Comprehensive Skeletal System Anatomy
Skeletal System Model
System Model: Osteon, Lamella, Osteocyte, Lacunae, Canaliculi, Central Canal
Bone and Cartilage Slides
Compact Bone (Ground Bone): Osteon, Lamella, Lacunae, Canaliculi, Central Canal
Hyaline Cartilage (Monkey Trachea): Chondrocyte, Matrix, Lacunae
Bone Types
Compact Bone: Dense and hard outer bone layer.
Spongy (Cancellous) Bone: Less dense, porous inner bone layer with a lattice-like structure.
Bone Structure
Diaphysis: Long, tubular bone shaft primarily composed of compact bone.
Proximal Epiphysis: Bone end closer to the body’s center with articular cartilage for joint connection.
Distal Epiphysis: Bone end farther from the body’s center with articular cartilage for joint connection.
Bone Properties
Bones in Acid: Removes inorganic components, remaining organic material provides flexibility.
Baked Bones: Removes organic components, remaining inorganic material provides rigidity and strength.
Adult Skull Bones
Bony Orbit (FLEZMS)
Frontal Bone: Supraorbital Foramen, Supraorbital Margin, Frontal Sinus
Lacrimal Bone // Ethmoid Bone: Perpendicular Plate of Ethmoid, Middle Nasal Conchae, Cribriform Plate, Crista Galli
Zygomatic Bone // Maxillary Bone: Infraorbital Foramen, Palatine Process of Maxilla
Sphenoid Bone: Lesser Wing and Greater Wing, Optic Foramen (Canal), Sella Turcica, Sphenoid Sinus
Mandible: Mental Foramen, Mental Protuberance, Mandibular Condyle, Coronoid Process, Mandibular Ramus
Palatine Bone // Nasal Bone // Vomer // Inferior Nasal Conchae // Parietal Bone
Temporal Bone: Zygomatic Process of Temporal, Mandibular Fossa, Styloid Process, Mastoid Process, External Acoustic Meatus, Petrous Ridge, Internal Acoustic Meatus, Carotid Canal, Jugular Foramen
Occipital Bone: Foramen Magnum, Occipital Condyle, External Occipital Protuberance
Sutures
Coronal Suture, Squamous Suture, Lambdoid Suture, Sagittal Suture
Fetal Skull
Anterior Fontanel, Posterior Fontanel, Anterolateral (Sphenoidal), Posterolateral (Mastoid)
Axial Skeleton
Hyoid Bone // Typical Vertebra: Body, Vertebral (Spinal) Foramen, Transverse Process, Spinous Process, Superior Articular Surface, Inferior Articular Surface, Lamina, Pedicle
Vertebrae
Cervical Vertebrae: C1 (Atlas), C2 (Axis), Dens (Odontoid Process), Transverse Foramen, Transverse Process
Thoracic Vertebrae: Costal Facets – Locate 2 Places, Transverse Costal Facet [Rib Facet] – on Transverse Process (for Tubercle of Rib), Superior Costal Facet [Demifacet] – on Side of Body (for Head of Rib)
Lumbar Vertebrae: Superior Articular Surface, Inferior Articular Surface
Sacrum: Sacral Promontory, Sacral Foramina, Coccyx
Ribs
True (Vertebrosternal), False (Vertebrochondral & Floating), Head, Tubercle, Shaft
Sternum
(Manubrium, Body, Xiphoid Process)
Appendicular Skeleton
Clavicle
Sternal (medial) end, acromial (lateral) end
Scapula
Acromion, coracoid process, glenoid cavity, lateral (axillary) margin, subscapular fossa, medial (vertebral) margin, supraspinous fossa, spine of scapula, infraspinous fossa, inferior angle
Humerus
Greater tubercle, lesser tubercle, head, anatomical neck, surgical neck, deltoid tuberosity, capitulum, trochlea, coronoid fossa, olecranon fossa
Radius
Head, neck, radial tuberosity, styloid process
Ulna
Coronoid process, olecranon process, trochlear (semilunar) notch, radial notch, styloid process
Coxal Bones (os coxae)
Ilium: iliac crest, anterior superior iliac spine (ASIS)
Ischium: ischial tuberosity, ischial spine
Pubis: symphysis pubis, sacrum articulating surface (sacroiliac joint), acetabulum, obturator foramen, greater sciatic notch
Femur
Head, neck, greater trochanter, lesser trochanter, linea aspera, gluteal tuberosity, patella surface, medial condyle, lateral condyle
Fibula
Head, lateral malleolus
Tibia
Tibial tuberosity, medial condyle, medial malleolus, lateral condyle
Patella
Joints
Shoulder, Elbow, Hip, Knee
Anatomical Landmarks
Acromion: Easily palpated as bone of the shoulder.
Anterior superior iliac spine: Important radiologic landmark; origin of sartorius muscle.
Atlas: 1st cervical vertebrae, has no body.
Bony Orbit of Eye: FLEZMS: frontal, lacrimal, ethmoid, zygomatic, maxillary, sphenoid (and palatine)
Cribriform plate: Also known as horizontal plate of ethmoid.
Crista galli: Serves as attachment for meninges.
Deltoid tuberosity: Insertion point for the deltoid muscle.
Fontanels: Where cranial bones of fetus or infant have not yet met; allows skull to change shape during parturition.
Foramen magnum: For passage of spinal cord.
Groove for radial nerve: Where radial nerve passes on lateral side of humerus.
Groove for ulnar nerve: Where ulnar nerve passes dorsal to elbow (“funny bone”)
Hard palate: Composed of palatine bone and palatine process of maxilla.
Intervertebral discs: Discs of fibrocartilage between bodies of vertebrae.
Intervertebral foramina: Openings for passage of spinal nerves.
Ischial spines: Of obstetrical significance; too large in males to permit childbirth.
Ischial tuberosities: The part you sit on.
Jugular (suprasternal) notch: Palpate as depression at superior end of sternum, sternal ends of clavicles.
Lacrimal fossa: Location of nasolacrimal duct.
Mental foramen: For passage of nerves and blood vessels.
Nasal septum
Occipital condyles: Articulate with the atlas.
Odontoid process
Olecranon process: Easily palpated as tip of elbow.
Olfactory foramina: For passage of olfactory nerves through cribriform plate.
Optic foramen
Paranasal sinuses: Ethmoid, maxillary, sphenoid, and frontal sinuses all drain into nasal cavity.
Radial tuberosity: Point of attachment for biceps muscle (located on radius).
Sacral promontory: Most anterior part of sacrum, obstetrical landmark.
Sacrum
Sella turcica: Location of the pituitary gland.
Spina bifida
Tibial tuberosity: Insertion point of Quadriceps femoris muscle.
Transverse foramina
Zygomatic arch: Composed of zygomatic and temporal bones.
Skeletal Questions
1. What is the only movable joint in the skull? The only movable joint in the skull is the temporomandibular joint (TMJ).
2. Which bones form the only movable joint in the skull? The temporomandibular joint is formed by the mandible (lower jaw bone) and the temporal bone of the skull.
3. Which bone contains the foramen magnum? The foramen magnum is located in the occipital bone.
4. What structure passes through this opening? The foramen magnum is the opening through which the spinal cord passes, connecting the brain to the spinal column.
5. Name the six bones that form the orbit of the eye: The six bones that form the orbit of the eye are the frontal bone, zygomatic bone, maxilla, palatine bone, lacrimal bone, and sphenoid bone.
6. What is the function of foramina? Foramina are openings or holes in bones that allow the passage of nerves, blood vessels, and other structures.
7. Olfactory nerves pass through what structure? Olfactory nerves pass through the cribriform plate, which is part of the ethmoid bone.
8. Which ribs are called “true ribs”? Ribs directly attached to the sternum (breastbone) are called “true ribs.” There are seven pairs of true ribs (ribs 1-7).
9. Which ribs are called “false ribs? Ribs that do not have a direct attachment to the sternum or attach indirectly are called “false ribs.” There are five pairs of false ribs (ribs 8-12).
10. Which ribs are called “floating ribs” and why? The last two pairs of ribs (ribs 11 and 12) are often referred to as “floating ribs” because they do not have a direct attachment to the sternum or to other ribs. They are free at their anterior ends.
11. What part of the scapula articulates with the head of the humerus? The part of the scapula that articulates with the head of the humerus is the glenoid cavity or glenoid fossa.
12. What part of the humerus is common site of fractures? Surgical neck
13. The projection of the wrist, along the thumb side of the arm, is what structure? The projection of the wrist along the thumb side of the arm is called the anatomical snuffbox, and it is formed by the scaphoid and trapezium bones.
14. Name the part of the os coxa which provides attachment of back, thigh, and abdominal wall muscles; as well as serves as a landmark for intramuscular injections. The part of the os coxae (hip bone) that provides attachment for back, thigh, and abdominal wall muscles and serves as a landmark for intramuscular injections is the iliac crest.
15. The lateral projection of the ankle is formed by which structure? The lateral projection of the ankle is formed by the lateral malleolus, which is part of the fibula.
16. The “shin” is the common name for which bone? The common name for the shin bone is the tibia.
Bone Features
- Head: The rounded, usually expanded end of a bone that forms part of a joint.
- Condyle: A rounded projection at the end of a bone, often for articulation with another bone.
- Tubercle: A small, rounded projection on a bone.
- Tuberosity: A large, rough projection on a bone, typically for muscle or tendon attachment.
- Trochanter: A large, blunt projection found only on the femur, serving as a muscle attachment site.
- Spine: A sharp, slender projection on a bone, often for muscle attachment.
- Meatus: A canal or passage in the body, such as the ear canal or the urethral meatus.
- Fossa: A shallow depression or hollow on the surface of a bone.
- Sinus: A cavity or space within a bone, often filled with air, such as the paranasal sinuses in the skull.
- Foramen: An opening or hole in a bone that allows the passage of nerves, blood vessels, or other structures.
- Osteon: A structural unit in compact bone.
- Lamella: Concentric rings of bone matrix in an osteon.
- Central Canal: Core channel within an osteon, containing blood vessels and nerves.
- Canaliculi: Microscopic channels connecting osteocytes within bone.
- Osteocytes: Mature bone cells found in lacunae.
- Lacunae: Small spaces in bone where osteocytes are housed.
- Chondrocyte: Specialized cell in cartilage tissue.
- Matrix: The extracellular material providing structure and support in bone or cartilage.