Anatomy & Physiology Study Notes: The Human Skeleton and Bone Features

General Anatomical Terms for Bone Features

Introduction

Understanding the terminology used to describe bone features is essential for studying the human skeleton. These terms help identify and classify the various structures found on bones, which are important for anatomical orientation and clinical applications.

Term	Description
Body	Main part
Head	Enlarged (often rounded) end
Neck	Constricted zone between head and body
Margin or border	Edge
Angle	Bend
Ramus	Branch off the body (beyond the angle)
Condyle	Smooth, rounded articular surface
Facet	Small, flattened articular surface
Ridges	Elevated linear structures
Line or linea	Low ridge
Crest or crista	Prominent ridge
Spine	Very high ridge
Processes	Prominent projections
Condyle	Rounded projection
Trochanter or tuber	Large tuberosity on the femur
Tubercle or tuberosity	Knob or lump
Epicondyle	Tuberosities on the proximal femur
Openings	Spaces in bone
Foramen	Hole
Canal or meatus	Tunnel
Fissure	Cleft
Sinus or labyrinth	Cavity
Depressions	General term for a depression
Notch	Depression in the margin of a bone
Groove or sulcus	Depressed, narrow depression

Skull: Cranial Bones and Facial Bones

Introduction

The skull is composed of cranial and facial bones, which protect the brain and form the structure of the face. Understanding the location and features of these bones is crucial for anatomy students.

Cranial Bones

• Frontal Bone (1): Forms the forehead and roof of the orbits.

  • Frontal sinus

  • Coronal suture

  • Supraorbital foramen (notch)

  • Supraorbital margin

• Parietal Bones (2): Form the sides and roof of the cranial cavity.

  • Coronal suture

  • Sagittal suture (top view)

• Occipital Bone (1): Forms the back and base of the skull.

  • Lambdoid suture

  • Foramen magnum

  • Occipital condyle

  • External occipital crest (protuberance) EOP

• Temporal Bones (2): Form the sides and base of the skull.

  • Squamous suture

  • Zygomatic process

  • Zygomatic arch (temporal + zygomatic bone)

  • Mastoid process

  • Styloid process

  • Mandibular fossa (temporal fossa)

  • External auditory meatus

• Sphenoid Bone (1): Forms part of the base of the skull and orbits.

  • Sella turcica (hypophyseal fossa, "Turkey saddle")

  • Greater wing

  • Lesser wing

  • Optic foramen (canal)

  • Sphenoidal sinus

• Ethmoid Bone (1): Forms part of the nasal cavity and orbits.

  • Crista galli

  • Cribriform plate

  • Perpendicular plate (vertical part of nasal septum)

  • Superior and middle nasal conchae (turbinates)

Facial Bones

• Vomer (1): Inferior half of the nasal septum

• Nasal septum: Formed by perpendicular plate of ethmoid + vomer

• Inferior nasal concha (1): Separate, distinct bone

• Lacrimal bones (2): Smallest bones on the face, medial wall of orbit

• Zygomatic bones (2): Cheek bones, form zygomatic arch

• Palatine bones (2): Form the posterior part of the hard palate

• Maxillae (2): Upper jaw, forms part of the hard palate

  • Alveolar process (margin)

  • Infraorbital foramen

  • Palatine process (anterior hard palate)

  • Median palatine suture

  • Maxillary sinus

• Mandible (1): Lower jaw

  • Body

  • Ramus (pl. rami)

  • Angle

  • Mandibular condyle (condylar process)

  • Coronoid process

  • Mental foramen

  • Mandibular foramen (inside)

Sinuses and Middle Ear Bones

• Sinuses: Frontal, Ethmoid, Sphenoid, Maxillary

• Middle Ear Bones (Ossicles): Malleus (hammer), Incus (anvil), Stapes (stirrup)

Hyoid Bone

• Allows speech

• Used in forensic analysis (strangulation)

Axial Skeleton: Spinal Column and Thorax

Introduction

The axial skeleton includes the skull, vertebral column, and thoracic cage. It provides support and protection for the central nervous system and vital organs.

Vertebral Regions

• Cervical (C1-C7): Neck region

  • C1 (Atlas): Ring-shaped, no body, articulates with occipital condyle

  • C2 (Axis): Has the dens (odontoid process)

  • C7: Longest spinous process (vertebra prominens)

  • Transverse foramina (for vertebral arteries)

  • Forked (bifid) spinous process (C2-C6)

• Thoracic (T1-T12): Chest region, all ribs attached

  • Coastal facets (articulate with ribs)

  • Long, pointed spinous process

• Lumbar (L1-L5): Lower back

  • Large, heavy body (support)

  • Short, horizontal spinous process, square shaped

• Sacral (Sacrum): 5 fused vertebrae

  • Base, sacral foramina, median sacral crest, sacral canal

  • Sacral hiatus (gap at end, "epidural block")

• Coccyx: 3-4 fused vertebrae

Parts of Vertebrae

• Body

• Vertebral arch

• Vertebral (spinal) foramen

• Transverse processes

• Spinous process

Ribs and Sternum

• Ribs:

  • 1-7 True ribs (vertebrosternal)

  • 8-10 False ribs (vertebrochondral)

  • 11-12 Floating ribs (vertebral)

• Sternum:

  • Manubrium (handle)

  • Body

  • Xiphoid process

  • Jugular notch (suprasternal notch)

Appendicular Skeleton

Introduction

The appendicular skeleton consists of the bones of the limbs and girdles, which facilitate movement and interaction with the environment. It is important to distinguish right and left bones for anatomical orientation.

Pectoral Girdle

• Clavicle (2): Acromial (flat) and sternal (rounded) ends, curves laterally and posteriorly

• Scapula (2): Right/Left

  • Acromion process

  • Coracoid process (hook-like)

  • Glenoid fossa (cavity)

  • Superior, vertebral (medial), axillary (lateral), and inferior borders/angles

Upper Limb Bones

• Humerus (2): Right/Left

  • Head (articulates with scapula)

  • Greater and lesser tubercles

  • Intertubercular groove (bicipital groove)

  • Deltoid tuberosity

  • Olecranon fossa (holds olecranon process)

  • Capitulum (articulates with radius)

  • Trochlea (articulates with ulna)

  • Lateral and medial epicondyles

• Ulna (2):

  • Olecranon process

  • Coronoid process

  • Radial notch of ulna

  • Head of ulna (distal end)

• Radius (2):

  • Head (rotates during pronation/supination, articulates with capitulum)

  • Radial tuberosity (attachment for biceps)

  • Styloid process

• Hand:

  • Carpals (wrist bones) (8)

  • Metacarpals (palm) (5)

  • Phalanges (fingers) (14): proximal, middle, distal

Pelvic Girdle

• Pelvis (Ossa coxae): 2 coxal bones + sacrum + coccyx

• Coxal Bone (2): Right/Left, each formed by fusion of three bones by age 25

  • Ilium: Iliac crest, acetabulum, greater sciatic notch

  • Ischium: Ischial tuberosity, lesser sciatic notch

  • Pubis: Obturator foramen

Lower Limb Bones

• Femur (2): Right/Left

  • Head, neck, greater and lesser trochanter

  • Gluteal tuberosity

  • Patellar surface

  • Medial and lateral condyle

• Patella (2): Knee cap

• Tibia (2): Shin, medial bone, strong, weight-bearing (Right/Left)

  • Medial and lateral condyle

  • Tibial tuberosity

  • Anterior margin (crest)

  • Medial malleolus

• Fibula (2): Lateral bone, stabilizes ankle, not weight-bearing

  • Lateral malleolus

  • Head of fibula (proximal)

• Tarsals (7): Ankle bones

  • Calcaneus (heel bone)

  • Talus

  • Navicular

  • Cuneiforms: lateral, intermediate, medial

• Metatarsals (5): Sole

• Phalanges (14): Toes (proximal, middle, distal)

Additional Info

• Be able to distinguish between right and left bones for proper anatomical orientation.

• Bone markings are important for muscle attachment, articulation, and passage of nerves and blood vessels.

• Clinical relevance: Fractures, forensic identification, and surgical approaches often depend on knowledge of bone features.