Chapter 4: Skeletal System and Joint Actions Flashcards
What are the five primary functions of the skeletal system?
Calcium storehouse: Calcium and other minerals are stored within bone.
Blood cell production: Marrow within bone produces blood.
Movement: Bones come together to form joints that allow motion.
Structure and support: The skeleton provides the structure and support needed for movement. This structure separates humans from amoebas or jellyfish.
Protection: Without the skeleton, such essential organs as the brain, spinal cord, heart, and lungs would have no protection.
The bones that make up the human framework can be divided into the . . .
Axial and appendicular skeleton
List the 5 classifications of bones
Long bones
Short bones
Flat bones
Sesamoid bones
Irregular bones
What are the characteristics of long bones?
- Hard, dense
- Provide strength, structure, and mobility
- Has a shaft and two ends
What are the characteristics of flat bones?
- Provide a large surface area for muscles to attach
- Somewhat flat and thin but may be curved, as in the ribs
What bones protect vital organs such as the spinal column and pelvis?
Irregular bones
What are sesamoid bones?
- A bone embedded within a tendon or a muscle
- Typically passes over an angular structure
- Provide a smooth surface for tendons to slide over
What do short bones provide?
Support and stability
What types of bones are the following?
Occipital Parietal Frontal Nasal Lacrimal Vomer Sternum Ribs Pelvis Coxal Shoulder Scupala
Long bones
Name the following types of bones
Scaphoid Lunate Triquetral Harnate Pisiform Capitate Trapezoid Trapezium Calcaneus Talus Navicular Cuboid Lateral cuneiform Intermediate cuneiform Medial cuneiform
Short bones
List the five different regions of the vertebral (spinal) column
- Cervical
- Thoracic
- Lumbar
- Sacrum
- Coccyx
What’s the location of the 9 fused vertebrae?
5 within the sacrum
4 within the coccyx
What do the facet joints of the spine do?
- Guide flexion and extension
- Limit rotation (especially in the lower portion of the vertebral column)
What are the 3 bony protrusions where muscles and ligaments attach to the cervical, thoracic, and lumbar regions?
- 1 spinous process on the back of the vertebrae
- 2 transverse processes on either side
How are bones formed?
-Bones are initially developed in the form of cartilage.
What happens at epiphyseal plate?
Bone growth near the end of immature bones
Cartilage cells divide to push newly formed cells toward the shaft of the bone
What are the 2 types of damage that bones can repair?
- Macro-damage: When a bone breaks into two or more pieces, requiring medical intervention
- Micro-damage: microscopic tears within the bone’s matrix.
- All bone is replaced every few years from the accumulation of microdamage and the subsequent repair process.
What is a stress fracture?
When activity levels drastically increase to the point where the balance between microdamage and repair can’t be maintained
What is the remodeling process?
Bone changing shape through an increase or decrease in diameter
What cell types drive the remodeling process?
Osteoclasts
Osteoblasts
Osteocytes
What are the two types of connective tissues that cover long bones?
Periosteum
Endosteum
What is the medullary cavity?
Central cavity of the bone shaft where marrow is stored
What is compact (cortical) bone?
- Hard outer layer of dense tissue
- Strong, solid, and resistant to bending
What do spongy bones form?
-A latticework of bony structures called trabeculae
What is osteoporosis?
- Bone disease characterized by a loss in bone mass and density
- Primarily due to the weakening of spongy bone
What are bony protrusions? What is their function?
An eminence on the surface of bones
Increases strength
Increases contact area for muscle and ligament attachments
What do bone angles attach to?
Bony or soft tissue attachments
What is the largest segment of bone?
The bone body
Femur and humerus
What is the large bony prominence that provides structural support to the hyaline cartilage and bears the brunt of the force exerted from the joints?
A condyle
What is the raised edge of a bone that attaches connective tissue to muscle and bone?
The crest
What is the diaphysis?
The main part (shaft) of a long bone
Femur, humerus, and tibia
What is a bony prominence that attaches muscle and connective tissue to bone and support the musculoskeletal system?
An epicondyle
Where is the epiphysis located?
At the proximal and distal poles of the bone
A smooth, flat surface that forms a joint with another flat bone, together forming a gliding joint
Facet
What is a fissure?
An open slit in a bone
Houses nerves and blood vessels
Superior and inferior orbital fissure
What passes through foramen? What’s the example?
A hole through which nerves and blood vessels pass
The cranium - supraorbital foramen, infraorbital foramen, and mental foramen
What is a fossa? Where is it found?
A shallow depression in the bone surface
Brain structures
Trochlear fossa and posterior, middle, and anterior cranial fossa
What is a groove? What does it do?
A furrow in the bone surface that runs along the length of a vessel or nerve
Provides space to avoid compression by adjacent muscle or external forces
A radial groove and the groove for the transverse sinus
What is a head? What is usually covered in?
A rounded, prominent extension of bone that forms part of a joint
Hyaline cartilage inside a synovial capsule
What is a margin?
The edge of any flat bones that define its borders
What is the tubelike channel that extends within the bone and provides passage and protection to nerves, vessels, and even sound?
Meatus
External acoustic meatus and internal auditory meatus
What is the neck?
The segment between the head and the shaft of a bone
What is a depression in a bone that stabilizes an adjacent articulating bone?
A notch
What is the curved part of a bone that gives structural support to the rest of the bone?
The ramus
Mandible
What is the sinus?
A cavity within any organ or tissue
Paranasal sinuses and dural venous sinuses
What is a sharp elevation of bone where muscles and connective tissue attach?
A spinous process
What is a trochanter?
A large prominence on the side of the bone
Attachment for the largest muscle groups and most dense connective tissues
The greater and lesser trochanters of the femur
What is a moderate prominence where muscles and connective tissues attach, and is similar to a trochanter?
Tuberosity
A small, rounded prominence where connective tissues attach?
A tubercle
The greater and lesser tubercle of the humerus
What are the 3 sources of blood for bones?
periosteal vessels
epiphyseal vessels
nutrient arteries
What is the functional unit of compact bone?
Osteons (Haversian systems)
Why is cartilage composed of collagen fibers?
Makes it more pliable than bone while still providing tensile strength
What are the 3 types of cartilage?
Hyaline
Fibrous
Elastic
Where is hyaline cartilage found? What are its characteristics?
Joint surfaces and the respiratory tract
Transparent and elastic
Contains no nerves or blood vessels
What is fibrocartilage? Where is it located?
Tough, elastic tissue
Intervertebral discs
The insertions of tendons and ligaments
What does articular cartilage cover? What is its function?
The surface end of long bones
Blocks the pain signal
Reduces compressive stress
What are nociceptors?
Pain-sensitive nerve endings that cover the periosteum and endosteum of bone
What is elastic cartilage? What’s an example?
The most pliable
Gives shape to the external ear and the middle ear
The epiglottis: a flap made of elastic cartilage that opens during breathing and closes during swallowing
What attaches bone-to-bone?
Ligaments
What is elastin?
A protein found in all connective tissues
Allows those tissues to regain their original shape after being stretched
What are the locations of ligaments?
Extrinsic
Intrinsic
Capsular
What are the bones of the axial skeleton?
The skull, vertebral column, rib cage, sternum, and sacrum
80 total
What are the bones of the appendicular skeleton?
The 126 bones of the upper and lower extremities
What is an extrinsic ligament?
- Outside the joint
- Lateral collateral ligament (LCL)
What is an intrinsic ligament? What are two examples and what is there function?
- Inside the joint
- The anterior cruciate (ACL) resists anterior movement of the tibia
- The posterior cruciate (PCL) resists posterior movement of the tibia
What is a capsular ligament?
-Continuous with the joint capsule
Where are long bones located?
- Lower extremity
- Upper extremity
What’s the location of flat bones?
-Skull and thoracic cage
Where are sesamoid bones found?
- Knee
- Hand
- Wrist
- Foot
- Neck
What is ossification and when does it take place?
Replacing softer cartilage with harder bone
After birth and throughout physical development between the ages of 18 and 25.
What is the epiphyseal line?
A line of cartilage near the end of mature long bones
What do osteoclasts do in the bone remodeling process?
- Chew up the impaired bone tissue after damage
- Decrease the bone’s diameter through a process called resorption
What do osteoblasts do in the bone remodeling process?
- Lay down new bone if there’s a stimulus for growth such as weightlifting
- This process of thickening diameter is called deposition
What do osteocytes do in the bone remodeling process?
Turn into mature bone cells from osteoblasts
What is the articulating segment of bone?
Ephysis, usually at the bone’s proximal and distal poles
Why is the epiphysis critical for bone growth?
Because it sits adjacent to the epiphyseal line
What separates the head from the shaft of the bone?
The neck
What is the main articulating surface that forms a ball-and-socket joint with an adjacent bone?
The head
Name 4 functions of ligaments
Hold together the skeletal structure
Passively stabilizes and guided joints
Resists excess movement at a joint
Senses the position of the joint in space
What happens when articular cartilage degrades?
Bone-on-bone contact leads to pain and stiffness at the joint and eventually osteoarthritis
What is a form of fibrocartilage present in the knee, wrist, acromioclavicular, sternoclavicular, and temporomandibular joints?
Meniscus
What is the most widespread form of cartilage? Where is it located?
- Hyaline
- In the nose, trachea, larynx, bronchi, and the ends of ribs
What is the edge of the temporal bone articulating with the occipital bone?
The occipital margin of the temporal bone
What is the edge of the occipital bone articulating with the temporal bone?
The temporal margin of the occipital bone
What is demarcated from the head by the presence of the physeal line in pediatric patients and the physeal scar (physeal line remnant) in adults??
The neck
What is the difference between the surgical neck and anatomical neck?
The anatomical neck is demarcated by its attachment to capsular ligaments.
The surgical neck is often more distal and is demarcated by the site on the neck that is most commonly fractured
What does the articulating bone slide into and out of, guiding the range of motion of the joint?
The notch
Why do the trabeculae of osteons contain a richer source of blood vessels?
Compact bone is denser than spongy bone
What ligaments resist varus stress, or an abnormal joint movement away from the midline of the body?
Extrinsic ligaments, such as the LCL that prevents bowlegs at the knee joints
What covers the outside of bones where osteoblasts are located?
Periosteum
What covers the inner lining of bones and the medullary cavity
Endosteum
What’s another name for spongy bones?
Trabecular or cancellous
Which bones protect the internal organs?
Flat bones
What makes up approximately 80 percent of a person’s skeletal mass?
Cortical bone
