xvii. musculoskeletal system

acetabulum

rounded depression, or socket, in the pelvis that joins the femur (thigh bone), forming the hip joint

acromion

outward extension of the shoulder blade forming the point of the shoulder; it overlies the shoulder joint and articulates with the clavicle

bone

dense, hard connective tissue composing the skeleton; examples are long (femur), short (carpals), flat (scapula), and sesamoid (patella); provides the framework on which the body is constructed, and protect and support internal organs; assist in movement

bone depression

opening or hollow region serving as a connection for bones, or as passageways for blood vessels and nerves; examples are fissure, foramen, fossa, and sinus

bone process

enlarged area that extends from bones; sometimes covered in articular cartilage (examples: bone head, condyle) and sometimes serving as an attachment for muscles, tendons, and ligaments (examples: epicondyle, trochanter, tubercle, and tuberosity)

calcium

one of the mineral constituents of bone

calcium phosphate

major calcium salt in bones

cancellous (spongy or trabecular bone

spongy, porous bone tissue in the inner part of a bone

cartilage

flexible, connective tissue; found in the immature skeleton, at the epiphyseal growth plate, and on joint surfaces (articular)

collagen

dense, connective tissue protein strands found in bone and other tissues, such as ligaments, tendons, and skin

compact (cortical) bone

hard, dense bone tissue, usually found around the outer portion (periosteum) of bones

cranial bones

skull bones: ethmoid, frontal, occipital, parietal, sphenoid, and temporal

diaphysis

shaft, or midportion, of a long bone

disc

flat, round, plate-like structure

intervertebral disc

a fibrocartilaginous structure between two vertebrae; between the body of one vertebra and the body of a vertebra beneath or above; provides flexibility and absorbs shocks to the vertebral column

epiphyseal plate

cartilaginous area at the ends of long bones where lengthwise growth takes place in the immature skeleton; calcifies and disappears when the bone has achieved full growth

epiphysis

each end of a long bone; the area beyond the epiphyseal plate

facial bones

bones of the face: lacrimal, mandibular, maxillary, nasal, vomer, and zygomatic

fontanelle

soft spot (incomplete bone formation) between the skull bones of an infant

foramen magnum

opening of the occipital bone through which the spinal cord passes

haversian canals

minute spaces filled with blood vessels; found in compact bone; contains yellow bone marrow

ligament

fibrous connective tissue that binds bones to other bones; bands, sheets, or strands located in and around joints; supports, strengthens, and stabilizes the joint

malleolus

round process on both sides of the ankle joint

manubrium

upper portion of the sternum; joins with the clavicle to form the sternoclavicular joint

mastoid process

rounded projection on the temporal bone behind the ear

medullary cavity

central, hollowed-out area in the shaft of a long bone

metaphysis

flared portion of a long bone, between the diaphysis (shaft) and the epiphyseal plate

olecranon

large process on the proximal end of the ulna at the elbow

orthopedist

medical doctor who specializes in bone, joint, and muscle conditions

osseous tissue

bone tissue

ossification

process of bone formation; gradual replacement of cartilage and its intracellular substance by immature bone cells and calcium deposits

osteoblast

bone cell that helps form bony tissue; immature osteocyte that produces bony tissue replacing cartilage during ossification

osteoclast

bone cell that absorbs and removes unwanted bony tissue; functions to reabsorb, or digest, bony tissue (bone phagocyte)

periosteum

membrane surrounding bones; rich in blood vessels and nerve tissue

phosphorus

mineral substance found in bones in combination with calcium

physiatrist

medical doctor specializing in rehabilitation

pubic symphysis

junction of the two pubic bones in the anterior of the pelvis; they are joined by a fibrocartilaginous disc

red bone marrow

soft spongy (cancellous) tissue found in the interior of flat bones, such as the hip bone and breastbone; site of hematopoiesis (formation of blood cells)

ribs

twelve pairs of curved bones that form the chest wall

true (costal) ribs

first 7 pairs of ribs; join with the sternum anteriorly (through cartilaginous attachments) and with the vertebral column posteriorly

false ribs

rib pairs 8 to 10; join with the vertebral column posteriorly but join the 7th pair anteriorly (instead of sternum)

floating ribs

rib pairs 11 and 12; completely free at their anterior ends

sella turcica

depression in the sphenoid bone where the pituitary gland is located

sinus

hollow air cavity within a bone; located in specific places within cranial and facial bones to lighten the skull, and warm and moisten air as it passes through

styloid process

pole-like process extending downward from the temporal bone on each side of the skull

suture (joint)

immovable joint between bones, such as the skull (cranium)

temporomandibular joint (TMJ)

connection on either side of the head between the temporal bone of the skull and mandibular bone of the jaw

tendon

fibrous connective tissue that binds muscles to bones

trabeculae

supporting latticework of bony fibers in cancellous (spongy) bone

vertebra

individual segment of the spine composed of the vertebral body, vertebral arch, spinous process, transverse process, and lamina, enclosing the neural canal and spinal cord

xiphoid process

lower, narrower portion of the sternum; attached to the ribs, diaphragm, and abdominal muscles

yellow bone marrow

fatty tissue found in the medullary cavity of most adult long bones

articular cartilage

smooth white tissue that covers the ends of bones at joints

articulation

any type of joint; place at which bones come together

bursa (plural: bursae)

sac of fluid near a joint; promotes smooth sliding of one tissue against another; serves as layers of lubrication between tissues

meniscus

crescent-shaped fibrocartilaginous structure, which helps provide cushion for a joint (such as the knee); helps to evenly transfer weight from one bone to another

synovial cavity

space between bones at a synovial joint; contains synovial fluid produced by the synovial membrane

synovial fluid

viscous (sticky) fluid within the synovial cavity; similar in viscosity to egg white

synovial joint

freely movable joint

synovial membrane

tissue lining the synovial cavity; it produces synovial fluid

abduction

movement away from the midline of the body

adduction

movement toward the midline of the body

dorsiflexion

upward movement of the foot; achieved through ankle motion

extension

straightening of a flexed limb; increasing the angle between the bones of a joint

fascia

fibrous membrane separating and enveloping muscles

flexion

bending a limb; decreasing the angle between bones

origin of a muscle

connection of the muscle to a stationary bone; usually proximal on the skeleton

plantar flexion

downward movement of the foot; achieved through ankle motion

pronation

turning the palm downward

rotation

circular movement around a central point; internal is toward the center of the body; external is away from the center of the body

striated muscle

muscle connected to bones; voluntary or skeletal muscle; its fibers (cells) have a pattern of dark and light bands of fibrils in the cytoplasm; fibers arranged in bundles

supination

turning the palm upward

visceral muscle

muscle connected to internal organs; involuntary or smooth muscle; forms sheet of fibers that wrap around tubes and vessels

muscle

attached to bones or internal organs; responsible for movement

rheumatologist

physician who (nonsurgical) specializes in joint problems (ex. arthritis)

physiatrist

medical doctor who focuses on rehabilitation after an injury or illness to muscles, bones, and nerves

osteopath

individual who has added training in the musculoskeletal system, with emphasis on body mechanics to promote good health

chiropractor

individual who has extensive and specialized training in using physical means to manipulate the spinal column, joints, and soft tissues

physical therapist

doctoral degree-prepared health care professional who develops a treatment plan based on a patient’s physical impairments with(out) a physician diagnosis

physical therapy (PT)

helps patients with movement disorders regain use of muscles and joints after injury or surgery; goals are to restore function, improve mobility, and relieve pain

athletic trainer

health care professional who works with a physician, provides therapeutic intervention, and rehabilitation of injuries and medical conditions

osteocyte

bone cell

osseous tissue consists of

1. osteocytes — bone cells

2. collagen — dense connective tissue strands

3. intracellular calcium salts

long bones

bones that are very strong, broad at ends where they join with other bones; have large surface areas for muscle attachment; found in the thigh, lower leg, and upper and lower arm

short bones

bones found in the wrist and ankle; small with irregular shapes

flat bones

bones that are small and rounded (resembling sesame seed); found near joints, and increase efficiency of tendons at particular joints; ex. kneecap (largest)

hematopoiesis

production of all types of blood cells in bone marrow

bone head

rounded end of a bone

condyle

rounded knuckle-like process, at the end of a bone

epicondyle

small rounded process above the condyle

trochanters

large and small processes for tendon attachments on the femur

tuberosity (tubercle)

round elevation where tendons and muscles attach on the humerus, calcaneous (heel bone), and pelvis

fissure

narrow groove or slit-like opening

foramen

opening for blood vessels and nerves

fossa

shallow cavity in or on a bone

ethmoid bone

supports the nasal cavity and eye sockets

frontal bone

forehead; part of the eye sockets

occipital bone

back and base of the skull

parietal bones

top and sides of the skull

sphenoid bone

base of the skull and the behind eyes (bat-shaped bone); joins with the frontal, occipital, and ethmoid bones, serving as an anchor to hold these skull bones together