3. Skeletal System Flashcards
Q: What are the four main types of bone cells?
A: Osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
Q: What do bone cells help maintain?
A: The mineral extracellular matrix around them.
Q: What are the two types of osseous (bone) tissue?
A: Compact bone and spongy bone.
Q: What percentage of the skeleton is made of compact bone?
A: About 80%.
Q: What percentage of the skeleton is made of spongy bone?
A: About 20%.
Q: What connective tissue is closely linked with bone?
A: Cartilage.
Q: What is the skeleton made of during embryonic development?
A: Cartilage.
Q: What is ossification?
A: The process of cartilage being converted into bone.
Q: In adults, where is cartilage found in bones?
A: At joints, where bones interact—often capping the bone ends.
osteogenic cells, osteoblasts, osteocytes, and osteoclasts:
the four main types of bone cells
Q: What is compact bone?
A: Dense bone tissue that can withstand compressive forces; contains relatively few spaces and forms the tough outer layer of each bone.
Q: What is spongy bone (also called cancellous bone)?
A: Trabeculated bone tissue that supports shifts in weight distribution; much lighter than compact bone due to the spaces between branches.
Q: What is ossification?
A: The process of conversion to bone tissue.
Q: What is cartilage?
A: Semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement; does not go through ossification.
Q: What are the four main types of bone cells found in osteogenic tissue?
A: Osteoblasts, osteocytes, osteogenic cells, and osteoclasts.
Q: What roles do the four main bone cell types play in the body?
A: They are responsible for the formation, repair, development, maintenance, and destruction of bone.
Q: What makes up the matrix in bone tissue?
A: A combination of collagen fibers and inorganic salt crystals.
Q: What role do collagen fibers play in bone tissue?
A: They provide flexibility and a surface for salt crystals to adhere to, helping bones resist brittleness.
Q: How is hydroxyapatite formed in bone tissue?
A: Calcium phosphate and calcium carbonate combine to form hydroxyapatite, which then crystallizes on collagen fibers.
Q: What other inorganic salts are incorporated into hydroxyapatite during calcification?
A: Magnesium hydroxide, fluoride, and sulfate.
Q: What gives bones their hardness and strength?
A: The hydroxyapatite crystals embedded in the collagen matrix.
Q: Why are bone cells important even though they make up a small portion of bone volume?
A: They are crucial to the function of bones, handling everything from building to breaking down bone tissue.
Q: What are the four types of bone cells?
A: Osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
Q: What is the function of osteogenic cells?
A: They are undifferentiated stem cells with high mitotic activity that divide and develop into osteoblasts.
Q: Where are osteogenic cells located?
A: In the deep layers of the periosteum and in the bone marrow.
Q: What is the role of osteoblasts?
A: They form new bone by synthesizing and secreting the collagen matrix and calcium salts.
Q: Where are osteoblasts found?
A: In the growing portions of bone, including the periosteum and endosteum.
Q: What happens to osteoblasts once they become trapped in the calcified matrix?
A: They change in structure and become osteocytes.
Q: What is the primary function of osteocytes?
A: To maintain the mineral concentration of the bone matrix by secreting enzymes.
Q: Where are osteocytes located?
A: In small spaces called lacunae, surrounded by bone tissue.
Q: How do osteocytes communicate and receive nutrients?
A: Through long cytoplasmic processes that extend through canaliculi (tiny channels in the bone matrix).
Q: Do osteoblasts and osteocytes divide?
A: No, they do not undergo mitosis.
Q: How are osteoblasts replenished if they don’t divide?
A: They are formed from osteogenic cells, which are the only bone cells capable of division.
Q: What is the function of osteoclasts?
A: They are responsible for bone resorption—breaking down old or damaged bone tissue
Q: What is the origin of osteoclasts?
A: They develop from monocytes and macrophages (white blood cells), not from osteogenic cells.
Q: Where are osteoclasts found?
A: On bone surfaces, where they break down bone tissue.
Q: Why is the balance between osteoblasts and osteoclasts important?
A: It maintains bone health through constant remodeling—forming new bone and resorbing old bone.
Q: What is the function of an osteoblast?
A: It is the bone cell responsible for forming new bone and is found in the growing portions of bone.
Q: What is an osteocyte?
A: The primary cell of mature bone and the most common type of bone cell.
Q: What is a lacuna?
A: The space where the osteocyte is located.
Q: What are canaliculi?
A: Singular channels within the bone matrix that allow communication and nutrient exchange between osteocytes.
Q: What are osteogenic cells?
A: Undifferentiated cells with high mitotic activity and the only bone cells that divide.
Q: What is the function of an osteoclast?
A: The cell responsible for bone resorption or breakdown.
Q: What makes bone the hardest connective tissue?
A: Its rigid extracellular matrix, which contains collagen fibers embedded in a mineralized ground substance containing hydroxyapatite.
Q: What is hydroxyapatite and what role does it play in bone tissue?
A: A form of calcium phosphate that provides hardness and strength to bone.
Q: What happens to bone without collagen?
A: It becomes brittle and shatters easily.
Q: What happens to bone without mineral crystals?
A: It would be flexible and offer little support.
Q: How are osteocytes arranged in the histology of a long bone?
A: In concentric circles around a central canal.
Q: How does bone tissue differ from cartilage in terms of healing?
A: Bone is highly vascularized and can recover from injuries relatively quickly, unlike cartilage.
Q: What gives compact bone its ability to withstand compressive forces?
A: Its dense, solid structure.
Q: What is the function of the open spaces in spongy (cancellous) bone?
A: They support shifts in weight distribution and make the bone lighter.
Q: Where is spongy bone typically found?
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A: In the interior of some bones and at the ends of long bones
Q: What structural feature is found in spongy bone but not in compact bone?
A: Trabeculae—arches of bone tissue creating open spaces.
Q: Where is compact bone found, and what is its function?
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A: Compact bone is located under the periosteum and in the diaphyses of long bones, where it provides support and protection
Q: How are osteocytes arranged in spongy (cancellous) bone?
A: They are housed in lacunae within a lattice-like network of matrix spikes called trabeculae, not in concentric circles.
Q: What are trabeculae?
A: Matrix spikes in spongy bone that form a lattice-like network and align along lines of stress to provide strength.
Q: What is the functional purpose of the open spaces within spongy bone?
A: They reduce the bone’s weight, making it easier for muscles to move bones.
Q: What do the spaces in some spongy bones contain, and why is it important?
A: Red marrow, where hematopoiesis (blood cell formation) occurs, protected by trabeculae.
Q: What is an osteon (also called a Haversian system)?
A: The basic structural unit of compact bone, made of concentric layers of calcified matrix.
Q: What are trabeculae (singular = trabecula)?
A: Spikes or sections of the lattice-like matrix in spongy bone.
Q: What does it mean that bone is a “replacement tissue”?
A: Bone forms by laying down its mineral matrix on a model tissue, most commonly cartilage.
Q: What type of tissue serves as the most common template for skeletal development?
A: Cartilage.
Q: What cells produce the cartilaginous matrix during fetal development?
A: Chondroblasts.
Q: What happens to chondroblasts when they become surrounded by the matrix?
A: They become chondrocytes.
Q: Why does damaged cartilage heal slowly?
A: Because cartilage is avascular and relies on diffusion through the matrix for nutrients and waste removal.
Q: What gives cartilage its distinctive appearance and structure?
A: Polysaccharides called chondroitin sulfates, which bind with ground substance proteins to form proteoglycans.
Q: What are lacunae in cartilage tissue?
A: The spaces within the matrix that house chondrocytes.
Q: What is the perichondrium?
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A: A layer of dense irregular connective tissue that encapsulates cartilage
Q: What are the three main types of cartilage?
A: Hyaline cartilage, fibrocartilage, and elastic cartilage.
Q: What are the characteristics and functions of hyaline cartilage?
A: It contains short, dispersed collagen fibers and large amounts of proteoglycans; it is smooth, strong, flexible, and found in joints, the rib cage, nose, and embryonic skeleton.
Q: What makes fibrocartilage tough?
A: Thick bundles of collagen fibers dispersed throughout its matrix.
Q: Where is fibrocartilage found?
A: In menisci of the knee and intervertebral discs.
Q: What makes elastic cartilage different from other types?
A: It contains elastic fibers along with collagen and proteoglycans, giving it both support and elasticity.
Q: Where can elastic cartilage be found in the body?
A: In the external ear.
Q: What is cartilage?
A: Semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement.
Q: What are chondrocytes?
A: Cartilage cells embedded within the cartilage matrix.
Q: What are lacunae in bone or cartilage tissue?
A: The spaces in which osteocytes (in bone) or chondrocytes (in cartilage) are located.
Q: What is hyaline cartilage?
A: The most common type of cartilage in the body; consists of short and dispersed collagen fibers and contains large amounts of proteoglycans.
Q: What is fibrocartilage?
A: A tough type of cartilage with thick bundles of collagen fibers dispersed throughout its matrix.
Q: What is elastic cartilage?
A: Cartilage that contains elastic fibers, collagen, and proteoglycans, providing both support and elasticity.
Q: What are the four types of bone cells found in bone tissue?
A: Osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
Q: What are the two types of osseous tissue that form bone?
A: Compact bone and spongy bone.
Q: What specialized connective tissue is closely associated with bones of the skeletal system?
A: Cartilage.
Q: What are the three major types of cartilage?
A: Hyaline cartilage, fibrocartilage, and elastic cartilage.
Q: What defines a long bone?
A: A bone that is cylindrical in shape and longer than it is wide; the term refers to shape, not size.
Q: Where are long bones found in the body?
A: In the arms (humerus, ulna, radius), legs (femur, tibia, fibula), fingers (metacarpals, phalanges), and toes (metatarsals, phalanges).
Q: What is the primary function of long bones?
A: They function as levers, moving when muscles contract.
Q: What are the two main parts of a long bone?
A: The diaphysis and the epiphysis.
Q: What is the diaphysis of a long bone?
A: The tubular shaft that runs between the proximal and distal ends of the bone.
Q: What is the medullary cavity?
A: The hollow region within the diaphysis, filled with yellow marrow.
Q: What type of bone tissue composes the walls of the diaphysis?
A: Dense and hard compact bone.
Q: What is the epiphysis of a long bone?
A: The wider section at each end of the bone, filled with spongy bone that contains red marrow.
Q: What is the metaphysis?
A: The narrow area where the epiphysis meets the diaphysis; it contains the epiphyseal plate in growing bones.
Q: What is the epiphyseal plate?
A: A layer of hyaline cartilage in growing bone that allows for lengthwise growth.
Q: What happens to the epiphyseal plate in adulthood?
A: It is replaced by osseous tissue and becomes the epiphyseal line.
Q: What is the endosteum?
A: A delicate membranous lining inside the medullary cavity where bone growth, repair, and remodeling occur.
Q: What is the periosteum?
A: A fibrous membrane covering the outer surface of bone (except at joints), containing blood vessels, nerves, and lymphatic vessels.
Q: What attaches to bones at the periosteum?
A: Tendons and ligaments.
Q: What is articular cartilage?
A: A thin layer of cartilage covering the epiphyses where bones meet to form joints, reducing friction and acting as a shock absorber.
Q: What is a flat bone?
A: A bone that is typically thin and often curved; it serves as a point of muscle attachment and helps protect internal organs.
Q: What are examples of flat bones?
A: Cranial bones (e.g., frontal, parietal), scapulae, sternum, ribs, and coxal bones.
Q: How are flat bones structurally different from long bones?
A: Flat bones do not have a diaphysis, medullary cavity, or epiphyses.
Q: What is diploë?
A: The spongy bone layer in flat bones, located between two layers of compact bone.
Q: How do the layers of a flat bone protect internal organs?
A: The compact bone layers and the spongy diploë work together; if the outer layer is fractured, the inner layer still protects the organ (e.g., the brain).
Q: Why are flat bones well-suited for muscle attachment and organ protection?
A: Their slightly curved shape and large surface area provide both structural strength and ample space for muscle attachment.
Q: Where is a good vascular supply especially prominent in bone?
A: In areas that contain red bone marrow.
Q: What is the nutrient foramen?
A: A small opening in the diaphysis where arteries enter to nourish bone tissue.
Q: How do arteries, veins, and nerves travel into bone?
A: Together, through designated entry points like the nutrient foramina.
Q: How is spongy bone and the medullary cavity nourished?
A: By arteries that pass through compact bone and by blood that circulates in the marrow cavities.
Q: How are osteocytes in spongy bone nourished?
A: By blood vessels from the periosteum and circulating blood in the marrow cavities.
Q: What role do nerves play in bone tissue?
A: They sense pain and may regulate blood flow and bone growth, concentrating in metabolically active regions.
Q: Why does the periosteum contain sensory nerves?
A: To detect pain, especially from fractures or bone tumors.
Q: What are the five shape-based classifications of bones?
A: Long, short, flat, irregular, and sesamoid bones.
Q: How are long bones structurally formed?
A: From a hollow, tubular shaft called the diaphysis, expanded at either end into articular heads called epiphyses.
Q: How are flat bones structurally formed?
A: From two thin plates of periosteum-covered compact bone, separated by a thin layer of endosteum-covered spongy bone.
Q: What are the gross functions of the skeletal system?
A: Support, facilitation of movement, and protection of the human body.
Q: How does the skeletal system provide structural support?
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A: It acts like a scaffold made of bones and cartilage to support the body’s weight and form
Q: How do bones facilitate movement?
A: By serving as points of attachment for muscles and acting as levers, with joints functioning as fulcrums.
Q: Why can’t bones move on their own?
A: Because a bone will not move unless a muscle spans a joint and contracts.
Q: How do bones protect internal organs?
A: By surrounding or covering them—for example, the ribs protect the heart and lungs, the vertebral column protects the spinal cord, and the cranium protects the brain.
Q: How does the cranium protect the brain?
A: It completely surrounds and protects the brain from nontraumatic injury.
Q: What does the skeletal system include?
A: All of the bones, cartilages, and ligaments that support and give shape to the body and body structures.
Q: How many bones are in the adult human skeleton?
A: 206 bones.
Q: Why do younger individuals have more bones than adults?
A: Because some bones fuse together during childhood and adolescence.
Q: What are the primary functions of the skeleton?
A: To provide structural support, enable body movement, protect internal organs, and store minerals and fat.
Q: How is the lower skeleton specialized?
A: For stability during walking or running.
Q: How is the upper skeleton specialized?
A: For greater mobility and a wider range of motion, allowing for actions like lifting and turning.
Q: What internal organs are protected by the skeleton?
A: The brain, spinal cord, heart, lungs, and pelvic organs.
Q: What minerals are primarily stored in bones?
A: Calcium and phosphate.
Q: What is stored in bone marrow?
A: Fat and blood-cell producing tissue.
Q: What are the two major divisions of the skeleton?
A: The axial skeleton and the appendicular skeleton.
Q: What are the two major divisions of the skeleton?
A: The axial skeleton and the appendicular skeleton.
Q: What does the axial skeleton form?
A: The vertical, central axis of the body, including the head, neck, chest, and back.
Q: What are the primary functions of the axial skeleton?
A: To protect the brain, spinal cord, heart, and lungs, and serve as attachment sites for muscles that move the head, neck, back, and limbs.
Q: How many bones are in the adult axial skeleton?
A: 80 bones.
Q: What are the main components of the axial skeleton?
A: The skull, vertebral column, and thoracic cage.
Q: How many bones form the skull?
A: 22 bones.
Q: What additional bones are associated with the head?
A: Seven bones, including the hyoid bone and six ear ossicles (three in each middle ear).
Q: What makes up the vertebral column in adults?
A: 24 vertebrae, plus the sacrum and coccyx.
Q: What bones make up the thoracic cage?
A: 12 pairs of ribs and the sternum.
Q: What does the appendicular skeleton include?
A: All bones of the upper and lower limbs, plus the bones that attach each limb to the axial skeleton.
Q: How many bones are in the adult appendicular skeleton?
A: 126 bones.
Q: What are the two groups of bones in the appendicular skeleton?
A: Limb bones and girdle bones that attach limbs to the axial skeleton.
Q: What bones form the pectoral (shoulder) girdle?
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A: The scapula and clavicle
Q: What is the function of the pectoral girdle?
A: It anchors the upper limb to the thoracic cage of the axial skeleton.
Q: How is the pelvic girdle different from the pectoral girdle?
A: It attaches the lower limb to the vertebral column for weight-bearing support and stability.
Q: Where is the clavicle located, and what does it connect?
A: It is an S-shaped bone on the anterior shoulder; it connects medially to the sternum and laterally to the scapula.
Q: Why are lower limbs adapted differently from upper limbs?
A: They support body weight and enable locomotion, while upper limbs are adapted for mobility and manipulation.
Q: What features of the upper limbs allow for a wide variety of movements and activities?
A: Their large range of motion and the dexterity of the hands with opposable thumbs.
Q: What does the axial skeleton support?
A: The head, neck, back, and chest, forming the vertical axis of the body.
Q: What are the main components of the axial skeleton?
A: The skull, vertebral column (including the sacrum and coccyx), and the thoracic cage (ribs and sternum).
Q: What does the appendicular skeleton consist of?
A: All bones of the upper and lower limbs.
Q: What are the five shape-based classifications of bones?
A: Long, flat, short, irregular, and sesamoid bones.
Q: What is the shape of a long bone, and what does the term refer to?
A: Cylindrical and longer than it is wide; the term refers to shape, not size.
Q: What are examples of long bones?
A: Humerus, ulna, radius, femur, tibia, fibula, metacarpals, metatarsals, and phalanges.
Q: What is the function of long bones?
A: They function as levers and move when muscles contract.
Q: What is a short bone?
A: A bone that is cube-like in shape—approximately equal in length, width, and thickness.
Q: Where are short bones found in the body?
A: In the carpals (wrists) and tarsals (ankles).
Q: What is the function of short bones?
A: They provide stability and support with limited motion.
Q: What is an irregular bone?
A: A bone with a complex shape that doesn’t fit into the other bone classification categories.
Q: What are examples of irregular bones?
A: Vertebrae and many facial bones, especially those containing sinuses.
Q: What is a sesamoid bone?
A: A small, round bone shaped like a sesame seed that forms in tendons where pressure is high in a joint.
Q: What is the function of sesamoid bones?
A: To protect tendons and help them withstand compressive forces.
Q: Where are sesamoid bones commonly found?
A: In tendons associated with the feet, hands, and knees.
Q: What is the only sesamoid bone found in everyone?
A: The patella (kneecap).
Q: What is a long bone?
A: A cylindrical bone that is longer than it is wide.
Q: What is a flat bone?
A: A typically thin bone that is often curved.
Q: What is a short bone?
A: A cube-like bone, approximately equal in length, width, and thickness.
Q: What is an irregular bone?
A: A bone with no easily characterized shape that doesn’t fit any other classification.
Q: What is a sesamoid bone?
A: A small, round bone shaped like a sesame seed, usually found in tendons.
Q: What are the three general classes of bone markings?
A: Articulations, projections, and holes.
Q: What is an articulation in bone anatomy?
A: A location where two bone surfaces come together, typically shaped to conform and facilitate joint function.
Q: What is a projection on a bone?
A: An area that extends above the surface of the bone, serving as an attachment point for tendons and ligaments.
Q: What does the size and shape of a bone projection indicate?
A: The amount of force exerted through the tendon or ligament attachment.
Q: What is a hole in a bone?
A: An opening or groove that allows blood vessels and nerves to enter the bone.
Q: What does the size and shape of holes in bones reflect?
A: The size of the blood vessels and nerves that pass through them.
Q: What is an articulation in bone anatomy?
A: Where two bones meet.
Example: Knee joint.
Q: What is a head (bone marking)?
A: A prominent, rounded surface.
Example: Head of femur.
Q: What is a facet?
A: A flat surface.
Example: Vertebrae.
Q: What is a condyle?
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A: A rounded surface.
Example: Occipital condyles
Q: What is a raised marking (projection)?
A: A projection on bone.
Example: Spinous process of vertebrae.
Q: What is a protuberance?
A: A protruding area of bone.
Example: Chin.
Q: What is a process?
A: A prominence feature.
Example: Transverse process of vertebra.
Q: What is a spine (bone marking)?
A: A sharp process.
Example: Ischial spine.
Q: What is a tubercle?
A: A small, rounded process.
Example: Tubercle of humerus.
Q: What is a tuberosity?
A: A rough surface.
Example: Deltoid tuberosity.
Q: What is a line (bone marking)?
A: A slight, elongated ridge.
Example: Temporal lines of the parietal bones.
Q: What is a crest?
A: A ridge.
Example: Iliac crest.
Q: What is a fossa?
A: An elongated basin.
Example: Mandibular fossa.
Q: What is a fovea?
A: A small pit.
Example: Fovea capitis on the head of the femur.
Q: What is a sulcus?
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A: A groove.
Example: Sigmoid sulcus of the temporal bones
Q: What is a canal (bone marking)?
A: A passage in bone.
Example: Auditory canal.
Q: What is a fissure?
A: A slit through bone.
Example: Auricular fissure.
Q: What is a foramen?
A: A hole through bone.
Example: Foramen magnum in the occipital bone.
Q: What is a meatus?
A: An opening into a canal.
Example: External auditory meatus.
Q: What is a sinus?
A: An air-filled space in bone.
Example: Nasal sinus.
Q: What is an articulation?
A: A location where two bone surfaces come together.
Q: What is a projection in bone anatomy?
A: An area of a bone that projects above its surface, often serving as an attachment point for tendons or ligaments.
Q: What is a hole in bone anatomy?
A: An opening or groove in the bone that allows blood vessels and nerves to enter.
Q: How are the 206 named bones of the human skeleton divided?
A: Into the axial skeleton and appendicular skeleton.
Q: What are the five classifications of bones based on shape?
A: Long, short, flat, irregular, and sesamoid bones.
Q: What are projections that give attachment to muscles or ligaments?
A: Bony features that extend from the bone surface to serve as attachment points for muscles or ligaments.
Q: What are projections that articulate with other bones?
A: Bone features that form joints by fitting with other bone surfaces.
Q: What are depressions that allow the passage of vessels?
A: Indentations or openings in bone that accommodate blood vessels and nerves.
Q: What does the anterior view of the skull show?
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A: The facial bones, orbits, nasal cavity, and upper and lower jaws with teeth
Q: What is the orbit?
A: The bony socket that houses the eyeball and the muscles that move the eyeball and open the upper eyelid.
Q: What is the supraorbital margin?
A: The upper boundary of the orbit on the anterior skull.
Q: What is the supraorbital foramen?
A: A small opening near the midpoint of the supraorbital margin that allows a sensory nerve to pass to the skin of the forehead.
Q: What is the infraorbital foramen?
A: An opening below the orbit that allows a sensory nerve to supply the anterior face below the orbit.
Q: What structures are visible in an anterior view of the skull?
A: The forehead, orbits (eye sockets), nasal cavity, nasal septum, and upper and lower jaws.
Q: What divides the nasal cavity into left and right halves?
A: The nasal septum.
A: The nasal septum.
Q: What bones form the nasal septum?
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A: The perpendicular plate of the ethmoid bone (upper portion) and the vomer bone (lower portion)
Q: What is the shape of each side of the nasal cavity?
A: Triangular, with a broad inferior space that narrows superiorly.
Q: What is the inferior nasal concha?
A: A large, independent bone that projects from each lateral wall of the nasal cavity.
Q: What is the middle nasal concha?
A: A bony plate located just above the inferior concha; it is part of the ethmoid bone.
Q: What is the superior nasal concha?
A: A small, upper bony plate of the ethmoid bone, located lateral to the perpendicular plate and not visible from the front.
Q: What dominates the lateral view of the skull?
A: The large, rounded brain case above and the upper and lower jaws with teeth below.
Q: What is the zygomatic arch?
A: A bony bridge on the side of the skull that spans from the cheek area to above the ear canal.
Q: Which bones form the zygomatic arch?
A: The temporal process of the zygomatic bone (anterior) and the zygomatic process of the temporal bone (posterior).
Q: What is the function of the zygomatic arch?
A: It serves as the origin site for a major muscle that pulls the mandible upward during biting and chewing.
Q: What is the temporal fossa?
A: A shallow space on the lateral side of the brain case above the zygomatic arch, containing muscles that move the mandible.
Q: What is the infratemporal fossa?
A: A deeper space located below the zygomatic arch and behind the vertical part of the mandible, also housing chewing muscles.
Q: What is the cranial cavity?
A: The interior space of the skull that is almost completely occupied by the brain.
Q: What is the calvaria?
A: The rounded top of the skull, also known as the skullcap, which forms part of the cranial cavity.
Q: What bones form the top and sides of the brain case?
A: The flat bones of the skull.
Q: What is the base of the skull?
A: The floor of the brain case, a complex area with varying depths and many openings for cranial nerves, blood vessels, and the spinal cord.
Q: What are the three cranial fossae?
A: The anterior cranial fossa, middle cranial fossa, and posterior cranial fossa.
Q: How do the cranial fossae change from front to back?
A: They increase in depth from anterior to posterior.
Q: What is the purpose of the shape and depth of each cranial fossa?
A: To correspond to the shape and size of the brain region it houses.
Q: What are the cranial fossae?
A: The subdivisions of the floor of the cranial cavity: anterior cranial fossa, middle cranial fossa, and posterior cranial fossa.
Q: How many bones make up the brain case, and what are they?
A: Eight bones: paired parietal and temporal bones, and unpaired frontal, occipital, sphenoid, and ethmoid bones.
Q: What does the parietal bone form?
A: Most of the upper lateral side of the skull.
Q: Where is the parietal bone located relative to surrounding bones?
A: Anteriorly bounded by the frontal bone, inferiorly by the temporal bone, and posteriorly by the occipital bone.
Q: What does the temporal bone form?
A: The lower lateral side of the skull.
Q: Why is the temporal bone named as such?
A: Because it’s located in the temple area, where hair often turns gray first, symbolizing the passage of time.
Q: What is the squamous portion of the temporal bone?
A: The flattened upper part of the temporal bone.
Q: What is the zygomatic process of the temporal bone?
A: The projection that forms the posterior part of the zygomatic arch.
Q: What is the mastoid portion of the temporal bone?
A: The posterior section of the temporal bone, which includes the mastoid process.
Q: What is the mastoid process?
A: A large, palpable bony prominence behind the earlobe that serves as a muscle attachment site.
Q: What is the petrous portion of the temporal bone?
A: The diagonally oriented ridge in the cranial floor that contains cavities housing the middle and inner ear structures.
Q: What three regions of the temporal bone are visible from a lateral view?
A: The squamous, mastoid, and zygomatic portions
Q: What is the external acoustic meatus?
A: A large opening on the lateral side of the skull associated with the ear (ear canal).
Q: What is the internal acoustic meatus?
A: An opening on the medial side of the petrous ridge inside the cranial cavity that connects to the middle and inner ear cavities.
Q: What is the mandibular fossa?
A: A deep, oval-shaped depression on the external base of the skull where the mandible joins the skull at the temporomandibular joint.
Q: What is the articular tubercle?
A: A smooth ridge just anterior to the mandibular fossa that helps form the temporomandibular joint.
Q: What is the styloid process?
A: An elongated, downward bony projection posterior to the mandibular fossa that serves as an attachment site for muscles and a ligament that supports the hyoid bone.
Q: What is the stylomastoid foramen?
A: A small opening between the styloid and mastoid processes that allows exit of the cranial nerve that supplies the facial muscles.
Q: What is the carotid canal?
A: A zig-zag shaped tunnel that carries a major artery to the brain, entering anteromedial to the styloid process and exiting in the floor of the middle cranial cavity.
Q: What bones form the hard palate?
A: Anteriorly by the palatine processes of the maxilla bones, and posteriorly by the horizontal plates of the palatine bones.
Q: What bones form the floor of the cranial cavity?
A: Frontal, ethmoid, sphenoid, temporal, and occipital bones.
Q: What separates the anterior and middle cranial fossae?
A: The lesser wing of the sphenoid bone.
Q: What separates the middle and posterior cranial fossae?
A: The petrous ridge of the temporal bone.
Q: What is the frontal bone?
A: A single bone that forms the forehead and part of the roof of the orbit and anterior cranial cavity.
Q: What is the glabella?
A: A slight depression between the eyebrows at the anterior midline of the frontal bone.
Q: What is the supraorbital margin?
A: The upper boundary of the orbit formed by the frontal bone.
Q: What is the supraorbital foramen?
A: An opening in the frontal bone near the supraorbital margin for passage of a sensory nerve to the forehead.
Q: What are brow ridges?
A: Thickened, rounded areas above each supraorbital margin, typically larger in males.
Q: What does the occipital bone form?
A: The posterior skull and the posterior base of the cranial cavity.
Q: What is the external occipital protuberance?
A: A bump on the posterior midline of the occipital bone for ligament attachment.
Q: What are the superior nuchal lines?
A: Lateral ridges on the occipital bone for neck muscle attachment, marking the uppermost muscle connection point.
Q: What is the foramen magnum?
A: A large opening in the base of the occipital bone that allows passage of the spinal cord.
Q: What are the occipital condyles?
A: Oval-shaped structures on either side of the foramen magnum that articulate with the first cervical vertebra.
Q: What is the sphenoid bone?
A: A single, complex bone of the central skull that connects with almost every other skull bone.
Q: Why is the sphenoid bone considered the “keystone” bone of the skull?
A: Because it joins with nearly every other bone of the skull.
Q: What do the lesser wings of the sphenoid bone form?
A: The lip of the ridge separating the anterior and middle cranial fossae.
Q: What is the sella turcica?
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A: A saddle-shaped bony structure on the sphenoid bone that contains the hypophyseal fossa
Q: What does the hypophyseal fossa house?
A: The pituitary (hypophyseal) gland.
Q: What do the greater wings of the sphenoid bone form?
A: The anterior floor of the middle cranial fossa and part of the lateral skull just anterior to the temporal bone.
Q: What are the medial and lateral pterygoid plates?
A: Thin, vertically oriented bony plates on the inferior sphenoid bone; the medial forms the posterior lateral walls of the nasal cavity, and the lateral serves as muscle attachment sites for chewing.
Q: What is the function of the lateral pterygoid plates?
A: To provide attachment sites for chewing muscles that act on the mandible.
Q: What does the sphenoid bone form in the cranial cavity?
A: The anterior walls and floor of the middle cranial fossa.
Q: What are the major parts of the sphenoid bone?
A: A pair of lesser wings, a pair of greater wings, the sella turcica, and the medial and lateral pterygoid plates.
Q: What structure surrounds the hypophyseal fossa?
A: The sella turcica.
Q: What are the major openings in the sphenoid bone?
A: Optic canal, superior orbital fissure, foramen rotundum, foramen ovale, and foramen spinosum.
Q: What is the ethmoid bone?
A: A single, midline bone that forms the roof and lateral walls of the upper nasal cavity, the upper portion of the nasal septum, and part of the medial wall of the orbit.
Q: What forms the upper portion of the nasal septum?
A: The perpendicular plate of the ethmoid bone.
Q: What are the superior and middle nasal conchae?
A: Thin, curved projections from the lateral walls of the ethmoid bone that extend into the nasal cavity.
Q: What is the crista galli?
A: A small upward projection in the anterior cranial fossa that serves as an attachment point for brain membranes.
Q: What are the cribriform plates and their function?
A: Flattened areas with olfactory foramina through which olfactory nerves pass into the brain.
Q: What do the lateral portions of the ethmoid bone form?
A: The lateral walls of the upper nasal cavity and part of the medial wall of the orbit.
Q: What is found within the lateral portions of the ethmoid bone?
A: Small air-filled spaces that are part of the paranasal sinus system.
Q: Where is the ethmoid bone located?
A: At the midline within the central skull.
Q: What is the crista galli?
A: The upward projection of the ethmoid bone that serves as an attachment point for brain membranes.
Q: What is the perpendicular plate of the ethmoid bone?
A: A downward projection that forms the upper portion of the nasal septum.
Q: What do the cribriform plates form?
A: The roof of the nasal cavity and a portion of the anterior cranial fossa floor.
Q: What structures arise from the lateral sides of the ethmoid bone?
A: The superior and middle nasal conchae.
Q: What do the lateral sides of the ethmoid bone contribute to?
A: The lateral walls of the upper nasal cavity and part of the medial wall of the orbit.
Q: What are ethmoid air cells?
A: Small air-filled spaces within the ethmoid bone that are part of the paranasal sinus system.
Q: What is the vomer bone?
A: An unpaired bone that forms the inferior and posterior portions of the nasal septum.
Q: What is the nasal concha (plural = conchae)?
A: Curved bony plates projecting from the lateral walls of the nasal cavity; the superior and middle are part of the ethmoid, and the inferior is an independent bone.
Q: What is the temporal process?
A: A short extension from the zygomatic bone that forms the anterior part of the zygomatic arch.
Q: What is the fossa (plural = fossae)?
A: A shallow depression on the surface of a bone.
Q: What is the acoustic meatus?
A: The ear canal opening in the temporal bone.
Q: What is the carotid canal?
A: A zig-zag tunnel in the base of the skull that allows passage of the internal carotid artery to the brain.
Q: What is the glabella?
A: A slight depression in the frontal bone located at the midline between the eyebrows.
Q: What is the nuchal line?
A: A pair of bony lines on the posterior skull that extend laterally from the external occipital protuberance.
Q: What is the sella turcica?
A: An elevated area of the sphenoid bone at the midline of the middle cranial fossa.
Q: What is the hypophyseal fossa?
A: A shallow depression on the sella turcica that houses the pituitary (hypophyseal) gland.
Q: What is the pterygoid plate?
A: A paired, flattened bony projection of the sphenoid bone located on the inferior skull, lateral to the medial pterygoid plate.
Facial Bones
Q: How many facial bones are there and how are they grouped?
A: 14 total: 6 paired (maxilla, palatine, zygomatic, nasal, lacrimal, inferior nasal conchae) and 2 unpaired (vomer, mandible).
Q: What does the maxilla form?
A: The upper jaw, medial floor of the orbit, lateral base of the nose, and most of the hard palate.
Q: What is the alveolar process of the maxilla?
A: The curved ridge that contains the upper teeth sockets (alveoli).
Q: What bones form the hard palate?
A: Anterior ¾ by palatine processes of the maxilla; posterior ¼ by horizontal plates of the palatine bones.
Q: What is the function of the zygomatic bone?
A: Forms the cheekbone, part of the lateral orbit wall, and the anterior part of the zygomatic arch.
Q: What do the nasal bones form?
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A: The bony bridge of the nose
Q: What is the lacrimal fossa and canal?
A: Depression and canal in the lacrimal bone that drain tears into the nasal cavity.
Q: What is the function of the inferior nasal conchae?
A: They swirl and humidify incoming air; they are independent bones.
Q: What forms the posterior-inferior part of the nasal septum?
A: The vomer bone.
Mandible
Q: What are the two projections on the mandible’s ramus?
A: Coronoid process (anterior, muscle attachment) and condylar process (posterior, forms TMJ).
Q: What is the mental protuberance?
A: The chin projection on the anterior mandible.
Q: What is the mandibular foramen?
A: The entry point for nerves and vessels that supply the lower teeth.
Q: What is the mylohyoid line?
A: Ridge on the inner mandible for attachment of the oral cavity floor muscle.
Orbit and Nasal Cavity
Q: Which bones contribute to the orbit?
A: Frontal, zygomatic, maxilla, palatine, ethmoid, lacrimal, and sphenoid bones.
Q: What structures pass through the optic canal and superior orbital fissure?
A: Optic nerve through the optic canal; nerves to eye muscles and forehead through the superior orbital fissure.
Q: What forms the nasal septum?
A: Perpendicular plate of ethmoid (upper), vomer (lower), and septal cartilage (anterior).
Q: What are the nasal conchae and their function?
A: Bony projections that swirl and warm incoming air; superior and middle are ethmoid, inferior is separate.
Cranial Fossae
Q: What bones form the anterior cranial fossa?
A: Frontal bone and lesser wings of the sphenoid; houses the frontal lobes.
Q: What defines the middle cranial fossa?
A: Between the lesser wings of the sphenoid and petrous ridges; houses temporal lobes.
Q: What are key openings in the middle cranial fossa?
A: Optic canal, superior orbital fissure, foramen rotundum, foramen ovale, foramen spinosum, carotid canal, foramen lacerum.
Q: What is the sella turcica?
A: A depression in the sphenoid bone housing the pituitary gland.
Q: What does the posterior cranial fossa contain?
A: The cerebellum; it includes the foramen magnum and internal acoustic meatus.
Q: What is the jugular foramen?
A: An opening for cranial nerves and venous blood exiting the brain.
🧠 Sutures of the Skull
Q: What is a suture in the skull?
A: An immobile joint between adjacent skull bones, filled with dense fibrous connective tissue.
Q: What does the coronal suture connect?
A: The frontal bone to the right and left parietal bones.
Q: What does the sagittal suture connect?
A: The right and left parietal bones, running along the midline of the top of the skull.
Q: What does the lambdoid suture connect?
A: The occipital bone to the right and left parietal and temporal bones.
Q: What does the squamous suture connect?
A: The squamous portion of the temporal bone with the parietal bone.
Q: What is the pterion?
A: A capital-H-shaped suture region uniting the frontal, parietal, temporal, and sphenoid bones—weakest part of the skull.
👶 Clinical: Infant Fontanelles
Q: What are fontanelles?
A: Soft connective tissue regions in an infant’s skull that allow movement during birth and brain growth.
Q: When does the posterior fontanelle ossify?
A: Between 3 and 9 months of age.
Q: When does the anterior fontanelle ossify?
A: Between 15 and 18 months of age.
Q: Why is the pterion clinically important?
A: A blow to this area may sever the middle meningeal artery, causing an epidural hematoma.
😮💨 Paranasal Sinuses
Q: What are paranasal sinuses?
A: Hollow, air-filled spaces within certain skull bones that reduce skull weight and add resonance to the voice.
Q: What does sinus congestion affect in terms of voice?
A: It obstructs sinus drainage, changing resonance and potentially causing pain or pressure
Q: Where is the frontal sinus located?
A: Above the eyebrows in the frontal bone; the most anterior sinus.
Q: Where is the maxillary sinus located, and why is it clinically relevant?
A: In the maxilla below the orbits; it’s the largest and most commonly infected due to poor drainage.
Q: Where is the sphenoid sinus located?
A: Midline in the sphenoid bone, just under the sella turcica; the most posterior sinus.
Q: What are ethmoid air cells?
A: Multiple small air spaces in the ethmoid bone between the nasal cavity and orbit.
Q: Why can sinusitis cause a toothache?
A: Because the maxillary sinus and upper teeth share the same nerve supply.
🦴 Hyoid Bone
Q: What is unique about the hyoid bone?
A: It does not articulate with any other bone in the body.
Q: Where is the hyoid bone located?
A: In the upper neck near the inferior mandible, shaped like a U with tips pointing posteriorly
Q: What is the function of the hyoid bone?
A: It supports the tongue and serves as an attachment for muscles involved in swallowing and speech.
Q: What are the two groups of bones that make up the skull?
A: The brain case (cranium) and the facial bones.
Q: What is the function of the brain case?
A: To protect the brain by enclosing it within a hard, bony case.
Q: What is the function of the facial bones?
A: To enclose, protect, and support the soft tissues of the orbits, nasal cavities, and oral cavity.
Q: How many bones make up the human skull?
A: 22 bones.
Q: What type of joint connects the bones of the cranium?
A: Sutures—immobile joints in adults, flexible in infants.
Q: How many facial bones are there, and how are they categorized?
A: 15 total facial bones—6 are paired, and 3 are single.
Q: Do facial bones make contact with the brain?
A: No, they articulate with the cranial bones but do not contact the brain.
Q: What are foramina?
A: Openings in cranial and facial bones (or their sutures) that allow passage of neurovascular structures.
🦴 Vertebral Column Overview
Q: What is another name for the vertebral column?
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A: The spinal column or spine
Q: What structures separate and unite the vertebrae?
A: Intervertebral discs.
Q: What are the main functions of the vertebral column?
A: To support the head, neck, and body; allow movement; and protect the spinal cord.
🔢 Vertebral Regions & Count
Q: How many vertebrae are in the adult vertebral column?
A: 24 vertebrae, plus the sacrum and coccyx.
Q: What are the five regions of the vertebral column?
A: Cervical, thoracic, lumbar, sacral, and coccygeal.
Q: How many cervical vertebrae are there?
A: 7 (C1–C7).
Q: How many thoracic vertebrae are there?
A: 12 (T1–T12).
Q: How many lumbar vertebrae are there?
A: 5 (L1–L5).
Q: What forms the sacrum and coccyx?
A: Sacrum: fusion of 5 sacral vertebrae; Coccyx: fusion of 4 coccygeal vertebrae.
Q: What unique fact is shared about cervical vertebrae in mammals?
A: Almost all mammals have 7 cervical vertebrae, regardless of body size.
🔄 Spinal Curvatures
Q: How many curvatures are in the adult vertebral column?
A: Four—two primary and two secondary.
Q: What are the two primary curves of the spine?
A: Thoracic and sacrococcygeal curves (retained from fetal development).
Q: What are the two secondary curves of the spine?
A: Cervical (develops when baby lifts head) and lumbar (develops when standing/walking).
🧠 Spinal Disorders
Q: What is kyphosis?
A: Excessive posterior curvature of the thoracic region (hunchback).
Q: What is lordosis?
A: Excessive anterior curvature of the lumbar region (swayback).
Q: What is scoliosis?
A: Abnormal lateral curvature of the spine, often with twisting.
🧱 Typical Vertebra Anatomy
Q: What are the main parts of a typical vertebra?
A: Vertebral body, vertebral arch, and seven processes.
Q: What forms the vertebral arch?
A: Paired pedicles and paired laminae.
Q: What is the vertebral foramen?
A: The large opening formed by the body and arch, housing the spinal cord.
Q: What is the vertebral foramen?
A: The large opening formed by the body and arch, housing the spinal cord.
Q: What forms the vertebral canal?
A: The aligned vertebral foramina of all the vertebrae.
Q: What is the intervertebral foramen?
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A: The opening between adjacent vertebrae where spinal nerves exit
Q: What are the seven processes of a typical vertebra?
A: Two transverse, one spinous, two superior articular, and two inferior articular processes.
Q: What do transverse and spinous processes do?
A: Serve as attachment points for muscles and ligaments.
Q: What is the function of articular processes?
A: To form joints between adjacent vertebrae and determine the range of motion.
🧽 Intervertebral Disc
Q: What is an intervertebral disc?
A: A fibrocartilaginous pad between vertebral bodies that provides cushioning and flexibility.
Q: What are the two parts of an intervertebral disc?
A: Anulus fibrosus (outer layer) and nucleus pulposus (gel-like center).
🧠 Cervical Vertebrae
Q: What is a unique feature of cervical vertebrae?
A: They have a small body, bifid (Y-shaped) spinous process (except C7), and transverse foramina
Q: What passes through the transverse foramen of cervical vertebrae?
A: An important artery that supplies the brain.
Q: What is the atlas (C1) and what makes it unique?
A: The first cervical vertebra; it has no body or spinous process and consists of anterior/posterior arches.
Q: What does the atlas articulate with superiorly and inferiorly?
A: Superiorly with the occipital condyles; inferiorly with the axis (C2).
Q: What is the axis (C2) and its defining feature?
A: The second cervical vertebra; features the dens (odontoid process) that articulates with the atlas.
🦴 Thoracic Vertebrae
Q: What distinguishes thoracic vertebrae from others?
A: Long, downward-projecting spinous process and costal facets for rib attachment
Q: What are costal facets?
A: Articulation points on the vertebrae for ribs—found on the body (head of rib) and transverse process (rib tubercle).
💪 Lumbar Vertebrae
Q: What features characterize lumbar vertebrae?
A: Large, thick vertebral bodies; short, blunt spinous processes; articular facets face medially and laterally.
Q: Why are lumbar vertebrae so large?
A: They bear the greatest amount of body weight.
Q: Between which vertebrae are epidurals commonly administered?
A: Between L4 and L5.
🔻 Sacrum & Coccyx
Q: What is the sacrum and how is it formed?
A: A triangular bone formed from the fusion of five sacral vertebrae after age 20.
Q: What is the median sacral crest?
A: A ridge formed by the fused spinous processes of sacral vertebrae.
Q: What is the lateral sacral crest?
A: A ridge formed by the fused transverse processes of sacral vertebrae.
Q: What is the sacral promontory?
A: The anterior lip of the superior base of the sacrum.
Q: What forms the sacroiliac joint?
A: The auricular surface of the sacrum and the ilium of the hip bone.
Q: What is the sacral canal and where does it end?
A: A bony tunnel through the sacrum; ends at the sacral hiatus.
Q: What are sacral foramina?
A: Paired openings on the anterior and posterior sacrum for spinal nerves to exit.
Q: What is the coccyx and its function?
A: The tailbone; formed from four fused coccygeal vertebrae and supports some body weight when sitting.
🧽 Intervertebral Discs
Q: What is an intervertebral disc?
A: A fibrocartilaginous pad between vertebrae that cushions and allows movement.
Q: What are the two parts of an intervertebral disc?
A: Anulus fibrosus (outer ring) and nucleus pulposus (gel-like center).
Q: What causes a herniated disc?
A: When the nucleus pulposus protrudes through a weakened anulus fibrosus.
Q: What is a common symptom of disc herniation at L4/L5 or L5/S1?
A: Sciatica—radiating pain from lower back down the leg.
🦴 Ligaments of the Spine
Q: What is the anterior longitudinal ligament?
A: A ligament on the front of the vertebral column that resists hyperextension.
Q: What is the supraspinous ligament?
A: Connects spinous processes of thoracic and lumbar vertebrae; resists forward bending.
Q: What is the nuchal ligament?
A: An expanded supraspinous ligament in the cervical region that supports the skull.
Q: What is the posterior longitudinal ligament?
A: A ligament found anterior to the spinal cord, connecting the posterior vertebral bodies.
Q: What is the ligamentum flavum?
A: Elastic ligaments connecting the laminae of adjacent vertebrae; allows flexion and recoil.
🫁 Thoracic Cage
Q: What bones form the thoracic cage?
A: The 12 pairs of ribs, their costal cartilages, and the sternum.
Q: What is the primary function of the thoracic cage?
A: To protect the heart and lungs.
Q: To what are the ribs anchored posteriorly?
A: The 12 thoracic vertebrae (T1–T12).
🦴 Sternum Anatomy
Q: What are the three parts of the sternum?
A: Manubrium, body, and xiphoid process.
Q: What is the manubrium?
A: The wider, superior portion of the sternum.v
Q: What is the jugular (suprasternal) notch?
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A: A U-shaped depression at the top of the manubrium, felt at the base of the neck
Q: What is the clavicular notch?
A: A shallow depression on the manubrium where the sternum and clavicle articulate.
Q: Where does the first rib attach?
A: To the manubrium.
Q: What is the sternal angle?
A: The junction between the manubrium and body of the sternum, forming a slight bend and marking the attachment of the second rib.
Q: What ribs attach to the body of the sternum?
A: Ribs 3–7.
Q: What is the xiphoid process?
A: The small, inferior tip of the sternum, cartilaginous early in life and ossifies in middle age.
🦴 Rib Anatomy
Q: What is the head of the rib?
A: The posterior end that articulates with thoracic vertebrae.
Q: What is the neck of the rib?
A: The narrowed region just lateral to the head.
Q: What is the tubercle of the rib?
A: A small bump that articulates with the transverse process of the same-numbered vertebra.
Q: What is the angle of the rib?
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A: The point of greatest curvature; aligns with the scapula’s medial border
Q: What is the costal groove?
A: A shallow groove on the rib’s inferior margin for blood vessels and nerves.
🧷 Rib Classifications
Q: How many pairs of ribs are there?
A: 12 pairs.
Q: What are true ribs?
A: Ribs 1–7; attach directly to the sternum via costal cartilage.
Q: What are false ribs?
A: Ribs 8–12; do not attach directly to the sternum.
Q: How do ribs 8–10 attach to the sternum?
A: Indirectly, via the cartilage of the next higher rib.
What bones form the pectoral girdle?
The clavicle and the scapula.
What is the function of the clavicle?
It supports the scapula, protects underlying nerves and vessels, and transmits forces from the upper limb.
What are the three regions of the clavicle?
Medial (sternal) end, lateral (acromial) end, and shaft.
Which bone is the most commonly fractured in the body?
The clavicle.
What is the glenoid cavity?
A shallow depression on the scapula that articulates with the humerus.
What is the function of the coracoid process?
Attachment site for muscles of the anterior chest and arm.
Which joint is formed by the clavicle and the scapula?
The acromioclavicular joint.
What are the three borders of the scapula?
Superior, medial, and lateral borders.
Which bone articulates with the scapula to form the shoulder joint?
The humerus.
What is the function of the deltoid tuberosity?
Attachment site for the deltoid muscle.
What bones make up the forearm?
The ulna and the radius.
Which bone is on the medial side of the forearm?
The ulna.
What is the olecranon process?
The bony tip of the elbow formed by the ulna.
Where is the radial tuberosity located?
On the medial side below the neck of the radius.
What is the function of the interosseous membrane?
Unites the ulna and radius.
What is the carrying angle?
A lateral deviation of the forearm from the arm when palms face forward.
Which bone articulates with the capitulum of the humerus?
The radius.
How many carpal bones are in the wrist?
Eight.
Name the proximal row of carpal bones from lateral to medial.
Scaphoid, lunate, triquetrum, pisiform.
Name the distal row of carpal bones from medial to lateral.
Hamate, capitate, trapezoid, trapezium.
How many metacarpals are in each hand?
Five.
How many phalanges are in each hand?
Fourteen: 3 in each finger, 2 in the thumb.
Which bone allows for thumb mobility?
The first metacarpal.
What forms the knuckles of the hand?
The distal ends of the metacarpal bones.
What is the appendicular skeleton composed of?
Upper and lower limbs and the supporting elements connecting them to the axial skeleton.
What connects the upper limb to the axial skeleton?
The pectoral girdle.
What bones make up the pelvic girdle?
The ilium, ischium, and pubis.
What is the acetabulum?
A deep, cup-shaped cavity formed by the ilium, ischium, and pubis that articulates with the femur.
Which part of the hip bone do you feel when placing hands on your waist?
The iliac crest.
What is the ischial tuberosity?
The part of the hip bone that supports body weight when sitting.
What structure joins the two pubic bones?
The pubic symphysis.
What is the function of the sacroiliac joint?
It connects the ilium of the hip bone to the sacrum and supports body weight.
What defines the pelvic brim?
It separates the greater pelvis from the lesser pelvis.
How is the female pelvis adapted for childbirth?
It is wider, has a larger subpubic angle, and a more rounded pelvic inlet.
What is the longest and strongest bone in the body?
The femur.
Where does the femur articulate proximally?
With the acetabulum of the hip bone.
What is the greater trochanter?
A large projection for muscle attachment on the femur.
What is the linea aspera?
A rough ridge on the posterior femur where muscles attach.
Which part of the femur articulates with the patella?
The patellar surface.
What is the intercondylar fossa?
A deep depression between the medial and lateral condyles on the posterior femur.
What bones form the lower leg?
The tibia and fibula.
What is the patella?
The largest sesamoid bone in the body located in the quadriceps tendon.
What is the tibial tuberosity?
An anterior site of attachment for the patellar ligament.
What is the medial malleolus?
A bony bump on the medial side of the ankle formed by the tibia.
What is the lateral malleolus?
A bony bump on the lateral ankle formed by the fibula.
How many tarsal bones are in the foot?
Seven.
What is the mnemonic to remember tarsal bones?
Tiger Cubs Need MILC (Talus, Calcaneus, Navicular, Medial, Intermediate, Lateral cuneiform, Cuboid).
Which bones form the arch of the foot?
Tarsals and metatarsals.
What is pes planus?
A condition also known as flat feet or fallen arches.
How many phalanges are in each foot?
Fourteen.
Which bones articulate with the talus at the ankle?
Tibia and fibula.
Which bone of the thigh articulates with the pelvis?
The femur.
What region of the lower limb includes the ankle and foot?
The leg.
What are the three structural classifications of joints?
Fibrous, cartilaginous, and synovial.
What are the three functional classifications of joints?
Synarthrosis (immovable), amphiarthrosis (slightly movable), and diarthrosis (freely movable).
Which structural joint classification allows the greatest range of motion?
Synovial joints.
What type of joint is found between skull bones?
Fibrous joint (suture).
What type of joint connects vertebral bodies?
Cartilaginous joint (symphysis).
What are the main components of a synovial joint?
Joint cavity, articular cartilage, synovial membrane, synovial fluid, joint capsule, and ligaments.
What is the function of synovial fluid?
To lubricate, nourish cartilage, and absorb shock.
What type of joint is the knee?
Synovial hinge joint.
Which type of synovial joint allows rotation?
Pivot joint.
Which joint type allows movement in all directions?
Ball-and-socket joint.
What movement decreases the angle between bones?
Flexion.
What movement increases the angle between bones?
Extension.
What is abduction?
Movement away from the midline.
What is adduction?
Movement toward the midline.
What is circumduction?
Circular movement combining flexion, extension, abduction, and adduction.
What is rotation?
Movement around a longitudinal axis.
What is dorsiflexion?
Lifting the foot upward toward the shin.
What is plantar flexion?
Pointing the toes downward.
What is supination of the forearm?
Turning the palm upward.
What is pronation of the forearm?
Turning the palm downward.
What bones form the TMJ?
Mandible and temporal bone.
What type of joint is the TMJ?
Modified hinge joint.
What is the function of the articular disc in the TMJ?
It smooths the movement between the temporal bone and mandible.
What motions occur at the TMJ?
Opening/closing, protraction/retraction, and side-to-side.
What can cause dislocation of the TMJ?
Opening too wide or trauma to the jaw.
What are symptoms of TMJ disorders?
Pain, jaw locking, headaches, difficulty chewing.
What bones form the shoulder joint?
Humerus and scapula.
What deepens the glenoid cavity?
The glenoid labrum.
What are the main ligaments of the shoulder joint?
Coracohumeral and glenohumeral ligaments.
Which muscles make up the rotator cuff?
Supraspinatus, infraspinatus, teres minor, subscapularis.
What is the main function of the rotator cuff?
To stabilize the shoulder joint.
Why is the shoulder joint prone to dislocation?
It has a wide range of motion and limited structural support.
What bones form the elbow joint?
Humerus, radius, and ulna.
What type of joint is the elbow?
Hinge joint.
What ligament encircles the head of the radius?
Annular ligament.
Which ligament prevents elbow hyperextension?
Ulnar collateral ligament.
What is Tommy John surgery?
Surgical repair of the ulnar collateral ligament.
What bones form the hip joint?
Femur and hip bone (acetabulum).
What type of joint is the hip?
Ball-and-socket joint.
What deepens the socket of the hip joint?
Acetabular labrum.
What ligaments stabilize the hip?
Iliofemoral, pubofemoral, and ischiofemoral ligaments.
What is the ligamentum teres?
A ligament inside the joint that carries an artery to the femoral head.
What is a common injury in elderly related to the hip?
Fracture of the femoral neck (broken hip).
What type of joint is the knee?
Hinge joint.
What are the three articulations in the knee?
Femoropatellar, medial tibiofemoral, lateral tibiofemoral.
What is the function of the menisci?
Provide cushioning and stabilize the joint.
What are the cruciate ligaments?
Anterior and posterior cruciate ligaments.
What is the function of the ACL?
Prevents anterior displacement of the tibia.
What is the function of the PCL?
Prevents posterior displacement of the tibia.
What ligaments are located on the sides of the knee?
Tibial (medial) and fibular (lateral) collateral ligaments.
What bones form the ankle joint?
Tibia, fibula, and talus.
What type of joint is the ankle?
Uniaxial hinge joint.
What are the ligaments on the lateral side of the ankle?
Anterior talofibular, posterior talofibular, and calcaneofibular.
What ligament supports the medial ankle?
Deltoid ligament.
Which joint allows foot inversion and eversion?
Subtalar joint.
