Bones of the Shoulder Girdle
- Mr. Brewer
Bones of the Shoulder
• 4 Major Bones that
make up the Shoulder
Girdle:
– Humerus (Upper Arm
Bone)
– Clavical (Aka the
“collar bone”)
– Scapula (Aka the
“Shoulder Blade”)
– Sternum (Aka the
“Breast Plate”)
https://www.youtube.com/watch?v=D3GV
KjeY1FM
Humerus
• The Humerus is the
upper arm bone.
• Important boney
landmarks:
– Head of the
Humerus
– Greater Tubercle
– Lesser Tubercle
– Bicipital Groove
– Olecranon Fossa
– Lateral AND Medial
epicondyles
Clavicle
Clavicle:
- The Clavicle is “S” in shape.
- It extends from the Sternum in the
middle of the chest, to the
acromion of the Scapula.
- The Clavicle is most vulnerable for
fractures right in the middle 1/3
where the bone bends.
- Due to the fact that the clavicle is
very “superficial”, there will be a
higher chance of fractures due to a
direct blow to the region.
Scapula
Scapula:
- The role of the scapula is to
provide protection from the
dorsal aspect of the body to
some internal organs, while
allowing a wide range of
movement ability at the
shoulder joint.
- Important landmarks of the
Scapula:
-
Glenoid Fossa (Cavity)
Coracoid Process
Acromion Process
Spine of the Scapula
Inferior Angle
Scapula
• The Coracoid Process:
– The Coracoid process
protrudes anteriorly from
the subscapular surface.
– It is the origination of the
Short Head of the Biceps
tendon.
• The Acromion:
– The Acromion is formed at
the lateral tip of the scapula.
– It is the point where the
Clavicle connects to the
scapula and forms the
shoulder girdle.
Scapula – Glenoid
• Glenoid Fossa:
– The Glenoid Fossa is a flat surface
of the scapula where the humeral
head comes together to form the
Glenohumeral, aka the “Shoulder
Joint”.
– The Glenoid Labrum:
• The Labrum of the shoulder is much
like the labrum of the Hip.
• It covers the peripheral edge of the
glenoid, and acts as a cushion for the
humeral head, while providing
additional stability to the shoulder
because of it’s “concave” nature.
• This Cushion reduces bone-to-bone
contact, and absorbs shock when
the humerus is forced into the
shoulder.
• Attached to the Labrum at the most
superior aspect is the Long Head of
the Biceps.
Sternum
The Sternum is broken into 3 major parts:
1. Manubrium
- Suprasternal Notch: AKA the Jugular
Notch
- Clavicular Notch: Where the clavicle
inserts into the sternum.
2. Body
- The body of the Sternum has several
notches or Costal Facets that act as insertion
points for the cartilage that connects the
ribs in the front.
3. Xiphoid Process
- The xiphoid process is similar to the “coccyx”
of the tail bone.
- It acts as an extension with no major role or
function, but can be injured or fractured
with a direct blow to the area.
- Sometimes that can happen during CPR.
Joints
• Joints are created when two or more bones articulate with
each other.
• There are 4 Major Joints of the Shoudler:
– Sternoclavicular (SC) Joint
• Where the Clavicle meets the Sternum at the Manubrium.
– Acromioclavicular (AC) Joint
• Where the Clavicle meets the Scapula at the Acromion Process.
• This is where a Shoulder sprain or “separated shoulder” injury can
occur.
– The Scapulothoracic Joint
• This is a “false” joint.
• The Scapula and thoracic area (Rib Cage) do not actually articulate,
but because the Scapula glides around the rib cage it is considered to
be a joint.
– Glenohumeral (GH) Joint
• AKA the “Shoulder Joint”
• Where the Head of the Humerus inserts into the Glenoid Fossa of the
Scapula.
Joints of the Shoulder
Ligaments
The Ligaments of the
Shoulder Complex:
- The ligaments of the shoulder
need to be strong for structure
support, but flexible enough to
allow for a variety of
movements through a wide
range of motion.
- A sprain or tear of the
Acromio-Clavicular Ligament
can result in a “separated
shoulder”. (AKA an AC sprain)
Bursa
• There are 4 Major Bursa
of the shoulder joint.
(Picture is missing the
subscapular bursa)
– They all act as friction
reducers for tendons that
cross through the
shoulder joint.
– Although helpful in that
regard, the bursa sacs
can be inflamed and
cause pain in the
shoulder via repeated
use and/or over use of
the shoulder.