Skeletal System Ch. 8

In addition to shaping us up the skeletal system performs other functions:

- The bones in the lower extremities support the weight of the body. - The bones support and protect the soft body organs. - With assistance of the muscles, the skeletal system enables the body to move about. - Bones store a number of minerals; the most important are calcium and phosphorus. - Red bone marrow produces blood cells.

Phalanges

14 finger bones, or digits. Each digit has three bones except the thumb (pollex) which only has 2 bones.

Metacarpal Bones

5 bones form the palm of the hand , each metacarpal bone is in line with the finger.

Hyoid Bone

A U-shaped bone located in the upper neck.

Cranium

A bony structure that encases and protects the brain.

Sphenoid Bone

A butterfly shaped bone that forms part of the floor and sides of the cranium. The sphenoid bone forms part of the orbits surrounding the eyes.

Circumduction

A combination of movements, as in the circular arm movement that a softball pitcher makes while pitching the ball.

Sternum (breastbone)

A dagger-shaped bone located along the midline of the anterior chest.

Olecranon Fossa

A depression of the humerus that holds the olecranon process of the ulna when the elbow is extended. (not bent)

Suprasternal Notch (Jugular Notch)

A depression on the upper part of the manubrium between the two clavicles; it is used as a landmark to locate other structures.

Epiphyseal Disc

A growing long bone, contains a band of hyaline cartilage located near the proximal and distal ends of the long bones. This band of cartilage is the epiphyseal disc or growth plate. It is here that the longitudinal bone growth occurs.

Haversian (osteon)

A haversian canal with the laminae of bone that surround it.

Scapula (shoulder blade or wing bone)

A large flat bone, shaped like a triangle. The two scapulae are located on the posterior thorax. Two large processes on the scapula allow it to articulate with the clavicle and serve as points of attachment for the arm and chest muscles.

Obturator Foramen

A large hole, formed as the pubic bone fuses with the part of the ischium. The obturator is the LARGEST foramen in the body.

Fibula

A long, thin bone positioned laterally along side the tibia in the leg. The proximal end of the fibula articulates with the tibia. It does not articulate with the femur, is not part of the knee, and does not bear any body weight. the lower end forms the LATERAL MALLEOLUS, which articulates with the outer ankle bones.

Styloid Process

A sharp projection used as a point of attachment for several muscles associated with the tongue and larynx.

Thorax

A term that refers to the chest region.

Periosteum

A tough, fibrous, connective tissue membrane that covers the outside of the diaphysis. It is anchored firmly to the outside of the bone on all surfaces except the articular cartilage. The periosteum protects the bone, serves as a point of attachment for muscle, and contains the blood vessels that nourish the underlying bone. Because the periosteum carries the blood supply to the underlying bone, any injury to this structure has serious consequences to the health of the bone. Like an other organ, the loss of blood supply can cause it's death.

Sinuses

Air filled cavities located in several of the bones of the skull. They also perform two important functions. First they lessen the weight of the skull. Second they modulate the sound of the voice.

Synovial Joints

All freely movable joints.

Pivot Joint

Allows for rotation around the length of a bone. The pivot joint allows only for rotation. (side to side movement, "no")

Hinge Joint

Allows movement similar to the movement of two boards joined together by a hinge. The hinge allows movement in one direction, where the angle at the hinge increases or decreases. Hinge joints include the elbows, knees, and fingers.

Lordosis

An exaggerated lumbar curvature and it is sometimes called a swayback.

Kyphosis

An exaggerated thoracic curvature, it too can impair breathing. Also called a HUNCHBACK.

External Auditory Meatus

An opening for the ear

True Ribs

Anteriorly, the top seven pairs of ribs attach directly to the sternum by costal cartilage.

Humerus

Arm bone

Medial Malleolus

At the distal end of the tibia, a protuberance, articulates with the inner ankle bones.

Plantar Flexion

Bending the foot down, as in toe dancing.

Osteoblasts

Bone cells that secrete an intercellular matrix, containing calcium, other minerals, and protein fibers. Osteoblasts mature into osteocytes that sit within the hard bone matrix and maintain the bone.

Osteoblasts

Bone forming cells

Rheumatology

Branch of medicine that studies disease of the joints.

Arthrology

Branch of science that studies joints.

Temporomandibular Joint (TMJ)

Can be felt as the depression immediately in front of the ear. Tension or stress often causes pain in the TMJ. This condition is often associated with tooth grinding (bruxism) during sleep. Bony processes on the mandible serve as points of attachment for the chewing muscles.

Maxilla

Carries the upper teeth. An extension of the maxilla, the palatine process, forms the anterior portion of the hard palate (roof) of the mouth. These bones also form parts of the nasal cavity and the eye orbits.

Pelvic Girdle

Composed of two coxal bones that articulate with each other anteriorly and with the sacrum posteriorly. The pelvic girdle performs three functions (1) it bears the weight of the body (2) It serves as a place of attachment for the thighs (3) it protects the organs located in the pelvic cavity, including the urinary bladder and reproductive organs.

Shoulder Girdle (pectoral girdle)

Contains two bones, one clavicle and one scapula. it supports the upper limbs and serves as a place of attachment for the muscles. It is designed for great flexibility.

Irregular Bones

Differently shaped and are not classified as long, short, or flat. They include hip bones, vertebrae, and various bones in the skull.

False Ribs

Five pairs of ribs that attach indirectly to the sternum or do not attach at all. The bottom two pairs of false ribs lack sternal attachment and therefore called floating ribs.

Sacrum

Five sacral vertebrae fuse into one sacrum. The sacrum forms the posterior wall of the pelvis.

Flat Bones

Flat bones are thin, flat, and curved. They form the ribs, breastbone, skull, and the bones of the shoulder girdle.

Palatine Bones

Form the posterior part of the hard palate and the floor of the nasal cavity.

Pelvis

Formed by the pelvic girdle, sacrum, and coccyx

Ball and socket Joint

Formed when the ball shaped end of one bone fits into the cup shaped socket of another bone, so that the bones can move in many directions around a central point. The shoulder and hip joints are ball and socket joints.

Condyloid Joint

Formed when the oval shaped articular surface of one bone fits into the oval shaped depression of the second articulating bone. The radiocarpal joint (wrist) and the metacarpophalangeal joints (knuckles) at the bases of the fingers are examples of condyloid joints.

Mastoid Process

Forms a point of attachment for some of the muscles of the neck.

Coccyx (tailbone)

Four small vertebrae fuse into the tailbone. It is called the coccyx because it resembles the beak of a cuckoo bird.

Calcaneus

Heel bone

Coxal Bone

Hipbone. Each coxal bone is composed of three parts the ilium, ischium, and pubis. The three bones join together to form the acetabulum.

Hydrocephalus

If excessive fluid accumulates within the brain of an infant, the bones are forced apart, and the skull enlarges. (aka water on the brain)

Acetabulum

Important because it receives the head of the femur and therefore enables the thigh to rotate at the hip joint.

Sella Turcica

In the midline of the sphenoid bone is a depression called Sella Turcica (turk's saddle) it forms the seat for the pituitary gland.

Axial Skeleton

Includes the bones of the cranium, face, middle ear bones, hyoid bone, vertebral column, and bony thorax.

Appendicular Skeleton

Includes the bones of the pelvic girdle, the upper extremities (arms, forearms, wrists, palms, and fingers) and lower extremities (thighs, legs, ankles, instep, and toes).

Articulation (A joint)

Is the site where two bones meet. Joints perform two functions they hold the bones together and the provide flexibility to a rigid skeleton.

Clavicle (collar bone)

It looks like a long, slender, S-shaped rod and articulates with both the sternum and scapula. It helps to stabilize the shoulder. The attachment is weak and is easily dislocated or broken. * The CLAVICLE is the MOST frequently broken bone in the body.

Patella

Kneecap

True Pelvis

Lies below the false pelvis and is much smaller. The true pelvis is a ring formed by fusion of the pelvic bones, it is aka the pelvic brim. The true pelvis has an inlet and outlet area.

Synovial Membrane

Lining the joint capsule is the synovial membrane. This membrane secretes synovial fluid into the joint cavity.

Intercostal muscles

Located between the ribs, contraction of these muscles helps move the thoracic cage during breathing.

Bursae

Many synovial joints contain bursae (singular bursa) Bursae are small sacs of synovial fluid between the joint and the tendons that cross over the joint. Bursae permit the tendons to slide and the bones to move. Excessive use of the joint may cause painful inflammation of the bursae, called bursitis.

Abduction

Movement away from the midline of the body (move your leg sideways AWAY from your body)

Condyles

On either side of the foramen magnum are bony projections called occipital condyles, that sit on the first vertebra of the vertebral column.

Glenoid Cavity

On the scapula is the site where the head of the humerus (arm bone) fits, therby allowing you to rotate your arm at the shoulder.

Glenoid Cavity

On the scapula is the site where the head of the humerus fits, thereby allowing you to rotate your arm at the shoulder.

Acromion & Coracoid Process

On the scapula near the glenoid cavity. Both processes serve as a point of attachment for the ligaments and muscles. The acromion process forms the "pointy" part of the shoulder.

Radius

One of the two bones in the forearm. The longer of the two bones, the ulna is located on the medial or little finger side of the forearm.

Hyperextension

Over extending the joint beyond it's normally straightened position, as in moving the hand toward the upper surface of the wrist.

Greater and Lesser Trochanters

Provide sites of attachment for many muscles.

Scoliosis

Refers to a lateral curvature, usually involving the thoracic vertebrae. If severe, a lateral curvature can compress abdominal organs. it can also diminish expansion of the ribcage and therefore impair breathing.

Compact Bone

Refers to dense, hard bone tissue found primarily in the shafts of long bones and on the outer surfaces of other bones.

Spina Bifida

Refers to the failure of the lamina to fuse during fetal development. The vertebral defect allows the spinal cord to protrude onto the surface of the back. Compression of the spinal cord then causes paralysis and loss of bladder and bowel control.

Ulna

Second bone in the forearm. The longer of the two bones, the ulna is located on the medial or little finger side of the forearm.

Short Bones

Short bones are shaped like cubes and are found primarily in the wrists and ankles.

Supporting Ligaments

Surrounding the joint are supporting ligaments. These ligaments join the articulating bones together and stabilize the joint. Sometimes a ligament is stretched or torn, causing pain and loss of mobility.

False pelvis

The area surrounded by flaring parts of the two iliac bones.

Articular Cartilage

The articulating surface of each of the two bones is lined with articular cartilage, forming a smooth surface within the joint.

Flexion

The bending of a joint that decreases the angle between the bones ( bending the leg at the knee or the fingers)

Suture

The bones of the adult skull form a unique type of joint. The sutures join the bones of the skull, muych like a zipper. The major sutures include the coronal suture, the lambdoidal suture, and the squamosal suture.

Zygomatic Bones

The cheek bones. They also form a part of the orbits of the eyes.

Costal Margins

The edges of the cartilage that form an angle as they converge near the xiphoid process. The angle should be less than 90 degrees.

Epiphysis

The enlarged ends of the long bone. It articulates, or meets, with a second bone at the joint. Each epiphysis consists of a thin layer of compact bone overlying spongy bone. The epiphysis are covered by cartilage.

Atlas

The first cervical vertebra (C1). It has no body but does have depressions into which fit the bony projections of the occipital bone of the skull.

Paranasal Sinuses

The four sinuses surround and connect with nasal structures. The names of the four sinuses reflect their location within the various skull bones- frontal sinuses, - ethmoidal sinuses, sphenoidal sinuses, and maxillary sinuses.

Hallux

The great toe.

Medullary Cavity

The hollow center of the diaphysis. In infancy, the cavity is filled with red bone marrow for blood cell production. In adult, the medullary cavity is filled with yellow bone marrow and functions as a storage site for fat.

Endosteum

The inside of the medullary cavity is lined with connective tissue.

Metatarsal Bones

The instep of the foot is formed by five metatarsal bones.

Foramen Magnum

The large hole in the occipital bone.

Vertebra Prominens

The large vertebrae C7, used as a landmark in assessing surface anatomy.

Ilium

The largest part of the coxal bone. The ilium is the flared upper part of the bone and can be felt at the hip. The outer edge of the ilium is called the iliac crest. The ilium connects in the back with the sacrum, forming the sacroiliac joint.

Mandible

The lower jaw bon, carries the lower teeth. The anterior portion of the mandible forms the only freely movable joint in the skull. Two posterior upright projections on the mandible have bony processes. These articulate with the temporal bones at the temporomandibular joint. (TMJ)

Ischium

The most inferior part of the coxal bone. The ischium contains three important structures, the ischial tuberosity, ischial spine, and lesser sciatic notch. The ischial tuberosity is the part of the coxal bone on which you sit.

Talus

The most proximal of the tarsal , articulates with the tibia and fibula.

Vertebral Foramen

The opening for the spinal cord. The vertebral foramen of all the vertebrae form the vertebral canal.

Ossification

The process of bone formation, it begins in the late embryonic period, with the formation of fibrous connective tissue and hyaline cartilage that is shaped like a mini-skeleton.

Ossification

The process of bone formation.

Fontanels

The rhythm of the baby's pulse can felt in these soft spots and they are called fontanels meaning little fountains.

Axis

The second cervical vertebra (C2). It has a projection, called the dens which fits into the Atlas and acts like a pivot or swivel for the Atlas. (It allows your head to rotate from side to side like when you say "No".

Tibia

The shinbone and articulates with the femur at the knee. The tibia is the largest weight bearing bone in the leg.

Thoracic Cage

The skeletal part of the chest, it is a bony, cone-shaped cage that surrounds and protects the lungs, heart, large blood vessels, and some of the abdominal organs, such as the liver and spleen. It plays a crucial role in breathing and helps support the bones of the shoulder. It is composed of the sternum, ribs, and thoracic vertebrae.

Femur

The thigh bone, it is the LONGEST and STRONGEST bone in the body.

Xiphoid Process

The tip of the sternum and serves as a point of attachment for some abdominal muscles. It is also a landmark for CPR.

Parietal Bones

The two parietal bones form the upper sides of the head and roof of the cranial cavity (top of the head)

Temporal Bones

The two temporal bones are on the sides of the head, close to the ears (commonly called temples) several important bone markings are found on the temporal bones.

Manubrium

The uppermost segment of the sternum that is somewhat triangular flattened bone with anterolateral borders which articulate with clavicles.

Spine (Vertebral Column)

The vertebrae becomes larger as the vertebral column descends. The larger vertebrae support a heavier load. The vertebrae are aligned so that if you run your hand down your back, you will feel the spinal processes.

Carpal Bones

The wrist contains 8 bones, which are tightly bound by ligaments.

Supination

Turning the hand so that the palms face upward.

Eversion

Turning the sole of the foot outward

Olecrannon Process

What you feel as the bony point of the elbow.

Microcephalia

When the sutures of the brain fuse too early, preventing the growth of the brain. It is characterized by a small cranium, restricted brain growth, and impaired intellectual functioning.

Tibial Tuberosity

a protuberance, is the site of attachment for muscles and ligaments from the thigh.

Ethmoid Bone

an irregularly shaped bone located between the eye orbits. It is the major supporting bony structure of the nasal cavity.

Dorsiflexion

bending the foot up toward the leg.

Oetoclasts

cells that cause break down of a bone

Vertebral Column (back bone)

extends from the skull to the pelvis. It consists of 26 bones called vertebrae stacked in a column.

Zygomatic process

forms part of the cheek bone

Frontal Bone

forms the forehead and the upper part of the bony structure surrounding the eyes.

Articular Cartilage

found on the outer surface of the epiphysis. It forms a smooth, shiny surface that decreases friction within a joint. Because a joint is also called an articulation, this cartilage is called articular cartilage.

Trabeculae

in spongy bone, the bone tissue is arranged in plates.

Joint Capsule

is made of fibrous connective tissue. It encloses the joint in a strong sleeve like covering.

Spongy or Cancellous Bone

less dense, located primarily at the ends of long bones and in the center of other bones

Occipital Bone

located at the back and the base of the cranium

Diaphysis

long shaft of the bone. It is composed primarily of compact bone and therefore provides considerable strength.

Synovial Fluid

lubricates the bones in the joint, thereby decreasing the friction within the joint. Synovial fluid gets its name from the ovum or egg, because the thick consistency of an egg white.

Pubis

most anterior part of the coxal bone. Two pubic bones join together in front as the SYMPHYSIS PUBIS.

Adduction

movement toward the midline of the body

Bone

osseous tissue

Bone Resorption

process whereby osteoclasts breakdown bone matrix

Extension

the straightening of a joint so that the angle between the bones increases (ex straightening the leg at the knee or the fingers to open the hand)

Long Bones

they are longer than they are wide. They are found in the arms, forearms, palms, fingers, thighs, legs, and instep. It is obvious that the femur (thigh) and the humerus (arm) are long bones, even small bones such as metacarpals and finger bones are considered long bones.

Ossicles

three small bones within each ear

Pronation

turning the hand so that the palms face downward

Inversion

turning the sole of the foot inward so that it faces the opposite foot