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Anatomy > 43 & 44 Overview and bones of the upper limb > Flashcards

43 & 44 Overview and bones of the upper limb Flashcards

1
Q

What are the key features of the upper limb?

A

Its mobility and ability to grasp, strike and conduct fine motor skills (manipulation)

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2
Q

The efficiency of hand function results in large part from the ability to place it in the proper position. This occurs from movements at which five (5) joints?

A
  1. Scapulothoracic
  2. Glenohumeral
  3. Elbow
  4. Radio-ulna
  5. Wrist joint
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3
Q

What are the four (4) major segments of the upper limb and list the regions for each.

A 
1.	Shoulder
•	Pectoral
•	Scapular
•	Deltoid regions
2.	Arm
•	Anterior and posterior regions of the arm
3.	Forearm
•	Anterior and posterior regions of the forearm
4.	Hand
•	Wrist
•	Palm
•	Dorsum of the hand
•	Digits
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4
Q 
Fig 6.2 p.672 
Name the regions identified
1.	Deltoid
2.	Clavipectoral triangle
3.	pectoral
4.	scapular
5.	axillary
6.	anterior arm
7.	posterior arm
8.	Cubital
9.	posterior elbow
10.	anterior forearm
11.	posterior forearm
12.	anterior wrist
13.	posterior wrist
14.	palm/palmar
15.	dorsum of hand
16.	digits
A
  1. Deltoid
  2. Clavipectoral triangle
  3. pectoral
  4. scapular
  5. axillary
  6. anterior arm
  7. posterior arm
  8. Cubital
  9. posterior elbow
  10. anterior forearm
  11. posterior forearm
  12. anterior wrist
  13. posterior wrist
  14. palm/palmar
  15. dorsum of hand
  16. digits
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5
Q

TEST YOURSELF Fig 6.3 p.673

A

TEST YOURSELF Fig 6.3 p. 673

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6
Q

The pectoral (shoulder) girdle is a bony ring formed by which structures?

A

It is an incomplete bony ring formed posteriorly by the scapulae and clavicles and completed anteriorly by the manubrium of the sternum (which is part of the axial skeleton)

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7
Q

The pectoral girdle and bones of the free part of the upper limb form what?

A

The superior appendicular skeleton.

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8
Q

Where does the superior appendicular skeleton articulate with the axial skeleton, what functional benefit does this provide?

A

By only attaching to the axial skeleton at the sternoclavicular joint, there is an increased capacity for movement of the superior appendicular skeleton.

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9
Q

Discuss the components of the axioappendicular muscles.

A

The clavicles and scapulae of the pectoral girdle are supported, stabilized and moved by the axioappendicular muscles that attach to the relatively fixed ribs, sternum, and vertebrae of the axial skeleton.

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10
Q

TEST YOURSELF Fig. 6.4 p. 674

A

TEST YOURSELF Fig. 6.4 p. 674

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11
Q

Provide a functional description of the clavicle.

A
  • It is an “S” shaped bone that connects the upper limb to the trunk wit hits curvature designed to give it resilience.
  • The superior surface lies just deep toe the skin and platysma muscle in subcutaneous tissue and is smooth.
  • The inferior surface is rough because of the strong ligamentous attachments that bind to it.
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12
Q

Discuss the structural components of the clavicle.

A
  • There is a sternal end that is enlarged and triangular where it articulates with the manubrium of the sternum at the sternoclavicular (SC) joint.
  • Three is an acromial end which is flat where it articulates with the scapula at the acromioclavicular (AC) joint.
  • The shaft of the clavicle has a double curve in a horizontal plane with its medial half convex anteriorly and its lateral half concave anteriorly.
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13
Q

List the three (3) key features of the clavicle

A
  1. It serves as a movable, crane-like strut (rigid support) from which the scapula and free limb are suspended, facilitating maximum freedom of motion for the limb at the “scapulothoracic joint”.
  2. Forms one of the bony boundaries of the cervico-axillary canal (passageway between the neck and the arm), affording protection to the neurovascular bundle supplying the upper limb.
  3. Transmits shocks (traumatic impacts) from the upper limb to the axial skeleton.
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14
Q

Provide a functional description of the scapula.

A
  1. It is a triangular flat bone that lies on the posterolateral aspect of the thorax, overlying the 2-7th ribs.
  2. The convex posterior surface of the scapula is unevenly divided by a thick projecting rige of bone, the spine o the scapula, into a small supraspinous fossa and a much larger infraspinous fossa.
  3. The concave costal surface of most of the scapula froms a large subscapular fossa.
  4. The bony surfaces of the three fossae provide attachments for fleshy muscles and its superiolateral surface is the glenoid cavity, a shallow, concave oval fossa that is directed anterolaterally and slight superiorly.
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15
Q

TEST YOURSELF Fig. 6.5 p.675

A

TEST YOURSELF Fig. 6.5 p. 675

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16
Q

Provide a functional description of the humerus.

A
  1. It is the largest bone in the upper limb
  2. It articulates with the scapula at the glenohumeral joint and the radius and ulna at the elbow joint.
  3. It has three distinct regions, the head, shaft and distal end.
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17
Q

What five (5) structures are associated with the proximal end of the humerus

A
  1. The head which articulates with the glendoid cavity of the scapula
  2. The anatomical neck which is formed by the groove sircumscrbing the head and separating it from the greater and lesser tubercles. It is indicated by the line of attachment of the glenohumeral joint capsule
  3. The greater tubercule is at the lateral margin of the humerus
  4. The lesser tubercle projects anteriorly from the bone
  5. The surgical neck of the humerus, is the narrow part distal to the head and tubercles and is a common site of fracture
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18
Q

What structure seperates the greater and lesser tubericles?

A

The intertubercular (bicipital) groove separates the tubercles and provides protected passage for the slender tendon of the long head of the biceps muscle.

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19
Q

What two prominent features are present on the shaft of the humerus?

A
  1. The deltoid tuberosity laterally, for attachment of the deltoid muscle
  2. The oblique radial groove (spiral groove) posteriorly in which the radial nerve and deep artery of the arm lie as they pass anterior to the long head and between the medial and the lateral heads of the triceps brachii muscle.
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20
Q

What five (5) structures make u the condyle of the humerus at it’s distal end?

A
  1. Trochlea
  2. Capitulum
  3. Olecranon
  4. Coronoid
  5. Radial fossae
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21
Q

What are the two articulating structures of the condyle?

A

A lateral capitulum for articulation with the head of the radius and a medial, spool-shaped or pulley-like trochlea for articulation with the proximal end of the ulna.

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22
Q

Why is the condyle considered to be “thin”?

A

The two hollos, or fosae, occur back to back superior to the trochlea, which makes the condyle quite thin between the epicondyles.

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23
Q

List the fossa and identify which processes they receive during flexion and extension of the elbow.

A
  • Anteriorly, the coronoid fossa receives the coronoid process of the ulna during full flexion of the elbow
  • Posteriorly, the olecranon fossa accommodates the olecranon of the ulna during full extension of the elbow
  • Superior to the capitlum anteriorly, a shallower radial fossa accommodates the edge of the head of the radius whenthe forearm is fully flexed.
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24
Q

TEST YOURSELF Fig 6.6 p.677

A

TEST YOURSELF Fig 6.6 p. 677

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25
Q

TEST YOURSELF Fig 6.7 p. 677

A

TEST YOURSELF Fig 6.7 p. 677

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26
Q

TEST YOURSELF Fig. 6.8 p. 688

A

TEST YOURSELF Fig. 6.8 p. 688

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27
Q

What are the main difference between the ulna and the radius?

A

The ulna is the stabilising bone of the forearm, it is the medial and longer of the two bones whereas the radius is placed laterally and is the shorter of the two bones.

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28
Q

What are the key features of the proximal ulna?

A
  • The ulna has a large proximal end that is specialised for articulation with the humerus proximally and the head of the radius laterally.
  • To articulate with the humerus, the ulna has two prominent projections: the olecranon and the coronid process.
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29
Q

Identify the key features of the olecranon and the coronoid process of the ulna

A
  • The olecranon projects proximally from its posterior aspect (to from the point of the elbow) and serve as a short lever for extension of the elbow.
  • The coronoid process projects anteriorly.
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30
Q

What two structures form the walls of the trochlear notch on the ulna?

A

The olecranon and the coronoid processes.

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31
Q

What direction of movement is possible from the ulna and the humerus?

A

Primarily these bones provide only flexion and extension of the elbow joint, however a mall amount of abduction and adduction occurs during pronation and supination of the forearm.

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32
Q

What is the position of the tuberosity of the ulna and where is it located?

A

The tuberosity of the ulna is the attachement point for the tendon of the brachialis muscle and located inferior to the coronoid process.

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33
Q

Describe the features of the radial notch

A

It is a smooth, rounded concavity that its on the lateral side of the coronoid process. It receive the broad periphery of the head of the radius.

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34
Q

What are the two (2) important aspects of the supinator crest and supinator fossa?

A
  1. The supinator crest and supinator fossa are the attachment points to the deep part of the supinator muscle, (which supinates the forearm).
  2. The supinator cres is a promonent ridge located inferior to the radial notch on the lateral surface of the ulnar shaft and between it and the coronoid process is a concavity, the supinator fossa.
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35
Q

Provide a function description of the shaft of the ulna.

A
  • The shaft is thick and cylindrical proximally, but tapers and diminishes in diameter as it continues distally.
  • At the narrow distal end of the ulna is an abrupt enlargement, the disc-like head of the ulna wit ha small, conical ulnar styloid process.
  • The ulna does not reach the radiocarpal (wrist) joint, therefore does not participate in its actions.
36
Q

What are the key features of the proximal radius?

A

• The proximal end of the radius has a short head, neck and medially directed tuberosity.

37
Q

Provide a functional description of the proximal radius

A
  • The discoid head has a smooth superior aspect that is concave and articulates with the capitulum of the humerus during flexion and extension of the elbow joint.
  • The head also articulates peripherally with the radial notch of the ulna, thus the head is covered with articular cartilage.
38
Q

What is the difference between the shaft of the radius in comparison to the unla?

A

• Unlike the ulna, it enlarges as it passes distally

39
Q

Describe the distal end of the radius

A
  • Essentially it has four sides when sectioned transversely.
  • It medial aspect forms a concavity for the ulnar notch to accommodate the head of the ulna
  • The lateral aspect becomes increasingly ridge-like terminating distally in the radial styloid process.
  • Dorsally the dorsal tubercle of the raius lies between otherwise shallow groves for the passage of the tendons of the forearm muscles.
40
Q

What are the differentiating features of the radial styoid process and that of the ulna?

A

• The radial styloid process is larger than the ulnar styloid process and extends father distally.

41
Q

How are forces received by the radius (via the hand) transmitted to the ulna and then on to the humerus?

A
  • The shafts of the radius and ulna are essentially triangular in cross section with a sharply formed apex, the interosseous border of the radius or ulna
  • This interosseous border connects to the thin, fibrous interoseous membrane of the forearm.
  • The majority of the fibres run at an oblique course, passing inferiorly from the radius as they extend medially to the ulna, thus transmitting forces from one bone to another.
42
Q

TEST YOURSELF Fig. 6.9 p.679

A

TEST YOURSELF Fig. 6.9 p. 679

43
Q

Provide a functional description of the bones of the wrist.

A
  • The wrist (or carpus) is composed of eight carpal bones arranged in proximal and distal rows of four designed to give flexibility to the wrist.
  • The carpus is markedly convex from side to side posteriorly and concave anteriorly
  • Augmenting movement at the wrist joint, the two rows of carpals glide on each other as well as the bone adjacent to it.
44
Q

List the four (4) bones of the proximal row of carpals from lateral to medial.

A
  1. Scaphoid
  2. Lunate
  3. Triquestrum
  4. Pisiform
45
Q

List the four (4) bones of the distal row of carpals from lateral to medial.

A
  1. Trapezium
  2. Trapezoid
  3. Capitate
  4. Hamate
46
Q

Provide a function description of the scaphoid.

A

The scaphoid is a boat-shaped bone that articulates proximally with the radius and has a prominent scaphoid tubercle and is the largest bone in the proximal row of carpals.

47
Q

Provide a function description of the lunate.

A

The lunate is a moon-shaped bone between the scaphoid and the triquetrals bone. It articulates proximally with the radius and is broader anteriorly than posteriorly.

48
Q

Provide a function description of the triquetrum

A

The triquetrum (three cornered) is a pyramidal bone on the medial side of the carpus. It articulates proximally with the articular discof the distal radio-ulnar joint.

49
Q

Provide a function description of the pisiform

A

The pisiform is a small, pea-shaped bone that lies on the palmar surface of the triquestrum

50
Q

Provide a function description of the trapezium

A

The trapezium (table) is a four-sided bone on the lateral side of the carpus. It articulates with the 1st and 2nd metacarpals, scaphoid and trapezoid bones

51
Q

Provide a function description of the trapezoid

A

The trapezoid is a wedge-shaped bone that reembe the trapezium. It articulates with the 2nd metacarpal, trapezium, capitate and caphoid bones.

52
Q

Provide a function description of the capitate

A

The capitate is a head-shaped bone with a rounded extremity and is the largest bone in the carpus. It articulates primarily with the 3rd metacarpal distally and with the trapezoid, scaphoid, lunate and hamate.

53
Q

Provide a function description of the hamate

A

The hamate (little hook) is a wedge-shaped bone on the medial side of the hand. It articulates it hthe 4th and 5th metacarpal, capitate, and triquetrals bones. It has a distinctive hooked process that extends anteriorly.

54
Q

Provide a function description of the metacarpus

A
  • The metacarpus forms the skeleton of the palm of the hand between the carpus and the phalanges.
  • It is composed of five metacarpal bones, each consisting of a base, that articulates with the carpal bones, a shaft and a distal head that articulates with the proximal phalanges to form the knuckles.
55
Q

Provide a function description of the phalanges.

A
  • With the exception of the 1st digit (thumb) which only has two, each phalanx has three phalanges that consists of a base proximally, a shaft and a head distally.
  • The proximal phalanges are largest, the middle ones are intermediate in size and the distal ones are the smallest
  • The shafts of the phalanges taper distally and the terminal phalanges are flattened and expand at their distal ends, which underlie the nail beds.
56
Q

Although there is great individual variability in the ossification of the carpal bones. Use this diagram of the right hand (looking from the anterior surface) to list the order at which they ossify and the approximate ossification times.

USE OSSIFICATION GRAPHIC

A

• Approximately one centre ossifies per year in a predictable sequence, starting at age 1 with the capitate, rotating anti-clockwise each year to year 7 with the trapezoid, and ending with the pisiform at 11 or 12 years.

57
Q

Where do ossification centres occur in the phalynx?

A
  • The primary sites occur at the 9th intra-uterine week in the middle of each phalynx
  • The secondary sites occur at the base of each phalynx with the exception of the 2nd - 5th proximal phalynx.

USE GRAPHIC

58
Q

TEST YOURSELF Fig. 6.10 p.680

A

TEST YOURSELF Fig. 6.10 p. 680

59
Q

When palpating bony prominences and the upper limb is in the anatomical position what level do the following structures lie?
• Superior angle of the scapula
• Media end of the root of the scapular spine
• Inferior angle of the scapula

A
  • T2- Superior angle of the scapula
  • Opposite the spinous process of T3 - Media end of the root of the scapular spine
  • T7, near the inferior border of the 7th rib and 7th intercotal space - Inferior angle of the scapula
60
Q

When the upper limb is abducted and the hand is placed on the back of the head, what movements occur with respect to the scapula, the glenoid cavity and what is the reference point created?

A
  • The scapular is rotated
  • There is a subsequent elevation of the glenoid cavity
  • The medial border of the scapula parallels the 6th rib and thus, can be used to estimate it’s position and, deep to the rib, the oblique fissure of the lung.
61
Q

TEST YOURSELF Fig. 6.11 p.681

A

TEST YOURSELF Fig. 6.11 p.681

62
Q

TEST YOURSELF Fig. 6.12 p.682

A

TEST YOURSELF Fig. 6.12 p.682

63
Q 
Anterior landmarks to palpate (refer p. 681- 683)  
•	Jugular notch
•	Manubrium
•	Superior border of the clavicle
•	Acromioclavicular joint
•	Acromion of scapula
•	Greater tubercle of humerus
•	Lesser tubercle of humerus
•	Coracoid process of the scapula
•	Lateral epicondyle of humerus
•	Medial epicondyle of humerus
•	Lateral border of distal radius
•	Head and styloid process of ulna
•	Styloid process of radius
•	Tubercle of scaphoid
•	Pisiform
•	Hook of hamate
•	Heads of metacarpals
•	Bases, lateral aspect and heads of phalanges
A 
Anterior landmarks to palpate (refer p. 681- 683)  
•	Jugular notch
•	Manubrium
•	Superior border of the clavicle
•	Acromioclavicular joint
•	Acromion of scapula
•	Greater tubercle of humerus
•	Lesser tubercle of humerus
•	Coracoid process of the scapula
•	Lateral epicondyle of humerus
•	Medial epicondyle of humerus
•	Lateral border of distal radius
•	Head and styloid process of ulna
•	Styloid process of radius
•	Tubercle of scaphoid
•	Pisiform
•	Hook of hamate
•	Heads of metacarpals
•	Bases, lateral aspect and heads of phalanges
64
Q

Posterior landmarks to palpate (refer p. 681- 683)

  1. Superior border of clavicle
  2. Acromion of scapula
  3. Acromial angle
  4. Greater tubercle of humerus
  5. Spine of scapula
  6. Medial (vertebral) border of scapula
  7. Inferior angle of scapula
  8. Olecranon
  9. Ulna nerve
  10. Lateral epicondyle of humeru
  11. Medial epicondyle of humerus
  12. Posterior border of ulna
  13. Lateral border of distal radius
  14. Styloid process of radius
  15. Head and styloid process of ulna
  16. Pisiform
  17. Capitate
  18. Styloid process of 3rd metacarpal
  19. Posterior aspects of metacarpals and phalanges
A

Posterior landmarks to palpate (refer p. 681- 683)

  1. Superior border of clavicle
  2. Acromion of scapula
  3. Acromial angle
  4. Greater tubercle of humerus
  5. Spine of scapula
  6. Medial (vertebral) border of scapula
  7. Inferior angle of scapula
  8. Olecranon
  9. Ulna nerve
  10. Lateral epicondyle of humeru
  11. Medial epicondyle of humerus
  12. Posterior border of ulna
  13. Lateral border of distal radius
  14. Styloid process of radius
  15. Head and styloid process of ulna
  16. Pisiform
  17. Capitate
  18. Styloid process of 3rd metacarpal
  19. Posterior aspects of metacarpals and phalanges
65
Q

List the key features of the clavicle.

A
  1. It varies more in shape than most other long bones
  2. Occasionally, the clavicle is piereced by a branch of the supraclavicular nerve
  3. The clavicle is thicker and more curved in manual workers, and the sites of muscular attachments are more marked
66
Q

The clavicle is one of the most frequently fractured bones, discuss this topic.

A
  1. It is one of the most frequently fractured bones, especially in children often being caused by indirect force transmitted from an outstretched hand through the bones of the forearm and arm to the shoulder.
  2. Shoulder injuries may alos result from a fall directly on the shoulder
  3. The weakest part of the clavicle is the junction of its middle and lateral thirds
  4. The slender clavicles of a newborn may be fractured during the delivery, especially if they are broad shouldered, however the fracture is usually incomplete (greenstick) and will heal quickly.
67
Q

What happens to the muscles around the clavicle following a fracture?

A
  1. The sternocleidomastoid muscle elevates the medial fragment of the bone.
  2. Because of the subcutaneous position of the clavicles, the end of the superiorly directed fragment is prominent – readily palpable and / or apparent.
  3. The trapezius muscle is unable to hold the lateral fragment up owning to the weight of the upper limb, so the shoulder drops.
  4. The lateral frament of the clavicle may be pulled medially by the adductor muscles of the arm, such as the pectoralis major
  5. Overriding of the bone fragments shortens the clavicle
68
Q

What prevents dislocation of the AC joint following a clavicular fracture?

A

The strong coracoclavicular ligament.

69
Q

Describe the ossification of the clavicle

A
  • It is the first long bone to ossify (via intramembranous ossification), beginning during the 5th to 6th embryonic weeks from medial and lateral primary centres that are close together in the shaft
  • A secondary ossification centre appears at the sternal end that forms a scale-like epiphysis that begins to fuse wit hthe shaft (diaphysis) between 18 to 25 years and is completely fused by 25 to 31 years of age. Accordingly, it is the last of the long bones to fuse.
  • Sometimes fusion of the two ossification centres fail and a bony defect forms between the lateral and medial thirds of the clavicle. This can be mistaken for a fracture, so both clavicles may need to be x-rayed for comparison.
70
Q

How did fractures of the scapula occur and what may they be associated with?

A
  • They usually occur as a result of severe trauma, (i.e. pedestrian accidents) and is usually associated with fractured ribs.
  • Most fractures require little treatment because the scapula is covered on both sides by muscles.
  • Most fractures involve the protruding subcutaneous acromion.
71
Q

Discuss proximal fractures of the humerus occur and identify in what context they occur?

A
  • Most proximal humeral fractures occur at the surgical neck and are especially common in elderly people with osteoporosis, often as a result of a minor fall on a hand.
  • They are typically an impacted fracture with one fragment being driven into the spongy bone of the other fragment
  • Because of the impaction, the fracture is often stable and the person is able to passively move the arm with minimal pain.
72
Q

Discuss avulsion fractures of the humerus occur and identify in what context they occur?

A
  • An avulsion fracture of the greater tubercle of the humerus is most commonly seen in middle aged and elderly people
  • A small part of the tubercle of the tendon is avulsed and the fracture usually results from a fall on the acromion.
  • In younger people an avulsion fracture of the greater tubercle usually results from a fall on the hand when the arm is abducted with muscles (esp. the subscapularis) that remain attached to the humerus pull the limb into a medial rotation.
73
Q

TEST YOURSELF Fig. B6.2 p.684

A

TEST YOURSELF Fig. B6.2 p. 684

74
Q

How does a transverse fracture of the shaft of the humerus usually occur?

A

Transverse humeral fractures frequently results from a direct blow to the arm. The pull of the deltoid muscle carries the proximal fragment laterally.

75
Q

How does a spiral fracture of the humeral shaft usually occur?

A

Spiral fractures of the humeral shaft usually result from an indirect injury such as fall on the outstretched hand.

76
Q

How might an oblique fracture of the humerus be managed?

A

Because the humerus is surrounded by muscles and has a well-developed periosteum, the bone fragments usually unite well, although one must consider foreshortening of the bone.

77
Q

How is an intercondylar fracture of the humerus likely to occur?

A

Intercondylar humeral fractures usually result from a severe fall on the flexed elbow. The olecranon of the ulna is driven like a wedge between the medial and lateral parts of the condyle, separating one or both parts from the humeral shaft.

78
Q 
What nerves are in direct contact with the following parts of the humerus? 
•	Surgical neck
•	Radial groove
•	Distal end of the humerus
•	Medial epicondyle
A
  • Surgical neck: axillary nerve
  • Radial groove: radial nerve
  • Distal end of the humerus: median nerve
  • Medial epicondyle: ulnar nerve
79
Q

Why are fractures of one forearm bone often associated with the fracture of the other bone?

A

• The shafts of the radius and ulna are firmly bound together by the interosseous membrane, this is typically also associated with a dislocation of the nearest joint.

80
Q

Provide the key points regarding a Colles fracture.

A
  • Colles fractures are the most common fracture of the forearm, often in adults >50 and more frequently occurring in women because of bones weakened by osteoporosis
  • It is a complete transverse fracture of the distal 2cm of the radius and the distal fragment is displaced dorsally and often comminuted.
  • The ulnar styloid process is avulsed. Normally the radial styloid projects father distally than the ulnar styloid on a lateral x-ray.
  • It results from forced dorsiflexion of the hand, usually as a result of try to ease a fall by outstretching the upper limb.
81
Q

Why is a colles fracture called a dinner fork deformity?

A
  • It is often referred to as a dinner fork deformity because of a posterior angulation that occurs in the forearm just proximal to the wrist and the normal anterior curvature of the relaxed hand.
  • The posterior bending is produced by the posterior displacement and tilt of the distal fragment of the radius.
82
Q

What happens when the distal end of the radius fractures in children?

A
  • The fracture line may extend through the distal epiphyseal plate. These are common in older children because of their frequent falls in which the forces are transmitted from the hand to the radius and ulna.
  • The healing process may result in misalignment of the epiphyseal plate and disturbance of the radial growth.
83
Q

The scaphoid is the most frequently fractured carpal bone. How do these fractures typically occur and what is the significance?

A
  • They often result from a fall on the palm when the and is abducted, with the fracture occurring across the narrow part of the scaphoid.
  • Owing to the retrograde blood supply to the proximal part of the scaphoid, union of the fractured parts may take at least 3 months.
  • It may take 10-14 days to present on x-ray and a high degree of clinical suspicion is required.
  • (Mis)diagnosed saphoid fractures may result in avascular necrosis of the proximal part and could result in degenerative joint disease of the wrist.
  • Corrective surgery is called arthrodesis
84
Q

What is the three (3) risk of a fracture of the hamate?

A
  • Non-union may occur from the traction produced by the attached muscles.
  • Because the ulnar nerve is close to the hook of the hamate, the nerve may be injured resulting in decreased grip strength
  • There is risk that the ulnar artery may also be damaged when the hamate is fractured.
85
Q

With the exception of the 1st metacarpal, why are metacarpal fractures generally considered stable and why do they heal so well? What is the exception to this?

A
  • Because they are closely bound together and have a good blood supply.
  • When severe crushing injuries of the hand produce multiple metacarpal fractures.
86
Q

Describe a boxer’s fracture.

A
  • It is a fracture of the 5th metacarpal caused by an unskilled person punching with a closed and abducted fist.
  • The head of the bone rotate over the distal end of the shaft, producing a flexion deformity.
87
Q

What is the significance of proximal and middle phalanges in comparison to distal phalanx fractures?

A
  • A distal phalanx fracture is usually comminuted and associated with a painful haematoma that develops soon after a crushing injury.
  • Fractures of the proximal and middle phalanges are usually the result of crushing or hyperextension injuries. Because of the close relationship of phalangeal fractures to the flexor tendons, the bone fragments must be carefully realigned to restore normal function of the fingers.

Anatomy (6 decks)

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