Anatomy: Axial and Appendicular Skeleton

Vocabulary practice flashcards covering bone classifications, surface markings, and key structures of the axial and appendicular skeletons.

Axial skeleton

The central division of the skeletal system consisting of 80 bones—including the skull, auditory ossicles, vertebral column, hyoid bone, and thorax—primarily responsible for protection.

Appendicular skeleton

The division of the skeletal system comprising 126 bones that make up the upper and lower limbs, as well as the pectoral and pelvic girdles, primarily functioning in movement.

Long bones

Bones characterized by a thick exterior of compact bone, exemplified by the femur and humerus.

Short bones

Square-shaped bones with a spongy bone interior, such as the carpals and tarsals.

Flat bones

Thin bones containing a spongy bone interior, such as the cranial bones and sternum.

Irregular bones

Bones with complex, variable shapes that do not fit other classifications, including facial bones and vertebrae.

Sesamoid bones

Small bones that develop within tendons to protect them against excessive wear and tear, such as the patella.

Foramen

A large opening through a bone that serves as a passage for blood vessels, nerves, or ligaments.

Fossa

A shallow depression on the surface of a bone, such as the mandibular fossa.

Head (bone marking)

A rounded articular projection or process on a bone.

Crest

A prominent, prominent ridge along the surface of a bone.

Trochanter

A very large, prominent projection found on a bone.

Tuberosity

A bone projection that features a rough or irregular surface.

Spinous process

A sharp, slender projection extending from a bone, characteristically seen on vertebrae.

Cranium

The cranial case consisting of 8 bones: frontal bone, parietal bone, temporal bone, occipital bone, sphenoid bone, and ethmoid bone.

Facial bones

The 14 bones forming the face: mandible, maxilla, zygomatic bone, nasal bones, lacrimal bones, palatine bones, inferior nasal conchae, and vomer.

Fontanelles

Soft, membrane-filled spaces between cranial bones present in infants that ossify into suture joints in adulthood.

Hyoid bone

A U-shaped bone situated at the top of the larynx; it is the only bone in the body that does not articulate with any other bone, supporting the tongue and providing attachments for neck and pharynx muscles.

Vertebral column

A flexible structure composed of 26 vertebrae arranged into 5 regions (cervical, thoracic, lumbar, sacrum, and coccyx) that encloses and protects the spinal cord, supports the head, and anchors limbs and muscles.

Intervertebral discs

Cartilaginous pads between adjacent vertebrae that absorb vertical shock and form flexible joints.

Thoracic cage

A bony enclosure formed by the thoracic vertebrae (T1–T12), sternum, and 12 pairs of ribs that protects thoracic and upper abdominal organs and assists in breathing.

Sternum

The breastbone, composed of the manubrium, body, and xiphoid process, which fuse together in adulthood.

Costal cartilage

Bars of hyaline cartilage that connect the ribs to the sternum, contributing elasticity and flexibility to the thoracic cage.

True ribs

Vertebrosternal ribs that attach directly to the sternum via their own costal cartilages.

False ribs

Vertebrochondral ribs that do not connect directly to the sternum; their costal cartilages attach to the cartilage of the rib above them.

Floating ribs

Vertebral ribs that have no anterior attachment to the sternum or costal cartilage.

Pectoral girdle

The shoulder girdle, composed of the clavicle and scapula, which attaches the upper limb to the axial skeleton and provides muscle attachment sites.

Scapula

The shoulder blade; provides attachment for muscles and articulates with other bones to form the shoulder joint.

Clavicle

The collar bone; enhances shoulder range of motion and articulates to form the sternoclavicular and acromioclavicular joints.

Humerus

The bone of the upper arm; articulates proximally with the scapula to form the shoulder (glenohumeral) joint and distally with the forearm to form the elbow joint.

Ulna

The medial bone of the forearm located on the pinky-finger side.

Radius

The lateral bone of the forearm located on the thumb side.

Carpals

A group of 8 short bones arranged in two rows forming the wrist.

Metacarpals

The five bones that form the framework of the palm of the hand.

Pollex

The anatomical term for the thumb, distinguished by possessing only two phalanges (proximal and distal) instead of three.

Pelvic girdle

The hip girdle, composed of two coxal bones, each made of three fused bones (ilium, ischium, and pubis); joined posteriorly to the sacrum and anteriorly at the pubic symphysis.

Acetabulum

The deep, cup-like socket of the coxal bone that articulates with the head of the femur to form the hip (coxal) joint.

Femur

The thigh bone; the longest, heaviest, and strongest bone in the human body, articulating with the acetabulum, tibia, and patella.

Tibia

The larger, medial bone of the leg that bears all the body's weight.

Fibula

The smaller, lateral bone of the leg that functions in stabilization and is non-weight bearing.

Calcaneus

The heel bone; recognized as the strongest and largest tarsal bone of the foot.

Talus

The tarsal bone that articulates directly with the tibia and fibula to form the ankle joint.

Hallux

The anatomical term for the big toe, containing only two phalanges compared to the three present in the other toes.