Chapter 8: Appendicular Skeleton

Question 2

What bones make up the pectoral girdle?

Answer 2

• Clavicle
• Scapula

These bones are located on each side of the body.

Question 3

What is the primary function of the clavicle?

Answer 3

• Brace shoulders, keeping upper limbs away from midline
• Transfer force from arm to axial skeleton (like in push-ups)

The clavicle plays a crucial role in shoulder stability.

Question 4

What happens when the clavicle is fractured?

Answer 4

Pectoralis major muscles pull shoulders forward and medially

This can lead to a noticeable change in shoulder position.

Question 5

Where do clavicular fractures most commonly occur?

Answer 5

About one-third of the way from the lateral end (weak point)

This area is particularly vulnerable to injury.

Question 6

What are the two ends of the clavicle called and what do they articulate with?

Answer 6

• Sternal end (medial) → sternum
• Acromial end (lateral) → scapula

These articulations are essential for shoulder movement.

Question 7

What are the main features of the scapula spine?

Answer 7

• Shelflike ridge on posterior surface
• Terminates laterally in acromion
• Divides into supraspinous and infraspinous fossae

The scapula spine is important for muscle attachment.

Question 8

What is the glenoid cavity?

Answer 8

Shallow socket for head of humerus, forms glenohumeral (shoulder) joint

This structure is crucial for shoulder joint mobility.

Question 9

Why is the shoulder joint less stable than the hip joint?

Answer 9

Glenoid cavity is shallow (unlike deep acetabulum of hip)

This anatomical difference contributes to the shoulder’s greater range of motion.

Question 10

What passes through the suprascapular notch?

Answer 10

• Suprascapular nerve
• Vessels

This notch is an important passageway for nerves and blood supply.

Question 11

What is the most commonly fractured part of the scapula and why?

Answer 11

Acromion - most exposed part; rest is protected by surrounding muscles

The acromion’s location makes it susceptible to injury.

Question 12

What are the key features at the proximal end of the humerus?

Answer 12

• Head (hemispherical)
• Anatomical neck
• Greater/lesser tubercles
• Surgical neck (common fracture site)

These features are important for muscle attachment and joint articulation.

Question 13

What articulates with the capitulum vs trochlea at distal humerus?

Answer 13

• Capitulum (lateral) → radius
• Trochlea (medial) → ulna

These articulations are critical for elbow movement.

Question 14

Why is the medial epicondyle called the ‘funny bone’?

Answer 14

Ulnar nerve passes through groove; sharp blow stimulates nerve causing tingling

This sensation is often described as ‘funny’ due to its unusual nature.

Question 15

What are the three fossae at the distal humerus and their functions?

Answer 15

• Olecranon fossa (posterior) - receives olecranon when elbow extended
• Coronoid fossa (anterior medial) - receives coronoid process when flexed
• Radial fossa (anterior lateral) - for radius head

These fossae accommodate the movements of the elbow joint.

Question 16

What attaches at the deltoid tuberosity?

Answer 16

Deltoid muscle of the shoulder

This attachment is crucial for shoulder abduction.

Question 17

Which bone is lateral and which is medial in the forearm?

Answer 17

• Radius = lateral (thumb side)
• Ulna = medial (pinky side)

This orientation is important for understanding forearm movements.

Question 18

What happens during pronation of the hand?

Answer 18

Radius crosses over ulna, rotating medially; ulna remains stationary as pivot point

This movement is essential for certain hand positions.

Question 19

What is the olecranon and where is it located?

Answer 19

Bony point of elbow; proximal end of ulna

The olecranon is a key landmark for elbow flexion.

Question 20

What is the trochlear notch?

Answer 20

Feature of ulna that wraps around trochlea of humerus

This notch is vital for elbow joint stability.

Question 21

What is the interosseous membrane and its function?

Answer 21

Ligament connecting radius and ulna; enables load sharing between bones, reduces wear on joints

This membrane plays a crucial role in forearm stability.

Question 22

Memory trick for forearm bones?

Answer 22

‘Radius is lateral (thumb side), Ulna is medial’

This mnemonic helps remember the orientation of the bones.

Question 23

Which forearm bone has NO direct articulation with carpal bones?

Answer 23

Ulna

This is an important distinction in wrist anatomy.

Question 24

How many bones total in the hand?

Answer 24

27 bones (8 carpals, 5 metacarpals, 14 phalanges)

Understanding the composition of the hand is essential for anatomy.

Question 25

Name the **proximal row of carpal bones** (lateral to medial)? | SLTP

Answer 25

* Scaphoid * Lunate * Triquetrum * Pisiform ## Footnote This row is crucial for wrist function.

Question 26

Name the **distal row of carpal bones** (lateral to medial)? | TTCH

Answer 26

* Trapezium * Trapezoid * Capitate * Hamate ## Footnote These bones are important for hand movements.

Question 27

Which carpal bone is a **sesamoid bone**?

Answer 27

Pisiform (develops 9-12 years in flexor carpi ulnaris tendon) ## Footnote Sesamoid bones are embedded in tendons and provide mechanical advantages.

Question 28

What is special about the **hamate bone**?

Answer 28

Has hamulus (hook) on palmar side; attachment for flexor retinaculum ## Footnote This feature is important for the carpal tunnel.

Question 29

How many **phalanges** in thumb vs other fingers?

Answer 29

* Thumb: 2 (proximal, distal) * Others: 3 (proximal, middle, distal) ## Footnote This difference is significant in hand anatomy.

Question 30

What forms the '**knuckles**' when you make a fist?

Answer 30

Heads of metacarpals ## Footnote This is a common term used to describe the visible joints.

Question 31

What three bones fuse to form each **hip bone**?

Answer 31

* Ilium * Ischium * Pubis ## Footnote These bones fuse between ages 15-25.

Question 32

What is the **acetabulum**?

Answer 32

Deep cup socket where ilium, ischium, and pubis meet; articulates with femur head ## Footnote This structure is crucial for hip joint stability.

Question 33

What is the difference between **greater (false)** and **lesser (true)** pelvis?

Answer 33

* Greater = above pelvic brim, forms lower abdominal walls * Lesser = below brim, encloses pelvic cavity ## Footnote This distinction is important in obstetrics.

Question 34

What passes through the **greater sciatic notch**?

Answer 34

Sciatic nerve (continues down posterior thigh) ## Footnote This notch is a significant passageway for nerves.

Question 35

What is the **ischial tuberosity** and its function?

Answer 35

Thickening where hamstrings attach; supports body when sitting ## Footnote This structure is important for posture.

Question 36

What is the **obturator foramen**?

Answer 36

Opening encircled by ischium and pubis; closed by obturator membrane in life ## Footnote This foramen is significant for muscle and nerve passage.

Question 37

What joint is formed between the two **pubic bones**?

Answer 37

Pubic symphysis (contains interpubic disc of fibrocartilage) ## Footnote This joint allows for slight movement during childbirth.

Question 38

What is the shape of **pelvic inlet** in males vs females?

Answer 38

* Male: heart-shaped * Female: round or oval ## Footnote This shape difference is important for childbirth.

Question 39

Compare the **subpubic angle** in males vs females?

Answer 39

* Male: narrow (<90°) * Female: wide (>100°) ## Footnote This angle is a key distinguishing feature in pelvic anatomy.

Question 40

How does the **greater sciatic notch** differ?

Answer 40

* Male: narrower * Female: wider ## Footnote This difference is significant for pelvic anatomy.

Question 41

Compare the overall structure of **male vs female pelvis**?

Answer 41

* Male: deeper, heavier, rougher * Female: shallower, smoother, wider ## Footnote These differences are adaptations for bipedalism and childbirth.

Question 42

How does the **sacrum** differ between sexes?

Answer 42

* Male: narrower and deeper * Female: wider and shallower ## Footnote This difference is important for pelvic shape.

Question 43

How does the **coccyx** differ?

Answer 43

* Male: less movable, more vertical * Female: more movable, tilted posteriorly ## Footnote This difference affects pelvic mobility.

Question 44

What is the **fovea capitis**?

Answer 44

Pit in femur head for ligament attachment ## Footnote This feature is important for hip joint stability.

Question 45

What is the most common '**broken hip**' fracture?

Answer 45

Fracture of femoral neck (weakest part) ## Footnote This type of fracture is common in the elderly.

Question 46

What are the **greater and lesser trochanters**?

Answer 46

* Projections on proximal femur for muscle attachment ## Footnote These projections are important for hip muscle function.

Question 47

What is the **linea aspera**?

Answer 47

Posterior ridge on femur shaft; attachment for gluteus maximus ## Footnote This ridge is significant for muscle attachment.

Question 48

What articulates with the **medial and lateral condyles** of femur?

Answer 48

Tibia (at knee joint) ## Footnote This articulation is crucial for knee joint function.

Question 49

Why does the human **femur angle medially**?

Answer 49

Places knees below center of gravity for bipedal walking ## Footnote This angling is important for balance.

Question 50

What is the **patellar surface**?

Answer 50

Anterior surface of distal femur for patella articulation ## Footnote This surface is essential for knee joint function.

Question 51

What type of bone is the **patella**?

Answer 51

Sesamoid bone (embedded in tendon) ## Footnote The patella provides mechanical advantages in knee movement.

Question 52

When does the **patella ossify**?

Answer 52

3-6 years of age (cartilaginous at birth) ## Footnote This ossification process is important for knee stability.

Question 53

What is the **quadriceps tendon** vs **patellar ligament**?

Answer 53

Same structure: tendon above patella, ligament below (terminology difference) ## Footnote Understanding this distinction is important in anatomy.

Question 54

Which bone of the leg is **weight-bearing**?

Answer 54

Only the tibia (medial bone) ## Footnote This is crucial for understanding leg function.

Question 55

What is the **tibial tuberosity**?

Answer 55

Anterior projection below patella; attachment for patellar ligament ## Footnote This projection is significant for knee function.

Question 56

What is the **medial malleolus**?

Answer 56

Knobby projection at distal tibia; medial ankle bump ## Footnote This structure is important for ankle stability.

Question 57

What is the **lateral malleolus**?

Answer 57

Distal end of fibula; lateral ankle bump ## Footnote This structure is crucial for ankle joint function.

Question 58

Can the **fibula** be used for bone grafts?

Answer 58

Yes - doesn't bear weight, so parts can be removed ## Footnote This makes the fibula a candidate for grafting procedures.

Question 59

Memory device for **leg bones**?

Answer 59

'Little Lateral fibuLa' (fibula is lateral, smaller) ## Footnote This mnemonic helps remember the orientation of the bones.

Question 60

How many **tarsal bones** are there?

Answer 60

7 (vs 8 carpal bones in wrist) ## Footnote Understanding the number of tarsal bones is important for foot anatomy.

Question 61

What is the **largest tarsal bone**?

Answer 61

Calcaneus (heel bone) ## Footnote This bone is crucial for weight-bearing and walking.

Question 62

What attaches to the **calcaneus**?

Answer 62

Calcaneal (Achilles) tendon from calf muscles ## Footnote This attachment is vital for walking and running.

Question 63

Which tarsal bone articulates with **tibia and fibula**?

Answer 63

Talus (has superior trochlear surface) ## Footnote This articulation is essential for ankle movement.

Question 64

Name the **distal tarsal bones** (medial to lateral)?

Answer 64

* Medial cuneiform * Intermediate cuneiform * Lateral cuneiform * Cuboid ## Footnote These bones are important for foot structure.

Question 65

How are **metatarsals numbered**?

Answer 65

I-V from medial to lateral (I = big toe) ## Footnote This numbering system is important for foot anatomy.

Question 66

Total bones in the **foot**?

Answer 66

26 bones (7 tarsals, 5 metatarsals, 14 phalanges) ## Footnote Understanding the composition of the foot is essential for anatomy.

Question 67

What are the three **arches of the foot**?

Answer 67

* Medial longitudinal * Lateral longitudinal * Transverse ## Footnote These arches are important for weight distribution.

Question 68

When do **limb buds** appear in development?

Answer 68

Around 4 weeks ## Footnote This is a critical stage in embryonic development.

Question 69

How do **upper and lower limbs rotate differently** in week 7?

Answer 69

* Upper limbs rotate laterally (90°) * Lower limbs rotate medially (90°) ## Footnote This rotation is significant for limb positioning.

Question 70

Why do **elbows and knees flex in opposite directions**?

Answer 70

Due to opposite 90° rotations during week 7 of development ## Footnote This anatomical feature is important for movement.

Question 71

When do the three **hip bones fully fuse**?

Answer 71

Age 25 ## Footnote This fusion is important for pelvic stability.

Question 72

What is **polydactyly**?

Answer 72

Extra fingers or toes ## Footnote This condition can affect hand and foot function.

Question 73

What is **syndactyly**?

Answer 73

Webbed digits ## Footnote This condition can affect the appearance and function of hands and feet.

Question 74

What is **clubfoot (talipes)**?

Answer 74

Feet adducted and plantar flexed with soles turned medially ## Footnote This condition requires medical intervention for correction.

Question 75

What is a **Colles fracture**?

Answer 75

Fracture at distal radius and ulna from falling on wrist ## Footnote This type of fracture is common in older adults.

Question 76

What is **pes planus**?

Answer 76

Flat feet/fallen arches ## Footnote This condition can lead to pain and mobility issues.

Question 77

Key difference between **human and chimp pelvis**?

Answer 77

Human ilium shorter and broader for bipedalism; gluteus maximus for hip extension ## Footnote These adaptations are crucial for upright walking.

Question 78

Difference in **great toe** between humans and chimps?

Answer 78

* Chimp: prehensile (grasping) * Human: robust, non-prehensile for push-off ## Footnote This difference reflects adaptations for locomotion.

Question 79

How does **femur angle differ** in humans vs chimps?

Answer 79

Human femur angles medially; chimp femur nearly vertical ## Footnote This angling is important for bipedalism.

Question 80

Which joint is more stable: **shoulder or hip**?

Answer 80

Hip (deep acetabulum vs shallow glenoid cavity) ## Footnote This stability is crucial for weight-bearing activities.

Question 81

What type of joint is the **sternoclavicular joint**?

Answer 81

Only bony attachment of upper limb to axial skeleton ## Footnote This joint is essential for shoulder movement.

Question 82

What type of joint is the **acromioclavicular joint**?

Answer 82

Between lateral clavicle and scapula acromion ## Footnote This joint allows for shoulder mobility.

Question 83

What is **pronation vs supination** of the foot?

Answer 83

* Pronation: foot leans inward * Supination: foot leans outward ## Footnote These movements are important for walking and running.

Question 84

Total bones in **upper limb** (per side)?

Answer 84

30 bones (1 humerus, 1 radius, 1 ulna, 8 carpals, 5 metacarpals, 14 phalanges) ## Footnote Understanding the number of bones is essential for anatomy.

Question 85

Total bones in **lower limb** (per side)?

Answer 85

30 bones (1 femur, 1 patella, 1 tibia, 1 fibula, 7 tarsals, 5 metatarsals, 14 phalanges) ## Footnote This count is important for understanding leg anatomy.

Question 86

Why do upper and lower limbs both have **30 bones** despite different carpal/tarsal counts?

Answer 86

Lower limb includes patella (upper doesn't have equivalent) ## Footnote This distinction is important for anatomical comparisons.

Question 87

What attaches at the **greater trochanter of femur**?

Answer 87

Hip abductor muscles ## Footnote This attachment is crucial for hip stability.

Question 88

What attaches at the **tibial tuberosity**?

Answer 88

Patellar ligament (from quadriceps) ## Footnote This attachment is important for knee extension.

Question 89

What attaches at the **radial tuberosity**?

Answer 89

Biceps brachii muscle ## Footnote This attachment is essential for elbow flexion.

Question 90

What muscles attach to **rotator cuff fossae** of scapula?

Answer 90

Supraspinous and infraspinous fossae house rotator cuff muscles ## Footnote These muscles are crucial for shoulder stability.

Question 91

Most common fracture site in **clavicle**?

Answer 91

Lateral third of bone ## Footnote This area is particularly vulnerable to injury.

Question 92

Most common fracture site in **humerus**?

Answer 92

Surgical neck ## Footnote This site is often affected in falls.

Question 93

Most common fracture site in **femur** in elderly?

Answer 93

Femoral neck ## Footnote This type of fracture is common due to falls.

Question 94

What is a **greenstick fracture**?

Answer 94

Incomplete fracture common in children's clavicles ## Footnote This type of fracture is often seen in pediatric cases.

Question 95

What forms the **carpal tunnel**?

Answer 95

Carpal bones covered by flexor retinaculum (attaches to hamulus of hamate) ## Footnote This tunnel is important for the passage of tendons and nerves.

Question 96

What is the **coronoid process**?

Answer 96

Anterior projection of ulna (fits in coronoid fossa when elbow flexed) ## Footnote This projection is crucial for elbow function.

Question 97

What is the **olecranon process**?

Answer 97

Posterior projection of ulna (fits in olecranon fossa when elbow extended) ## Footnote This process is important for elbow extension.

Question 98

What are the **styloid processes**?

Answer 98

Pointed projections at distal radius and ulna ## Footnote These projections are important for wrist stability.

Question 99

How is the **human foot adapted** for bipedalism vs chimp?

Answer 99

* Non-prehensile big toe * Strong arches for weight transfer * Robust for push-off ## Footnote These adaptations are crucial for efficient walking.

Question 100

How does **pelvic shape support bipedalism**?

Answer 100

Shorter, broader ilium positions gluteus maximus for upright posture ## Footnote This shape is essential for walking efficiency.

Question 101

Why can humans **lock knees** but apes cannot?

Answer 101

Medially angled femur places knees under center of gravity ## Footnote This anatomical feature is important for stability.

Question 102

What is a **sesamoid bone**? Name examples.

Answer 102

Bone embedded in tendon; Examples: patella, pisiform ## Footnote Sesamoid bones provide mechanical advantages in movement.

Question 103

Which **carpal bones articulate** with radius?

Answer 103

* Scaphoid * Lunate ## Footnote These articulations are crucial for wrist function.

Question 104

What forms the '**true wrist joint**'?

Answer 104

Radius articulating with scaphoid and lunate (not ulna) ## Footnote This joint is essential for wrist mobility.

Question 105

What is the **auricular surface**?

Answer 105

Part of ilium that articulates with sacrum (sacroiliac joint) ## Footnote This surface is important for pelvic stability.

Question 106

What is **avascular necrosis** in femoral neck fractures?

Answer 106

Death of bone tissue due to disrupted blood supply after fracture ## Footnote This condition can lead to significant complications.