Download The Elbow

Elbow Joint
Bones
humerus
ulna
radius
1
Elbow Joint
A very stable joint that assists shoulder
in application of force and controlling
placement of hand in space
humeroulnar
joint
humeroradial
joint
proximal
radioulnar
joint
Asymmetrical structure
of trochlea creates
angulation of ulna
when extended known
as the carrying angle
2
Elbow Structures
coronoid fossa
radial fossa
lateral epicondyle
trochlea
capitulum
medial
epicondyle
coronoid process
Anterior View3
Elbow Ligaments
Anterior view of right elbow joint
Valgus
annular ligament
holds radius up
into the elbow jt.
lateral/radial collateral resists varus
stresses
because varus stresses are rare support
from
these ligaments is less significant
Varus
medial/ulnar collateral resists valgus
stresses
ulnar collateral is taut in all joint
positions
valgus support very important since
most forces are directed medially
(creating a valgus force)
4
Elbow ROM
flexion/extension
145º active, 160º passive
need 100-140º to perform ADL’s
(e.g., reach back of head to comb hair need 140º
only 15º needed to tie a shoe)
supination/pronation
85º supination; 70º pronation
need 50º supination & 50º pronation to perform ADL’s
5
Elbow Flexors
biceps brachii
multi-articular muscle
whose effectiveness
is dependent on
position of shoulder
& radioulnar jts
Flexors are almost
twice as strong as
the extensors making
us better pullers than
pushers
brachialis
brachioradialis
(Used more in rapid mvmts or against resistance)
Note: brachialis is the
MOST EFFECTIVE
elbow flexor!
biceps brachii not
effective when pronated
6
Elbow Extensors
triceps brachii
long head is bi-articular
so its force production
dependent on shoulder
position
lateral head is strongest
yet is relatively inactive
unless acting against
resistance
anconeus
medial head is the
‘workhorse’ of this group
active in all positions
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supinator
always active
biceps brachii
active in rapid
mvmts or
against
large loads
Radioulnar Joints
Supination
Pronation
pronator teres
active in rapid mvmts
or against large loads
pronator quadratus
always active
8
Biceps brachii & brachialis active to
flex elbow (& abduct shoulder)
Forearm muscle
contribution in throwing
Biceps most
susceptible
to strain during this
phase
triceps brachii becomes active
to extend elbow (some dispute this)
triceps activity drops off sharply biceps brachii and brachialis
quickly become active to
decelerate elbow
9
Injury potential in forearm
Mainly a consequence of repetitive activities
dislocations are possible
often accompanied by fracture
of medial epicondyle
myositis ossificans of brachioradialis
deposits of ectopic bone in muscle
2nd most common site behind quads
high velocity overhead movements
(e.g., throwing, tennis serve)
large tensile forces developed medially
large compressive forces developed laterally
large shear forces developed posteriorly
this is created by the development of a large
VALGUS force on elbow during late cocking and
early acceleration
10
Medial Epicondylitis
linked to movements containing
high velocity valgus extension
mechanism
large valgus torque near maximal
external rotation resisted by
a large varus torque generated
by the soft tissue in the elbow
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Little Leaguer’s Elbow
• medial epicondylitis
– medial strain imparted during the initial forward phase of
throw as hand and elbow lag behind trunk and shoulder
– curveball pitching will magnify this medial strain throughout
pitch and therefore is not recommended for young pitchers12
Medial Elbow Injuries
(“Little Leaguer’s Elbow”)
Sprain or rupture of
ulnar collateral ligaments
medial epicondylitis
tendinitis of wrist flexors
avulsion fractures of medial epicondyle
osteochondritis dissecans to the capitulum
(a lesion in the bone and articular cartilage)
where the radial head is pushed up into
the capitulum due to the compressive
load developed from the valgus force
13
Tennis elbow
• lateral epicondylitis inflammation/microdamage to tissues on the
lateral side of the humerus, 30%-40% of
tennis players will develop some amount of
this injury
• causes include poor technique and
equipment
– e.g. off-center shots and rackets strung
too tightly
• The pain is exacerbated by activities
involving extension of the wrist. These
include lifting a suitcase, shaking hands,
turning doorknobs, etc
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The Wrist
and Hand
Radiocarpal
Joint
Distal
Radioulnar Joint
WRIST - radiocarpal joint
condyloid joint
I
Carpals
ulna makes no contact withMetacarpals
carpals but floats on disc so
it does not influence wrist
mvmt during
Phalanges
supination/pronation
II
P
M
III
D
V
IV
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Radiocarpal jt is the articulation
between the scaphoid & radius
scaphoid
The scaphoid may be
one of the most
important carpals
because it supports
the weight of the arm
and transmits the
forces between the
hand and the forearm
Midcarpal joint
Wrist ROM
flexion: 70-90º need 10-15º for ADL’s
extension: 70-80º need 35º for ADL’s
ROM reduced when fingers are flexed
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Radial & Ulnar Deviation
proximal row of carpals
glides over distal row
ROM
radial dev. 15-20º
ulnar dev. 30-40º
17
Carpometacarpal (CMC) jt
CMC of thumb is a saddle
jt that allows flex/ext,
ab-/adduction & rotation
these movements permit
thumb to touch each finger
(known as opposition)
opposition is very
important in all gripping &
prehension tasks
Concave transverse arch metacarpals
to facilitate gripping
18
Metacarpophalangeal (MCP) jts
MCP of thumb is a hinge
jt allowing only flex/ext
MCP of fingers is a condyloid jt
permitting flex/ext and ab-/adduction
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extensor carpi
radialis longus
extensor
digitorum
extensor carpi
radialis brevis
Wrist Extensors
NOTE: Origin
on lateral
epicondyle
extensor carpi
ulnaris
Because the extensors act
on the elbow jt, elbow jt pos.
will influence extensor output
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flexor carpi
radialis
Wrist Flexors
all fusiform muscles
NOTE: Origin
on medial
epicondyle
palmaris
longus
Absent in 13%
of population
flexor carpi
ulnaris
strongest flexor
strength increased by
encasing the pisiform in
its tendon such that it
becomes a sesamoid bone
that improves the mechanical
advantage of the muscle
21
Radial Deviation - created by the radial muscles
Extensor carpi radialis longus
& brevis
Flexor carpi radialis
Ulnar Deviation - created by the ulnar muscles
Extensor carpi ulnaris
Flexor carpi ulnaris
22
Most of the muscles acting on wrist
& fingers originate outside of the hand
in the region of the elbow so they are
known as extrinsic muscles
Tendons are held in place
on the dorsal and palmar
sides by the extensor &
flexor retinaculum respectively
(a thick band of fibrous tissue
running transversely across
the wrist)
intrinsic muscles of the hand include
4 muscles on thumb forming the
thenar eminence and 3 muscles on the pinky
forming the hypothenar eminence
23
Grip strength
related to wrist position
strongest when wrist is slightly ulnar deviated and hyperextended
grip @ 40º extension is 3X stronger than in 40º flexion
neutral grip is safest position that minimizes strain on wrist structures
power grip utilizes extrinsic muscles
precision grip utilizes intrinsic muscles
Thumb position greatly influences grip
thumb in plane of the hand in an
adducted position such that fingers
flex around object a power grip is
created
thumb is positioned perpendicular to
hand and moved into opposition a
precision grip is created
24
Wrist actions in activities
dynamic actions
golf/baseball swing: active radial and ulnar
deviation in the preparatory and power phases respectively
static actions
piano playing/typing: must maintain a stable, static
position in order to maximize finger action
25
Wrist/Hand Injuries
falls - broken with outstretched hand
forces wrist into position of extreme
extension or flexion
sprain wrist ligaments
strain wrist flexors
fracture schaphoid
fracture distal radius
one of the most frequently fractured
areas of the body because of its
lower density and the size of the
forces it usually accommodates
Overuse injuries - repetitive strain injuries
tenosynovitis of radial flexors and thumb muscles
from canoeing, rowing, tennis, and fencing
medial epicondylitis due to overuse of wrist flexors
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Carpal Tunnel Syndrome
repeated wrist flexion/extension may inflame
wrist flexor tendons to the point that
they apply pressure and constrict
the median nerve which innervates
the radial side of the hand (thenar muscles)
wrist stabilization in a neutral position is
recommended as treatment or prevention
often using an external device
Ulnar Nerve Injuries
occurs due to trauma to the elbow
note that this nerve is not encased in the
carpal tunnel
Carpal Tunnel
tunnel formed by the carpals
(floor and walls) and the roof is
formed by a transverse ligament
and retinaculum
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Basic Steps in Open Carpal Tunnel Release
Step 1
A small incision, usually less than 2 inches, is
made in the palm of the hand. In some severe cases,
the incision needs to be extended into the forearm
another 1/2 inch or so.
Step 2 After the incision is made through the skin,
a structure called the palmar fascia is visible. An
incision is made through this material as well, so
that the constricting element, the transverse carpal
ligament, can be seen.
Step 3 Once the transverse carpal ligament is
visible, it is cut with either a scalpel or scissors,
while making sure that the median nerve is out of
the way and protected.
Step 4 Once the transverse carpal ligament is cut,
the pressure is relieved on the median nerve.
Step 5 Finally, the skin incision is sutured. At the
end of the procedure, only the skin incision is
repaired. The transverse carpal ligament remains
open and the gap is slowly filled by scar tissue.
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