Skeletal System: Axial and Appendicular Skeleton Flashcards

A set of vocabulary flashcards covering the axial and appendicular skeletal systems, including major bones, features, and sexual dimorphism in the pelvis.

Axial skeleton

Bones located along the central body axis, including the skull, vertebral column, hyoid, auditory ossicles, and thoracic cage.

Appendicular skeleton

Bones governing the upper and lower limbs, as well as the pectoral and pelvic girdles that attach the limbs to the axial skeleton.

Bone Markings

Surface features characterizing each bone, including projections, smooth areas, grooves, depressions, and openings.

Cranial bones

The $8$ bones that form the portion of the skull enclosing the brain.

Facial bones

The $14$ bones that form the structure of the face.

Coronal suture

The articulation between the frontal bone and the parietal bones.

Sagittal suture

The articulation that connects the left and right parietal bones.

Lambdoid suture

The articulation of the occipital bone with the parietal bones.

Nasal septum

A structural partition dividing the nasal cavity into left and right halves, formed by the perpendicular plate of the ethmoid bone and the vomer bone.

External acoustic meatus

The external ear opening located in the tympanic part of the temporal bone.

Mastoid process

A prominent bump behind the external ear opening that serves as a muscle attachment site.

Styloid process

A thin, pointed projection located anteromedial to the mastoid process.

Sella turcica

A bony, saddle-shaped depression on the sphenoid bone that houses the pituitary gland.

Cribriform plate

A perforated portion of the ethmoid bone that provides passageways for the olfactory nerves.

Paranasal sinuses

Air-filled chambers within the skull (ethmoidal, frontal, maxillary, and sphenoidal) that lighten the skull and provide resonance to the voice.

Hyoid bone

A U-shaped bone that does not articulate with any other bone, serving as an attachment site for tongue and larynx muscles.

Fontanelles

Dense regular connective tissue membranes or 'soft spots' between fetal cranial bones that allow for brain growth and passage through the birth canal.

Cervical vertebrae

The $7$ bones of the neck region of the vertebral column.

Thoracic vertebrae

The $12$ vertebrae that articulate with the ribs of the thoracic cage.

Lumbar vertebrae

The $5$ large vertebrae located in the inferior concave region (the small of the back).

Atlas (C1)

The first cervical vertebra which lacks a body and spinous process; it articulates with the occipital condyles to permit the 'yes' nodding motion.

Axis (C2)

The second cervical vertebra characterized by the dens (odontoid process), which acts as a pivot for the 'no' rotation of the head.

Nucleus pulposus

The inner gelatinous region of an intervertebral disc that serves as a shock absorber.

Anulus fibrosus

The outer ring of fibrocartilage that forms the external structure of an intervertebral disc.

True ribs

Rib pairs $1-7$ that connect directly to the sternum via their own costal cartilages.

False ribs

Rib pairs $8-12$ whose costal cartilages do not attach directly to the sternum.

Floating ribs

Rib pairs $11-12$, which are false ribs that have no connection to the sternum at all.

Pectoral girdle

The combination of the clavicles and scapulae that articulates with the trunk and supports the upper limbs.

Glenoid cavity

The shallow socket on the scapula that articulates with the head of the humerus.

Humerus

The single bone of the upper arm that articulates proximally with the scapula and distally with the radius and ulna.

Trochlear notch

A C-shaped feature of the ulna that interlocks with the trochlea of the humerus.

Carpals

The $8$ bones of the wrist, including the scaphoid, lunate, triquetrum, pisiform, hamate, capitate, trapezoid, and trapezium.

Pelvic girdle

The structure formed by the left and right ossa coxae bones.

Os coxae

The hip bone, formed by the fusion of three bones: the ilium, ischium, and pubis.

Acetabulum

The deep, circular socket on the lateral surface of the os coxae where the femur articulates.

Subpubic angle

The angle formed by the pubic bones, which is usually greater than $100^{\circ}$ in females and less than $90^{\circ}$ in males.

Femur

The longest, heaviest, and strongest bone in the body, located in the thigh.

Linea aspera

A posterior elevated midline ridge on the femur that serves as an attachment site for many thigh muscles.

Tibia

The larger, medial bone of the lower leg; it is the only weight-bearing bone in the crural region.

Fibula

The smaller, lateral bone of the lower leg that provides lateral stability.

Tarsal bones

The $7$ bones of the ankle and proximal foot, including the talus, calcaneus, cuboid, navicular, and three cuneiforms.