The Skeletal System - Practice Flashcards

A comprehensive set of practice flashcards covering skeletal system anatomy, bone histology, development, axial and appendicular skeleton, skull, vertebrae, joints, and major landmarks.

What are the five primary functions of bones?

Support; protect; muscle attachment; hematopoiesis (red bone marrow); storage of minerals (calcium and phosphorus).

What components make up the bone matrix and what do they provide?

Collagen fibers provide resilience; calcified ground substance (calcium phosphate and calcium carbonate) provides hardness.

Name the three main bone cell types and their general roles.

Osteoblasts (bone formation), osteocytes (mature bone cells maintaining bone tissue), osteoclasts (bone resorption/remodeling).

What is the function of osteoblasts in bone formation?

They synthesize and secrete bone matrix and eventually become osteocytes.

What is the function of osteocytes?

Mature bone cells that maintain the bone matrix and communicate with other bone cells.

What is the function of osteoclasts?

Resorb bone during remodeling, releasing minerals into the blood.

What hormone is released by the parathyroid glands and what effect does it have on calcium?

Parathormone (PTH) increases blood calcium by promoting release from bone, increasing renal calcium reabsorption, and activating vitamin D.

What effect does calcitonin have on calcium levels?

Lowers blood calcium by promoting calcium deposition in bone.

Which organ systems coordinate calcium homeostasis with PTH and calcitonin?

Bones and kidneys (with vitamin D metabolism) regulate calcium balance.

In bone remodeling, what is the role of osteoclasts vs osteoblasts in the sequence of events?

Osteoclasts resorb bone to create space; osteoblasts lay down new bone during formation.

What is an osteon (Haversian system) and where is it found?

A structural unit of compact bone consisting of concentric lamellae around a central canal with blood vessels.

What surrounds the outside of compact bone?

Periosteum.

What lines the medullary cavity of bone?

Endosteum.

What are the two main bone tissues by structure?

Compact (dense) bone and cancellous (spongy) bone.

What is cancellous bone characterized by?

Trabeculae with marrow-filled spaces; lighter and porous compared to compact bone.

What are bone cells grouped as embryonic bone cells, mature bone cells, and bone-resorbing cells?

Osteoblasts (embryonic/young), osteocytes (mature), osteoclasts (bone resorption).

What is the term for bones that develop within a tendon?

Sesamoid bones (e.g., the patella).

What are the two ossification processes producing bone?

Endochondral (cartilaginous) ossification and intramembranous ossification.

Which bone starts developing first in fetal development?

The clavicle (around the 5th week of intrauterine life).

How many bones are in the axial skeleton?

80 bones.

How many bones are in the appendicular skeleton?

126 bones.

What are the skull bones divided into by category?

Cranial bones (8) and facial bones (14).

Which skull suture forms the H-shaped junction associated with a major artery and risk of epidural hematoma?

Pterion (junction of frontal, parietal, sphenoid, and temporal bones).

What are fontanelles and what do they indicate?

Soft spots in an infant skull; sunken fontanelle indicates dehydration, bulging fontanelle may indicate meningitis.

Name the three auditory ossicles.

Malleus (hammer), Incus (anvil), Stapes (stirrup).

What is unique about the hyoid bone?

No articulation with other bones; anchors tongue and neck muscles.

What are the three parts of the sternum?

Manubrium, body, and xiphoid process.

What is the Jugular notch and where is it located?

Notch on the superior border of the manubrium; marks the level of T2-T3 vertebrae.

What is the 'Angle of Louis' and what does it mark?

Sternal angle; junction of manubrium and body at T4-T5; marks the second rib.

Which ribs are true, false, and floating?

True ribs: 1-7; False ribs: 8-10; Floating ribs: 11-12.

Which ribs are typical versus atypical?

Typical ribs: 3-9; Atypical ribs: 1, 2, 10-12.

Describe the atlas (C1) and axis (C2) vertebrae.

C1 (atlas) lacks a body and supports the skull; C2 (axis) has a dens/odontoid process that articulates with atlas for rotation.

Which vertebra is called vertebra prominens?

C7; characterized by a long, often non-bifid spinous process.

What are the key features of a typical cervical vertebra?

Small body; has transverse foramina; bifid spinous process; triangular vertebral foramen.

What are the features of thoracic vertebrae?

Heart-shaped body; costal facets on body and transverse processes; long, downward-sloping spinous processes.

How many vertebrae are in the sacrum and coccyx regions?

Sacrum: five fused vertebrae (S1-S5); Coccyx: typically 3-5 fused coccygeal vertebrae.

What bones form the pelvic girdle?

Ilium, ischium, and pubis (coxal bone).

What are the major landmarks of the pelvis for muscle attachment?

Iliac crest, anterior superior iliac spine, ischial tuberosity.

What forms the acetabulum?

Fusion of ilium, ischium, and pubis.

What are the major bones of the upper limb and pectoral girdle?

Clavicle and scapula (pectoral girdle); humerus, radius, ulna; carpals, metacarpals, phalanges.

Describe the humerus landmarks.

Head; anatomical neck; surgical neck; greater and lesser tubercles; deltoid tuberosity; capitulum; trochlea; medial/lateral epicondyles; olecranon fossa.

What are the bones of the forearm and their key features?

Radius and ulna; olecranon, semilunar notch, radial tuberosity; styloid processes.

What are the names of the carpal bones?

Scaphoid, Lunate, Triquetrum, Pisiform (proximal row); Trapezium, Trapezoid, Capitate, Hamate (distal row).

What bones comprise the hand and fingers?

Metacarpals (5) and phalanges (14: proximal, middle, distal).

What bones form the pelvic girdle and lower limb bones?

Pelvic girdle: pelvis bones; lower limb bones: femur, patella, tibia, fibula; tarsals, metatarsals, phalanges.

Name the major bones of the lower limb and their landmarks.

Femur (head, neck, greater/lesser trochanters, linea aspera, epicondyles, condyles), patella, tibia, fibula; tarsals (Calcaneus, Talus, Navicular, Cuboid, cuneiforms), metatarsals, phalanges.

What is the acetabulum and which bones contribute to it?

Hip socket formed by the union of ilium, ischium, and pubis.

What joints are classified by mobility as synarthroses, amphiarthroses, and diarthroses?

Synarthrosis (immovable), Amphiarthrosis (slightly movable), Diarthrosis (freely movable).

Name the six types of synovial joints.

Ball-and-socket (spheroid); hinge (ginglymus); pivot (trochoid); condyloid (ellipsoid); saddle (sellar); plane (gliding).

Which synovial joint type is exemplified by the hip and shoulder?

Ball-and-socket joint.

Which synovial joint type is exemplified by the elbow and knee?

Hinge (ginglymus) joint.

Which synovial joint allows rotation between C1 and C2?

Pivot joint (atlantoaxial joint).

What is the carpometacarpal joint of the thumb an example of?

Saddle (sellar) joint.

What is a plane (gliding) joint?

A joint where two flat articular surfaces glide over each other, e.g., some carpal joints.

What is a fontanelle, and what conditions can it indicate when sunken or bulging?

A soft spot on an infant’s skull; sunken fontanelle suggests dehydration, bulging suggests meningitis.

What bones are the ossicles in the ear and why are they important?

Malleus, Incus, Stapes; they transmit and amplify sound vibrations in the middle ear.

What bones constitute the facial skeleton’s major groups?

Vomer (unpaired); maxillae, palatine, inferior nasal concha, nasal, lacrimal, zygomatic, mandible, etc.

What is the significance of the pterion in neuroanatomy?

H-shaped union of the frontal, parietal, sphenoid, and temporal bones; related to the middle meningeal artery and risk of epidural hematoma.

Where are the frontal sinuses located?

Within the frontal bone of the skull.

What bones form the coronal, sagittal, and lambdoid sutures?

Coronal between frontal and parietal; sagittal between parietal bones; lambdoid between parietal and occipital bones.

What are the major components of a vertebra?

Body, vertebral foramen, pedicles, laminae, spinous process, transverse process, superior/inferior articular facets, vertebral arch.

What are the accessory processes on lumbar vertebrae called?

Mamillary processes; accessory, superior articular processes, and pars interarticularis features.

Which vertebrae have transverse foramina and what is their function?

Cervical vertebrae; transmit the vertebral arteries and veins.

What are the features used to identify typical thoracic vertebrae?

Heart-shaped body, facets for ribs on body and transverse processes, downward-sloping spinous processes.

What bones comprise the sternum’s anatomical landmarks?

Manubrium, body, xiphoid process; jugular notch and sternal angle (Angle of Louis) are key landmarks.

What is the difference between the diaphysis and the epiphyses in long bones?

Diaphysis is the shaft; epiphyses are the ends of the bone, often with articular cartilage and growth plates.

What are the major components of the knee joint region in terms of bursae and tendons?

Synovial joint with patellar ligament, suprapatellar fat body, suprapatellar and infrapatellar bursae, menisci (medial and lateral).

What bones form the foot’s arches and how are they grouped?

Tarsals (Calcaneus, Talus, Navicular, Cuboid, and cuneiforms); metatarsals; phalanges; arches supported by ligaments and tendons.

What is the function of the acetabulum in the hip joint?

Socket formed by the fusion of ilium, ischium, and pubis that articulates with the femoral head.

Which joints are examples of synovial joints that allow angular movements (condyloid type)?

Metacarpophalangeal joints (knuckles) and radiocarpal joints show ellipsoid/condyloid movement.

What structural feature distinguishes the atlas (C1) from other cervical vertebrae?

Atlas lacks a vertebral body and has anterior and posterior arches accommodating occipital condyles.