone.

Radius (bone features)

• This section details major features of the radius bone, including the head, neck, radial tuberosity, styloid process and articular surfaces.

Ulna (bone features)

• This section details major features of the Ulna bone, including the olecranon process, trochlear notch, coronoid process, radial notch, and styloid process.

Carpal Bones (location)

-Detailed features describe the location and arrangement of carpal bones (8).

Metacarpal and Phalanges Bones (location)

• Detailed description about metacarpal and phalanges bones location and arrangement.

Pelvic Girdle and Lower Limb

• This section covers structures, such as the pelvic girdle (ilium, ischium, and pubis), femur, tibia, fibula, tarsals, metatarsals, and phalanges.

Pelvic Girdle

• The pelvic girdle encompasses the os coxae (ilium, ischium, and pubis) and is crucial for supporting the trunk and protecting internal organs.
• The bones are interconnected to form a stable and supportive structure.

Coxae and features

• This section provides a description of the ilium, ischium, and pubis, which are part of the os coxae. Also provided are detailed landmarks of the bone.

Femur and Patella (bone features)

• This section covers features of the Femur (the long bone of the thigh) and the patella. These include the head, neck, greater and lesser trochanters, patellar surface, medial and lateral condyles, and intercondylar fossa.

Tibia and Fibula (bone features)

• Section describes the features of the tibia and fibula, including their relative thicknesses, locations, and articulations.

Pedis (ankle and foot)

• This section covers the tarsal bones (7), calcaneus, metatarsals (5), and phalanges (14).

Explore the skeletal system's structure and functions, including the roles of bones, cartilages, and ligaments. Understand how the skeletal system supports movement, protects organs, forms blood, and maintains electrolyte balance. This quiz will deepen your knowledge of anatomy and the vital functions of the skeletal framework.