chapter 2- summarize Flashcards
(93 cards)
1
Q
most mobile of all joints
3 degrees of freedom and 3 planes in space
A
shoulder Joint
2
Q
3 axis of shoulder joint
A
transverse axis-flex and extension
anteroposterior axis-sagital plane- abd- adductiom
3
Q
Shoulder complex
A
- glenohumeral
- sternoclavicular
- acromioclavicular
- scapulothoracic
4
Q
Flexion and extension (1): performed in a sagittal plane, about a transverse axis.
A
a) Extension to 45 to 50 degrees
(b) Flexion to 180 degrees
5
Q
Adduction (2): adduction in the frontal plane starting from the position of reference is mechanically impossible owing to the presence of the trunk. Starting from the position of reference, adduction is only possible when combined with:
A
(a) extension, which allows a trace of adduction.
(b) Flexion, in this case adduction can reach 30° to 45
6
Q
Abduction (3,4): the movement of the upper limb away from the trunk, takes place in a frontal plane, about an antero -posterior axis. When abduction reaches 180° the arm is vertically above the trunk.
A
Two points must be noted :
After the 90° position, the movement of abduction brings the upper limb once more closer to the sagittal plane of the body.The final position of abduction at 180° can also be achieved by flexionto 180°.
Abduction passes through three stages:
Abduction to 60°
Abduction to 120°
Abduction to 180
7
Q
(1) : this occurs about the longitudinal axis of the humerus.
(a) Position of reference: in order to measure the range of movements of rotation the elbow must be bent at 90°, the forearm thus lying in a sagittal plane. Otherwise the range of the movements of rotation would also include that of the pronation and supination of the forearm.
(b) Lateral rotation: to 80°
(c) Medial rotation: to 95°
A
Axial rotation of the arm
8
Q
to reach this far, the forearm must be pulled behind the trunk, and This introduces a certain degree of extension.
A
For medial rotation
9
Q
(2) : these take place about a vertical axis and involve not only the shoulder joint but also the scapula. Their total range falls short of 180°
(a) Position of reference: 90° abd. in a frontal plane. Muscles involved: deltoid, supraspinatus, trapezius.
A
Horizontal movements
10
Q
Flexion + adduction anteriorly: range 140°. Muscles involved
A
deltoid, subscapularis, pectoralis major, pectoralis minor, serratus anterior.
11
Q
Extension + adduction posteriorly: range 30°.
A
Muscles involved: deltoid,infraspinatus, teres major, teres minor, rhomboid muscles, trapezius, latissimus dorsi.
12
Q
Structurally = GH is not stable but mobile joints sacrifice stability for mobility.
represents a third of a sphere of diameter 3 Cm. and facing superiorly, medially and posteriorly. Its axis forms with the axis of the shaft an angle of 135° and with the frontal plane at an angle of 30°. It is separated from the rest of the humerus by the anatomical neck which makes an angle of 45° with the horizontal plane.
A
Head of humerus;
13
Q
is situated at the superolateral angle of the scapula and
points laterally, anteriorly and slightly superiorly. It is biconcave (vertically and transversely), but its concavity is irregular and less deep than the convexity of the
humeral head.
A
Glenoid cavity of the scapula;
14
Q
is a ring of fibro-cartilage attached to the margin of the glenoid cavity. It widens the cavity slightly but deepens it appreciably so as to make the articular surfaces congruent.
A
Glenoid labrum
15
Q
glenoid labrum It is triangular in section and has three surfaces:
A
A basal surface attached to the margin of the glenoid.
An outer (peripheral) surface giving attachment to the ligaments.
An inner surface in contact with the head of the humerus and lined by cartilage continuous with that of the glenoid cavity.
16
Q
axis of head and frontal plane
head of humerus being tilted superior/posterior/medially
A
retroversion angle- 30 to 40 degrees
17
Q
head is an oblique plane, sup and medially rotated 135 degrees
axis of the head and axis of the shaft
A
angle of inclination
18
Q
gleno-humeral ligament with its three bands
A
The superior band (9) running from the upper margin of the glenoid over the humeral head
the middle band (10) running from the upper margin of the glenoid in front of the humerus
the inferior band (11) running across the anterior edge of the glenoid and below the humeral head.
19
Q
Between superior and middle GH ligament is called the ____ and is the most common site of anterior dislocation of humerus. (spaces between ligaments are also weak spots
A
Weitbrecht area
20
Q
These three bands form a Z in front of the joint capsule. Between these bands lie two points of weakness which connect the synovial membrane of the joint to the
A
- subscapular
2. subacromial bursa
21
Q
from coracoid process to greater tuberosity of humerus
- extrinsic ligament( not originating from joint capsule
A
coracohumeral ligament
22
Q
cover the long head of biceps tendon
-supports biceps doesn’t support the joint
Biceps tendon longhead is an extra synovial (covered in synovial membrane), intracapsular tendon.
A
transversehumeral ligament
23
Q
between acromion and coracoid process, creates arch on top
A
coracoacromial ligament
24
Q
Weak points of Gh capsule
gh joint is a loose joint not a tight joint
A
between sup and middle gh ligament bands
between middle and inf ligament bands
25
An extrinsic, protective structure formed by the smooth inferior aspect of the acromion and coracoid processes of the scapula, and the coracoacromial ligament bridging the gap between them. This arch overlies the head of the humerus, preventing its superior displacement from the glenoid cavity.
The coracoacromial arch
26
Ligaments provide static stabilization
Tendons provide dynamic stabilization
Glenoid cavity bottom is wider than top
27
is the space between subacromial arch
Subacromial space
28
There are two surfaces (A), saddle-shaped, torus-like, reciprocally concave-convex. The clavicular surface fits easily on to the sternal surface, as a rider on the saddle. The two axes of both surfaces coincide so closely that the joint has only two perpendicular axes shown in perspective on the diagram.
one anterior and posterior-intrinsic ligament
10 cm-protraction
3 cm-retraction
10 cm elevation
3 cm depression
30 degree rotation up and downwards ( more space created and lateral end as bone
sternoclavicular joint
| *fibrocartilage disc between sternoclavicular joint-increase conguency-intraarticular disc
29
flat or slightly convex articular space on acromial process of scapula to meet articular surface
also planar or slightly convex on clavicle
acromialclavicular joint- planar synovial joint(only gliding movement
intrinsic ligament-superior acromioclavicular ligament
-links gh joint with sternoclavicular ligament-movement are synchronized -gh joint
30
between coracoid process and clavicle
2 parts are conoid and trapezoid ligament
1. conoid attaches to conoid tubercle -prevents clavicle from superior dispalcement
2.trapezoid attaches to trapezoid ligamnet- prevents clavicle from too much lateral displacement
coracoclavicular ligament
31
all of supportive ligament of the Ac joint
suprascapular ligament attaches over the suprascapular notch and suprascapular nerve passes through the notch and under the ligament-goes to supraspinatus and infraspinatus
Ac dislocation-bumb on top of shoulder(shoulder seperation)
32
This is a physiological (false) joint without possessing an anatomical structure. The movements of this joint is provided by the muscles attached to scapula and it:
1. Provides a movable base for the Humerus, hence increasing arm ROM.
2. Helps deltoid function with proper tension with arm above 90. Over 90 scapula moves to keep humerus in the GH cavity
3. Provides glenohumeral stability for overhead work.
4. Absorbs shocks to outstretched arms.
Scapulothoracic Joint
33
Different movements of the scapula may be classified as follows:
1. Medial and lateral movements (Protraction or Abduction and Retraction or Adduction) of the scapula round the chest wall (1): the total range of this movement is 15 Cm.
2. Elevation and depression of the scapula (2): the total range of this movement is 10 – 12 Cm, and they are necessarily associated with some tilting.
3. Tilting or rotation of the scapula (3): this movement occurs on an axis perpendicular to the plane of the scapula and situated a little below the spine, not far from the lateral angle. Total range of this movement is 60°. Meanwhile, displacement of the inferior angle is 10 – 12 Cm. and that of the lateral angle is 5 – 6 Cm. The rotational movements are:
Upward Rotation – movement of the scapula so that the glenoid fossa faces superiorly, the inferior scapular angle slides laterally
Downward Rotation – glenoid fossa moves to face inferiorly, the inferior scapular angle slides medially
34
Scapulothoracic / scapulohumeral rhythm
Precisely coordinated series of synchronous movements
First 30 degrees abduction occurs as glenohumeral movement
30-170 degrees abduction 10 degrees glenohumeral movement accompanied by 5 degrees scapulothoracic (2:1ratio)
Last 10 degrees abduction occurs as spine extension
Precisely coordinated series of synchronous movements
35
(Overlies the anterior joint capsule and lies beneath the subscapularis muscle). These bursae serve to decrease friction between the tendon and/or muscle of joint capsule.
subscapular bursa
36
Is between the acromion and the fibrous capsule of the joint. It facilitates movements of the supraspinatus tendon under the coracoacromial arch and of the deltoid over the fibrous capsule and greater tubercle of the humerus. It is subject to impingement beneath the acromial arch if it is inflamed and swollen.
The subacromial bursa
37
Is between the deltoid and the fibrous capsule. It may be continuous with the subacromial bursa
Subdeltoid bursa:
38
❖ The close pack position of GH joint
Abd. & Lat. Rot.
39
these muscles, running transversely across the joint, act as active ligaments and keep the head of the humerus pressed against the glenoid cavity. (it also pushes down to the wider space of glenoid cavity)
1. Supraspinatus
2. Subscapularis
3. Infraspinatus
4. Teres minor
5. Tendon of long head of the biceps.
40
The muscles of the arm are tonically active and prevent infra glenoid dislocation of the head of the humerus as a result of a weight carried in the hand. By contrast the superior dislocation, brought about by an excessive strong contraction of the long muscles, is prevented and checked by the presence of the coraco acromial arch, and supraspinatus muscle.
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Short head of biceps
Coraco brachialis
Long head of triceps
Deltoid
Clavicular head of pectoralis major
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41
1 Painful phase
2 Frozen phase
3 Thawing phase (sometimes body heals on its own for thawing phase but sometimes through physio)
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Risk factors:
Gender: Female > Male (2:1)
Age: over 40
Prolonged immobility
Trauma
Diabetes
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Frozen shoulder (adhesive capsulitis) capsule becomes tight and stiff
AROM; decreased (Apley’s scratch test) opposite scapula medial or lat rot.
PROM; painful capsular end-feel
Capsular pattern; Abduction > Lateral Rotation > Medial Rotation
Treatment
NSAIDs
Ice / heat
ADL in pain free range
Massage therapy; in thawing phase
Mobilization; antero-inferior capsular stretch + inferior glide / anterior glide / distraction of humeral head
Exercise; towel stretch / door stretch / finger wall walking / pendulum motion (with weight)
42
Articular Surfaces of the Sterno-clavicular Joint KNOW THE CM AND DEGREES!
There are two surfaces (A), saddle-shaped, torus-like, reciprocally concave-convex. The clavicular surface fits easily on to the sternal surface, as a rider on the saddle. The two axes of both surfaces coincide so closely that the joint has only two perpendicular axes shown in perspective on the diagram.
Axis 1 corresponds to the concavity of the clavicular surface and allows clavicular movements in the horizontal plane (10 Cm. anteriorly and 3 Cm. posteriorly).
Axis 2 corresponds to the concavity of the sterno-costal surface and allows clavicular movements in the vertical plane (10 Cm. superiorly and 3 Cm. inferiorly).
It should be noted that clavicle may also be rotated around its longitudinal axis for 30°.
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In figure (B), the following elements of the right joint are shown: Medial end of clavicle (1), Clavicular articular surface (2), Superior sterno-clavicular ligament (3), Anterior sterno-clavicular ligament 4), Costo-clavicular ligament (5), Posterior sterno-clavicular
igament (6), Sterno-costal articular surface (7).
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43
Muscles of the Shoulder Girdle
| Different muscles are involved in movements of the shoulder girdle.
1. Trapezius
2. Rhomboid muscles
3. Levator scapula
4. Serratus anterior
5. Pectoralis minor
6. Subclavius
44
Phase of Abduction
First phase of abduction: 0° to 90° the muscles involved are essentially the deltoid (1) and supraspinatus (2), which form a couple at the level of the shoulder joint. This first phase ends at 90° when the shoulder locks as a result of the greater tuberosity hitting the superior margin of the glenoid. Lateral rotation of the humerus, by displacing the greater tuberosity posteriorly, delays this mechanical locking.
Second phase of abduction: 90° to 150°. The shoulder is locked and abduction can only proceed with participation of the shoulder girdle.The scapula rotates upwards up to 60°. Axial rotation of the sterno-clavicular and acromio-clavicular joints will take place up to 30°. The muscles involved in this second phase are: trapezius (3 and 4); and serratus anterior (5). This movement is checked at about 150° by resistance of the stretched adductor muscles.
The third phase of abduction: 150° to 180° to allow the hand to reach the vertical position once more, movement of the spinal column becomes necessary. If only one arm is in abduction, lateral displacement of the spinal column produced by the contralateral spinal muscles (6) is adequate. If both arms are in abduction, they can only come to lie parallel vertically by being maximally flexed. For the vertical position to be attained, exaggeration of the lumbar lordosis becomes necessary, and this is achieved by action of the spinal muscles.
45
Phases of Flexion
First phase of flexion: 0°to 50°- 60°. The muscles involved are: the anterior fibers of the deltoid (1); coraco-brachialis (2); the clavicular fibers of pectoralis major (3). This phase is limited by: tension of the coraco-humeral ligament, and resistance offered by teres minor, teres major and infraspinatus.
Second phase of flexion: 60° to 120°. In this part of the movement, the shoulder girdle participates as follows: 60° upward rotation of scapula. Axial rotation at the sterno-clavicular and acromio-clavicular joints, each joint contributing 30°. The muscles involved are the same as in abduction: trapezius (4 and 5); serratus anterior (6). At this phase flexion is limited by the resistance of the latissimus dorsi and the costo-sternal fibers of pectoralis major.
Third phase of flexion: 120° to 160°. When flexion is checked at the shoulder and at the scapulothoracic joint, movement of the spinal column becomes necessary. If one arm is being flexed, it is possible to complete the movement by passing into the position of maximal abduction and then bending the spinal column to one side. If both arms are flexed, the terminal phase of the movement is identical with that of abduction, i.e. exaggeration of the lumbar lordosis by the lumbar muscles (7).
46
muscular coupes
1. teres major and rhomboids
| 2. latissimus dorsi and long head of triceps
47
Elbow complex
| Contains three bony articulations all within a single joint capsule.
Humeroulnar joint is a synovial hinge joint. (Main movement of the elbow)
Humeroradial (joint is a synovial condyloid joint
Proximal Radioulnar joint is a synovial pivot joint.
48
Axis for flexion and extension is slightly oblique line
imaginary line through capitulum and trochlea
carrying angle 15 to 19 degree
average=15 degrees
49
women have larger pelvis so the angle is greater (T/F)
true
50
angle is greater forearm deviated laterally
| arm deviated medially
cubitus valgus
51
angle is less, forearm deviated medially
| -arm deviatted laterally
cubitus varus
52
prevent joint from any side to side displacement
The main function of these ligaments is to keep the articular surfaces in apposition. These ligaments will also keep the half-ring fitted to the pulley and prevent all sideways movements
*lateral and medial epicondyle have thick intrinsic ligament
-medial epicondyle- ulnar collateral ligament(medial collateralby mcl
-lateral epicondyle-radial collateral ligament(lateral collateral by LCL
anterior oblique ligament- was obliquely,also intrinsic ligament
53
The distal end of the humerus resembles a fork which holds between its two prongs the axis of the articular surfaces . Immediately above the articular surfaces two concavities are present: anteriorly, the coronoid fossa which receives the coronoid process of the ulna during flexion ; and posteriorly the olecranon fossa which receives the olecranon process during extension . These fossae increase the range of flexion and extension. They also allow the trochlear notch of the ulna to glide over the trochlea for an appreciable distance on either side of the neutral position.
The distal end of the humerus bulges anteriorly at an angle of 45 ° to the shaft so that the trochlea lies in front of the axis of the shaft. In the same way, the trochlear notch of the ulna projects anteriorly and superiorly at an angle of 45° to the ulnar shaft and so lies in front of the axis of the ulna.
These angles promote flexion in the following two ways:
1. Contact of the coronoid process with the humerus occurs only when the two bones are parallel. I.e. theoretically flexed to 180°
2. Even during full flexion the two bones are separated by a space (double arrow) which lodges the muscles. in the absence of these two mechanical factors flexion would clearly be limited to 90 ° by the impact of the coronoid process on the humerus, and during full flexion there would be no space left for the muscles assuming that the bones could come into contact with each other as a result of, say, communication between the coronoid and olecranon fossae.
54
Articular Surfaces of the Elbow Complex
The distal end of the humerus has two articular surfaces the trochlea pulley-shaped with a central groove lying in a sagittal plane and bounded by two convex lips. The capitulum, a spherical surface lying lateral to the trochlea.
The proximal ends of the two bones of the forearm have two surfaces corresponding to those of the humerus: the trochlear notch of the ulna, which articulates with the trochlea and has corresponding shape. It consists of a longitudinal rounded ridge extending from the olecranon process superiorly to the coronoid process anterioirly and inferiorly. On either side of this ridge, which corresponds to trochlear groove, is a concave surface corresponding to the lips of the trochlea. The cupped proximal end of the radius, with a concavity corresponding to the convexity of the capitulum. It is bonded by a rim which articulates with the radial groove. These two surfaces constitute in effect one articular surface owing to the annular ligament
A coronal section taken through the joint shows the capsule invests a single anatomical joint cavity with two functional joints:
the true elbow joint and the superior radio-ulnar joint (horizontal strips).
The coronoid process -lying inside the olecranon fossa during extension.
55
Limitation of Flex and Ext.
Extension is checked by three factors
1. The impact of the olecranon process on the olecranon fossa.
2. The tension of the anterior ligaments of the joint.
3. The resistance of the flexor muscles (biceps, and brachialis).
If extension proceeds any further , rupture of one the above mentioned structures may occur (B, C).
Limitation of flexion depends upon whether flexion is active or passive.
Active flexion the first and foremost limiting factor is the apposition of the anterior muscles of the arm and forearm , hardened by contraction, which prevents active flexion beyond 145°. This effect is more prominent the more sinewy the subject is.
The other factors, i.e. impact of the corresponding bony surfaces and tension of the capsular ligaments (3), are insignificant.
Passive flexion secondary to an external force (black arrow) tending to close the joint: the relaxed muscles (1) can be flattened against each other allowing flexion to reach beyond 145°; at this stage the other limiting factors may become more important, i.e. impact of the head of the radius against the radial fossa and of the coronoid process against the coronoid fossa (2); tension developed passively in the triceps (4). Flexion can then reach 160°
56
Also known as ‘Tennis’ elbow.
Typically follows repetitive use of the superficial extensor muscles of the forearm.
Pain is felt over the lateral epicondyle of the humerus and can radiate distally down the posterior surface of the forearm.
Repeated forceful extension of the wrist strains the attachment of the common extensor tendon at the lateral epicondyle, eliciting an inflammation response of the periosteum and the common extensor tendon attachment
Lateral Epicondylitis or Elbow Tendonitis
57
is the inflammation of the Subcutaneous Olecranon Bursa.
Falls onto the elbow, or infection from abrasions of the skin covering the olecranon can be the cause, or repeated excessive pressure and friction may cause the bursa to become inflamed.
Also know as “Dart thrower’s elbow” and “Miner’s elbow”.
“Student’s Elbow”
58
consists of three parts
the anterior fibers some of which strengthen the annular ligament
The posterior fibers and the transverse fibers or Cooper’s ligament .
The medial (ulnar) collateral ligament
59
also consists of three parts
the anterior fibers which strengthen the annular ligament anteriorly
. The Ulnar fibers attaches to ulna.
Joint capsule
The capsule is strengthened anteriorly by the anterior ligament and oblique anterior ligament and posteriorly by the fibers of the posterior ligament which run transversely across the humerus and obliquely from humerus to olecranon.
The lateral (radial) collateral ligament
60
Triceps biarticular -crosses 2 joints ( shoulder and elbow
| -length and tension principle- triceps only on elbow not shoulder by flexion of arm becomes strong in elbow
90-100 degree- flexion-maximum point for brachialis
100- 120 flexion -maximum point for brachioradialis
triceps concentrically contract to extend forearm
-eccenterically contract and stablize flexor for flexors
61
intrinsic ligament ,transverse under radial notch to neck of radius, hold head in place
It consists of a fibrous band attached to the inferior border of the radial notch and to the neck of the radius. Its two borders are strengthened by the fibers of the upper border of the annular ligament. It acts to reinforce the inferior aspect of the capsule. The rest of the capsule (10) encloses all the joints at the elbow within one anatomical cavity
quadrate ligament
62
below radial notch, goes obliquely to shaft of radius and helps support extrinsic
oblique ligament
63
between shaft made by interousseus membrane
| -syndesmosis joint
middle radioulnar joint
64
that consists of a strong fibrous band attached by its ends to the anterior and posterior margins of the radial notch of the ulna and lined internally by cartilage continuous with that lining the radial notch
The annular ligament
65
This joint is a synovial pivot with cylindrical surfaces and one type of movement: i.e. rotation about the axis of the two cylinders in contact. It can therefore be compared mechanically to a system of ball -bearings (B). It consists of the following two cylindrical surfaces:
the head of radius (C) with its cylindrical rim (1) covered by articular cartilage and corresponding to the central ball in a ball -bearing. The cupped surface of the head also articulates with the capitulum of humerus.
Sup. Radio-Ulnar Joint
66
This joint like the superior radio-ulnar joint, has cylindrical surfaces and only one degree of freedom (rotation) and thus is classified as a synovial pivot joint.
The articular surfaces include:
The head of the ulna. Its articular surface resembles a crescent wrapped over a cylinder.
The second articular surface is the ulnar notch of the radius (3) lying at the distal end of the bone (B,C) between the two edges of its interosseous border (2). It faces medially (3) and is concave. It articulates with the cylindrical portion of the ulnar head (4).
There is an articular disc (5), which lies in a horizontal plane and is attached the styloid process (9) of the ulna and lower border (6) of the ulnar notch of the radius (B). The articular disc appears biconcave (C). Its proximal surface, covered by articular cartilage, is in contact with the distal surface (7) of the head of the ulna. Its distal surface, also covered by cartilage, is flush with the carpal surface of the radius (8) and forms the medial part of the radio-carpal joint.
The thickening of the capsule make the palmar (anterior) and dorsal (posterior) radio-ulnar ligaments that support the joint anteriorly and posteriorly (Refer to image on page 31). During supination, the anterior ligament of the radio-ulnar joint becomes taut and is torn during dislocations of that joint. The posterior ligament becomes taut during pronation.
Inf. Radio-Ulnar Joint
67
Is a syndesmosis (amphiarthrosis) joint between the shafts of the ulna and radius by the interosseous membrane
Middle Radio-ulnar joint
68
The axis of motion of the radio -ulnar articulation is represented by a line running from the center of the radial head proximally through to the center of the ulnar head distally
To understand the mode of action of these muscles one must mechanically analyze the shape of the radius (A). The radius comprises three segments which together give it roughly the shape of a “crank”. The neck joins the intermediate segment at an obtuse angle to form the “supinator bend” of the radius. This is at the level of the radial tuberosity (black arrow), into which is inserted the biceps. The intermediate segment also joins the lower segment at an obtuse angle to form the “pronator bend” of the radius. This is at the level of the insertion of the pronator teres.
To move this crank two mechanisms are available (D):
To unwind a cord coiled round one of the arms of the crank (arrow 1).
To pull on the apex of one of the bends (arrow 2). • These mechanisms form the basis of the mode of action of the muscles of rotation. These muscles are four in number and fall into two groups of two. For each of these movements there is a short and flat muscle which acts by unwinding; and a long muscle inserted into the apex of a bend.
The muscles involved in supination are: supinator (B,1), and biceps (B,2);
while the pronator muscles are: pronator quadratus (C,1), and pronator teres (C,2).
69
lateral collateral from radial styloid process to capitate
| extrinsic ligament are:
1. ulno-carpal ligament- palmar and distal
2. medial carapal ligament
3. inferior radioulnar ligament-not wrist joint
70
information: capitate is center of v shape
scaphoid to capitate- triquetrum to capitate=v ligament (palmar only
V ligament- connect proximal now to distal row bones
if you need flexor to work on fingers only not wrist grabbing a book then extensors need to work to stabilize wrist for flexors
if median nerve is paralyze-it may not appear as total paralysis as same mm. innervated by median are also innervated by ulnar nerve
8 in midcarpal= only 7 in radiocarpal = 15 total for radial deviation
flexion =50 wrist and 35 (midcarpal
extension=35 radiocarpal joint and 50 midcarpal joint
71
between the radial distal end and the proximal row of carpal bones (except pisiform). This is a condyloid (ellipsoid) joint.
The carpal aspect presents the following two convexities: a transverse convexity and an antero -posterior axis . Each convexity has an axi; AA” for flexion / extension, and BB” for abduction/ adduction movements.
The radio-carpal joint
72
between the proximal and distal rows of carpal bones.
The ligaments of the radio-carpal joint are arranged in two groups:
The collateral ligaments the lateral is attached to the styloid process of the radius and the scaphoid bone.
The medial is attached to the styloid process of ulna and the pisiform and triquetrum bones.
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The mid-carpal joint
The anterior (palmar) and posterior (dorsal) ligaments (C): the radio -carpal and the ulno-carpal ligaments.
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73
The articular surfaces are (A,B): the proximal row of carpal bones; the distal aspect of the radius and the articular disc. Fig B (antero-lateral view) shows the carpal surface which consists of the proximal surface of three carpal bones, i.e. the scaphoid (1), the lunate (2), and the triquetrum (3). Note that the pisiform bone (4) and the distal row of carpal bones, i.e. trapezium (5), the trapezoid (6), the capitate (7), and the hamate (8), do not belong to the radio-carpal joint. Fig A shows the proximal aspect of the joint which consists of :
The distal surface of the radius (9), concave, covered by cartilage, and divided by a shallow ridge into the scaphoid impression laterally (10) and the lunate impression medially (11).
Both Aspects of the articular disc (12), are concave and covered by cartilage. Its apex is inserted at the root of the styloid process of the ulna (13) so that the head of the ulna (14) overreaches it anteriorly and posteriorly. Its base, is inserted at the inferior ridge of the ulnar notch of the radius (15).
The Radio-Carpal Joint
The action of the ligaments varies with the type of movement performed. In adduction and abduction (C,D,E), the collateral ligaments are active so that, starting from the resting position, the lateral ligament becomes taut and the medial ligament relaxes during adduction and vice versa in abduction. In flexion and extension (F,G,H), the anterior and posterior ligaments are involved so that, from the position of rest, the posterior ligament becomes taut in flexion and the anterior ligament in extension.
74
As suggested by its name, this joint lies between the two rows of carpal bones.
The proximal surface comprises three bones from lateral to medial: the scaphoid with two slightly convex surfaces, one (1) for the trapezium laterally, and the other (2) for the trapezoid medially and a concave surface medially for the capitate. The distal surface of the lunate (4) with its concavity articulating with the capitate; the distal surface of the triquetrum (5), is concave and relates to the proximal surface of the hamate. The pisiform (6), in contact with the palmar surface of the triquetrum, does not belong to the mid-carpal joint.
The distal surface consists of the following bones from lateral to medial. The proximal surface of the trapezium (7) and the trapezoid (8); the head of the capitate (9) articulating with the scaphoid and the lunate; the proximal aspect of the hamate (10) which articulates mostly with the triquetrum but also slightly with the lunate (11). The movements at this joint are influenced by the elasticity of the ligaments which allows a certain degree of “joint play”.
Fig C (palmar view) shows the ligaments which fall into two groups: the interosseous ligaments (black dots), and the ligaments of the midcarpal joint stretching from the proximal to the distal row (black squares).
The Mid-Carpal Joint
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The Muscles of the Wrist Complex
F.P.L (1), P.L (2), F.C.U (3), E.C.U (4), E.C.R.B (5), E.C.R.L (6), A.P.L (7), E.P.L (8), E.D (9), F.D.P (10), F.D.S (11), F.C.R (12).
Classically these muscles may fall into four groups (E,F,G,H).
1. F.C.U, anterior to axis AA’, and medial to axis BB’.
2. E.C.U, posterior to axis AA’, and medial to axis BB’.
3. F.C.R & F.P.L, anterior to axis AA’, and lateral to axis BB’.
4. E.C.R.L & E.C.R.B, posterior to axis AA’, and lateral to axis BB’.
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of the thumb is a synovial saddle joint (with 2 DOF), with the surfaces of the 1st metacarpal and the trapezium both having convex and concave characteristics.
The joint capsule is thick, but loose.
Motions include abduction/adduction (in a right angle to the palm), and flexion/extension (parallel to the palm), and opposition(a rotation of the 1st metacarpal on the trapezium).
Due to the laxity of the joint, 15 to 20 of rotation is possible.
The CMC joint
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The distal row of carpal bones articulate with the bases of the 2nd to 5th metacarpals in an irregular manner.
A common joint cavity is found between the four distal carpals, the CMC joints, and into the intermetacarpal joints.
The 2nd and 3rd CMC joints have a motion of 2 or less. (3rd is the least mobile usually less than 2 degrees)
The 4th CMC joint has 10 to 15 of dorso-volar movement. (dorso-volar = dorsal and palmar)
➢ The 5th CMC joint is the most flexible, with 25 to 30 of motion.
These movements are important to hand function with relation to the transverse arch of the hand from the closed fist to the open hand
Carpometacarpal (CMC) Joints II – V
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are synovial condylar (ellipsoid) joints between the heads of the metacarpal bones and the base of the proximal phalanges of the digits with 2 DOF.
Medial and lateral collateral ligaments attach the heads of the metacarpals to the bases of the phalanges . They are also supported by the palmar plates (ligaments) ventrally.
Metacarpophalangeal (MCP) Joints
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Digits II to V have two interphalangeal joints; the Proximal Interphalangeal (PIP) joint and the Distal Interphalangeal (DIP) joint.
The thumb only has one IP joint.
Classified as hinge joints with 1 DOF
Interphalangeal (IP) Joints
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The FDP vs. FDS Muscle Testing:
Isolated action of the FDS is obtained if the proximal IP joint is flexed while the distal joint remains inactive (best to try this with one finger at a time).
Another way to test the FDS of one digit without the participation of the FDP is for the examiner to maintain the other digits in full extension at all joints. This inactivates the FDP so that the subject is unable to flex the distal joint.
In testing the Profundus, one finger at a time is stabilized over the middle phalanx. Typically the index finger is able to move well without drawing the other fingers into action, and the middle finger can be moved alone comparatively well, while isolated flexion of the 4th and 5th fingers is difficult or impossible.
Typically, a person is unable to move only the DIP joint when the fingers are not being stabilized, as the FDP tendon acts on the two IP joints simultaneously.
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The 3 arches of the hand, the proximal transverse arch, distal transverse arch and longitudinal arch, allow the hand to conform to objects being held. This maximizes the amount of surface contact which enhances stability and increases sensory input. Loss of these arches results in severe impairment in the functional use of the hands.
The proximal transverse arch is at the level of the carpometacarpal joint with the keystone being the capitate. It is a relatively fixed arch, remaining arched even when the hand is open.
The distal transverse arch is at the level of the metacarpophalangeal joints with the keystone being the 2nd and 3rd metacarpals. It is relatively mobile. The 1st , 4th, and 5 th metacarpals rotate around the 2nd and 3rd metacarpals to either flatten or increase its arc.
The longitudinal arch is best observed by following the 3rd digit. It deepens with finger flexion and somewhat flattens with finger extension.
hand arches
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Incorporates the entire hand and is used for gross activities to grasp an object rather than to manipulate it.
It involves holding an object between the partially flexed fingers and the palm while the thumb usually applies counter pressure to maintain and stabilize the object within the hand; there is only one power grip in which the thumb is not required to participate, the hook grip.
In the power grips, the thumb is in adduction or opposition, and it reinforces the pressure of the fingers to stabilize the object in the hand.
power grip
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The power grips include: Lateral Pinch Grip (AKA Key Grip)
A thin object (card/key) is grasped between the thumb and the lateral side of the index finger.
The index finger is abducted at the MCP and partially flexed at the MCP and IPs.
Muscles used include the FD, FDS, and 1st interosseous.
Hook Grip -Digits II to V are used as a hook, as in carrying a briefcase or a purse. The thumb dose not contribute in this grip.
FDS muscle primarily & FDP muscle secondarily function.
Cylinder Grip The entire palmar surface of the hand grasps around cylindrical object, such as a glass jar or can of pop. The thumb closes in over the object to secure the object to the palm.
Spherical Grip Fingers are spread more than in the cylinder grip, so interossei muscles work more in this grip. MCPs are abducted and partially flexed. Both FDS & FDP are work to flex the fingers. The grip is adjusted to a spherical object like a ball or an apple .
Fist Grip (AKA Digital Palmar Prehension Pattern) The palm and fingers flex around the object and the thumb wraps around from the other direction to enclose the object.
All MCPs, PIPs, and DIPs are flexed.
Firm grasping is provided by the FDP & FDS muscles.
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The object is pinched between the palmar surfaces of one or more fingers and the opposing thumb.
It is used when accuracy and refinement of touch are needed.
In the precision grips, the thumb is in abduction and is usually positioned to oppose the pulp of the fingers.
precision grip
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Three-prong chuck (AKA pad-to-pad prehension Grip or Palmar Grip)
The pads of digits #2-3 digits contact the pad of the distal thumb for the purpose of picking up or grasping objects.
Fingers are in flexion at the MCP and PIP joints which is done primarily FDS (and FDP if DIPs are flexed too).
Example: grasping a coin, using a writing utensil such as a pen or pencil.
Tip-to-tip Grip (AKA Tip Prehension Grip) The tip of the thumb is used against a tip of another digit (usually index finger) to pick up a small object such as a pin or bead.
The finger used is position in flexion at all three of its joints, i.e. MCP, PIP, and DIP
Lateral Pinch Grip (AKA Key Grip)
A thin object (card/key) is grasped between the thumb and the lateral side of the index finger.
The index finger is abducted at the MCP and partially flexed at the MCP and IPs.
Muscles used include the FD, FDS, and 1st interosseous.
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A wrist-drop develops; the wrist can neither be actively extended or stabilized for effective grasp.
If a splint is used to support the wrist in an extended position, grip strength is good because the flexor muscles are intact.
Radial nerve paralysis affects the extensors of the wrist and the long extensors of the digits.
The Radial nerve is usually injured in the arm by a fracture of the humerus body.
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ulnar nerve paralysis
Ulnar nerve injury commonly occurs where the nerve passes posterior to the medial epicondyle of the humerus. Injury results when the medial part of the elbow hits a hard surface, fracturing the medial epicondyle (“funny bone”).
Ulnar nerve entrapment is the compression of the ulnar nerve at the elbow. It usually produces numbness and tingling of the medial part of the palm and the medial one and a half digits.
In Ulnar nerve paralysis the 4th and 5th digits are the ones most affected as the FDP, the Lumbricals belonging to these digits areparalyzed, as well as the Hypothenar group and all the Interossei muscles.
The Extensor Digitorum tends to keep the MCP joints of digits IV and V hyperextended.
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Radial side digits have only median N. supply and are thus more severely affected than those on the ulnar side.
Flexion and opposition of the thumb are lost, the thenar muscles atrophy, and the entire thumb is pulled in a dorsal direction by the extensor muscles so that it remains in the plane of the palm or even further back.
The adductor pollicis (ulnar N.) is the useful muscle in this case, and may allow a subject to hold a small object between the thumb and index finger.
The index and middle fingers lose their ability to flex as the FDS, radial half of FDP, and the lumbricals of these two fingers have median nerve supply.
In Median nerve paralysis, the flexors of the digits lose action which seriously affects grasping.
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Sudden severe tension on a long extensor tendon may avulse part of its attachment to the phalanx.
This can occur when the DIP is suddenly forced into extreme flexion, such as when a baseball is miscaught or a finger is jammed into the a base when sliding head first.
This results in an avulsion of the attachment of the tendon from the base of the distal phalanx. As a result, the patient cannot extend the DIP joint and the resultant deformity bears some resemblance to a mallet.
Mallet or Baseball Finger:
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Injury to the scaphoid results in regional tenderness in the anatomical snuff box.
Often a fracture of the scaphoid initially appears to be a severely sprained wrist, and is subsequently diagnosed as a fracture after repeated x-rays 2 to 3 weeks later reveal a fracture site because bone resorption has occurred there.
Because of poor blood supply to the proximal part of the scaphoid, it may take several months for the fractured bone to heal.
Avascular necrosis of the proximal fragment of the scaphoid (pathological death of bone resulting from inadequate blood supply) may occur and produce degenerative joint disease of the wrist. In some cases it is necessary to fuse the carpals surgically
The scaphoid is the most frequently fractured carpal bone, typically due to falls onto the palm when the hand is abducted.
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Within the tunnel runs the finger flexor tendons and the median nerve.
Swelling within the tunnel will result in compression of the nerve restricting motor function as well as sensation in the lateral three and a half digits.
Possible atrophy of the thenar eminence, and persons with this median N. compression are unable to oppose the thumb.
As the condition progresses, sensory changes can radiate into the forearm, and even the axilla.
To relieve symptoms, partial or complete surgical division of the flexor retinaculum may be necessary – this is known as ‘carpal tunnel release’.
Carpal Tunnel Syndrome
The carpal tunnel is defined proximally by the pisiform and tubercle of the scaphoid bones and distally by the hook of the hamate and the trapezium. It is covered over by the Flexor Retinaculum (transverse carpal ligament)
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defined by the depression between the pisiform and the hook of the hamate and is covered over by the pisohamate ligament.
Within the tunnel runs the ulnar nerve and artery.
Swelling within the tunnel results in compression of the nerve and artery, restricting motor function of the intrinsic muscles of the hand and loss of sensation of the 5th and medial half of the 4th digits.
The Guyon tunnel
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People who ride long distances on bicycles with their hands in an extended position against the handlebars put pressure on the hooks of their hamates, compressing the ulnar nerve.
This injury results in sensory loss on the medial side of the hand and weakness of the hypothenar intrinsic hand muscles.
Cyclist’s Palsy
