Appendicular Skeleton Development

Question 1

What does the appendicular skeleton consist of?

Answer 1

The pectoral and pelvic girdles, the limb bones, and the bones of the hands and feet.

Question 2

What two bones form the pectoral girdle?

Answer 2

Clavicle and scapula.

Question 3

The clavicle is attached on its medial end to the _________ of the thoracic cage.

Answer 3

Sternum

Question 4

The lateral end of the clavicle articulates with the _______ just above the shoulder joint.

Answer 4

Scapula

Question 5

What does the pectoral girdle serve to attach the upper limb to?

Answer 5

Sternum of the axial skeleton.

Question 6

Where does the scapula lie?

Answer 6

On the posterior aspect of the shoulder.

Question 7

What shape is the scapula?

Answer 7

Flat, triangular-shaped.

Question 8

Are the right and left pectoral girdles joined to each other?

Answer 8

No.

Question 9

Why is the clavicle anchored to the axial skeleton by a single, highly mobile joint?

Answer 9

To allow for extensive mobility of the entire pectoral girdle.

Question 10

What is the only long bone that lies in a horizontal position?

Answer 10

Clavicle.

Question 11

Functions of the clavicle include:

Answer 11

• Serving as a strut to support the scapula
• Transmitting forces to the sternum
• Protecting underlying nerves and blood vessels

Question 12

What forms the sternoclavicular joint?

Answer 12

The articulation between the medial end of the clavicle and manubrium of the sternum.

Question 13

What ligament supports the sternoclavicular joint?

Answer 13

Costoclavicular ligament.

Question 14

Sex differences in the morphology of the clavicle: Female clavicle tends to be _______.

Answer 14

Shorter, thinner, and less curved.

Question 15

What is the most commonly fractured bone in the body?

Answer 15

Clavicle.

Question 16

Why do clavicle breaks often occur?

Answer 16

Due to force exerted on the clavicle when falling onto outstretched arms.

Question 17

What surrounds the scapula?

Answer 17

Muscles on both its anterior and posterior sides.

Question 18

What are the three margins or borders of the scapula?

Answer 18

• Superior Border
• Medial Border
• Inferior Border

Question 19

What landmark of the scapula is located lateral to the midpoint of the superior border?

Answer 19

Suprascapular notch.

Question 20

What is the most inferior portion of the scapula called?

Answer 20

Inferior angle.

Question 21

What shallow depression articulates with the humerus to form the glenohumeral joint?

Answer 21

Glenoid Cavity or Glenoid Fossa.

Question 22

What is another name for the shoulder joint?

Answer 22

Glenohumeral Joint.

Question 23

What are the two prominent projections of the scapula?

Answer 23

• Coracoid process
• Acromion

Question 24

What joint does the acromion articulate with?

Answer 24

Acromioclavicular joint.

Question 25

What ligament provides primary support for the acromioclavicular joint?

Answer 25

Coracoclavicular ligament.

Question 26

What is a common injury in contact sports involving the acromioclavicular joint?

Answer 26

Complete dislocation of the acromioclavicular joint.

Question 27

What are the three regions the upper limb is divided into?

Answer 27

* Arm * Forearm * Hand

Question 28

How many bones are there in each upper limb?

Answer 28

30 bones.

Question 29

What is the single bone of the upper arm region?

Answer 29

Humerus.

Question 30

What is the medial bone of the forearm?

Answer 30

Ulna.

Question 31

What forms the inferior margin of the trochlear notch?

Answer 31

Coronoid process of the ulna.

Question 32

What is the lateral bone of the forearm?

Answer 32

Radius.

Question 33

What attaches the radius and ulna to each other?

Answer 33

Interosseous membrane.

Question 34

What is the most common forearm fracture?

Answer 34

Colles Fracture of the distal radius.

Question 35

What bone forms the pelvic girdle?

Answer 35

Hip bone or coxal bone.

Question 36

What forms the pelvis?

Answer 36

The two hip bones, sacrum, and coccyx.

Question 37

What are the three separate bones that fuse to form each adult hip bone?

Answer 37

* Ilium * Ischium * Pubis

Question 38

What is the difference between male and female pelvis?

Answer 38

The female pelvis is broader and adapted for childbirth.

Question 39

What is the single bone of the thigh region?

Answer 39

Femur.

Question 40

What does the femur articulate with superiorly and inferiorly?

Answer 40

* Superiorly with the hip bone * Inferiorly with the tibia

Question 41

What is the shape of the lesser pelvic cavity?

Answer 41

The lesser pelvic cavity is shorter and wider

Question 42

What is the shape of the greater pelvic cavity?

Answer 42

The greater pelvic cavity is longer and narrower

Question 43

What is the subpubic angle in females?

Answer 43

The subpubic angle is greater than 80 degrees

Question 44

What is the subpubic angle in males?

Answer 44

The subpubic angle is less than 70 degrees

Question 45

How is the pelvic outlet described in females?

Answer 45

The pelvic outlet is rounded and larger

Question 46

How is the pelvic outlet described in males?

Answer 46

The pelvic outlet is smaller

Question 47

What is the single bone of the thigh region?

Answer 47

The femur

Question 48

What joints does the femur articulate with?

Answer 48

The hip joint superiorly and the knee joint inferiorly

Question 49

Which bone only articulates with the distal end of the femur?

Answer 49

The patella

Question 50

What is the largest sesamoid bone in the body?

Answer 50

The patella (kneecap)

Question 51

Define a sesamoid bone.

Answer 51

A sesamoid bone is a bone incorporated into the tendon of a muscle where that tendon crosses a joint

Question 52

What is the primary function of sesamoid bones?

Answer 52

To prevent damage to the muscle tendon due to rubbing against the bones during movements

Question 53

What is the Q Angle?

Answer 53

The Q-angle is a measure of lateral deviation of the femur from the vertical line of the tibia

Question 54

Why do females have a larger Q-angle than males?

Answer 54

Females have a wider pelvis than males

Question 55

What is the medial bone of the leg?

Answer 55

The tibia

Question 56

What is the primary function of the tibia?

Answer 56

It is the main weight-bearing bone of the lower leg

Question 57

What is the role of the fibula?

Answer 57

The fibula is a slender bone that does not bear weight

Question 58

How many phalanx bones do the toes contain?

Answer 58

14 phalanx bones (phalanges)

Question 59

What are the three groups of bones in the foot?

Answer 59

* Tarsal bones * Metatarsal bones * Phalanges

Question 60

What important role do the arches of the foot play?

Answer 60

They absorb shock and distribute body weight

Question 61

What are the three arches of the foot?

Answer 61

* Transverse arch * Medial longitudinal arch * Lateral longitudinal arch

Question 62

What is the primary function of the transverse arch?

Answer 62

To distribute body weight from side to side within the foot

Question 63

What is the condition called when the ligaments supporting the longitudinal arches are stretched?

Answer 63

Pes planus (flat foot)

Question 64

What is a limb bud?

Answer 64

A small bulge that appears on the lateral side of the early embryo

Question 65

When do the upper and lower limb buds appear?

Answer 65

Upper limb bud appears at the end of the fourth week of development; lower limb bud appears shortly after

Question 66

What is the apical ectodermal ridge?

Answer 66

A narrow crest formed by thickening ectoderm at the end of the limb bud

Question 67

What does the apical ectodermal ridge do?

Answer 67

Stimulates underlying mesenchyme to proliferate, promoting limb outgrowth

Question 68

Which bones develop by endochondral ossification?

Answer 68

All girdle and limb bones, except for the clavicle

Question 69

What is endochondral ossification?

Answer 69

The process that converts hyaline cartilage models into bone

Question 70

When does endochondral ossification begin in most appendicular bones?

Answer 70

By the 12th fetal week

Question 71

How does the clavicle develop?

Answer 71

Via intramembranous ossification

Question 72

What is club foot?

Answer 72

A common deformity where one or both feet/ankles are twisted out of their normal positions