Lab 9: The Skeletal System

Question 1

What makes up the skeletal system?

Answer 1

The entire framework of bones and their cartilages, joints and ligaments

Question 2

How many bones does a human have?

How many in each of the 2 skeleton systems?

Answer 2

206 named bones.

• axial skeleton (80) skull, vertebral column and thoracic cage.
• appendicular skeleton (126) upper/lower limbs, girdles

Question 3

5 types of bones

• how are they classified?
• location

Answer 3

Classified: based on their shape

long

• Cylinder-like shape, longer than it is wide
• Femur, tibia, fibula, metatarsals, humerus, ulna, radius, metacarpals, phalanges

short

• Cube-like shape, approximately equal in length, width, and thickness
• Carpals, tarsals

flat

• Thin and curved
• Sternum, ribs, scapulae, cranial bones

irregular

• Complex shape
• Vertebrae, facial bones

sesamoid

• Small and round; embedded in tendons
• Patellae

Question 4

fontanels

-function?

Answer 4

• areas of fibrous connective tissue stil exist between the cranial bones at birth.
• “soft spots” of a baby’s skull
• provide flexibility for the skull to compress as it passes through the birth canal

Question 5

Sutures

-how many in adults

Answer 5

• immoveable joints in the adult skull

* four major ones: coronal, sagittal, squamous, and lambdoid sutures

Question 6

Function of facial bones

Answer 6

form the face, hold the teeth and anchor the muscles of facial expression.

Question 7

What is the only movable bone in the skull?

Answer 7

mandible

Question 8

Which structure passes through the foramen magnum?

Answer 8

spinal chord

Question 9

The occipital condyles rest upon which bone?

Answer 9

atlas vertebra

Question 10

How many bones form the face? Name them.

Answer 10

14 Bones:

Maxilla (2)
Zygomatic (2)
Mandible (1)
Nasal (2)
Palatine (2)
Inferior nasal concha (2)
Lacrimal (2)
Vomer (1)

Question 11

How many bones form the eye orbit? Name them.

Answer 11

7 Bones:

maxilla
zygomatic bone
lacrimal bone
palatine bone
frontal bone
ethmoid bone  
sphenoid bone

Question 12

Hyoid Bone

Answer 12

• isolated U-shaped bone, just below the mandible
• function: attachment point for the muscles of the tongue and larynx
• only bone of the body that does not directly articulate with any other bone.

Question 13

vertebral column

Answer 13

Function
• protect spinal cord
• supports head
• attachment point for ribs/pelvic girdle/muscles of the neck and back.

Question 14

Function of the curvature (S-shape) in the vertebral column

Answer 14

• increase its strength
• help maintain balance when upright
• absorb shocks when moving
• help protect the vertebrae from fracture

Question 15

Cervical Vertebrae

Answer 15

• 7 vertebrae
• smallest and lightest
• first are: atlas: & axis
• transverse foramen
• spinous process is bifid (Except C1, C2 and C7)

Question 16

Atlas

Answer 16

• C1

* allow you to nod your head “yes”.

Question 17

Axis

Answer 17

• C2
• dens or odontoid process
• allows you to shake your head “no”.

Question 18

Thoracic Vertebrae

Answer 18

• 12 vertebrae
• heart-shaped body
• circular vertebral foramen
• long spinous process that points inferiorly
• facets for rib articulation

Question 19

Lumbar Vertebrae

Answer 19

• 5 vertebrae
• large, heavy vertebrae that are well equipped for weight-bearing.
• large size; a massive body; a short, “hatchet-shaped” spinous process and a triangular vertebral foramen.

Question 20

Sacrum

Answer 20

• 5 fused sacral vertebrae
• provide strong support for the pelvic girdle
• The lateral surfaces articulate with the ilium of each hipbone forming the sacroiliac joint.

Question 21

Coccyx

Answer 21

• 3-5 five fused coccygeal vertebrae

* form the triangular “tailbone”

Question 22

Ribs:

• number
• type

Answer 22

• Twelve pairs
• True Ribs: 1-7, direct anterior attachment to sternum.
• False Ribs: 8-12, costal cartilages do not attach directly to the sternum. Ribs 8–10, costal cartilages attached to cartilage of the next higher rib
• Floating Ribs: 11-12, do not attach to the sternum at all

Question 23

What is scoliosis?

Answer 23

a sideways curvature of the spine that occurs most often during the growth spurt just before puberty

Question 24

What is kyphosis

Answer 24

exaggerated, forward rounding of the back, often due to weakness in the spinal bones that causes them to compress or crack

Question 25

What two bones contribute to the zygomatic arch?

Answer 25

zygomatic bone + temporal bone

Question 26

What are the functions of the thoracic cage?

Answer 26

* protects the heart and lungs | * provides attachments for muscles of the neck, thorax, upper limbs, abdomen, and back

Question 27

What two bones compose the hard palate?

Answer 27

palatine processes of the maxilla & horizontal plates of the palatine bones.

Question 28

Why are the bodies of the lumbar vertebrae so large?

Answer 28

well equipped for weight-bearing

Question 29

pectoral girdle

Answer 29

• 2 clavicles + 2 scapulae

Question 30

Clavicle | •function

Answer 30

* (or collarbone) | * serves as an anterior brace which helps to prevent dislocation of the shoulder.

Question 31

The skeleton of the upper limbs | • sections and the bones in each

Answer 31

* consists of the bones of the arms, forearms, wrists and hands. * The Arm (or brachium): humerus. * The Forearm (or antebrachium): ulna and radius make * The Wrist (or carpus): 8 carpal bones * The Hand: 5 metacarpal bones, 14 phalanges.

Question 32

The Wrist

Answer 32

- 8 carpal bones, | - two rows of four bones each

Question 33

The Hand: • number of bones • numbering

Answer 33

Metacarpals •5 metacarpal bones • Roman numerals beginning with the lateral metacarpal bone (thumb = I). Phalanges •14 phalanges • Each finger has three phalanges: proximal, middle and distal phalanx. • The thumb has only two (proximal and distal phalanx)T

Question 34

Why is the thumb special

Answer 34

* The metacarpal bone which forms the thumb has a wide range of movement. This is due to the saddle type of joint between this metacarpal and its associated carpal. It is called an opposable thumb because of the ability to oppose the thumb to the fingers. This gives the human hand its dexterity and manipulative ability. * has only two phalanges (proximal and distal phalanx)

Question 35

Pelvic girdle

Answer 35

* Composed of two hip bones or coxae (os coxae or coxal bones) * Originally consists of three separate bones: the ilium, the ischium and the pubis (fuse to form one solid bone)

Question 36

What bones form the bony pelvis.

Answer 36

coxae + sacrum + coccyx

Question 37

Female Pelvis

Answer 37

``` Shallow and wide Light and thin bone Broad (round) pubic arch Oval (large) pelvic brim Small and far apart acetabula ```

Question 38

Male Pelvis

Answer 38

``` Deep and narrow Heavy and thick bone Acute (sharp) pubic arch Heart-shaped pelvic brim Large and close together acetabula ```

Question 39

True vs. False Pelvis

Answer 39

False Pelvis - broad, superior region True Pelvis -inferiorly, the narrow, rounded space of the lesser pelvis

Question 40

The skeleton of the lower limbs consists of

Answer 40

* the bones of the thighs, kneecaps, legs, ankles and feet. * Thighs: femur * Kneecaps: patella * Legs: tibia / fibula * Ankles: 7 tarsal bones * Feet: 5 metatarsal bones and 14 phalanges.

Question 41

Tibia/Fibula

Answer 41

The tibia (or shin bone) • medial and larger bone. • serves to transmit the weight of the body from the femur onto the foot. The fibula • lateral side • not a weight bearing bone • does not enter into the formation of the knee joint.

Question 42

Tarsal Bones, the Metatarsal Bones and the Phalanges • articulation • number of bones • numbering

Answer 42

The ankle • composed of 7 tarsal bones. • talus is the tarsal bone which articulates with the tibia and the fibula. • calcaneus is the large, strong heel bone. Metatarsals • 5 metatarsal bones extend from the tarsal bones to the “ball” of the foot, to form the plantar surface (the sole). • These bones articulate with the phalanges or toes bones. • the “big” toe is composed of only two phalanges