Bones of the upper limb

Question 1

Which segments constitute the upper limb?

Answer 1

Shoulder, arm, forearm, and hand

Question 2

What is the pectoral girdle?

Answer 2

Bony ring incomplete posteriorly, formed by scapulae and clavicles + completed anteriorly by manubrium and sternum

Question 3

Where does the upper limb articulate with the axial skeleton?

Answer 3

Only at the sternoclavicular joint

Question 4

Mention and describe the parts that constitute the clavicle

Answer 4

Sternal end: clavicle articulates with the manubrium of the sternum (sternoclavicular joint)
Acromial end: clavicle articulates with the acromion of scapula (acromioclavicular joint)
Shaft: medial 2/3 are convex anteriorly, while the lateral third is flattened and concave anteriorly

Question 5

Mention and describe the structural features of the clavicle

Answer 5

Trapezoid line
Conoid tubercle
Impression for costoclavicular ligament
Impression of pectoralis major

Question 6

What are the main functions of the clavicle?

Answer 6

• Serves as pivoting strut from which the scapula and free limb are suspended
• Protects neurovascular bundles supplying the upper limb (forms one of the cervico-axillary canal boundaries)
• Transmits shocks from UL to axial skeleton

Question 7

Mention and describe the parts that constitute the scapula

Answer 7

• Head: inferior to spine of scapula and superior to the neck
• Neck: medial to the head
• Body: triangular surface contained by the three borders of the
  scapula
• Borders
  -Medial (vertical elongation, parallel to the midline)
  -Lateral (inferior diagonal surface); contains head and neck of
  scapula
  -Superior (top part of the scapula)
• Angles:
  
  • Superior: where the superior and medial border meet
  • Inferior: where the medial and lateral border meet

Question 8

What are the structural features of the posterior surface of the scapula?

Answer 8

• Convex
• Spine of scapula: horizontal ridge on the superior aspect of the bone; divides the posterior surface into two fossae
• Infraspinous fossa (large): indentation inferior to the spine of scapula
• Supraspinous fossa (small): indentation superior to the spine of scapula

Question 9

What are the structural features of the anterior (costal) surface of the scapula

Answer 9

Subscapular fossa: major indentation on the anterior aspect of scapula

Question 10

What is the suprascapular notch?

Answer 10

Indentation near the junction of the medial 2/3 and lateral third of the superior border of the scapula

Question 10

What is the acromion?

Answer 10

Subcutaneous point of the shoulder, resulting from the continued lateral expansion of the spine of scapula

Question 11

What is the glenoid cavity?

Answer 11

Shallow, concave, oval fossa directed anterolaterally and slightly superiorly, which articulates with the head of the humerus; located on the lateral surface of the head of the scapula

Question 12

What is the coracoid process

Answer 12

Bony projection superior to the glenoid cavity, directed anterolaterally

Question 13

Mention and describe the parts that constitute the humerus

Answer 13

Head: superiormost ball-shaped part of the bone that articulates with the scapula (glenohumeral joint)
Neck: anatomical and surgical
- Anatomical neck: distal to humeral head, separates the head from the tubercles
- Surgical neck: distal to the tubercles
Shaft: longitudinal continuation of the bone between the neck and the distal end
Distal end: end of bone on the opposite side of the head, distal to glenoid cavity

Question 14

Which are the structural features of the head of humerus?

Answer 14

Intertubular sulcus: indentation in between the tubercles
Greater tubercle: larger prominence of the proximal end facing laterally
Lesser tubercle: lesser prominence located on the proximal end of humerus, medially to the grater tubercle

Question 15

Which are the structural features of the shaft of the humerus?

Answer 15

Deltoid tuberosity: laterally
Radial groove: posteriorly
Supra-epicondylar ridges: the inferior end of humeral shaft widens as the medial and lateral supra-epicondylar ridges and end distally in the medial epicondyle and lateral epicondyle
- Medial and lateral epicondyles: inferior round prominences
that articulate with the radius and ulna

Question 16

Which are the structural features of the distal end of the humerus?

Answer 16

Capitulum (lateral): for articulation with the head of the radius
Trochlea (medial): for articulation with the trochlear notch of the ulna
Coronoid fossa (anteriorly): receives the coronoid process of ulna during full flexion of the elbow
Olecranon fossa (posteriorly): accomodates olecranon of ulna during extension of the elbow
Radial fossa: superior to capitulum, accomodates the edge of the head of the radius when elbow is fully flexed

Question 17

Which are the structural features of the proximal end of the ulna?

Answer 17

Trochlear notch: articular indentation made of the olecranon posteriorly and the coronoid process anteriorly, that articulates with the trochlea of the humerus
Olecranon (posteriorly): posterior elevation of the proximal end of the ulna
Coronoid process (anteriorly): anterior, less prominent elevation of the proximal end of ulna
Tuberosity of ulna: slight elevation inferior to the coronoid process
Radial notch: rounded concavity on the lateral side of coronoid process, which articulates with the head of radius
Supinator crest: prominent ridge distal to radial notch
Supinator fossa: concavity between the crest and distal part of coronoid process

Question 18

Which are the structural features of the distal end/head of the ulna

Answer 18

Head of ulna: rounded narrow distal end of ulna
Ulnar styloid process: small conical projection arising from the head of the ulna

Question 19

Which are the structural features of the proximal end of radius

Answer 19

Cylindrical head: concave for articulation with the capitulum of humerus and the radial notch of ulna
Neck: narrow part between the head and radial tuberosity
Radial tuberosity: projection from the medial surface, demarcates proximal end from shaft

Question 20

Which are the structural features of the distal end of the radius?

Answer 20

Ulnar notch: concavity on the medial aspect of the distal end that accomodates the head of the ulna
Radial styloid process: small conical projection of the lateral aspect of the distal end of the radius
Dorsal tubercle of the radius: posterior narrow elevation in the middle of the posterior aspect of the distal end of the radius

Question 21

How do the carpals articulate with the forearm?

Answer 21

1. The proximal surfaces of the proximal row of carpals articulate with the inferior end of radius and the articular disc of the wrist joint
2. The distal surfaces of the proximal row of carpals articulate with the distal row of carpals at their proximal surfaces
3. The distal surfaces of the proximal row of carpals articulate with the metacarpals at their proximal bases
4. Distal heads of metacarpals articulate with the proximal phalange

Question 22

From lateral to medial. Which are the 4 bones in the proximal row of carpals?

Answer 22

Scaphoid (scaphoid tubercle), lunate, triquetrum, pisiform

Question 23

From lateral to medial. Which are the 4 bones in the distal row of carpals?

Answer 23

Trapezium, trapezoid, capitate, hamate

Question 24

How many phalanges does each digit have? Name them

Answer 24

Each digit has 3 phalanges (proximal, middle, and distal); except for the thumb, which only has 2 (proximal and distal)