Skeletal system

Review general terms for some structures on bones such as fissure, foramen, line, condyle, epicondlyle, fossa, process, tubercle, crest. There are 206 bones in the adult human body (after bones have fused). Bones are connected to other bones by joints or articulations. Contraction of muscles attached to bones causes voluntary movement. We will be discussing these next classes. Immovable joints in the skull are called sutures. Soft spots in an infant skull are called fontanels.

Axial skeleton

Skull

Cranium

Frontal bone-1

Parietal bones-2

Occipital bone-1

Temporal bones-2

Sphenoid-1

Ethmoid-1

(auditory ossicles-malleus, incus, stapes in middle ear to be discussed later with senses)-6

Face

Mandible-1

Maxillae-2

Zygomatic bones-2

Palentine bones-2

Nasal bones-2

Vomer-1

Lacrimal bones-2

Inferior nasal conchae-2

Hyoid-1

Vertebrae- 7 cervical, 12 thoracic, 5 lumbar, 1 sacrum fused from 5) and 1 coccyx (fused from 4)

Ribs- 24, 14 true (vertebrosternal); remainder false ribs are vertebrochondral or vertebral -floating)

Sternum (ends are manubrium and xiphoid process)-1

Appendicular skeleton

Shoulder girdle and Upper extremity

Clavicle-2

Scapula-2

Humerus-2

Radius-2

Ulna-2

Carpals (16) and metacarpals (10) with phalanges (28 )

Pelvic girdle and Lower extremity

Ileum, ischium, and pubis (6)- fuse to os coxae after puberty -2

Femur-2

Patellae (2)- form only after walking begins

Tibia (2) and fibula (2)

Tarsal bones-14

Metatarsal bones (10) with 28 phalanges

Articulations (joints) are a point of contact between 2 bones

Characterized by movement:

Synarthrosis (no movement

Ampharthrosis (limited movement)

Diarthrosis (freely moveable

Characterized by type of connective tissue (cartilage, fibrous, or synovial)

Fibrous (fixed or limited movement)

Sutures- ossified teethlike projectins- skull only

Gomphosies- between teeth and mandible or maxillae

Syndesmoses (attach two bones such as the radius and ulna)

Cartilage- limited movement

Symphyses- connected by fibrous cartilage (pubic bones, vertebral discs)

Synchrondoses-connected by hyaline cartilage- (diaphysis and epiphyses of bones, ribs and

sternum)

Synovial joints- freely moveable joints with articular cartilage at the ends of bones. Joint is enclosed in a joint capsule. There may be menisci (disks of cartilage between the epiphyses. Ligaments connect the epiphyises. A synovial membrane within bursae inside the joint capsule secretes lubricating synovial fluid.

Types of synovial joint-

Uniaxial joints such as hinge joint (elbow or knee) or pivot joints (such as atlas-axis)- move in one plane

Biaxial joints move in two planes. Examples are saddle joint (thumb) and condyloid joints

(atlantooccipital)

Multiaxial move in three or more planes. Ball-and-socket joint. Discuss hip vs. shoulder joint

Types of movement:

Flexion- decreases the angle of a joint

Extension- increases the angle of a joint

Rotation- moves around an axis

Circumduction- end moves in a circle

Adduction- apart moves toward the center

Abduction- movement of a part away from the center

Elevation- raising a part

Depression- lowering a part

Supination- palm up

Pronation- palm down

Plantar flexion- toes pointed down

(plantar) dorsiflexion) toes pointed up

Inversion- soles of feet pointed inward

Eversion- soles pointed outward

Protraction- pushing a part forward

Retraction- pulling a part backward

Specific joints

Knee- locate ACL, PCL, M (tibial) CL, LCL (fibular), quadriceps femoris tendon, patellar ligament

Hip- locate ischiofemoral, pubofemoral, iliofemoral ligaments, ligament of head of femur

Elbow- locate annular radial collateral, and ulnar collateral ligaments and tendon of biceps brachii

Shoulder- identify coracohumeral, glenohumeral, coracoacromial, coracoclavicular, acromioclavicular ligaments, biceps brachii tendon, and tendons of rotator cuff muscles