Skeletal System - Vocabulary Flashcards

Vocabulary flashcards covering the key terms, definitions, bone classifications, skeleton divisions, and joint structures from the lecture on the Skeletal System.

Bone Classifications

The five structural categories of bones based on their shape: long, short, flat, irregular, and sesamoid (round).

Acetabulum

The socket in the hip bone into which the head of the femur fits.

Amphiarthrosis

A slightly moveable joint, such as the pubic symphysis or the joint connecting ribs to the sternum.

Articulation

A joint formed between bones.

Calcitonin

A hormone that increases the mineralization of bone and thus reduces blood calcium levels.

Parathyroid Hormone (PTH)

A hormone that decreases calcium in the bone, which acts to increase the blood calcium level.

Hematopoiesis

The process of blood cell formation.

Diaphysis

The hollow tube or shaft of a long bone composed of hard compact bone.

Medullary Cavity

The hollow area inside the diaphysis of a long bone that contains yellow bone marrow.

Epiphyses

The ends of a long bone made of spongy bone that contains red bone marrow.

Diploe

The layer of spongy (cancellous) bone sandwiched between two layers of compact bone in flat bones.

Cartilage

A type of connective tissue consisting of embedded chondrocytes in a firm plastic or gristle-like gel matrix that provides flexible support.

Axial Skeleton

The division of the skeleton consisting of the bones of the skull, spine, thorax, and hyoid bone in the neck.

Appendicular Skeleton

The division of the skeleton comprising the upper extremities (shoulder girdle, arms, hands) and lower extremities (hip girdle, legs, feet).

Frontal Bone

The cranial bone that forms the forehead.

Parietal Bones

A pair of cranial bones ($2$) forming the posterior top and much of the side walls of the skull.

Temporal Bones

A pair of cranial bones ($2$) located on each side of the skull close to the ears.

Occipital Bone

The cranial bone located at the lower base and posterior part of the skull.

Sphenoid Bone

The cranial bone that forms part of the floor and sides of the cranium.

Ethmoid Bone

An irregularly shaped cranial bone located between the eye orbits that forms the roof and upper walls of the nasal cavities.

Cranial Bones

Bones that enclose and protect the brain, including the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones.

Paranasal Sinuses

Air cavities located within corresponding skull bones (frontal, maxillary, sphenoid, and ethmoid).

True Ribs

The upper $7$ pairs ($14$ total) of ribs that articulate directly with the sternum by costal cartilages.

False Ribs

The lower $5$ pairs ($10$ total) of ribs; the upper $3$ pairs attach to the sternum via the costal cartilage of the $7$th rib, while the lowest $2$ pairs do not attach.

Floating Ribs

The lowest $2$ pairs of false ribs that do not attach to the sternum.

Thorax

The chest structure consisting of $12$ pairs of ribs and the sternum.

Sternum

The dagger-shaped breastbone composed of three parts: the manubrium, body, and xiphoid process.

Vertebral Column

The spine made of $24$ individual vertebrae plus the sacrum and coccyx.

Cervical Vertebrae

The upper $7$ vertebrae located in the neck region; includes the atlas ($C1$) and axis ($C2$).

Thoracic Vertebrae

The $12$ vertebrae located in the chest region to which the ribs attach.

Lumbar Vertebrae

The $5$ vertebrae located in the small of the back, which are the largest and strongest of the vertebrae.

Sacrum

A bone at the base of the spine formed by $5$ separate vertebrae in a child that fuse into $1$ bone in an adult.

Coccyx

The tailbone formed by $3$ to $5$ separate vertebrae in a child that fuse into $1$ bone in an adult.

Atlas

The first cervical vertebra ($C1$) located in the neck region.

Axis

The second cervical vertebra ($C2$) located in the neck region.

Pelvic Girdle

The hip girdle structure comprising two coxal bones composed of the ilium, ischium, and pubis.

Ilium

The upper flaring part of the coxal (hip) bone.

Ischium

The lower back part of the coxal (hip) bone.

Pubic Bone

The lower front part of the coxal (hip) bone.

Humerus

The long bone of the upper arm.

Radius and Ulna

The two bones of the forearm: the radius on the lateral (thumb) side and the ulna on the medial (little finger) side.

Olecranon

The process of the ulna known as the elbow or 'funny bone'.

Carpal Bones

The $16$ short bones ($8$ in each wrist) located at the upper end of the hand.

Metacarpals

The $10$ bones ($5$ in each hand) forming the framework of the palm.

Phalanges

The finger bones ($28$ total in upper extremities) or toe bones ($28$ total in lower extremities), with three in each finger/smaller toe and two in each thumb/great toe.

Femur

The thigh bone, which articulates with the coxal bone in the acetabulum.

Patella

The kneecap; a type of sesamoid bone.

Tibia and Fibula

The lower leg bones consisting of the tibia (medial shinbone) and fibula (slender lateral bone).

Medial Malleolus

The rounded projection at the lower end of the tibia commonly called the inner anklebone.

Lateral Malleolus

The rounded projection at the lower end of the fibula commonly called the outer anklebone.

Tarsal Bones

The $14$ bones ($7$ in each ankle) forming the heel and back part of the foot, the largest of which is the calcaneus.

Calcaneus

The heel bone, which is the largest of the tarsal bones.

Synarthrosis

An immovable joint, such as cranial sutures.

Diarthrosis

A freely moveable joint characterized by a joint capsule, joint cavity, synovial membrane, and articular cartilage.

Synovial Membrane

The membrane lining the joint capsule in a diarthrotic joint that secretes lubricating fluid.

Bursa

A fluid-filled sac located near joints that acts as a cushion to reduce friction.

Hinge Joint

A diarthrotic joint that allows movement in only two directions, such as the elbow joint.

Pivot Joint

A diarthrotic joint in which a small projection of bone pivots in an arch of another bone.

Ball-and-Socket Joint

A diarthrotic joint in which a ball-shaped head of one bone fits into a concave socket of a second bone.

Saddle Joint

A diarthrotic joint whose articulating surfaces are shaped like a saddle, such as the carpometacarpal joint of the thumb.