Upper Limb Flashcards

1
Q

The clavicle develops via both intramembranous & endochondral ossification. The medial growth plate is the last in the body to close – approx 23-25 yrs. Why is that useful to know?

A
  • Help identify the age of the skeleton

- To tell if skeletal growth is complete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the plane of the scapula relative to the frontal (coronal) plane of the body:

A

30-45 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the position of the scapula relative to the thorax:

a) Root of the spine of scapula
b) Inferior angle

A

a) 3rd rib

b) 7th rib/ intercostal space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

State the attachments of the intra-articular disc.
Inferior attachment =
superior attachment =

A
inferior = cartilage of 1st costal
superior = articular surface of clavicle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the function of the intra-articular disc?

A

To enhance joint curvature and contact and to absorb joint forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why is rotation of the clavicle termed conjunct rotation?

A

conjunct rotation occurs as a results of the tightening of a passive structure. During UL abduction the conoid ligament is tightened and causes clavicular rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain how the conoid ligament produces upward rotation of the clavicle.

What is the advantage of this?

A

The conoid ligament attaches to the posterior medial part of the clavicle (conoid tubercle), when tightened, the tubercle is pulled towards the coracoid process of the scapular creating upwards rotation. This is advantageous as upwards rotation of the clavicle allows increased rotation of the scapular and this increased GHJ range of motion, through conjunct rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

the glenoid labrum
• where does it attach?
• what is it made of?
• what are its functions?

A

attachment: margin of the glenoid cavity
made of: fibrocartilage
functions: to increase articular surface and absorb joint forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which tendon attaches to the supraglenoid tubercle and the superior aspect of the labrum and what is a possible consequence of this?

A

The tendon of the long head of biceps brachii, as a result is can become impinged during GHJ movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The inferior glenohumeral ligament complex (IGHLC) – has anterior & posterior bands with a loose axillary pouch between them. Why?

A

The pouch allows extra range of movement when stretched

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The transverse humeral ligament is extra-capsular. What is its function?

A

To hold the tendon of the long head of biceps brachii in place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which 2 ligaments provide the main resistance to Inferior translation of the humerus when the upper limb is adducted (relaxed standing)?

A

coracohumeral ligament and superior glenohumeral ligament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The GHJ is the most mobile and most commonly dislocated joint in the body. Anterior-inferior (subcoracoid) dislocation is by far the most common. Which ligament resists anterior / inferior translation of the humeral head on the glenoid when the upper limb is in a position of 90 degrees abduction + external rotation:

A

anterior band of the inferior glenohumeral ligament complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which structures form the coracoacromial arch?

A

coracoid process of clavicle, acromion process of scapular and coracoacromial ligament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the subacromial space?

A

The space below the coracoacromial arch, which contains the sub-acromial bursa, supraspinatus and long head of biceps brachii tendon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name the 3 anatomical joints of the shoulder region involved in achieving full (~180 degrees) UL abduction AND state their relative contribution to that movement (in degrees or fractions).

A
  1. GHJ > 120 degrees - 2 thirds
  2. ACJ > 20 degrees
  3. SCJ > 40 degrees

ACJ & SCJ make up 1 third

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is meant by medial winging of the scapular?

A

lifting of the medial boarder of the scapular during dynamic movement due to instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What could cause medial winging of the scapular?

  1. Muscle weakness:
  2. Nerve dysfunction:
A
  1. Muscle weakness: serratus anterior

2. Nerve dysfunction: long thoracic n. or C5 to C7 trunk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What muscle does the suprascapular nerve innervate?

A

supraspinatus

infraspinatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Define varus alignment

A

distal end is medial compared to the proximal end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define valgus alignment

A

distal end is lateral compared to the proximal end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The normal alignment of the humerus and ulna in the frontal plane is

A

10-15 degrees valgus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The olecranon process of the ulna is an attachment for?

A

triceps brachii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The ulnar tuberosity of the ulna is an attachment for?

A

brachialis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
The articular fovea of the head of the radius articulates with?
The captiulum of humerus
26
The articular circumference of the head of the radius articulates with?
The radial notch of the ulna
27
Which structures limit elbow flexion?
humeroulnar and humeroradial articulation & muscle bulk
28
Which structures limit elbow extension?
the olecranon process of the ulna and muscle tension
29
Which structures limit elbow supination?
IOL tension, the oblique cord & pronators
30
Which structures limit elbow pronation?
IOL tension, oblique cord and supinators
31
In elbow extension, what limits valgus?
AMCL + humeral-ulnar articulation
32
In elbow flexion, what limits valgus?
AMCL > humeral-ulnar articulation
33
In elbow extension, what limits varus?
humeral-ulnar articulation > LCLC
34
In elbow flexion, what limits varus?
humeral-ulnar articulation > LCLC
35
Any muscle involved in supination – pronation must insert onto the:
cubital fossa
36
Name the 2 primary muscles of supination:
supinator and biceps brachii
37
Identify the boundaries of the cubital fossa.
medial border of brachioradialis, medial border of pronator teres and the epicondyle line
38
The main contents of the cubital fossa (from lateral to medial) are the: 1. biceps brachii tendon 2. brachial artery 3. median nerve 4. ?
ulnar nerve
39
Palpate the cubital tunnel behind the medial epicondyle of the humerus. Which nerve travels through here?
ulnar nerve
40
The humerus has two necks; the anatomical and the surgical, why are they called this?
Anatomical neck is directly below the head of the humerus - anatomical location Surgical neck is located at a common fracture site that often requires surgery
41
What movement does the anterior sternoclavicular ligament resist?
Anterior glide of the medial end of clavicle; retraction of clavicle
42
What movement does the posterior sternoclavicular ligament resist?
Posterior glide of the medial end of clavicle; protraction of clavicle
43
What movement does the interclavicular ligament resist?
Superior glide of the medial end of clavicle; lateral displacement
44
What movement does the Intra-articular disc resist?
Medial displacement of the clavicle
45
What movement does the costoclavicular ligament resist?
Everything except inferior displacement
46
What movement does the Superior acromioclavicular ligament resist?
all glides of clavicle on acromion
47
What movement does the Inferior acromioclavicular ligament resist?
all glides of clavicle on acromion
48
What movement does the Trapezoid ligament resist?
Scapula moving medial relative to clavicle
49
What movement does the Conoid ligament resist?
Lateral clavicle moving superiorly | suspends the scapula
50
What movement does the Coracoacromial ligament resist?
If GHJ is very unstable it can resist the superior migration of the HOH
51
What muscles perform Sternoclavicular / clavicular elevation?
superior fibers of trapezius
52
What muscles perform Clavicular depression?
Subclavius
53
What muscles perform Scapular elevation?
superior fibers of trapezius Levator scapulae Rhomboid minor Rhomboid major
54
What muscles perform Scapular depression?
Lower trapezius +/- pectoralis minor
55
What muscles perform Scapular abduction / protraction?
Serratus anterior | Pectoralis minor
56
What muscles perform Scapular adduction / retraction?
Superior, middle + lower trapezius Levator scapulae Rhomboid major Rhomboid minor
57
What muscles perform Scapular upward rotation?
Superior, middle & lower trapezius | Serratus anterior
58
What muscles perform Scapular downward rotation?
Levator scapulae Rhomboid major Rhomboid minor
59
What muscles perform Scapular anterior tilt?
Rhomboid major Rhomboid minor Levator scapulae Pectoralis minor
60
What muscles perform GHJ flexion?
``` Anterior deltoid Middle deltoid Clavicular head pectoralis major Coracobrachialis Biceps brachii ```
61
What muscles perform GHJ Extension?
Sternal head pectoralis major Latissimus dorsi Teres major Posterior deltoid
62
What muscles perform GHJ Abduction?
Middle deltoid* Anterior deltoid Supraspinatus (SST)
63
What muscles perform GHJ Adduction?
Posterior deltoid | Sternal head pectoralis major
64
What muscles perform GHJ Internal (medial) rotation?
Subscapularis (SSC) Anterior deltoid Pectoralis Major Latissimus dorsi
65
What muscles perform GHJ External (lateral) rotation?
``` Infraspinatus (IST) Teres minor (T min) Posterior deltoid ```
66
What muscles perform GHJ Horizontal flexion/ adduction?
Pectoralis major | Anterior deltoid
67
What muscles perform GHJ Horizontal extension/ abduction?
Posterior deltoid | infraspinatus
68
What spinal levels make up the Brachial Plexus
C5 - T1
69
What major nerves are part of the Posterior Cord?
``` Axillary Radial Upper subscapular Thoracodorsal Lower subscapular ```
70
What major nerves are part of the Lateral Cord?
Lateral pectoral | Musculocutaneous
71
What major nerves are part of the Medial Cord?
Medial pectoral | Ulnar
72
What major nerve is part of both the medial and lateral cord?
Median
73
What are the boundaries and contents of the suprascapular foramen?
Boundaries: superior border of scapula, superior transverse scapular ligament Contains: suprascapular nerve
74
What are the boundaries and contents of the quadrangular space?
Boundaries: shaft of the humerus laterally, the long head of the triceps medially, the teres minor muscle superiorly, and the teres major muscle inferiorly Contains: Auxiliary nerve and posterior humeral circumflex artery
75
What are the boundaries and contents of the triangular interval?
Boundaries: teres major superiorly, the long head of the triceps medially, and the lateral head of the triceps laterally Contains: Radial nerve and profunda brachii artery
76
What type of joint is the humeroulnar joint and what is it made up of?
Synovial hinge | Trochlea of humerus & trochlear notch of ulna
77
What type of joint is the humeroradial joint and what is it made up of?
Synovial hinge | Capitulum of humerus & fovea of radial head
78
What type of joint is the proximal radioulnar joint and what is it made up of?
Synovial pivot | Radial notch of ulnar & head of radius
79
What does the articular capsule of the elbow resist?
minimal (lax) | Anterior capsule may resist valgus in Ext.
80
What does the radial collateral ligament (RCL) of the elbow resist?
varus & posterolateral instability
81
What does the lateral ulnar collateral ligament (LUCL) resist?
varus | & posterolateral instability
82
What does the medial collateral ligament (MCL) resist?
valgus force anterior band important
83
What does the annular ligament resist?
Lateral & distal subluxation of the radial head
84
What does the oblique cord resist?
End range supination
85
What does the interosseous membrane (ligament) (IOM/IOL) resist?
separation of radius / ulna
86
What does 'close-packed position' of a joint refer to?
The “close-packed position” of a joint is defined as the position of great articular contact & when the capsuloligamentous stabilisers are most taut.
87
What is the close packed position of the humeroulnar joint?
extension
88
What is the loose packed position of the humeroulnar joint?
80~ degrees Flexion
89
In which direction do the fibres of the interosseous ligament run?
From distal radius to proximal ulna | Proximomedially
90
Describe the axial transmission of force from the wrist to the humerus
When falling on a pronated & flexed wrist with an extended arm (most common), force is first directed at the carpals. This is then received at the radius, the IOM then distributes this force to the ulna as the force moves proximally. Force is then distributed from the olecranon of the ulna to the humerus and up the upper arm
91
In which range of pronation – supination is there maximal force transmission across the PRUJ & DRUJ?
PRUJ: 0-30 degrees DRUJ: 0-60 degrees Supination
92
What is the significance of force transmission across the PRUJ & DRUJ functionally?
Greatest load transmission across the joints in neutral to 60 degrees supination distally
93
In which range of pronation – supination is the interosseous membrane lax? What is the significance of this functionally?
Full pronation - Falling on a pronated wrist increases the susceptibility of injury to the radius as the IOM's ability to distribute force is impaired when it is lax
94
What are the medial and lateral intermuscular septa?
The lateral intermuscular septum separates the anterior and posterior compartments of the arm whilst the medial septum separates the lateral and medial compartments of the arm
95
What movement(s) does Biceps brachii (Long and Short head) produce?
Elbow F & forearm sup’n | + GHJ F
96
What movement(s) does brachialis produce?
Elbow Flexion
97
``` What movement(s) does triceps brachii (long head, lateral head & medial head) produce? ```
``` Elbow E (+ GHJ E by long head) ```
98
What movement(s) does pronator teres produce?
Elbow flexion | Wrist Pronation
99
What movement(s) does flexor carpi radialis produce?
Wrist flexion + abduction
100
What movement(s) does palmaris longus produce?
wrist flexion
101
What movement(s) does flexor carpi ulnaris produce?
wrist flexion and adduction
102
What movement(s) does pronator quadratus produce?
wrist pronation
103
What movement(s) does flexor digitorum superficialis produce?
flex 2nd - 5th digit (PIP joint)
104
What movement(s) does flexor digitorum profundus produce?
flex 2nd - 5th digit (PIP & DIP joint)
105
What movement(s) does flexor pollicis longus produce?
flex 1st digit
106
What movement(s) does brachioradialis produce?
Elbow flexion
107
What movement(s) does extensor carpi radialis longus produce?
Wrist extension and abduction
108
What movement(s) does extensor carpi radialis brevis produce?
wrist extension and abduction
109
What movement(s) does extensor carpi ulnaris produce?
wrist extension and adduction
110
What movement(s) does supinator produce?
wrist supination
111
What movement(s) does anconeus produce?
Retracts joint capsule during elbow E. Abduction of ulna during pronation. Posterolateral stability
112
What movement(s) does extensor digitorum produce?
2nd - 5th digit extension
113
What movement(s) does extensor digiti minimi produce?
5th digit extension
114
What movement(s) does extensor pollicis brevis produce?
1st digit extension
115
What movement(s) does extensor pollicis longus produce?
1st digit extension
116
What movement(s) does abductor pollicis longus produce?
1st digit abduction
117
What movement(s) does extensor indices produce?
2nd digit extension
118
Which nerve travels through pronator teres?
Median Nerve
119
Which nerve travels through supinator?
Radial (deep)
120
Name the 2 main superficial veins of the upper limb
cephalic and basilic veins
121
name the vein in the cubital fossa that connects the two main superficial veins of the upper limb
median cubital vein
122
Which nerve travels deep to brachioradialis
radial nerve
123
What attaches at the fovea of the distal ulna?
TFCC
124
What articulates with the articular circumference of the distal ulna?
ulnar notch of the radius
125
What is the dorsal tubercle of the distal radius a pulley for?
the tendon of extensor pollicus longus
126
The lunate tends to dislocate in what direction?
volar (Towards flexor surface)
127
the tubercle of the trapezium is an attachment for?
flexor retinaculum
128
The hook of the hamate provides attachment for?
flexor retinaculum
129
the most common carpal bone to fracture is?
scaphoid
130
the common mechanism of injury to the scaphoid is?
forceful hyperextension where the scaphoid impacts the dorsal rim of the radius
131
At the radiocarpal joint the radius articulates with?
the lunate and scaphoid
132
which carpal bone has greater contact with the radius
scaphoid
133
The TFCC articulates with the?
radius, ulna, lunate, triquetrium
134
What is the structural classification of the radiocarpal joint?
synovial, ellipsoid
135
Explain the term “avascular necrosis” and why it is a possible secondary complication post-scaphoid fracture
Avascular necrosis is the death of bone tissue due to a lack of blood supply. It can lead to tiny breaks in the bone and the bone's eventual collapse. A broken bone or dislocated joint can interrupt the blood flow to a section of bone. Since the scaphoid blood supply comes from two different vascular branches of the radial artery, fractures can limit access to blood supply
136
The volar aspect of the head of the metacarpal is wider than the dorsal aspect. What is the significance of this?
The dorsal surface, broad and flat, supports the tendons of the extensor muscles. The volar surface is grooved in the middle line for the passage of the flexor tendons. The wider heads of the metacarpals allow the tendons to sit in the grooves during flexion. All of these features are to increase stability which tightens ligaments, improves grip and restricts abduction
137
What is the “midcarpal joint”?
A synovial joint between the proximal row (scaphoid, lunate & triquetrum) and distal row (trapezoid, trapezium, capitate & hamate) of carpal bones
138
Which row of carpals exhibits a greater amount of movement between adjacent carpal bones?
The proximal row - each carpal moves independently
139
Which row generally moves as a unit? Which bone is most commonly used as the reference in measurement of ROM?
The distal row. The capitate is generally used as a reference
140
Do you have greater range of flexion or extension at the wrist? Why?
Flexion, bony features and volar tilt
141
Do you have greater range of abduction or adduction at the wrist? Why?
Adduction, styloid of radius
142
Compare the mobility of the 1st CMC to the 2nd – 5th CMC joints.
1st > 2nd -5th: saddle joint compared to plane joint
143
The 2nd metacarpal articulates with the trapezium, trapezoid, capitate & 3rd metacarpal which makes it the least mobile. What is the advantage of this?
It creates a stable column in the center of the hand which allows for force transfer and stablises the 2nd digit when pointing or pushing
144
Compare the mobility of the 1st MCP to the 2nd – 5th MCP’s.
1st < 2nd -5th
145
Pinch your thumb & index – what force does it exert on your 1st MCP joint? Which collateral ligament of the thumb resists this force?
Valgus force Ulnar collateral ligament of the thumb
146
Compare the articular surface areas on the metacarpal and phalange in the MCP joints. What structure improves contact area of this joint?
Palmar plate
147
Identify the collateral ligaments of the MCP joint. In which position are they taut?
Flexion
148
What is the transverse carpal ligament / flexor retinaculum function?
To protect the entrance of tendons and nerves into the hand from the wrist
149
Many muscles of the forearm cross the wrist. Which of these inserts onto the base of the metacarpals?
``` Flexor carpi radialis Flexor carpi ulnaris Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris ```
150
Give examples of how muscles of the forearm that cross the wrist work together in teams
Flexor carpi radialis and flexor carpi ulnaris work together to flex the wrist Extensor carpi radialis longus, Extensor carpi radialis brevis and extensor carpi ulnaris work together to extend the wrist. If only the radial or ulnaris muscle(s) was to contract in one of these movements abduction or adduction would occur instead of flexion or extension
151
Which muscles of the forearm that cross the wrist is best designed to produce wrist extension and why?
extensor carpi radialis brevis, due to its line of action (longus would provide more abduction)
152
Which muscles of the forearm that cross the wrist produces a varus force on the elbow when it contracts?
extensor carpi ulnaris
153
Which muscles travel through the carpal tunnel?
Flexor digitorum superficialis Flexor digitorum profundus Palmaris longus
154
What movement(s) does abductor pollicis brevis produce?
Abduction of 1st digit (thumb)
155
What movement(s) does flexor pollicis brevis produce?
Flexion of 1st digit (thumb)
156
What movement(s) does opponens pollicis produce?
Opposition of 1st digit (thumb)
157
What movement(s) does abductor digiti minimi produce?
Abduction of 5th digit
158
What movement(s) does flexor digiti minimi produce?
Flexion of 5th digit
159
What movement(s) does opponens digiti minimi produce?
Opposition of 5th digit
160
What movement(s) does palmaris brevis produce?
improves grip
161
What movement(s) does adductor pollicis produce?
Adducts the 1st digit (thumb) at the CMC joint
162
What movement(s) does palmar Interossei produce?
Adduction, flexion and extension
163
What movement(s) does dorsal Interossei produce?
Abduct fingers
164
What movement(s) does the lumbricles produce?
Flex MCP joints and extends IP joints
165
Describe the distal insertion of the extensor digitorum
The extensor digitorum expands into three bands at the MCP. The central band extends to the middle phalanx whilst the lateral bands wrap around the middle phalanx and insert onto the distal phalanx.
166
What is the extensor hood mechanism? What is its function?
Expansion of the extensor digitorum to provide an attachment for the interossei and lumbricales and allows specialised dorsal grip at the fingers
167
The ulnar nerve passes superficial to the flexor retinaculum and enters the hand via?
Guyon's canal
168
What are the 2 arteries of the forearm (branches of the brachial artery)?
Radial artery | Ulnar artery
169
which tendon travels around the dorsal tubercle of the radius
extensor pollicis longus
170
Which muscles form the anatomical snuff box?
* Radial side - abductor pollicis brevis & extensor pollicis brevis * Ulnar side - extensor pollicis longus
171
What is palpable in the floor of the snuffbox
* proximal = radial styloid * middle = scaphoid * distal = scaphotrapezial joint
172
Describe the common mechanism of a clavicle fracture? i.e. how do they fall? what causes the bone to break?
Occurs through fall on shoulder or direct shoulder trauma. The middle third is the thinnest part of the clavicle. The medial and lateral thirds are well supported by their ligamentous and muscle attachments. Therefore, the middle third is the weakest and most likely to fracture, as this bends the clavicle over the 1st costal. The costal is stronger and this results in fracture.
173
In a midshaft clavicle fracture, explain the reason for the inferior and medial movement of the lateral end
The clavicle is acting as a strut for the scapula, so the scapula moves downwards when this strut is broken
174
What is the common mechanism of ACJ dislocation?
A fall onto the point of the shoulder
175
There are multiple ligaments that stabilise the ACJ. Which ones usually tear first in a sprain? With increasing force and deformity, which additional ligaments are possibly affected?
Acromioclavicular ligament Coracoclavicular ligaments (trapezoid and conoid ligaments)
176
Describe AND explain the anatomical basis for the resultant deformity of an ACJ dislocation. i.e. How does it appear and why?
A superior displacement of the distal (lateral) clavicle. This dislocation/ displacement often damages the structural ligaments holding the clavicle, such as the acromioclavicular ligament. After the trauma of the dislocation and lack of structure holding the clavicle in place, the clavicle is forced superiorly.
177
Explain why SCJ dislocations are much less common than ACJ joint dislocations
The SCJ is sturdier and least mobile joint of the two as it is a plane joint whilst the SCJ is a saddle joint. Usually an ACJ dislocation would occur before a SCJ one.
178
Why are posterior SCJ dislocations potentially life threatening?
Posterior to the SCJ are many major blood vessels and the trachea which could be punctured in a posterior SCJ dislocation.
179
Which passive & active structures provide support to the GHJ in the anatomical position?
Passive = coracohumeral ligament, superior glenohumeral ligament, middle glenohumeral ligament, inferior glenohumeral ligament complex, transverse ligament Active =supraspinatus, infraspinatus, subscapularis, teres minor
180
What would be the disadvantage of excessive superior translation of the head of humerus during upper limb abduction?
Impingement of structures in the subacromial space
181
List 5 muscles that may act to stabilise (or depress) the pectoral girdle when using the upper limbs for weight-bearing purposes such as using crutches or lifting the trunk off a chair:
- Pectoralis major - Latissimus dorsi - Pectoralis minor - Lower traps - Subclavius
182
Describe and explain the roles of the deltoid and the rotator cuff muscles during upper limb elevation in the scapular plane.
- Deltoid – upper limb abduction (anterior & middle fibres) - Rotator cuff (GH head stabilisation) o Supraspinatus > abduction - The prime mover = middle deltoid o Largest PCSA & largest moment arm o In first 80 degrees of abduction > supraspinatus has the largest moment arm but a smaller PCSA - During deltoid and supraspinatus contraction there is superior translation o This is resisted by infraspinatus and teres major through inferior translation o To avoid impingement of the subacromial space which contains:  Subacromial bursa – very pain sensitive  Supraspinatus tendon  Long head of biceps tendon
183
Clavicular features Ensure that you are able to identify the following bony features AND understand their relevance. Consider questions such as: Is this feature for attachment or articulation? etc Note any distinguishing features which may assist you in identifying the feature in the future. From lateral to medial: - Lateral articular surface - Trapezoid line - Conoid tubercle - Subclavian groove - Impression for costoclavicular ligament - Medial articular surface
From lateral to medial: - Lateral articular surface > articulates with the acromion of scapula - Trapezoid line > attachment for trapezoid part of coracoclavicular ligament - Conoid tubercle > attachment for conoid part of coracoclavicular ligament - Subclavian groove > attachment for subclavian muscle - Impression for costoclavicular ligament - Medial articular surface > articulates with manubrium of sternum and 1st costal cartilage
184
``` Scapular Features Anterior: Lateral to Medial (Including shared structures): - Acromion - Glenoid cavity - Coracoid process - Infraglenoid tubercle - Lateral border - Suprascapular notch - Subscapular fossa - Superior border - Inferior angle - Superior angle - Medial boarder ``` Posterior: Lateral to Medial - Articular surface of acromion - Greater scapular notch - Spine of scapula - Supraspinatus fossa - Infraspinatus fossa
Anterior: Lateral to Medial (Including shared structures): - Acromion > attachment for lower trapezius & middle deltoid muscles - Glenoid cavity > articulates with head of humerus - Coracoid process > attachment for pectoralis minor & coracobrachialis muscles - Infraglenoid tubercle > attachment for long head of biceps brachii muscle - Lateral border > attachment for teres minor muscle - Suprascapular notch > passage for suprascapular nerve - Subscapular fossa > attachment for subscapularis muscle - Superior border > shortest and thinnest border - Inferior angle > attachment for teres major & part of latissimus dorsi muscles - Superior angle > attachment for levator scapulae muscle - Medial boarder > attachment for serratus anterior, levator scapulae, rhomboid major & rhomboid minor muscles Posterior: Lateral to Medial - Articular surface of acromion > articulates with lateral end of the clavicle (acromial end) - Greater scapular notch > connects supraspinous and infraspinous fossas > passageway for suprascapular nerve and suprascapular artery - Spine of scapula > attachment for levator scapulae, middle & lower trapezius, posterior deltoid & supraspinatus muscles - Supraspinatus fossa > attachment for supraspinatus muscle - Infraspinatus fossa > attachment for infraspinatus muscle
185
Proximal to Distal (Proximal End): - Head of humerus - Anatomical neck - Greater tubercle - Lesser tubercle - Intertubercular sulcus - Surgical neck - Lateral lip of intertubercular sulcus - Medial lip of intertubercular sulcus - Roughening of floor of intertubercular sulcus - Deltoid tuberosity - Radial groove
Proximal to Distal (Proximal End): - Head of humerus > articulates with glenoid cavity of scapula - Anatomical neck > directly below head of humerus - Greater tubercle > attachment of supraspinatus (superior facet), infraspinatus (middle facet) & teres minor (inferior facet) muscles - Lesser tubercle > attachment for subscapularis muscle - Intertubercular sulcus > passageway for tendon of long head of biceps brachii muscle - Surgical neck > common fracture site - Lateral lip of intertubercular sulcus > attachment for pectoralis major muscle - Medial lip of intertubercular sulcus > attachment for teres major muscle - Roughening of floor of intertubercular sulcus > attachment for latissimus dorsi muscle - Deltoid tuberosity > attachment for deltoid muscles - Radial groove > passageway for radial nerve & deep brachial artery
186
``` Humerus: Proximal – Distal (Distal End): Lateral supracondylar ridge Lateral Epicondyle Medial supracondylar ridge Medial epicondyle Coronoid fossa Capitulum Trochlear Olecranon fossa ```
Humerus: Proximal – Distal (Distal End): Lateral supracondylar ridge > attachment for brachioradialis, extensor carpi radialis longus and triceps brachii muscles and for the lateral intermuscular septum Lateral Epicondyle > attachment for common supinator tendon (anconeus, supinator, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi and extensor carpi ulnaris) and the radial collateral ligament Medial supracondylar ridge > attachment for brachialis, pronator teres and medial head of triceps brachii muscles and for the medial intramuscular septum Medial epicondyle > attachment for pronator teres, common flexor tendon (flexor carpi ulnaris, flexor carpi radialis, flexor digitorum superficialis and palmaris longus) and ulnar collateral ligament Coronoid fossa > articulates with the coronoid process of the ulna Capitulum > articulates with the articular fovea of the head of the radius Trochlear > articulates with the trochlear notch of the ulna Olecranon fossa > articulates with the olecranon of the ulna
187
``` Radius: Proximal – Distal Head (articular fovea) Head (articular circumference) Neck Radial tuberosity Supinator crest Oblique line Interosseous border Radial styloid process Ulna notch Dorsal tubercle ```
Radius: Proximal – Distal Head (articular fovea) > articulates with the capitulum of the humerus Head (articular circumference) > articulates with the radial notch of the ulna Neck > directly below the head of the radius Radial tuberosity > attachment for biceps brachii tendon Supinator crest > attachment for supinator muscle and lateral ulnar collateral ligament Oblique line > attachment for oblique cord Interosseous border > attachment for interosseus membrane/ ligament Radial styloid process > attachment for brachioradialis, abductor pollicis longus and extensor pollicis brevis muscles and radial collateral ligament Ulna notch > articulates with the articular circumference of the head of ulna Dorsal tubercle > pulley attachment for the tendon of extensor pollicis longus
188
``` Ulna: Proximal – Distal Olecranon Coronoid process Trochlear notch Ulnar tuberosity Radial notch Oblique line Interosseous border Ulnar styloid process Head of ulna ```
Ulna: Proximal – Distal Olecranon > articulates with the olecranon fossa of the humerus Coronoid process > articulates with the coronoid fossa of the humerus and attachment for flexor digitorum superficialis, flexor digitorum profundus, pronator teres and flexor pollicis longus muscles Trochlear notch > articulates with the trochlear of the humerus Ulnar tuberosity > attachment for brachialis muscle and oblique cord Radial notch > articulates with the articular circumference of the head of the radius Oblique line > attachment for oblique cord Interosseous border > attachment for interosseus membrane/ ligament Ulnar styloid process > attachment for TFCC Head of ulna > articulates with ulnar notch of radius