iCEV Slides - The Skeletal System

Flashcards reviewing iCEV's slides on the skeletal system.

Skeletal system

The body’s framework of bones, providing structural support to the body and protecting vital organs

Types of skeletal tissue

Bone, cartilage, and ligaments

Types of bone

Cortical (compact) and cancellous (spongy)

Cortical bone (compact bone)

The hard, dense outer layer of a bone

Cancellous bone (spongy bone)

The lighter, porous inner layer of a bone

Periosteum

The thin outer layer of a bone

Diaphysis

The shaft extending throughout the middle of the bone containing the medullary cavity lined with endosteum

Epiphyses

Ends containing cancellous bone covered with hyaline cartilage for growth

Bone marrow

Cells in the medullary cavity which can become platelets or red or white blood cells

Medullary cavity

Cavity in the diaphysis (middle) of a bone that holds the bone marrow

Types of bone cells

Osteoblasts, osteocytes, and osteoclasts

Osteoblasts

Cells that develop bone matrix through ossification

Osteocytes

Mature, inactive osteoblasts incorporated into mature bone

Osteoclasts

Cells that break down old or damaged bone

Types of bone shapes

Long, short, flat, irregular, and sesamoid (classified by shape and function)

Long bones

Hard, dense bones which provide strength, structure, and mobility—have a diaphysis and two epiphyses; types invlude the humuerus, radius and ulna, femur, and tibia and fibula

Short bones

Cube-like bones that do not contain a diaphysis and contain almost entirely cancellous (spongy) tissue; includes carpals and tarsals

Flat bones

Thin, broad, and often curved bones with a cancellous bone layer sandwiched between two layers of cortical bone; protects internal organs and allows for attachment

Types include the skull, sternum, and ilium

Irregular bones

Bones that are not uniform in shape with different types of surfaces; includes the vertebrae, sacrum, and coccyx

Sesamoid bones

Bones developed and embedded inside tendons that vary in shape and serve to protect the tendons

Tendons

Tough, flexible connective tissue connecting bones to muscles

Articulation

Where two bones meet

Head

The rounded surface of an articulation

Crest

A ridge on a bone

Condyle

A rounded surface on a bone

Projection

A raised marking on a bone

Process

A prominent feature on a bone

Fossa

A shallow depression on a bone

Foramen

A hole in a bone

Cartilage

A flexible connective tissue found in elbows, knees, and ankles, enhancing bone strength and providing support for the joints

Hyaline cartilage

Glassy cartilage which reduces friction and absorbs shock on most joint surfaces

Fibrocartilage

The strongest type of cartilage which provides ridigity and absorbs shock; lines bony grooves

Elastic cartilage

The most flexible type of cartilage; it provides shape and support and is found in the ears, nose, and parts of the respiratory system

Ligaments

Tough, dense, and fibrous connective tissue that form connections among bone and cartilage to stabilize joints

Human skeleton

Contains 206 bones with the axial and appendicular skeleton

Axial skeleton

Forms the central axis of the body; supports the brain, spinal cord, and organs

Includes the skull, vertebral column, sternum, and ribs

Skull

Consists of 22 bones forming the head; 8 form the cranial cavity and 14 form the facial bones

Cranial cavity

Cavity made of 8 bones that protects the brain

Facial bones

14 bones that form the face to provide sensory organ cavities for the eyes, nose, and mouth

Consists of:

• two zygomatic (cheek) bones

• two lacrimal (tear duct) bones

• two nasal (nose bridge) bones

• two inferior nasal (below nose) bones

• vomer (nose)

• two maxillary (upper jaw) bones

• mandible (lower jaw)

Cranial bones

Consists of:

• the frontal bone

• two parietal bones

• two temporal bones

• the occipital bone

• the sphenoid bone

• the ethmoid bone (inside)

Vertebral column

Also called the spinal column or spine, it is a curved structure of 26 irregular bones including the cervical, thoracic, and lumbar vertebrae, as well as the sacrum and coccyx

Cervical vertebrae

The top seven vertebrae of the neck for flexibility, notated as C1 to C7

Thoracic vertebrae

The twelve vertebrae below the cervical neck vertebrae, has overlapping spinous processes for stability and attaches to ribs

Lumbar vertebrae

The largest and strongest vertebrae to support the weight of the upper body

Thoracic cage

Also known as the rib cage, it forms the thoracic cavity to enclose and protect organs of the chest with 12 pairs of ribs and the sternum

Sternum

A narrow, flat bone at the body’s midline about six inches long formed by the manubrium, body, and xiphoid process bones; it attahces to the ribs

Manubrium

The widest and most superior portion of the sternum

Body (corpus)

The elongated middle portion of the sternum

Xiphoid process

The smallest and most inferior portion of the sternum; it is initially cartilaginous and ossifies gradually

Appendicular skeleton

Consists of symmetrical pairs of bones on either side of the axial skeleton; includes the clavicles, upper and lower limbs, and pelvis

Clavicle

A long bone with a slight S-curve in the anterior shoulder to transfer force and allow motion from the arm to the trunk

Scapula

A flat, triangular-shaped bone forming the posterior shoulder surrounded by muscle to anchor the arms

Upper limbs

Limbs attached to the pectoral girdle at the scapula, made of 30 bones with:

• the arm (humerus)

• the forearm (ulna and radius)

• the hand (8 carpals, 5 metacarpals, and 14 phalanges)

Carpal bones

Short bones in the wrist and base of the hand

Metacarpal bones

Long bones forming the palm of the hand

Phalanges (fingers)

Long bones forming the digits divided into proximal, middle, and distal sections

Pelvic girdle

Sometimes referred to as the hip; is a large, curved bone formed by the fusion of three bones (ilium, pubis, and ischium)

Ilium

The flat, superior, and largest portion of the pelvis attached to the sacrum and the sacroiliac joint

Pubis

The anterior portion of the pelvis; is a V-shaped bone

Ischium

The roughly arc-shaped bone in the pelvis; the posteroinferior (lower back) portion

Lower limbs

Consists of 30 bones in the three regions with the:

• thigh (femur)

• leg (patella, tibia, and fibula)

• foot (tarsals, metatarsals, and phalanges)

Tarsal bones

The short bones in the ankle organized in three rows

Metatarsal bones

Long bones along the foot; the distal tarsal bones to the proximal phalanges

Phalanges (toes)

Long bones forming the toes

Calcaneus

The longest bone in the foot; it is also called the heel bone and transmits force to the ground

Joints

Also known as articulations, these are where two bones come together to support body movement

Joint functional classifications

Synarthrosis, amphiarthrosis, and diarthrosis

Synarthrosis

Joints that are nearly immobile, such as the sutures of the skull

Amphiarthrosis

Joints that provide limited mobility, such as the pubic symphysis of the pelvis

Diarthrosis

Joints that provide the greatest range of motion and are the most common, such as the elbow, shoulder, or ankle

Joint structural classifications

Fibrous, cartilaginous, and synovial joints

Fibrous joints

Joints joining bones by fibrous connective tissue, most commonly synarthroses (immovable)

Cartilaginous joints

Joints joining bones by hyaline cartilage or fibrocartilage; are mainly amphiarthroses (somewhat movable)

Synovial joints

Joints joining bones through a joint cavity with synovial fluid; are most common diarthroses (very movable)

Flexion

The decrease of the angle between two bones of a joint

Extension

The increaes of the angle between two bones of a joint

Adduction

Movement towards the body’s midline

Abduction

Movement away from the body’s midline

Circumduction

Movement of a limb in a circle (circumference)

Rotation

The movement of a limb around an axis (turn arm)

Inversion

The tilting of the foot towards the midline

Eversion

The tilting of the foot away from the midline

Synovial joint classifications

Can be further divded based on movement, such as:

• ball and socket joint

• pivot joint

• hinge joint

• saddle joint

• plane joint

• condyloid (ellipsoid) joint

Ball-and-socket joints

Rounded surface of a bone within a depression in another bone, allowing for the most movement in all axes; includes the shoulder and hip

Pivot joints

Rounded portion of a bone enclosed in a ring shape of another bone held in place by a ligament; allows rotational movement in the neck and radius and ulna

Hinge joints

Formed by a convex edge of one bone fitting into a concave edge; allows for flexion and extension in the elbow, knee, and ankle

Saddle joints

Formed by two joints with concave and convex regions allowing flexion, extension, abduction, and adduction in the thumbs and inner ears

Plane joints

Formed by two sliding flat bones allowing for inversion, eversion, flexion, and extension in the vertebrae, metacarpals, and metatarsals

Condyloid joints

Also called ellipsoid joints, they are formed by egg-shaped bones in a similarly shaped socket allowing for flexion, extension, abduction, and adduction in the wrist, fingers, and jaw