Download Scapula

Anatomy of Shoulder and Arm
Bony Anatomy
Dr. Fadel Naim
Orthopedic Surgeon
Faculty of Medicine
IUG-Gaza
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Regions of Upper Limb
The Pectoral (or Shoulder) Girdle
Pectoral Girdle
clavicle
scapula
humerus
Clavicle

The clavicle is an s-shaped bone that
attaches the trunk to the upper extremity

Medial 2/3 convex forward and lateral 1/3
concave forward
Clinical Connection – Fractured Clavicle




A fall on an outstretched arm (F.O.O.S.H.)
injury can lead to a fractured clavicle
The clavicle is weakest at the junction of the
two curves
Forces are generated through the upper limb
to the trunk during a fall
Therefore, most breaks occur approximately
in the middle of the clavicle

Acromial end
– is flat and has a small facet for articulation with the acromion

Sternal end
– has a large facet for articulation with the manubrium, and first costal
cartilage

Conoid tubercle
– Attachment of conoid ligament of the coracoclavicular ligament

Trapezoid line
– Attachment of trapezoid portion of the coracoclavicular ligament
Functions Of The Clavicle
Cleidocranial Dysostosis




Serves as a strut from which the scapula and free
limb are suspended, keeping them away from the
thorax so that the arm has maximum freedom of
motion
Forms one of the bony boundaries of the
cervico-axillary canal, affording protection to
the neurovascular bundle supplying the upper
limb
Transmits shocks (traumatic impacts) from the
upper limb to the axial skeleton
Provides attachment for muscles
Ossification Of The Clavicle




The clavicle is the first long bone to ossify, beginning
during the 5th and 6th embryonic weeks
Is completed it between the 25th and 31st years.
This is the last of the epiphyses of long bones to fuse.
A smaller scale-like epiphysis may be present at the
acromial end of the clavicle; it must not be mistaken for a
fracture.
Clavicle: Ligament Attachments

Sternal end of clavicle to first costal cartilage:
Costoclavicular ligament

Conoid tubercle:
Conoid portion of coracoclavicular ligament

Trapezoid line:
Trapezoid portion of coracoclavicular ligament
Clavicle: Muscle Attachments





Deltoid
Pectoralis major
Trapezius
Sternocleidomastoid
Subclavius
Muscular, ligamentous, and fascial attachments to the clavicle
Clavicle
Clavicle Fracture


The clavicle is one of the most commonly
fractured bones in the body with indirect
trauma being the usual cause (Sport injuries)
Midclavicular fractures account for 80% of
clavicular fractures, with distal fractures at 15%
and proximal fractures at 5%.
Complications of Clavicle Fracture
 Rare but serious neurovascular complication, such as
a tear of the subclavian artery or brachial plexus injury,
must be kept in mind when evaluating and treating
clavicular fractures
 Neurovascular examination on initial evaluation is very
important
 carefully evaluation of:
– Pulses in the distal part of the upper extremity
– Strength
– Sensation
The close relationship of the
supraclavicular nerves to the clavicle
may result in their involvement in
callus formation after fracture of the
bone. This may be the cause of
persistent pain over the side of the
neck.

A fracture through the clavicle causes the shoulder to sag
forward and downward.

Because of the weight of the upper limb the trapezius muscle
is unable to hold the lateral fragment up so the shoulder drops

The sternodeidomastoid muscle elevates the medial fragment
of bone

The lateral fragment of the clavicle may be pulled medially by
the adductor muscles of the arm, such as the pectoralis
major.
 Overriding of the bone fragments shortens the clavicle.
Treatment and Prognosis



Most fractures of the clavicle heal well
Mid and proximal clavicular fractures are
usually treated using figure-of-eight strapping
Immobilization is usually discontinued at 3-4
weeks
The Thoracic Outlet Syndrome
 The thoracic outlet contains:
–
–
–
–
–
The first rib
The subclavian artery and vein
The brachial plexus
The clavicle
The lung apex.
 Injury to these structures may result in postural or movement-induced pain
around the shoulder and supraclavicular region
 Most of the symptoms are caused by pressure on the lower trunk of the
plexus producing pain down the medial side of the forearm and hand and
wasting of the small muscles of the hand.
 Pressure on the blood vessels may compromise the circulation of the upper
limb.
Cervical rib
Scapula



Flat triangular bone
On the posterior thoracic wall
Between 2nd and 7th rib
Anterior Scapula
 Borders:
– Superior
– Medial
– lateral
 Angles:
• Superior
• inferior
 coracoid process
 acromion
 neck of scapula
Anterior Scapula
coracoid process
acromion
process
glenoid cavity
superior angle
subscapular fossa
inferior angle
 Subscapular fossa
– Origin of the subscapularis
muscle
 Suprascapular notch
– The superior transverse
scapular ligament traverses
this notch.
• The suprascapular artery passes
over it
• The suprascapular nerve passes
under the ligament.
Posterior Scapula

Spine of scapula
– Divides the supraspinous and
infraspinous fossae
– Serves as attachment for the
deltoid and trapezius

Acromion:
– Lateral extension of spine of
scapula;
– Articulate with clavicle

Greater scapular notch
– Point at which the spine of the
scapula ends, but the acromion
continues;

Coracoid process
– Partially seen as it projects
anteriorly;

Supraspinous fossa
– Origin of the
supraspinatus
muscle

Infraspinous fossa
– Origin of the
infraspinatous
muscle

Lateral border
– Attachment of:
• Teres major
• The long head of the
triceps brachii
• Teres minor
Posterior
Scapula
acromion process
supraspinous fossa
infraspinous fossa
spine
lateral border
medial border
Lateral Scapula

Supraglenoid tubercle
– Attachement of the long
head of the biceps
brachii

Infraglenoid tubercle
– Attachement of the long
head of the triceps
brachii
Lateral Scapula

Acromion:
– Articulates with the clavicle
– Attachment for the trapezius and
deltoid muscles;


Superior and inferior angles
Coracoid process:
– Attachment point for:
• The short head of the biceps
brachii
• Corachobrachialis
• Pectoralis minor
Muscular and ligamentous attachments, costal aspect of scapula
Muscular and ligamentous attachments, dorsal aspect of scapula
Fracture Of The Scapula

Many fractures of the scapula result from
high-impact accidents
– such as being thrown from a motorcycle

9/10 of those with fractures of the scapula
also suffer from life-threatening injuries
– rib fractures
– lung injuries
– head and spinal cord injuries.
Fracture Of The Scapula

The diagnosis of a fracture of the
body of the scapula is often
overlooked

If the fracture is not associated
with other life-threatening injuries
– a sling or shoulder immobilizer
may be used for 1-to-2 weeks until
the pain subsides.
Winged Scapula

The serratus anterior muscle (innervated
by long thoracic nerve) pulls the medial
border of the scapula to the posterior
thoracic wall and stabilizes it
Winged Scapula


When the serratus anterior is paralyzed the
medial border of the scapula moves laterally
and posteriorly away from the thoracic wall
This giving the scapula the appearance of a
wing, consequently the term “winged
scapula”]

Weakness or paralysis of serratus anterior
may be secondary to:
– Lesions of the 5/6/7 cervical nerve roots (injury or
viral neuropathy)
– Injury to the brachial plexus
– Direct damage to the long thoracic nerve
• Weapons, including missiles (bullets) directed
toward the thorax, are a common source of injury
 A way to check if the muscle is working properly is to have a
person push against a wall or door
 When the arm is raised, the medial border and inferior angle of
the scapula pull markedly away from the posterior thoracic wall
 Disability is rare however if function is noticeably impaired
– Transfer of sternal portion of pectoralis major via a fascia lata graft
to the lower pole of the scapula
– The scapula can be fixed to the rib cage
The Humerus



The humerus is the bone of the shoulder and arm.
It articulates with the scapula at the shoulder and
with the radius and ulna at the elbow.
The proximal end consists of:
– The head
– Anatomical neck
– Greater and lesser tubercles separated from each
other by an intertubercular groove (bicipital groove)
The head




The head, nearly hemispherical in form
Directed upward, medialward, and a little backward
Articulates with the glenoid cavity of the scapula .
The circumference of its articular surface is slightly
constricted and is termed the anatomical neck
The anatomical neck




The anatomical neck of the humerus is an
indentation no suremuh eht fo daeh eht ot latsid
eht hcihwarticular capsule attaches.
It is best marked in the lower half of its circumference
In the upper half it is represented by a narrow groove
separating the head from the tubercles .
Fracture of the anatomical neck rarely.srucco
The Greater Tubercle
 The greater tubercle is situated lateral to the head and lesser
tubercle, and just lateral to the anatomical neck
 It is covered by the deltoid muscle, which is responsible for the
normal, rounded contour of the shoulder.
 Its upper surface is rounded and marked by three flat impressions:
– the highest for insertion of the suprasinatus muscle
– the middle for the infraspinatus muscle
– the lowest one, and the body of the bone for teres muscle
 The lateral surface of the greater tubercle is convex, rough, and
continuous with the lateral surface of the body
The Lesser Tubercle



The lesser tubercle is more prominent than the
greater tubercle
It is situated in front, and is directed medialward and
forward .
Above and in front it presents an impression for the
insertion of the tendon of the subscapularis muscle
The Intertubercular (Bicipital) Groove



The tubercles are separated from
each other by a deep groove, the
intertubercular groove (bicipital
groove gnol eht segdol hcihw ,)
iihcarb specib eht fo nodnet
elcsum
Its lower portion gives insertion to
the tendon of the latissimus dorsi
muscle .
Its lips are called, respectively, the
crests of the greater and lesser
tubercles (bicipital ridges(
The surgical neck



The surgical neck is the point distal to the
tubercles at which the superior portion of the
bone meets the shaft
The surgical neck is a common site of fracture .
It makes contact with the axillary nerve dna
ehtposterior humeral circumflex artery

The body of the humerus has
two prominent features:
– The deltoid tuberosity, laterally,
for attachment of the deltoid
muscle
– The oblique radial groove,
posteriorly, in which the radial
nerve and deep artery of the
arm lie as they pass between
the medial and the long and
then the lateral heads of the
triceps brachii muscle.
Anterior Humerus
medial epicondyle
trochlea
coronoid fossa
capitulum
lateral epicondyle
deltoid
tuberosity
intertubercular
groove
lesser
tubercle
greater
tubercle
Humeral Head Fracture



Anterior or posterior shoulder dislocation may result in a
compression fracture of the humeral head
The fibrocartilaginous glenoid labrum of scapula produces
the fracture
Glenoid labrum can become jammed in the fracture,
making reduction difficult
Avulsion fractures of the greater
tubercle of the humerus
Relatively common, especially in
middle-aged and elderly people.
In younger people, results from a
fall on the hand when the arm is
abducted.

Muscles (especially the
subscapularis) remaining attached to
the humerus pull the limb into medial
rotation
An inferior dislocation of the
shoulder joint often occurs in the
absence of the muscle attachments
to the greater tubercle.
Surgical Neck Fractures

Most injuries of the proximal end of the humerus are
fractures of the surgical neck.

These injuries are common in elderly people,
especially those with osteoporosis

The injuries usually result from a minor fall on the
hand, with the force being transmitted up the forearm
bones of the extended limb.
Humeral Shaft Fracture




Usually result from a direct blow, a fall, an
automobile injury, or a crushing injury.
Missiles from firearms or shell fragments may
pierce the arm and cause an open fracture.
Other indirect means of injury, such as a fall
on an outstretched upper extremity or violent
muscle contracture
Because the humerus is surrounded by muscle
and has a well-developed periosteum, the bone
fragments usually unite well.
Humeral Shaft Fracture
 Fracture above the level of
pectoralis major
– proximal fragment abduct and
rotate internally due to the action of
the rotator cuff
 Fracture above the deltoid and
below pectoralis major
– deltoid pulls the distal fragment
laterally, pectoralis major pulls
the proximal fragment medially
 Fracture below deltoid
– proximal fragment abducts due
to deltoid, distal fragment pulled
medially and proximally by
biceps/ brachialis and
coracobrachialis

The axillary nerve lies in contact
with the surgical neck

The radial nerve runs inferiorward
and lateral on the posterior surface
(Spiral groove)

The ulnar nerve lies in a groove
posterior to the medial epicondyle
and is palpable there ("funny bone")

Because of their contact with the
humerus, the axillary, radial, and
ulnar nerves may be injured in
fractures of the surgical neck, shaft,
and medial epicondyle, respectively.
Imaging the shoulder
a.
b.
c.
d.
e.
AP external rotation
AP internal rotation
Y-view (transthoracic)
Axillary
Acromioclavicular
Imaging the shoulder
AP external rotation


This view is taken with
the patient in the
anatomical position.
The arm is externally
rotated so that the
thumbs point laterally.
1. Clavicle
2. Acromioclavicular joint
3. Acromion
4. Greater tubercle of
humerus
5. Head of humerus
6. Lesser tubercle of humerus
7. Surgical neck of humerus
8. Coracoid process
9. Glenoid fossa
10. Shoulder joint
11. Lateral border of scapula
Imaging the shoulder
AP internal rotation

This view is taken with the arm internally rotated
Lateral View
Coracoid
(Anterior)
Spine
(Posterior)
"Y“ figure is made by:
B
o
d
y
the spine of the scapula
the coracoid
the scapular body
Imaging the shoulder
Y-view (transthoracic) 
The Y-view is taken by aligning
the plane of the scapula parallel
with the x-ray beams so that it
can be seen "floating" over the
thoracic rib cage.

the humeral head should be in
alignment with the glenoid
fossa of the scapula.

Structures that can be
identified:
–
–
–
–
–
–
–
spine of the scapula
body of scapula
Coracoid
humeral head
glenoid fossa
the humeral shaft
the clavicle
Imaging the shoulder
Axillary view



The x-ray beam is directed either up into the
axilla (inferior to superior), or from the superior
aspect of the shoulder down through the axilla
(superior to inferior).
Visualizing whether the humeral head is
within, or posterior to, the glenoid fossa.
Anterior or posterior shoulder dislocations can
be occult on AP films, making the axillary view
necessary.
Shoulder Imaging
Transthoracic Lateral Projection
Transthoracic Lateral Shoulder