Comprehensive Study Notes on Bones and Skeletal Structures

Bones and Skeletal Structures

Overview of Bone Types and Structures

The human skeletal system is composed of various bones and connective tissues that provide structure, protection, and support for the body. Understanding the names, locations, and features of these bones is essential for students of Anatomy & Physiology.

• Bone Types: Includes long bones, short bones, flat bones, irregular bones, and sesamoid bones.

• Key Functions: Support, movement, protection, mineral storage, and blood cell formation.

Histology and Connective Tissues

Types of Epithelial and Connective Tissues

Bone and cartilage are specialized connective tissues. Epithelial tissues line surfaces and cavities throughout the body.

• Simple squamous epithelium: Single layer of flat cells; found in alveoli and blood vessels.

• Simple columnar epithelium: Single layer of tall, column-like cells; lines digestive tract.

• Stratified squamous epithelium: Multiple layers; protects against abrasion (e.g., skin).

• Areolar connective tissue: Loose connective tissue; supports and binds other tissues.

• Elastic cartilage: Flexible cartilage; found in ear and epiglottis.

• Hyaline cartilage: Most common cartilage; found in nose, trachea, and at joints.

• Reticular tissue: Forms supporting framework of lymphoid organs.

• Blood: Fluid connective tissue; transports nutrients and gases.

• Bone: Rigid connective tissue; supports and protects organs.

Cranial and Facial Bones

Major Bones of the Skull

The skull consists of cranial and facial bones, each with distinct features and functions.

• Frontal bone: Forms the forehead; contains frontal sinuses and supraorbital foramen.

• Temporal bone: Includes squamous, petrous, and mastoid portions; features external acoustic meatus, zygomatic process, styloid process, and carotid canal.

• Ethmoid bone: Contains cribriform plate, crista galli, perpendicular plate, and nasal conchae.

• Sphenoid bone: Features greater and lesser wings, pterygoid processes, sella turcica, optic canal, foramen rotundum, foramen ovale, foramen spinosum, superior orbital fissures, and sphenoidal sinuses.

• Mandible: Lower jaw; includes mandibular condyle, coronoid process, mental foramen, alveoli, and alveolar processes.

• Maxilla: Upper jaw; contains maxillary sinus, infraorbital foramen, palatine process, and zygomatic process.

• Palatine bone: Forms part of the hard palate.

• Inferior nasal conchae, lacrimal bones, vomer, hyoid bone, parietal bones, ossicles: Additional facial and cranial bones with specialized functions.

Sutures of the Skull

Major Cranial Sutures

Sutures are immovable joints between skull bones.

• Sagittal suture: Between the two parietal bones.

• Coronal suture: Between frontal and parietal bones.

• Squamous suture: Between parietal and temporal bones.

• Lambdoidal suture: Between parietal and occipital bones.

Vertebral Column

Structure and Regions of the Vertebral Column

The vertebral column supports the body and protects the spinal cord. It is divided into several regions.

• Cervical vertebrae (C1-C7): Includes atlas (C1) and axis (C2).

• Thoracic vertebrae (T1-T12): Articulate with ribs.

• Lumbar vertebrae (L1-L5): Largest vertebrae; support lower back.

• Sacrum and coccyx: Fused vertebrae at the base of the spine.

• Key features: Intervertebral discs, transverse foramen, articular facets, vertebral foramen, spinous and transverse processes.

Thoracic Cage

Components of the Thoracic Cage

The thoracic cage protects vital organs and supports breathing.

• Ribs: 12 pairs; true, false, and floating ribs.

• Sternum: Manubrium, body, xiphoid process.

• Costal cartilage: Connects ribs to sternum.

• Clavicular notch, jugular notch: Features of the sternum.

Pectoral Girdle

Shoulder Bones and Features

The pectoral girdle connects the upper limb to the axial skeleton.

• Clavicle: Sternal end, acromial end, conoid tuberosity.

• Scapula: Body, spine, vertebral border, supraspinous fossa, infraspinous fossa, subscapular fossa, acromion process, coracoid process, glenoid cavity.

Upper Limb Bones

Major Bones and Landmarks of the Upper Limb

The upper limb consists of the humerus, radius, ulna, and bones of the hand.

• Humerus: Head, greater and lesser tubercles, deltoid tuberosity, trochlea, medial and lateral epicondyles, capitulum, coronoid fossa, olecranon fossa.

• Ulna: Olecranon process, coronoid process, trochlear notch, radial notch, styloid process.

• Radius: Head, radial tuberosity, ulnar notch, styloid process.

Pelvic Girdle

Structure and Features of the Pelvis

The pelvic girdle supports the lower limb and protects pelvic organs.

• Os coxa: Composed of ilium, ischium, and pubis.

• Ilium: Iliac crest, greater sciatic notch, anterior superior and inferior iliac spines.

• Ischium: Ischial tuberosity, lesser sciatic notch.

• Pubis: Pubic symphysis, obturator foramen.

• Acetabulum: Socket for femur head (hip joint).

Lower Limb Bones

Major Bones and Landmarks of the Lower Limb

The lower limb includes the femur, tibia, fibula, and bones of the foot.

• Femur: Head, neck, greater and lesser trochanters, intertrochanteric crest, gluteal tuberosity, lateral and medial condyles, linea aspera.

• Tibia: Tibial tuberosity, lateral and medial condyles, medial malleolus.

• Fibula: Head, lateral malleolus.

Summary Table: Major Bones and Key Features

The following table summarizes major bones and their key anatomical features for quick reference.

Bone	Key Features	Location
Frontal	Frontal sinuses, supraorbital foramen	Forehead
Temporal	External acoustic meatus, mastoid process, zygomatic process	Side of skull
Mandible	Mandibular condyle, mental foramen	Lower jaw
Vertebrae	Body, spinous process, transverse process	Spinal column
Clavicle	Sternal end, acromial end	Shoulder
Scapula	Spine, acromion, glenoid cavity	Shoulder blade
Femur	Head, greater trochanter, medial/lateral condyles	Thigh
Tibia	Tibial tuberosity, medial malleolus	Lower leg
Fibula	Head, lateral malleolus	Lower leg

Additional info:

• Some terms and features were inferred based on standard anatomical knowledge and context.

• Scientific names and terms are italicized where appropriate.