Comprehensive Study Guide: Bones, Bone Features, and Joints of the Human Skeleton

Bones and Bone Features of the Human Skeleton

Overview of the Human Skeleton

The human skeleton is divided into two main regions: the axial skeleton and the appendicular skeleton. Each region contains specific bones and features that are essential for structure, movement, and protection. Understanding the names, locations, and features of these bones is fundamental in anatomy and physiology.

• Axial Skeleton: Includes the skull, vertebral column, ribs, and sternum.

• Appendicular Skeleton: Includes the pectoral girdle, pelvic girdle, and limbs.

Bone Features and Anatomical Terminology

Bones possess various features that serve as attachment points, passageways, or structural landmarks. Key anatomical terms include:

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

• Fossa: A shallow depression or hollow.

• Process: A projection or outgrowth for muscle attachment.

• Condyle: A rounded articular surface.

• Epicondyle: A projection above a condyle.

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

• Sinus: A cavity within a bone.

Directional terms:

• Anterior: Front surface

• Posterior: Back surface

• Lateral: Away from midline

• Medial: Toward midline

• Proximal: Nearer to trunk

• Distal: Farther from trunk

Axial Skeleton

Skull

The skull protects the brain and supports facial structures. It consists of cranial bones, facial bones, and associated features.

• Ear Ossicles: Malleus, Incus, Stapes (transmit sound vibrations)

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

• Facial Bones: Mandible, Vomer, Nasal, Maxilla, Zygomatic, Palatine, Lacrimal, Inferior Nasal Conchae

• Sutures: Sagittal, Coronal, Lambdoidal, Squamous (immovable joints between skull bones)

• Landmarks: Zygomatic arch, Mastoid process, Foramen magnum, Orbits, External occipital protuberance, Hard palate, Superior and inferior orbital fissures, Lacrimal foramen/sulcus, Paranasal sinuses

Key Features by Bone

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

• Temporal Bone: External acoustic meatus, Zygomatic process, Styloid process, Mandibular fossa, Carotid canal, Jugular foramen, Internal acoustic meatus

• Occipital Bone: Occipital condyles, Nuchal lines, External occipital protuberance, Hypoglossal canal, Condyloid canal

• Sphenoid Bone: Pterygoid processes, Superior orbital fissures, Optic canal, Sella turcica, Hypophyseal fossa, Foramen rotundum, Foramen ovale, Foramen spinosum, Sphenoid sinus

• Ethmoid Bone: Cribriform plate, Perpendicular plate, Crista galli, Nasal conchae, Ethmoid sinus

• Zygomatic Bone: Temporal process, Frontal process

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

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

Vertebral Column

The vertebral column supports the body and protects the spinal cord. It consists of cervical, thoracic, lumbar vertebrae, sacrum, and coccyx.

• Cervical, Thoracic, Lumbar Vertebrae: Recognize differences in size and features

• Intervertebral Disc: Cartilaginous pad between vertebrae

• Vertebral Canal: Passage for spinal cord

• Facets and Demifacets: Articulation points (thoracic only)

Vertebrae Features

• Body, Pedicle, Lamina, Transverse process, Spinous process, Vertebral foramen, Transverse foramen (cervical), Superior and inferior articulating processes and facets

Sacrum and Coccyx

• Sacrum: Sacral promontory, Median sacral crest, Lateral sacral crests, Sacral canal, Superior articulating process, Sacral foramina, Transverse lines

• Coccyx: Terminal portion of vertebral column

Ribs and Sternum

• Ribs: Head, Neck, Angle, Shaft, Costal groove, Articulating tubercle, Sternal attachment, Costal cartilages

• Sternum: Manubrium, Gladiolus (body), Xiphoid process

Appendicular Skeleton

Pectoral Girdle

• Clavicle: Sternal and acromial ends, Conoid tubercle

• Scapula: Spine, Acromion process, Coracoid process, Glenoid fossa, Glenoid labrum, Supraspinous fossa, Infraspinous fossa, Subscapular fossa, Angles and borders, Scapular notch

Upper Limb

• Humerus: Head, Surgical neck, Greater and lesser tubercles, Epicondyles, Capitulum, Trochlea, Fossae, Shaft, Deltoid tuberosity, Intertubercular sulcus

• Ulna: Olecranon and coronoid processes, Trochlear notch, Styloid process, Radial notch, Head, Shaft

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

• Carpals: Proximal row: Scaphoid, Lunate, Triquetrum, Pisiform; Distal row: Trapezium, Trapezoid, Capitate, Hamate

• Metacarpals: I-V, Head, Body, Base

• Phalanges: Distal, Middle, Proximal for digits II-V; Proximal and distal for pollex (digit I)

Pelvic Girdle

• Os Coxa: Articulates with sacrum; consists of ilium, ischium, pubis

• Pelvis: True pelvis, False pelvis, Acetabulum, Obturator foramen

• Ilium: Iliac crest, Anterior/posterior superior/inferior iliac spines, Greater sciatic notch, Iliac fossa, Iliac tuberosity, Gluteal lines

• Ischium: Ischial spine, Ischial tuberosity, Lesser sciatic notch, Ramus

• Pubis: Superior/inferior rami, Pubic symphysis

Lower Limb

• Femur: Head, Neck, Linea aspera, Trochanters, Intertrochanteric crest/line, Shaft, Condyles, Epicondyles, Intercondylar fossa, Patellar surface, Gluteal tuberosity

• Patella: Base, Apex, Articular facets

• Tibia: Tuberosity, Malleolus, Intercondylar eminence, Condyles, Crest, Fibular notch

• Fibula: Head, Apex, Lateral malleolus (not weight bearing)

• Tarsals: Talus, Calcaneus, Navicular, Cuneiforms (medial, intermediate, lateral), Cuboid

• Metatarsals: I-V, Head, Body, Base

• Phalanges: Distal, Middle, Proximal for digits II-V; Proximal and distal for hallux (digit I)

Anatomy of a Long Bone

Long bones are characterized by distinct structural regions and tissues.

• Epiphysis: Ends of the bone

• Diaphysis: Shaft of the bone

• Compact Bone: Dense outer layer

• Spongy Bone: Porous inner layer

• Medullary Cavity: Central cavity containing marrow

• Yellow Marrow: Fat storage

• Red Marrow: Hematopoiesis (blood cell formation)

• Epiphyseal Plates/Lines: Growth regions

• Periosteum: Outer fibrous covering

• Endosteum: Inner lining

• Articulating Cartilage: Covers joint surfaces

Joints of the Human Skeleton

Major Joints and Their Features

Joints (articulations) connect bones and allow movement. Major joints include:

• Temporomandibular Joint: Jaw joint between temporal bone and mandible

• Glenohumeral Joint: Shoulder joint between scapula and humerus

• Humeralulnar (Elbow) Joint: Between humerus and ulna

• Tibiofemoral (Knee) Joint: Between tibia and femur

Knee Joint Features

• Joint Capsule: Encloses the joint

• Intracapsular Ligaments: ACL (anterior cruciate ligament), PCL (posterior cruciate ligament)

• Extracapsular Ligaments: MCL (medial collateral ligament), LCL (lateral collateral ligament)

• Menisci: Medial and lateral fibrocartilage pads

Table: Classification of Bones in the Human Skeleton

Region	Main Bones	Key Features
Axial Skeleton	Skull, Vertebral column, Ribs, Sternum	Protection, support, attachment for muscles
Appendicular Skeleton	Pectoral girdle, Pelvic girdle, Limbs	Movement, manipulation, weight bearing
Long Bones	Femur, Humerus, Tibia, Fibula, Ulna, Radius	Epiphysis, diaphysis, marrow cavity
Short Bones	Carpals, Tarsals	Cube-shaped, limited movement
Flat Bones	Skull, Sternum, Ribs, Scapula	Protection, broad surfaces
Irregular Bones	Vertebrae, Os coxa	Complex shapes

Additional info:

• Bone features are critical for muscle attachment, joint formation, and passage of nerves and vessels.

• Understanding right vs. left bones is essential for anatomical orientation.

• Growth plates (epiphyseal plates) are sites of longitudinal bone growth in children and adolescents.