Anatomy & Physiology Study Guide: Skeletal System, Axial & Appendicular Skeleton, and Joints

Skeletal System

Overview

The skeletal system provides the structural framework for the human body, protects vital organs, supports movement, and serves as a reservoir for minerals. Understanding the names, locations, and features of bones is essential for identifying anatomical structures and their functions.

• Bone Identification: Learn to distinguish bones and their features, including right vs. left orientation, and recognize anatomical landmarks.

• Major Bone Groups: The skeleton is divided into the axial skeleton (central core) and appendicular skeleton (limbs and girdles).

Axial Skeleton

Skull Features

The skull protects the brain and supports facial structures. It consists of cranial and facial bones, as well as specialized features such as foramina and processes.

• Ear Ossicles: Small bones in the middle ear (Malleus, Incus, Stapes) that transmit sound vibrations.

• Cranial Bones: Frontal, Parietal, Occipital, Sphenoid, Temporal, Ethmoid.

• Facial Bones: Mandible, Vomer, Nasal, Maxilla, Zygomatic, Palatines, Inferior nasal conchae.

• Landmarks: Zygomatic arch, Mastoid process, Nasal concha, Mandibular fossa, Foramen magnum, Orbits, Superior/inferior orbital fissures, Lacrimal foramen/sulcus.

• Frontal Bone Features: Zygomatic process, Frontal sinuses, Supraorbital foramen/notch, Supraorbital margin.

• Temporal Bone Features: External acoustic meatus, Mandibular fossa, Carotid canal, Jugular foramen, Internal acoustic meatus.

• Occipital Bone Features: Occipital condyles, Superior/inferior nuchal lines, Hypoglossal canal, Foramen magnum, Condyloid canal.

• Sutures: Immovable joints between skull bones (Sagittal, Lambdoid, Coronal, Squamous).

Other Axial Bones

• Ethmoid Bone: Cribriform plate, Perpendicular plate, Ethmoid sinus.

• Zygomatic Bone: Temporal process, Frontal process.

• Maxilla: Infraorbital foramen, Alveolar processes, Palatine process, Maxillary sinuses.

• Mandible: Body, Angle, Ramus, Coronoid process, Condyloid process, Mandibular foramen, Mental foramen, Mandibular notch.

Vertebral Column

The vertebral column supports the body and protects the spinal cord. It is divided into cervical, thoracic, lumbar, sacral, and coccygeal regions.

• Vertebrae: Recognize cervical, thoracic, and lumbar vertebrae by their features.

• Key Features: Body, Pedicle, Lamina, Transverse process, Spinous process, Vertebral foramen, Transverse foramen (cervical), Atlas (C1), Axis (C2), Dens/odontoid process, Articulating processes, Sacrum, Coccyx.

• Ribs: Head, Neck, Angle, Shaft, Costal groove. Know right vs. left orientation.

Appendicular Skeleton

Pectoral Girdle

The pectoral girdle connects the upper limb to the axial skeleton and allows for a wide range of motion.

• Clavicle: Sternal end, Acromial end, Conoid tubercle.

• Scapula: Scapular spine, Acromion process, Coracoid process, Glenoid fossa, Infraspinous/supraspinous/subscapular fossae, Borders (lateral, medial, superior).

Upper Limb

• Humerus: Head, Neck, Greater/lesser tubercle, Intertubercular sulcus, Deltoid tuberosity, Trochlea, Capitulum, Coronoid/olecranon fossae, Shaft.

• Ulna: Olecranon process, Coronoid process, Trochlear notch, Styloid process, Head, Shaft.

• Radius: Head, Neck, Radial tuberosity, Styloid process, Ulnar notch, Shaft.

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

• Metacarpals (1-5): Bones of the palm.

• Phalanges (1-5): Proximal, middle, distal (fingers).

Pelvic Girdle

• Os coxa: Ilium, Ischium, Pubis, Acetabulum, Obturator foramen, Iliac crest, Spines, Notches, Tubercles.

• Pelvic symphysis: Joint between pubic bones.

Lower Limb

• Femur: Head, Neck, Greater/lesser trochanter, Linea aspera, Medial/lateral condyles, Epicondyles, Intercondylar fossa, Patellar surface.

• Patella: Kneecap.

• Tibia: Medial/lateral condyles, Tibial tuberosity, Anterior crest, Medial malleolus.

• Fibula: Head, Lateral malleolus, Shaft.

• Tarsals: Talus, Calcaneus, Navicular, Medial/intermediate/lateral cuneiforms, Cuboid.

• Metatarsals (1-5): Bones of the foot.

• Phalanges (foot): Proximal, middle (2+ only), distal.

Ligaments

Ligaments are strong bands of connective tissue that stabilize joints.

• ACL: Anterior cruciate ligament (knee).

• PCL: Posterior cruciate ligament (knee).

• MCL: Medial collateral ligament (knee).

• LCL: Lateral collateral ligament (knee).

• Menisci: Medial and lateral meniscus (cartilage pads in the knee).

Joints

Overview

Joints, or articulations, are connections between bones that allow for movement and provide mechanical support. They are classified by structure and function.

Synovial Joint Structures

• Synovial fluid: Lubricates the joint, reducing friction.

• Joint capsule: Encloses the joint cavity.

• Articular cartilage: Covers bone surfaces at the joint, providing smooth movement.

• Synovial membrane: Produces synovial fluid.

• Ligaments: Reinforce the joint capsule.

• Meniscus: Crescent-shaped cartilage that improves fit and cushioning (e.g., knee).

• Bursa: Fluid-filled sac reducing friction between tissues.

Joint Subcategories (Synovial Types)

• Ball and socket: Multiaxial movement (e.g., shoulder, hip).

• Condylar (ellipsoid): Biaxial movement (e.g., wrist).

• Hinge: Uniaxial movement (e.g., elbow, knee).

• Pivot: Rotation around a single axis (e.g., atlas/axis in neck).

• Plane (gliding): Sliding movements (e.g., intercarpal joints).

• Saddle: Biaxial movement (e.g., thumb carpometacarpal joint).

Fibrous and Cartilaginous Joint Types

• Suture: Immovable joint between skull bones.

• Syndesmosis: Bones connected by a ligament (e.g., distal tibiofibular joint).

• Symphysis: Bones joined by fibrocartilage (e.g., pubic symphysis, intervertebral discs).

Table: Comparison of Joint Types

Joint Type	Structure	Movement	Example
Synovial	Joint cavity, synovial fluid, capsule	Freely movable	Shoulder, knee
Fibrous	Dense connective tissue	Immovable/slightly movable	Sutures, syndesmosis
Cartilaginous	Cartilage connection	Slightly movable	Pubic symphysis, intervertebral discs

Key Terms and Definitions

• Foramen: Opening or hole in a bone for passage of nerves or blood vessels.

• Process: Projection or outgrowth of bone for muscle attachment or articulation.

• Condyle: Rounded articular surface.

• Fossa: Shallow depression in a bone.

• Sinus: Air-filled cavity within a bone.

Example Application: The glenoid fossa of the scapula articulates with the head of the humerus to form the shoulder joint, a classic example of a ball-and-socket synovial joint.

Additional info: This guide expands on the original list format by providing definitions, context, and examples to support understanding and exam preparation.