7.1 - Bones of the limbs

Question 1

anatomic planes and positions

Answer 1

Question 2

what does the axial skeleton consist of

Answer 2

bones of the head - cranium / skull

neck - hyoid bone / cervical vertebrae

trunk - rubs / sternum / vertebrae / sacrum

Question 3

what does the appendicular skeleton consist of

Answer 3

bones of the limbs = including those forming the pectoral (shoulder) and pelvic girdles

Question 4

bones in appendicular skeleton

Answer 4

Question 5

what is the skeleton composed of

Answer 5

cartilage and bones

Question 6

what is cartilage

Answer 6

resilient, semirigid form of connective tissue that forms parts of the skeleton where more flexibility is required

Question 7

what is ossification

Answer 7

process by which cartilage turns into bone

Question 8

what is primary ossification

Answer 8

process of bone formation that occurs in the diaphysis (shaft/ middle) of a long bone, starting during embryonic development.

Question 9

when does primary ossification occur

Answer 9

Occurs at the primary ossification center, usually in the middle of the cartilage model of a long bone (hyaline cartilage)

Question 10

process of primary ossification

Answer 10

Cartilage model of bone is replaced by bone tissue.

Chondrocytes in the cartilage hypertrophy and die, and the surrounding matrix calcifies.

Osteoblasts invade and lay down bone matrix.

Perichondrium becomes the periosteum, and the first bone tissue is formed.

Blood vessels invade the region, bringing in osteoblasts and osteoclasts.

Question 11

What is secondary ossification and where does it occur?

Answer 11

process of bone formation that occurs in the epiphyses (ends) of a long bone, generally after birth.

Occurs at the secondary ossification centers in the epiphyses.

Question 12

process of secondary ossification

Answer 12

Hypertrophic chondrocytes in the epiphyses begin to calcify, followed by osteoblast invasion.

Epiphyseal cartilage remains in the form of articular cartilage (on the joint surface) and the epiphyseal plate (growth plate).

Spongy bone forms in the epiphysis, while the shaft continues to elongate

Question 13

What are the diaphysis and epiphyses in long bones

Answer 13

diaphysis = central shaft

epiphyses = expanded ends

Question 14

what is the growth plate

Answer 14

is a cartilage layer located between the epiphysis (end of the bone) and the diaphysis (shaft of the bone)

Question 15

types of bone

Answer 15

compact / cortical

spongy / trabecular

Question 16

compact / cortical bone

Answer 16

Dense form of bone found in bone shafts and external surfaces of bone

Haversian canal = compact nature of the bone requires channels for blood
vessels to reach the bone cells to provide nutrition = seen microscopically

Question 17

Spongy/ trabecular bone

Answer 17

Lightweight + porous + elastic structure

Found in the ends of long bones, short bones and in bodies of vertebrae

Red bone marrow may be found -> contains stem cells that can give rise to
WBCs (erythrocytes and leucocytes) and platelets -> via haematopoiesis

Question 18

function of compact bone

Answer 18

provides strength for weight bearing / resistance to bending and torsion

minimal deformability in daily activities = low strain tolerance + limited flexibility

Question 19

function of spongy bone

Answer 19

acts like shock absorber in regions with excessive compressive forces

undergoes deformation even under normal activities

Question 20

types of bone in the appendicular skeleton

Answer 20

long

flat

short

irregular

sesamoid

Question 21

flat bones - function + location

Answer 21

Question 22

long bone - function + location

Answer 22

Question 23

short bone - function and location

Answer 23

Question 24

irregular bones - function + location

Answer 24

Question 25

sesamoid bone - function + location

Answer 25

Question 26

How are long bones (e.g., femur, humerus) adapted for strength and force transmission?

Answer 26

The shaft provides leverage for muscles to act on, facilitating movement. Spongy bone at the ends absorbs shock and distributes forces across joints

Question 27

How are flat bones (e.g., skull, ribs) adapted for strength and force transmission?

Answer 27

Strength and resilience against impact forces, like a shield. The spongy bone (diploë) helps to distribute force and reduce weight while maintaining strength. The structure is optimized for energy absorption during trauma (e.g., skull during a fall).

Question 28

How are short bones (e.g., carpals, tarsals) adapted for strength and force transmission?

Answer 28

Provide stability and allow for a wide range of motion. Facilitate complex movements by offering a high degree of flexibility without sacrificing strength. Absorb shock and distribute force within joints to reduce wear and tear. Adapted for force transmission between bones in joints, especially where flexibility and mobility are needed.

Question 29

know these

Answer 29

Question 30

how are bone impressions formed

Answer 30

appear wherever tendons / ligaments / fascia's / muscles are attached large muscle attachments form elevations on the bone - ridges / crests / tubercles = serve as support for movement

Question 31

bones of the upper limb

Answer 31

shoulder girdle - clavicle + scapula arm - humerus forearm - ulna (medial) + radius (lateral) hand - carpal / metacarpal / phalanges

Question 32

bones of the lower limb

Answer 32

pelvic girdle - pubis / ischium / illium / acetabulum thigh - femur leg - tibia (medial) + fibula (lateral) foot - tarsals / metatarsals / phalenges

Question 33

weight transmission of upper limb

Answer 33

Question 34

bones of shoulder girdle

Answer 34

clavicle and scapula (shoulder blade) Each clavicle articulates with the scapula laterally at the acromioclavicular joint Each clavicle articulates with the manubrium (of the sternum) medially at the sternoclavicular joint Glenoid fossa articulates with the head of the humerus at the glenohumeral joint

Question 35

key structures of the scapula

Answer 35

Glenoid fossa: Socket that forms the shoulder joint with the humerus. Acromion: The bony process on the scapula that forms the highest point of the shoulder. Coracoid process: A hook-like structure for muscle attachment. Spine of scapula: A prominent ridge that divides the back of the scapula.

Question 36

bones of the arm

Answer 36

between radius and ulna - interosseus membrane

Question 37

bones of the hand

Answer 37

thumb = only has 2

Question 38

ulna and radius disclaimer

Answer 38

head of radius is proximal but head of ulna is distal

Question 39

bones of the pelvic girdle

Answer 39

Pubis Ischium Ilium Acetabulum

Question 40

bones of the thigh

Answer 40

femur

Question 41

bones of the leg

Answer 41

Question 42

bones of foot

Answer 42

calcaneus talus

Question 43

How do the shoulder girdle (clavicle, scapula) compare to the pelvic girdle (pubis, ischium, ilium)?

Answer 43

glenoid fossa (shoulder) - shallow BUT acetabulum (pelvis) is more deep so acetabulum - more stable ------------------------ The shoulder girdle is more flexible and mobile (allows arm movement) but less stable, whereas the pelvic girdle is more stable and robust for weight-bearing and supports locomotion. The pelvic girdle is closed and provides strength for walking, while the shoulder girdle is open to provide more range of motion in the arm.

Question 44

How does the humerus compare with the femur?

Answer 44

humerous - short neck femur = long neck trochanter = on femur not humerous fossa = on humerous not femur ----------------------- The femur is much larger and more robust, designed for weight-bearing in the lower limb, whereas the humerus is relatively lighter and adapted for arm movement. The femur has larger trochanters for more muscle attachment, while the humerus has greater tuberosities

Question 45

How do the ulna and radius compare to the tibia and fibula?

Answer 45

The ulna and radius allow for forearm rotation (pronation/supination), while the tibia and fibula are involved in weight-bearing and stability = cant do that The radius and fibula are smaller than their corresponding partner bones (ulna and tibia), and the tibia is the primary weight-bearing bone in the lower leg, whereas the ulna and radius share load-bearing in the forearm.

Question 46

How do the bones of the hand compare to the bones of the foot?

Answer 46

metatarsal bones = stronger + higher cortical density then metacarpal thumb + big toe = sesamoid bones metacarpal = longer - more skilfull movements ----------------------- Hand bones are more flexible and adapted for grip, dexterity, and fine motor skills, while the foot bones are designed for weight-bearing, shock absorption, and balance during standing, walking, and running. The foot has a sturdier structure, with tarsals that provide support and stability, whereas the carpals in the hand allow for mobility and flexibility

Question 47

function of the coracoid and spine on the scapula

Answer 47

coracoid = Provides attachment for muscles (e.g., pectoralis minor, biceps brachii) spine = Provides attachment for the trapezius and deltoid muscles.

Question 48

What are the important landmarks on the humerus?

Answer 48

lesser tuberosity greater tuberosity epicondyles / condolyes

Question 49

what are greater and lesser tuberosity on the humerous

Answer 49

lesser =Attachment for the subscapularis muscle (part of the rotator cuff). greater =Attachment for the supraspinatus, infraspinatus, and teres minor muscles (rotator cuff muscles).

Question 50

what are condyles and epicondyles

Answer 50

The condyle is the smooth surface area at the end of a bone that forms part of a joint. The epicondyle is a rounded protuberance at the end of a bone, serving as a place of attachment for ligaments, tendons, and muscles.

Question 51

function of epicondyles - humerus

Answer 51

Function: Sites for attachment of the forearm muscles. Medial Epicondyle: Attachment for flexor muscles of the forearm. Lateral Epicondyle: Attachment for extensor muscles of the forearm. Located at the distal end of the humerus, near the elbow.

Question 52

function of condyles - humerus

Answer 52

Capitulum (Lateral Condyle): Located at the distal end of the humerus. Articulates with the radius to form the elbow joint. Trochlea (Medial Condyle): Located at the distal end of the humerus. Articulates with the ulna to form the elbow joint.

Question 53

function of epicondyles - femur

Answer 53

Medial Epicondyle: Located on the medial side of the distal femur, just above the medial condyle. Attachment site for the medial collateral ligament (MCL) of the knee. Lateral Epicondyle: Located on the lateral side of the distal femur, just above the lateral condyle. Attachment site for the lateral collateral ligament (LCL) of the knee.

Question 54

function of condyles - femur

Answer 54

Medial Condyle: Located at the distal end of the femur. Articulates with the tibia to form the knee joint. Larger and more prominent than the lateral condyle. Lateral Condyle: Located at the distal end of the femur. Articulates with the tibia to form the knee joint. Smaller than the medial condyle.

Question 55

What are the important landmarks on the femur?

Answer 55

greater and lesser trochanters linea aspera epicondyles

Question 56

What is the greater trochanter of the femur, and what is its function?

Answer 56

Located on the lateral side of the proximal femur, at the junction of the femur's neck and shaft. Provides attachment points for muscles like the gluteus medius and gluteus minimus (important for hip abduction and stabilization).

Question 57

What is the lesser trochanter of the femur, and what is its function?

Answer 57

Located on the medial side of the femur, just below the neck of the femur. Attachment for the iliopsoas muscle (primary hip flexor).

Question 58

What is the linea aspera of the femur, and what is its function?

Answer 58

A prominent ridge running along the posterior surface of the femur shaft. Serves as an attachment site for muscles such as the adductors / hamstrings / vastus muscles

Question 59

What are the major palpable bony landmarks around the shoulder, elbow, and wrist?

Answer 59

Clavicle Acromion: Coracoid Process: Greater Tuberosity of Humerus Olecranon Process: Medial Epicondyle of the Humerus Lateral Epicondyle of the Humerus Styloid Process of Radius Styloid Process of Ulna Scaphoid Pisiform

Question 60

what is the metaphysis

Answer 60

A metaphysis is the region linking the epiphysis and the central diaphysis/shaft of the bone,such as the femoral neck, and tends to be the last part to ossify during development as the ossification centres link together

Question 61

What are the key functions of bone in the human body?

Answer 61

- Support the body and prevent it crumpling under its own weight - Provide a surface onto which muscles can be attached and hence transfer force for movement - Protect soft tissues within, such as in the vertebral column - Act as a calcium store so there isn’t too much in the blood - Haematopoiesis – synthesise erythrocytes within the bone marrow

Question 62

What are the main components of bone

Answer 62

Collagen & Hydroxyapatite

Question 63

collagen - structure + function

Answer 63

superhelical protein made of Gly-X-Y triplet repeats. Provides flexibility and elasticity to bone, allowing it to withstand stress without breaking easily.

Question 64

Hydroxyapatite - structure + function

Answer 64

Crystalline form of calcium phosphate and calcium carbonate. Gives bone its rigidity and hardness, making it strong and able to bear weight Hydroxyapatite crystals are interspersed within collagen fibers, enhancing bone strength and rigidity.