Surface markings are critical due to the presence of blood vessels.
Blood vessels run through the body, such as ulnar vessels to the meninges, carpals, and metacarpals.
The location of blood vessels determines the placement of foramina, which are holes for nerves and blood vessels to pass through.
Ridges and projections facilitate muscle attachment to the bone.
Bone is foundational for blood vessels and nerves, essential for diagnosing clinical disorders.
Holes in bones, like the mental foramen (chin), are important, such as in root canals.
Spinal cord runs through vertebrae, with intervertebral foramen between vertebrae allowing spinal nerves to pass.
Bone marking is critical for features like ridges and valleys.
Bone Anatomy
Cross anatomy of a long bone must be understood both outside and inside.
Macroscopic anatomy includes the periosteum, compact bone, and spongy bone (with osteons).
Osteons contain osteocytes (bone cells) and inorganic material (lamellae).
Osteocytes communicate through cytoplasmic extensions called canaliculi.
Organic components are collagen fibers; inorganic components are minerals like calcium and phosphorus (hydroxyapatite).
Microscopic examination involves slides; chemical composition is tested by placing bones in an oven or acid.
Oven removes collagen fibers, making the bone brittle.
Acid removes inorganic substances, making the bone flexible like a rubber hose.
Skeletal Divisions
Two divisions: axial skeleton and appendicular skeleton.
Axial skeleton includes the skull.
Mandible is a key bone to identify.
Appendicular skeleton includes the humerus, radius, and ulna.
Radius is located towards the thumb, ulna towards the pinky.
A dime-like structure exists on top of the radius where it joins the humerus.
The ulna has a hook-like structure.
Carpals are in the wrist; the trapezium needs identification, in two rows.
Metacarpals and digits (with two phalanges in the thumb and three in other fingers) are important.
Clavicle, cervical vertebrae (atlas and axis - "yes" and "no" movement), thoracic and lumbar ribs, scapula, sternum, and costal cartilage are other components.
Two ribs are floating ribs; true ribs attach directly to the sternum.
Pelvic region includes pelvic (coxal) bones, forming the pelvic girdle.
The scapula and clavicle form the shoulder girdle; upper limbs extend from here.
Lower limbs include the femur (longest bone), tibia, and fibula (lateral side).
Malleolus (medial and lateral) are bumps on the tibia and fibula.
Calcaneus (heel bone), tarsals, and metatarsals are key structures in the foot.
Types of Bones
Bones can be long, short, irregular, or flat.
Identification is articulated or disarticulated with consideration of surface markings.
Bone Surface Features
Surface markings include elevation and projection.
Processes can be in the mandible (e.g., angle, ramus).
Procanter presents only in the female.
Tubercle comes only over here.
Greater and lesser tubercles are on the humerus.
Femur also shows phobia capitis and greater/lesser trochanters.
Using PAL (Practice Anatomy Lab)
Use Practice Anatomy Lab (PAL) for diagrams; find it in the textbook; access models and histology.
Instructions explain models, histology, skeletal, muscular, and nervous levels.
3D models and animation can enhance practice.
PAL helps in learning the location of bones like the zygomatic and temporal bones.
The site shows superior, middle, and inferior concha for moisturizing and cleaning air.
Anterior views are essential for labs; learn to locate lateral and sagittal processes on skulls.
Skull isn't a single piece; babies have fontanels because cervical region of the uterus is small.
Sagittal suture is in the middle; external occipital protuberance (bump) can be felt.
Inferior view shows zygomatic bone, maxilla, and occipital condyle.
Sella turcica (sphenoid bone) houses the pituitary gland.
C<em>5 and C</em>6 articulation
Learn all models for upper and lower limbs.
Cartilage Types
Cartilage can be hyaline, elastic, or fibrocartilage.
Long bones are longer than wide; located in appendicular skeleton. Example; femur.
Short bones are cube-shaped; provide support and stability, little movement. Example: carpals in the wrist.
Flat bones are thin, protect internal organs and attach to muscles. Example cranial bones.
Irregular bones don't fit other categories. Example: patella.
Sesamoid bones (round bones) are sometimes listed as irregular bones. Example: patella.
Hinge joints (e.g., humerus) have an olecranon fossa; phobia capitates attach ligaments.
Cervical vertebrae have openings (canal) for vertebral artery supply to brain (essential).
External auditory meatus, middle ear, and internal
Cross Anatomy of Long Bone
Classify bone by proximal vs. distal ends, epiphysis, diaphysis.
Growth plate (epiphyseal plate) becomes epiphyseal line (done growing) around age 22-23.
Medullary cavity is in the center with endosteum lining.
Periosteum is outer lining made of Sharpey's fibers and connective tissue.
Compact bone surrounds spongy bone; osteons form structures.
Central canal contains blood vessels and nerves.
Osteocytes (bone cells) maintains in lacunae.
Canaliculi connect osteocytes.
Lamellae are bony layers; perforating (Volkmann’s) canals connect nutrient artery.
Long Bone Structure Video
Diaphysis: shaft of bone (compact and spongy bone tissue), rigid to withstand strong forces.
Epiphysis: mainly spongy bone tissue, contains red marrow (blood cell production).
Articular cartilage: smooth tissue where bones form joints, shock absorption, cushioning, minimizes friction (poor blood supply).
Periosteum: fibrous membrane covering bone (except articular cartilage), attachment for ligaments/tendons, bone formation/repair, nerve fibers (painful when bruised).
Medullary cavity: contains red marrow (childhood), replaced by yellow marrow (aging).
Endosteum: thin membrane lining medullary cavity, important in bone growth/repair.
Arteries and veins: well-supplied in bones.
Osteon Structures
Perforating (Volkmann’s) artery connects to central arteries within the osteon (central canal).
Osteons are cylindrical structures with concentric lamellae (layers of bone laid down).
Osteocytes present between lamellae, connected by canaliculi.
Overlapping fibers are also found within the lamellae.
Bone Chemical Composition
Organic components provide flexibility (collagen).