Skeletal System and Bones

Flashcards about the skeletal system and bones

Six anatomic and physiologic functions of bones

Protect internal tissues and organs, stabilize and support the body, provide surfaces for muscle attachment, move through lever action, produce red blood cells, store mineral salts

Axis (Latin)

Axle or wheel

Appendare (Latin)

To add or append

Axial skeleton

Forms the body’s vertical axis and contains 74 bones in the head and torso; also includes 6 bones of the middle ear, for a total of 80 bones.

Appendicular skeleton

Contains 126 bones and includes the body’s appendages, or upper and lower extremities

Axial skeleton

Forms the long axis of the body and includes bones of the skull, vertebral column, and rib cage.

Skull

Contains 28 irregular bones in two major areas: the brain case, or cranium, and the face.

Kranion (Greek)

Upper part of the head

Ossiculum (Latin)

Bone

Mandibula (Latin)

Jaw

Sutures

Immobile joints that hold the skull bones together

Coronal suture

Unites the frontal bone and the two parietal bones.

Sinuses

Air-filled spaces within the skull that lessen the bone weight, moisten incoming air, and act as resonating chambers for the voice.

Coronal suture

Connects the frontal bone with the parietal bones.

Squamous suture

Connects the parietal bones with the temporal bones.

Lambdoid suture

Connects the parietal bones to the occipital bone.

Occipital bone

Forms the rear portion and the base of the skull and forms a movable joint with the first cervical vertebra.

Foramen magnum

Large hole

Sphenoid bone

Located in the cranial floor, this bone is an anchor for the frontal, parietal, occipital, and ethmoid bones. It also supports part of the eye sockets and forms the lateral walls of the skull.

Maxillary bones

Form the upper jaw, nose, orbits, and roof of the mouth as well as the maxillary sinuses

Zygomatic or malar bones

Attach to chewing muscles

Nasal bones

Form the upper part of the bridge of the nose

Mandible

Forms the lower jaw

Lacrymal bones

Contain the lacrymal bag

Vomer

Part of the nasal septum

Palatine bones

Form the posterior portion of the hard palate, lateral side of the nasal cavity, and small part of the orbit.

Spinal column

Supports the head while suspending the ribs and organs in front. It also anchors the pelvic girdle and provides attachment points for many important muscles.

Spina (Latin)

Thorn

Sacrum

Was formerly known as the os sacrum, literally the holy bone

Coccyx

Derives its name from the Greek word for the cuckoo, kokkyx

Cervical (neck) vertebrae

Support the skull and rotate

Thoracic (chest) vertebrae

Attach to the ribs

Lumbar (lower back) vertebrae

Support the small of the back

Sacrum

A single bone that results from the fusion of five vertebrae and attaches to the pelvic girdle

Coccyx, or tailbone

Located at the bottom tip of the spinal column and is a single bone formed from the fusion of four or five vertebrae.

Sternum

Located in the center of the chest, the sternum is a flat, sword-shaped bone that’s attached to the clavicles (collarbones) and the innermost part of the first two pairs of ribs.

Thoracic cage, or thorax

The sternum, ribs, and thoracic vertebrae

Costal

The term costal refers to ribs

True ribs

Attached to the sternum by costal cartilage

False ribs

Aren’t attached directly to the sternum

Clavicles, or collarbones

Attached to the sternum on their anterior side and to the scapulae (shoulder blades) laterally. This forms the sternoclavicular joint.

Scapulae

A pair of large, triangular bones that are located at the back of the thorax. These bones, plus the clavicles, form the shoulder girdles.

Humerus

The upper arm bone

Ulna

Located on the little finger side of the humerus

Radius

Located on the thumb side

Carpel bones

Aligned in two rows. Ligaments bind the carpals together.

Metacarpal bones

Attach to the carpals and form the palm of the hand

Phalanges, or fingerbones

Miniature long bones

Three pairs of bones

Fused during childhood to form the pelvic girdle, the broadest bone in the body. This bone supports the trunk, protects the abdominal organs within its basin, and attaches the lower extremities to the body.

Ilium

The largest and uppermost of the three

Ischium

The lower and strongest set of bones

Pubis

A pair of anterior bones that meet at the symphysis pubis—a cartilaginous joint.

Femurs, or upper leg bones

The longest and heaviest bones in the body

Kneecap, or patella

A small, flat bone that protects the knee joint and overlaps the distal end of the femur and the proximal end of the tibia.

Tibia, sometimes called the shinbone

The largest and strongest of the lower leg bones

Articulation of the fibula, tibia, and talus bones

Creates the bony prominence on the outside of the ankle, called the lateral malleolus.

Talus bone (astragalus)

Forms part of the ankle joint

Heel, called the calcaneus

The largest tarsal bone

Scaphoid bone

Also called the navicular because of its boat shape

Cuneiforms (the lateral, intermediate, and medial)

Three wedge-shaped bones that form the arch of the foot.

Cuboid bone

Articulates in the front with the metatarsal bones.

Five metatarsal bones

Form the foot and articulate with the tarsal bone and the phalanges.

Long bones

The main bones of the limbs, except the patella, and those of the wrists and ankles.

Short bones

The bones of the wrists and ankles

Flat bones

Include the sternum, scapulae, and cranium, among others.

Irregular bones

Include the vertebrae and hip bones

Two types of bone material

An outer layer of dense, smooth compact bone and an inner layer of spongy, cancellous (porous) bone

Epiphysis

The end of a long bone where bone formation takes place

Osteoblasts

Add new tissue to the outside of a bone

Osteoclasts

Eat away bony tissue in the medullary cavity to keep the bone from becoming too thick.

Cartilage

A dense connective tissue that has these capabilities. It consists of fibers embedded in a strong, gel-like substance. Unlike rigid bone, cartilage has the flexibility of firm plastic.

Osteon

Greek for bone

Clast

To break or fragment

Os

Latin word os, or oss-, also meaning bone

Fibrous cartilage

Forms at the meniscus and the intervertebral disks.

Hyaline cartilage

Covers articular bone surfaces (where one or more bones meet at a joint), connects the ribs and sternum, and appears in the trachea, bronchi, and nasal septum.

Elastic cartilage

Located in the auditory canal, external ear, and epiglottis

Articulations

Joint sites

Synarthrosis

Immovable

Amphiarthrosis

Slightly movable

Diarthrosis

Freely movable

Fibrous joints

The articular surfaces of the two bones are bound closely by fibrous connective tissue and little movement is possible.

Cartilaginous joints

Cartilage connects one bone to another; these joints allow slight movement.

Synovial joints

Body surfaces are covered by articular cartilage and joined by ligaments lined with synovial membrane.

Ligaments

Dense, strong, flexible bands of fibrous connective tissue that bind bones to other bones

Articular capsule

A saclike envelope, whose outer layer is fibrous and whose inner layer is a synovial membrane