Skeletal System: Bone Tissue, Axial Skeleton, and Appendicular Skeleton

Vocabulary practice flashcards covering bone tissue histology, bone classification, skull anatomy, priority bone markings, vertebral column, thoracic cage, and appendicular skeleton components from BIO 171 Labs 7 and 8.

Axial Skeleton

The division of the human skeleton consisting of the bones of the skull, vertebrae, ribs, and sternum.

Appendicular Skeleton

The division of the human skeleton consisting of the bones of the pectoral girdle, upper limbs, pelvic girdle, and lower limbs.

Long Bones

A shape classification for skeletal bones characterized by being longer than they are wide, such as the femur or tibia.

Short Bones

A shape classification for skeletal bones that are roughly cube-shaped, such as carpals and tarsals.

Flat Bones

A shape classification for skeletal bones that are thin, flattened, and usually curved, such as the sternum and cranial bones.

Irregular Bones

A shape classification for skeletal bones that do not fit into other shape categories, such as vertebrae.

Diaphysis

The tubular shaft that runs between the proximal and distal ends of a long bone, containing yellow bone marrow.

Epiphysis

The expanded end of a long bone that contains spongy bone and red bone marrow.

Periosteum

The fibrous membrane covering the outer surface of a bone.

Epiphyseal Line

The bony remnant of the growth plate located between the epiphysis and diaphysis in an adult long bone.

Medullary Cavity

The hollow central cavity within the diaphysis of a long bone that houses bone marrow.

Ground Bone

A histology bone preparation where a solid sample of bone is ground down into a thin section.

Decalcified Bone

A histology bone preparation where the solid, mineralized matrix of a bone sample has been dissolved away.

Osteon

The fundamental microscopic structural and functional unit of compact bone.

Central (Haversian) Canal

The microscopic canal running longitudinally through the center of an osteon containing blood vessels and nerves.

Concentric Lamellae

Concentric rings or layers of calcified bony matrix arranged around the central canal of an osteon.

Lacunae

Small cavities situated between adjacent concentric lamellae that contain osteocytes.

Osteocyte

A mature bone cell residing inside a lacuna in compact bone.

Canaliculi

Tiny, hairlike canals radiating from lacunae that connect them to each other and to the central canal.

Cranial Bones

Bones of the skull whose primary function is to protect the brain, including the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones.

Facial Bones

Bones of the skull that form the facial structure, including the mandible, maxilla, lacrimal, palatine, zygomatic, nasal, vomer, and inferior nasal conchae.

Sutures

Immovable fibrous joints that firmly unite the adult cranial bones together.

Coronal Suture

The immovable joint that unites the frontal bone with the parietal bones.

Sagittal Suture

The immovable joint running along the midline that joins the left and right parietal bones.

Lambdoid Suture

The immovable joint between the occipital bone and the two parietal bones.

Squamous Suture

The immovable joint that unites each temporal bone with a parietal bone.

Supraorbital Foramen

A first priority bone marking; an opening located on the frontal bone above the eye orbit.

Glabella

A second priority bone marking; the smooth region of the frontal bone located directly between the orbits/eyebrows.

Zygomatic Process

A first priority bone marking; a projection extending anteriorly from the temporal bone to meet the zygomatic bone.

Carotid Canal

A first priority bone marking; a passageway through the temporal bone for the internal carotid artery.

External Acoustic Meatus

A first priority bone marking; the prominent external ear canal opening within the temporal bone.

Mandibular Fossa

A third priority bone marking; a depression on the temporal bone that articulates with the condylar process of the mandible.

Styloid Process

A third priority bone marking; a slender, needle-like projection pointing downwards from the inferior surface of the temporal bone.

Mastoid Process

A second priority bone marking; a prominent rough projection of the temporal bone posterior to the external acoustic meatus.

Foramen Magnum

A first priority bone marking; the large opening in the base of the occipital bone through which the spinal cord connects to the brainstem.

Occipital Condyles

A first priority bone marking; rounded articulating surfaces flanking the foramen magnum on the occipital bone that articulate with the atlas ($C1$).

Jugular Foramen

A first priority bone marking; an opening located between the temporal and occipital bones.

External Occipital Protuberance

A third priority bone marking; a midline prominence on the posterior surface of the occipital bone.

Sella Turcica

A first priority bone marking; a saddle-shaped depression located on the sphenoid bone that houses the pituitary gland.

Greater Wings

A second priority bone marking; large lateral projections of the sphenoid bone forming portions of the cranial floor and orbit.

Lesser Wings

A second priority bone marking; horn-like projections extending from the anterior-superior part of the sphenoid bone.

Superior Orbital Fissure

A third priority bone marking; a slit-like opening between the greater and lesser wings of the sphenoid bone.

Cribiform Plate

A second priority bone marking; a perforated horizontal plate of the ethmoid bone that allows olfactory nerve fibers to pass into the nasal cavity.

Crista Galli

A third priority bone marking; a vertical upward crest on the ethmoid bone that serves as an attachment site for the brain's covering membranes.

Perpendicular Plate

A first priority bone marking; a vertical plate of the ethmoid bone that forms the superior portion of the bony nasal septum.

Condylar Process

A first priority bone marking; the posterior projection of the mandibular ramus that articulates with the mandibular fossa to form the TMJ.

Coronoid Process

A third priority bone marking; the sharp, anterior superior projection of the ramus of the mandible serving as an attachment site for muscles.

Mental Foramen

A second priority bone marking; an opening on the anterolateral body of the mandible.

Mandibular Foramen

A third priority bone marking; an opening located on the medial surface of the mandibular ramus.

Alveolar Processes

A first priority bone marking; the ridges and sockets on the margins of the maxillae and mandible that hold the teeth.

Temporomandibular Joint (TMJ)

A second priority landmark; the articulation formed between the condylar process of the mandible and the mandibular fossa of the temporal bone.

Palatine Process

A first priority bone marking; the horizontal projection of the maxilla forming the anterior portion of the hard palate.

Hyoid Bone

A bone associated with the skull that does not articulate directly with any other bone.

Auditory Ossicles

Three tiny middle ear bones (malleus, incus, and stapes) that associate with the skull but do not directly attach to it.

Paranasal Sinuses

Air-filled mucosal-lined cavities located within specific skull bones: the frontal sinus, ethmoidal sinus, sphenoidal sinus, and maxillary sinus.

Fontanels

Fibrous membrane-covered regions (soft spots) in the fetal skull that allow compression during birth and rapid brain growth.

Cervical Curvature

The curvature of the vertebral column comprising $7$ vertebrae ($C1$ to $C7$).

Thoracic Curvature

The curvature of the vertebral column comprising $12$ vertebrae ($T1$ to $T12$).

Lumbar Curvature

The curvature of the vertebral column comprising $5$ vertebrae ($L1$ to $L5$).

Sacral Curvature

The curvature of the vertebral column formed by the sacrum, which consists of $5$ fused vertebrae.

Body (of Vertebrae)

A second priority bone marking; the rounded, anterior weight-bearing portion of a typical vertebra.

Vertebral Arch

A third priority bone marking; the bony arch posterior to the vertebral body that encloses the spinal cord.

Vertebral Foramen

A first priority bone marking; the large central opening bounded by the vertebral body and arch through which the spinal cord passes.

Spinous Process

A first priority bone marking; a single median posterior projection extending from the vertebral arch.

Transverse Processes

A third priority bone marking; paired lateral projections extending from each side of the vertebral arch.

Superior & Inferior Articular Processes

A second priority bone marking; paired vertical processes on vertebrae that articulate with adjacent vertebrae above and below.

Intervertebral Discs

A first priority structure; fibrocartilaginous pads positioned between adjacent vertebral bodies to absorb shock and allow spinal flexibility.

Atlas

The first cervical vertebra ($C1$); has no body and features an articular surface for the dens of the axis.

Axis

The second cervical vertebra ($C2$); features an odontoid process (dens) on its body that articulates with the atlas.

Thoracic Cage

The skeletal enclosure that protects vital thoracic organs and serves as an attachment site for muscles, consisting of the sternum, ribs, and thoracic vertebrae.

Manubrium

A second priority bone marking; the superior, widest portion of the sternum articulating with the clavicles and first ribs.

Body (of Sternum)

A second priority bone marking; the elongated central portion of the sternum.

Xiphoid Process

A first priority bone marking; the small, cartilaginous/bony inferior tip of the sternum.

Suprasternal Notch

A third priority bone marking (also known as jugular notch); a central indentation located on the superior border of the manubrium.

True Ribs

Rib pairs $1$ to $7$ that attach directly to the sternum via individual costal cartilages.

False Ribs

Rib pairs $8$ to $10$ that attach to the sternum indirectly via the costal cartilage of the rib above.

Floating Ribs

Rib pairs $11$ and $12$ that have no anterior attachment to the sternum.

Costal Cartilage

Hyaline cartilage strips that connect most ribs to the sternum.

Pectoral Girdle

The skeletal girdle consisting of the clavicle and scapula that attaches the upper limbs to the axial skeleton.

Upper Appendages (Limbs)

The limb bones of the upper body consisting of the humerus, ulna, radius, carpals, metacarpals, and phalanges.

Supination (of Forearm)

The position or movement of the forearm in which the radius and ulna are parallel to each other.

Pronation (of Forearm)

The rotational movement or position of the forearm where the radius rotates medially and crosses over the ulna.

Lower Appendages (Limbs)

The limb bones of the lower body comprising the femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges.

Pelvic Girdle

The skeletal girdle composed of two os coxae (hip bones), the sacrum, and the coccyx that attaches the lower limbs to the axial skeleton.

Os Coxae

The hip bone, which forms the lateral and anterior aspects of the pelvic girdle through the fusion of three bones: the ilium, ischium, and pubis.

Ilium

The largest and most superior of the three fused bones forming the os coxae.

Ischium

The posteroinferior bone of the os coxae, bearing weight when seated.

Pubis

The anterior and inferior bone of the os coxae that joins its counterpart anteriorly at the pubic symphysis.

Acetabulum

The deep lateral socket on the os coxae formed by the fusion of the ilium, ischium, and pubis that articulates with the head of the femur.

Obturator Foramen

The large opening in the os coxae bounded by the rami of the ischium and pubis.