Skeletal System: Axial and Appendicular Skeleton Study Guide

Skeletal System: Axial and Appendicular Skeleton

Introduction

The human skeletal system is divided into two main sections: the axial skeleton and the appendicular skeleton. The axial skeleton forms the central axis of the body, while the appendicular skeleton consists of the limbs and girdles. Understanding the names, locations, and anatomical landmarks of bones is essential for students of anatomy and physiology.

Axial Skeleton

1a. Head/Neck Bones

• Skull Bones: Parietal Bone, Occipital Bone, Frontal Bone, Sphenoid Bone, Nasal Bone, Zygomatic Bone, Maxilla, Mandible, Palatine Bone, Temporal Bone, Vomer Bone, Lacrimal Bone, Hyoid Bone

• Skull Landmarks: Coronal Suture, Sagittal Suture, Squamous Suture, Lambdoid Suture, Frontal Suture, Intermaxillary Suture, Sagittal Suture, Zygomaticomaxillary Suture, Palatine Suture

• Skull Foramina: Supraorbital Foramen, Infraorbital Foramen, Mental Foramen, External Auditory Meatus, Optic Foramen, Zygomaticofacial Foramen, Mental Foramen, Greater Palatine Foramen, Incisive Foramen, Lacrimal Fossa

• Skull Processes: Condylar Process, Coronoid Process, Mastoid Process, Occipital Condyle, Styloid Process

1b. The Spine

• C1 (Atlas): Superior articular facets, Dens, Transverse Process, Transverse Foramen, Vertebral Foramen

• C2 (Axis): Superior articular facets, Dens, Transverse Process, Transverse Foramen, Vertebral Foramen

• Cervical Vertebrae (excluding C1 and C2): Spinous Process, Transverse Process, Vertebral Foramen

• Thoracic Vertebrae: Spinous Process, Transverse Process, Vertebral Foramen, Vertebral Body

• Lumbar Vertebrae: Spinous Process, Transverse Process, Vertebral Foramen, Vertebral Body

• Sacrum: Sacral Canal, Transverse Ridges, Median Sacral Crest, Sacral Foramina

1c. The Rib Cage and Sternum

• Sternum: Manubrium, Sternum Body, Xiphoid Process, Jugular Notch, Clavicular Notches

• Rib Sections: True Ribs (1-7), False Ribs (8-10), Floating Ribs (11-12)

Appendicular Skeleton

2a. The Pectoral Girdle

• Scapula: Suprascapular notch, Acromion Process, Glenoid Cavity, Scapular Spine, Coracoid Process

• Clavicle: Sternal End, Acromial End

2b. Pelvic Girdle

• Male Pelvic Girdle and Female Pelvic Girdle: Iliac Crest, Acetabulum, Obturator Foramen, Pubic Symphysis Surface

2c. Arm Bones

• Humerus: Head, Greater Tubercle, Lesser Tubercle, Capitulum, Trochlea

• Radius: Head, Neck, Styloid Process

• Ulna: Olecranon Process, Coronoid Process, Head, Trochlear Notch, Radial Notch

2d. Leg Bones

• Patella: Apex

• Femur: Patellar Surface, Head, Greater Trochanter, Lesser Trochanter, Intertrochanteric Crest, Lateral Condyle, Medial Condyle, Intercondylar Fossa

• Fibula: Head

• Tibia: Intercondylar Eminence, Tibial Tuberosity

2e. Hand & Wrist Bones

• Carpals: Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate

• Metacarpals: I, II, III, IV, V

• Phalanges: Distal, Middle, Proximal (I, II, III, IV, V)

• Note: The most lateral finger (i.e., thumb) lacks the middle phalanx.

2f. Foot & Ankle Bones

• Tarsals: Calcaneus, Talus, Navicular, Lateral Cuneiform, Medial Cuneiform, Intermediate Cuneiform, Cuboid

• Metatarsals: I, II, III, IV, V

• Phalanges: Proximal, Middle, Distal (I, II, III, IV, V)

Key Terms and Definitions

• Foramen: An opening or hole in a bone for the passage of nerves and blood vessels.

• Process: A projection or outgrowth from a bone, often serving as an attachment for muscles or ligaments.

• Condyle: A rounded articular projection, often part of a joint.

• Fossa: A shallow depression in a bone.

• Notch: An indentation at the edge of a bone.

• Tubercle/Tuberosity: Small/large rounded projections for muscle attachment.

Comparing Axial and Appendicular Skeletons

Feature	Axial Skeleton	Appendicular Skeleton
Main Components	Skull, vertebral column, rib cage, sternum	Limb bones, pectoral girdle, pelvic girdle
Function	Protection of vital organs, support, posture	Movement, manipulation of environment
Number of Bones	80	126

Study Tips for Bone Identification

• Use anatomical terms for direction and location (e.g., superior, inferior, medial, lateral).

• Practice with models, diagrams, and online resources to reinforce bone names and landmarks.

• Pay attention to unique features and landmarks that distinguish similar bones.

• Group bones by region (e.g., skull, arm, leg) for easier memorization.

Additional Resources

• Visible Body: Overview of the Skeleton

• GetBodySmart: Skeletal System

• PurposeGames: Skeletal System Quiz

• Skelbiolib: Bone Landmarks

• 3D Skeleton Viewer