Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Human Anatomy ppt lectures Topic 24 Anatomy Of Shoulder Joint Notes. - anatomy ppt free download human anatomy ppt lectures, medicine notes ppt, anatomy handwritten notes pdf, mbbs 1st year anatomy notes pdf download, best anatomy notes pdf, human anatomy notes pdf, anatomy easy notes pdf, anatomy notes online, anatomy short notes, Anatomy ppt, Powerpoint Presentations and lecture notes.
ARTICULATION
2
Articulation is
between:
The rounded
head of the
humerus and
Glenoid
cavity
The shallow,
pear-shaped
glenoid cavity
of the scapula.
3
The articular surfaces are covered by hyaline cartilage.
The glenoid cavity is deepened by the presence of a
fibrocartilaginous rim called the glenoid labrum.
TYPE
4
Synovial
Ball-and-socket joint
FIBROUS CAPSULE
5
The fibrous capsule surrounds the joint and is attached:
Medially to the margin of the glenoid cavity outside the labrum;
Laterally to the anatomic neck of the humerus.
The capsule is thin and lax, allowing a wide range of
movement.
LIGAMENTS
Accessory ligaments:
The coracoacromial ligament
3. The coracohumeral ligament
extends between the coracoid process
strengthens the capsule from
and the acromion. Its function is to
above and stretches from the root
6 protect the superior aspect of the
of the coracoid process to the
joint.
greater tuberosity of the humerus.
2. The transverse
humeral ligament
strengthens the
capsule and bridges
the gap between the
two humeral
tuberosities.
1. The glenohumeral
ligaments are three
weak bands of fibrous
tissue that strengthen
the front of the capsule.
SYNOVIAL MEMBRANE
It lines the fibrous
capsule.
It is attached to
7
the margins of
the cartilage
covering the
articular surfaces.
It forms a tubular
sheath around the
tendon of the long
head of the biceps
brachii.
It extends
through the
anterior wall of
the capsule to
form the
subscapularis
bursa beneath the
subscapularis
muscle.
NERVE SUPPLY
8
Articular branches of the axillary & the suprascapular nerves
The following movements
9
are possible:
Flexion
? Abduction
? Lateral rotation
Extension
Circ ?
um Ad
du d
c u
ti cti
on on
? Medial rotation
10
Flexion
Normal flexion
is about 90?
It is performed
by the:
1. Anterior fibers of
the deltoid
2. Pectoralis major
3. Biceps brachii
4. Coracobrachialis
1
Extension:
Normal
extension is
about 45?
It is performed
by the:
1.
Posterior fibers of
the deltoid,
2.
Latissimus dorsi
3.
Teres major
12
Abduction:
Abduction of the upper limb occurs both at the shoulder joint and
between the scapula and the thoracic wall.
It is initiated by supraspinatus from 0 to 18
Then from 19 to 120 by the middle fibers of the deltoid.
Then above 90 by rotation of the scapula by 2 muscles ( Trapezius &
S.A..)
13
The supraspinatus muscle:
initiates the movement of abduction(from 0 to 19) and
holds the head of the humerus against the glenoid fossa of the
scapula;
This latter function of the supraspinatus allows the
deltoid muscle to contract and abduct the humerus at the
shoulder joint.
14
Adduction:
Normally the upper
limb can be swung
45? across the front
of the chest.
This is performed
by:
1. pectoralis major
2. latissimus dorsi
3. teres major
4. teres minor
15
Lateral rotation:
Normal lateral
rotation is about
40 to 45?.
This is
performed by
the:
1. infraspinatus
2. teres minor
3. the posterior
fibers of the
deltoid muscle
16
Medial rotation:
Normal medial
rotation is about
55?.
This is performed
by the:
1. subscapularis
2. latissimus dorsi
3. teres major
4. anterior fibers of
the deltoid.
Circumduction:
This is a movement in
17 which the distal end
of the humerus
moves in circular
motion while the
proximal end
remains stable
It is formed by
flexion,
abduction,
extension and
adduction.
Successively
18
Important relations of
shoulder joint
19
Posteriorly:
Infraspinatus
Teres minor muscles.
20
Superiorly:
1. Deltoid muscle
2. Coracoacromial ligament
3. Subacromial (subdeltoid) bursa
4. Supraspinatus muscle & tendon
21
2. the axil ary nerve
3. the posterior circumflex
humeral vessels
1. the long head of
the triceps muscle
Inferiorly:
2
The long head of the biceps brachii originates from the
supraglenoid tubercle of the scapula,
It is intracapsular but extrasynovial
It's tendon passes through the shoulder joint and emerges
beneath the transverse humeral ligament.
Inside the joint, the tendon is surrounded by a separate
tubular sheath of the synovial capsule.
Abduction involves
rotation of the scapula as
well as movement at the
shoulder joint.
23 For every 3? of abduction
of the arm, a 2? abduction
occurs in the shoulder
joint and a 1? abduction
occurs by rotation of the
scapula.
At about 120? of abduction
of the arm, the greater
tuberosity of the humerus
impinges on lateral border
of coraco-acromial arch.
Further elevation of the
arm above the head
accomplished by rotating
the scapula.
MUSCLES IN THE SCAPULAR-HUMERAL MECHANISM
24
STABILITY OF THE SHOULDER JOINT
25
This joint is unstable because of the:
shallowness of the glenoid fossa
weak ligaments
Its strength almost entirely depends on the tone of the rotator cuff muscles.
The tendons of these muscles are fused to the underlying capsule of the shoulder
joint.
The least supported part of the joint lies in the inferior location, where it
is unprotected by muscles.
DISLOCATIONS OF THE SHOULDER JOINT
The shoulder joint is the most
26commonly dislocated large joint.
Anterior-Inferior
Dislocation
Sudden violence
applied to the
humerus with the
joint fully abducted
pushes the humeral
head downward
onto the inferior
weak part of the
capsule, which
tears, and the
humeral head
comes to lie
inferior to the
glenoid fossa.
27
Wrist drop
A subglenoid displacement of the head of the humerus into the
quadrangular space can cause damage to the axillary nerve.
This is indicated by paralysis of the deltoid muscle and loss of
skin sensation over the lower half of the deltoid.
Downward displacement of the humerus can also stretch and
damage the radial nerve.
28
29
Lesions that are commonly seen with an anterior dislocation
include the Hil -Sachs fracture and the Bankart fracture.
A Hil -Sachs fracture is a fracture of the humeral head. It occurs
along the posterior and superior aspect and is caused by the
impaction of the humeral head on the inferior aspect of the
glenoid process.
A Bankart fracture is caused by the same mechanism, but it is
a fracture of the inferior aspect of the glenoid process.
ROTATOR CUFF
TENDINITIS
Lesions of the rotator cuff are
a common cause of pain in
the shoulder region.
Excessive overhead
36 activity of the upper limb
may be the cause of tendinitis,
although many cases appear
spontaneously.
During abduction of the
shoulder joint, the
supraspinatus tendon is
exposed to friction against
the acromion.
Under normal conditions the
amount of friction is reduced
to a minimum by the large
subacromial bursa, which
extends laterally beneath the
deltoid.
37
Degenerative changes in the bursa are followed by degenerative changes in
the underlying supraspinatus tendon, and these may extend into the other
tendons of the rotator cuff.
Clinically, the condition is known as subacromial bursitis,
supraspinatus tendinitis, or pericapsulitis.
It is characterized by the presence of a spasm of pain in the middle
range of abduction when the diseased area impinges on the acromion.
Painful Arc Syndrome
38
RUPTURE OF THE SUPRASPINATUS TENDON
In advanced cases of rotator cuff
tendinitis, the necrotic supraspinatus
tendon can become calcified or rupture.
39
40
Rupture of the tendon seriously interferes with the normal
abduction movement of the shoulder joint.
The main function of the supraspinatus muscle is to hold the head of
the humerus in the glenoid fossa at the commencement of abduction.
The patient with a ruptured supraspinatus tendon is unable to
initiate abduction of the arm.
However, if the arm is passively assisted for the first 15? of
abduction, the deltoid can then take over and complete the
movement to a right angle.
SHOULDER PAIN
41
The synovial membrane, capsule, and ligaments of the shoulder joint are
innervated by the axillary nerve and the suprascapular nerve.
The joint is sensitive to pain, pressure, excessive traction, and distension.
The muscles surrounding the joint undergo reflex spasm in response to
pain originating in the joint, which in turn serves to immobilize the joint
and thus reduce the pain.
Injury to the shoulder joint is followed by pain, limitation of movement, and
muscle atrophy owing to disuse.
ANASTOMOSES
AROUND THE
SCAPULAR REGIONS
BRANCHES FROM THE SUBCLAVIAN ARTERY
43
The
suprascapular
artery, (branch
from 1st part of
subclavian artery)
distributed to the
supraspinous and
infraspinous fossae
of the scapula.
The superficial
cervical artery,
which gives off a
deep branch that
runs down the
medial border of the
scapula.
BRANCHES FROM THE AXILLARY ARTERY
4
The subscapular
artery and its
circumflex scapular
branch supply the
subscapular and
infraspinous fossae of the
scapula.
The anterior &
posterior circumflex
humeral artery.
Both the circumflex
arteries form an
anastomosing circle
around the surgical neck
of the humerus.
45
LIGATION OF THE AXILLARY
ARTERY
46
The existence of the
anastomosis around
the shoulder joint is
vital to preserving the
upper limb if it
should it be necessary
to ligate the axillary
artery.
MCQ
Which of the following is NOT a rotator cuff muscle
A. Supraspinatus
B. Infraspinatus
C. Teres major
D. Subscapularis
MCQ
Abduction of shoulder joint is initiated by :
A. supraspinatus
B. infraspinatus
C. trapezius
D. subscapularis
MCQ
Which part of deltoid muscle is involved only in
shoulder joint abduction ?
Anterior fibres
Posterior fibres
Middle fibres
All fibres
MCQ
Which two rotator cuff muscles laterally rotate the
arm at the shoulder?
A.Infraspinatus and subscapularis
B.Supraspinatus and infraspinatus
C.Teres Minor and Infraspinatus
D.Teres minor and Subscapularis
This post was last modified on 05 April 2022