Facts on File Encyclopedia of Health and Medicine

This section, “The Musculoskeletal System,” pres-
ent a discussion of the structure and function of
the bones, muscles, and other connective tissues.
It also contains entries about the health condi-
tions that can affect musculoskeletal function.The
section “The Nervous System” contains entries for
conditions that affect musculoskeletal function
but are primarily neurologic in nature.

Structures of the Musculoskeletal System

Bones
axial SKELETON: 80 bones spine: 26
head (cranium): 8 ervical vertebrae 7
frontal 2 thoracic vertebrae 12
parietal 1 lumbar vertebrae 5
temporal 2 sacrum 1
occipital 1 coccyx 1
ethmoid 1 sternum: 1
sphenoid 1 ribs: 24
auditory ossicles: 6 12 pairs each side
malleus 1 each ear appendicular skeleton: 120 bones
incus 1 each ear clavicle (collarbone): 2
stapes 1 each ear scapula (shoulder blade): 2
face: 14 upper arm: 2
lacrimal 2 humerus 1 each arm
nasal 2 lower arm: 4
zygoma 2 radius 1 each arm
turbinate 2 ulna 1 each arm
vomer 1 carpal (wrist): 16
maxilla 2 scaphoid 1 each wrist
palate 2 lunate 1 each wrist
mandible 1 triquetrum 1 each wrist
hyoid: 1 pisiform 1 each wrist

trapezium 1 each wrist bicuspid 4 top, 4 bottom,

trapezoid 1 each wrist in pairs on each side

capitate 1 each wrist of MOUTH

hamate 1 each wrist molar 6 top, 6 bottom,

metacarpal (hand): 10 3 at the back of each

5 each hand side of mouth

phalanx (finger): 28

14 each hand Major Skeletal Muscles

innominate (pelvis): 2 head, neck, and shoulders

fusion of ilium, ischium, frontalis

pubis 1 each side orbicularis oculi

upper leg: 2 masseter

femur 1 each leg temporalis

patella (kneecap): 2 medial pterygoid

1 each leg trapezius

lower leg: 4 semispinalis capitis

fibula 1 each leg splenis capitis

tibia 1 each leg sternocleidomastoid

tarsal (ankle): 14 arm

talus 1 each ankle deltoid

calcaneus 1 each ankle biceps

navicular 1 each ankle triceps

cuboid 1 each ankle brachialis

cuneiform 3 each ankle brachioradialis

metatarsal (foot): 10 palmaris longus

5 each foot extensor carpi radialis

phalanx (toe): 28 flexor carpi radialis

14 each foot extensor carpi ulnaris

TEETH(permanent): 32 flexor carpi radialis

incisor 4 top, 4 bottom, extensor digitorum

front center of mouth lexor digitorum

cuspid 2 top, 2 bottom, abductor pollicis brevis

each side of mouth abductor pollicis longus

THE MUSCULOSKELETAL SYSTEM

The musculoskeletal system encompasses the bones, muscles, tendons, ligaments, and fasciae. Practitioners who diag-
nose and treat health conditions of the musculoskeletal system are orthopedists (also called orthopedic surgeons).
Orthopedists may further specialize in sports medicine or physiatry (rehabilitative medicine).

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