Comprehensive Study Notes: Skeletal, Articular, and Muscular Systems in Human Anatomy & Physiology

Skeletal System

' Learning Objectives

The skeletal system provides the structural framework for the human body, protects vital organs, and facilitates movement. Key learning objectives include understanding bone structure, types, and anatomical features.

• Describe bone structure: Relate the structure of bones to their functions, such as support, protection, and movement.

• Raised projections: Understand why bones have raised projections (e.g., tuberosities) for muscle attachment.

• Compare bone types: Contrast spongy bone and compact bone in terms of structure and function.

• Axial vs. Appendicular skeleton: Differentiate between these two major divisions of the skeleton.

• Os Coxae and pelvic bones: Clarify relationships among the ilium, ischium, and pubis.

• Connective tissue: Explain why bone tissue is classified as connective tissue.

• Zygomatic arch: Name the two processes forming the zygomatic arch.

• Sinuses: Define and locate major sinuses in the skull.

Osseous (Bone) Histology

Bone tissue is a specialized connective tissue with unique structural and functional properties.

• Central canal: The central canal (Haversian canal) contains blood vessels and nerves.

• Osteon: The basic structural unit of compact bone, consisting of concentric lamellae around a central canal.

• Lamellae: Layers of bone matrix within an osteon.

• Canaliculi: Small channels connecting osteocytes for nutrient and waste exchange.

• Lacunae with osteocytes: Small spaces housing bone cells (osteocytes).

Appendicular Skeleton

The appendicular skeleton includes the bones of the limbs and girdles, enabling movement and manipulation of the environment.

• Long bone anatomy: Key features include proximal/distal epiphyses, diaphysis, articular cartilage, periosteum, compact/spongy bone, medullary cavity, endosteum, red/yellow marrow, and epiphyseal lines.

• Upper limb bones: Humerus, radius, ulna, carpals, metacarpals, phalanges, clavicle, scapula.

• Pelvic girdle: Os coxae (hip bone) composed of ilium, ischium, and pubis.

• Lower limb bones: Femur, tibia, fibula, patella, tarsals, metatarsals, phalanges.

Bone	Key Features
Humerus	Head, neck, greater/lesser tubercle, deltoid tuberosity, epicondyles
Femur	Head, neck, greater/lesser trochanter, epicondyles, condyles
Scapula	Acromion, coracoid process, glenoid cavity
Os Coxae	Ilium (iliac crest, spines), ischium (spine, tuberosity), pubis (symphysis, foramen)
Tibia	Condyles, tibial tuberosity, malleolus
Fibula	Head, lateral malleolus
Phalanges	Distal, middle, proximal

Axial Skeleton

The axial skeleton forms the central axis of the body, including the skull, vertebral column, and thoracic cage.

• Skull: Composed of cranial and facial bones, with key features such as sinuses, sutures, and processes.

• Vertebral column: Includes cervical, thoracic, lumbar vertebrae, sacrum, and coccyx.

• Thorax: Sternum (manubrium, body, xiphoid), ribs (true, false, floating), costal cartilage.

Region	Key Structures
Skull	Frontal sinus, parietal/coronal/sagittal sutures, zygomatic arch, mandibular fossa
Vertebrae	Body, lamina, pedicle, processes, foramen
Thorax	Sternum, ribs, costal cartilage

Arthrology (Joints)

Learning Objectives

Arthrology is the study of joints, their structure, and function. Understanding joint types and movements is essential for comprehending body mechanics.

• Synovial joint structure: Describe and relate structure to function.

• Joint movements: Examples include flexion, extension, circumduction, rotation, etc.

• Fontanels: Explain their importance in the developing skull.

• Synovial fluid: Describe its composition and function.

Anatomy of Joints

• Joint classifications:

  • Function: Synarthroses (immovable), Amphiarthroses (slightly movable), Diarthroses (freely movable)

  • Structure: Synovial, cartilaginous, fibrous

  • Synovial joint types: Ball-and-socket, ellipsoid, hinge, plane, pivot, saddle

• Synovial joint anatomy: Joint capsule, cavity, articular cartilage, ligaments

Major Joints and Ligaments

Joint	Key Ligaments/Features
Knee	Tibial/fibular collateral, anterior/posterior cruciate, menisci
Shoulder	Coracoacromial, coracoclavicular, glenohumeral
Skull	Fontanels: frontal, sphenoidal, occipital, mastoid

Myology (Muscular System)

Learning Objectives

Myology is the study of muscles, including their structure, function, and mechanisms of contraction.

• Sliding filament theory: Steps of muscle contraction at the sarcomere level.

• Muscle tissue types: Compare and contrast skeletal, cardiac, and smooth muscle.

• Motor unit: Diagram and describe its components.

• Isometric vs. isotonic contraction: Differentiate these types of muscle contractions.

• Agonist, antagonist, synergist: Describe how these muscle roles coordinate movement.

Histology of Muscle Tissue

• Skeletal muscle: Striated, voluntary, multinucleated fibers.

• Cardiac muscle: Striated, involuntary, intercalated discs.

• Smooth muscle: Non-striated, involuntary, spindle-shaped Z

• platysma, scalenes

• Back: Trapezius, teres major/minor, rhomboids, latissimus dorsi, supraspinatus, infraspinatus, subscapularis, erector spinae

• Chest: Pectoralis major/minor, serratus anterior, intercostals

• Abdomen: External/internal oblique, rectus abdominis, transversus abdominis

• Shoulder/upper arm: Triceps brachii (long, medial, lateral heads), biceps brachii (long/short heads), brachialis

• Forearm: Wrist extensors

• Anterior thigh/hip: Tensor fascia latae, sartorius, iliopsoas, adductors, quadriceps group

• Posterior thigh/hip: Gluteus maximus/medius/minimus, piriformis, hamstrings group

• Lower leg: Tibialis anterior, fibularis longus, gastrocnemius, soleus, extensor digitorum longus

Additional info:

• For muscle groups, know the general function and major movements produced.

• For bones and joints, be able to identify features on models or diagrams.

• For histology, recognize tissue types under the microscope and label connective tissue layers.

Key Formulas and Concepts

• Bone growth: $\text{Epiphyseal plate growth:} \quad \text{Cartilage} \rightarrow \text{Bone}$

• Sliding filament theory: $\text{Force} = \text{Number of cross-bridges formed}$

• Motor unit: $\text{Motor unit} = \text{Motor neuron} + \text{All muscle fibers it innervates}$