Skeletal System I

Skeletal System I

• The skeletal system includes bones, cartilages, and ligaments
• These components are tightly joined to form a strong and flexible framework for the body
• Cartilage, the embryonic precursor to most bones, covers many joint surfaces in the mature skeleton
• Ligaments connect bones, and tendons attach muscles to bones

Functions of the Skeletal System

• Support: Bones of the legs, pelvis, and vertebral column support the body
• Movement: Skeletal muscles connect to bones to facilitate movement
• Protection: Bones enclose and protect internal organs including the brain and spinal cord
• Blood formation: Red bone marrow produces blood cells
• Electrolyte balance: The skeleton is the body's main reservoir for calcium and phosphate
• Acid-base balance: Bone buffers blood against excessive pH changes

Bone Materials

• Bone tissue consists of approximately 1/3 organic and 2/3 inorganic material.
• Organic matter includes collagen and large protein-carbohydrate complexes
• Inorganic matter is primarily hydroxyapatite, a crystallized calcium phosphate salt, along with smaller amounts of other minerals.

Bones and Osseous Tissue

• Bone is a connective tissue whose matrix is hardened by minerals
• The hardening process is called mineralization or calcification
• Osseous tissue is one component of bone, along with blood, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue.
• Osteology is the study of bone

General Features of Bones

• Bones have a dense outer shell of compact bone, which is composed of dense osseous tissue
• The space inside the bone often contains bone marrow
• At the ends of bones, there is spongy (cancellous) bone. This is a more loosely organized form of osseous tissue

Anatomical Structures in Bones

• Bones have various protrusions, cavities, and holes that provide landmarks for medical procedures.
• Knowing these structures is important for later learning and procedures

Types of Bones

• Flat bones: Thin, curved structures, such as parts of the cranium, sternum, scapulae, and ribs.
• Long bones: The most important bones for movement, such as the humerus, radius, ulna, femur, tibia, and fibula.
• Short bones: Found in the wrists and ankles (carpals and tarsals)
• Irregular bones: The vertebrae and some facial bones

Appendicular Skeleton

• The appendicular skeleton includes the bones of the upper and lower limbs (arms and legs), and pectoral and pelvic girdles
• Detailed anatomy of each bone in these areas is outlined elsewhere

Pectoral Girdle

• The pectoral girdle consists of the clavicle (collarbone) and scapula (shoulder blade).
• The Clavicle articulates with the sternum and scapula.
• The scapula articulates with the clavicle, and humerus

Upper Limb

• The upper limb consists of the humerus, radius, ulna, carpals, metacarpals, and phalanges
• Detailed anatomy of these bones is described elsewhere

Humerus

• The humerus is the bone of the upper arm
• The humerus has a head, anatomical neck, greater and lesser tubercles, intertubercular sulcus, surgical neck, and distal aspects (capitulum, trochlea, lateral and medial epicondyles).
• Other detailed anatomical markers are outlined elsewhere.

Radius

• The radius is a bone in the forearm.
• Key anatomical markers are the head, neck, radial tuberosity, styloid process, articular facets, and ulnar notch.
• Detailed views are included

Ulna

• The ulna is a bone in the forearm.
• Its anatomical markers include the olecranon, trochlear notch, coronoid process, radial notch, and styloid process.

Carpal Bones

• The carpal bones are part of the wrist, located between the distal radius/ulna and the metacarpals.
• They are categorized as short bones and consist of 8 bones (scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate)

Metacarpal Bones and Phalanges

• The 5 metacarpal bones are the articulated bones of the palm
• Each hand has 14 phalanges.

Pelvic Girdle and Lower Limb

• The pelvic girdle (coxae) consists of ilium, ischium, and pubis.
• The lower limb consists of femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges.

Femur

• The femur is the longest bone in the body.
• Its anatomical landmarks include the greater and lesser trochanters, head, neck, patellar surface, medial and lateral condyles, and intercondylar fossa

Tibia and Fibula

• The tibia is located on the medial aspect of the lower leg
• The fibula is a smaller bone on the lateral side of the lower leg
• Anatomical features are detailed in other sections of the notes

Pedis (Ankle and Foot)

• The tarsal bones include the talus, calcaneus, navicular, cuboid, and medial, intermediate, and lateral cuneiforms
• The metatarsals and phalanges are also part of the foot.