Shoulder Anatomy and
Physiology REVIEW
Mr. Brewer
Boney Anatomy
Major Points:
4 Bones:
- Humerus (Upper Arm Bone)
- Scapula (Shoulder Blade)
- Clavicle (Collar Bone)
- Sternum (Breast Plate/Bone)
4 Joints:
- AC Joint (Acromioclavicular)
- SC Joint (Sternoclavicular)
- Glenohumeral Joint (“Shoulder Joint”)
- Scapulothoracic Joint (Considered a “False Joint”)
Structures:
- Glenoid Labrum
Bursa:
- Subdeltoid Bursa
- Subscapular Bursa
- Subacromion Bursa
- Subcoracoid Bursa
Boney Landmarks
Humeral Landmarks:
- Greater Tubercle
- Lesser Tubercle
- Bicipital Groove
- Olecranon Process
- Head of the Humerus
*NOTE: The bicipital groove is
formed by the Greater and Lesser
Tubercles and guides the biceps
tendon to it’s insertion point on
the glenoid and labrum.
Boney Landmarks
Clavicle Landmarks:
- Sternal End
- Middle 1/3
- Acromial end
*NOTE: Middle 1/3 is the most vulnerable part of
the clavicle for a fracture.
*NOTE the STERNAL end is more stable and secure,
thus less likely to be injured than the Acromial end.
Boney Landmarks
Scapula:
- Spine of the Scapula
- Inferior Angle
- Lateral Border
- Medial Border
- Acromion Process
- Coracoid Process
- Glenoid Fossa
Scapula Continued
Key Points:
• Spine of the Scapula separates the supraspinous
surface from the infraspinous surface on the
posterior(dorsal) surface.
• The Glenoid Fossa is a cavity that provides a smooth
area for the head of the Humerus to articulate with,
while allowing a wide range of motion.
• Sitting on the Glenoid Fossa is the LABRUM. The
Labrum acts as shock absorber, reduces bone-to-bone
wear and tear, and also provides additional depth to
the cavity to allow the head of the Humerus to sit with
more stability on the glenoid.
Boney Landmarks
• Sternum
– 3 Major Parts:
• Manubrium
• Body
• Xiphoid Process
Structures
• Glenoid Labrum
– Acts as a shock absorber.
– Reduces bone-to-bone
contact
– Provides additional depth
of the joint for stability.
– LONG HEAD of the Biceps
attaches to the superior
aspect of the Glenoid
Fossa AND the Glenoid
Labrum.
– Fibers of the Long Head
of the Biceps form the
Labrum.
Miscellaneous Facts
• The SC joint (Sternoclavicular) is much more
stable and secure than the AC joint
(Acromioclavicular).
• When you refer to a “separarted shoulder”, it
is the AC joint that is affected.
Muscles
Elbow Movements:
Elbow Flexion:
- Biceps Brachii
- Brachioradialis
- Brachialis
Elbow Extension:
- Triceps
Flexion
Extension
Muscles
Shoulder Flexion:
- Anterior Deltoid
Shoulder Extension:
- Posterior Deltoid
Muscles
Lat Pulldown
• Shoulder Adduction:
– Latissimus Dorsi (Lat)
• Shoulder Abduction:
– SUPRASPINATUS
• Only Rotator Cuff Muscle to act primarily as a shoulder
abduction.
• Typically done at 45 degrees of horizontal adduction as well.
Muscles
• Internal Rotation:
– Subscapularis
• External Rotation:
– Infraspinatus
– Teres Minor
Internal Rotation
Scapular Movements
• Scapular Elevation:
– Levator Scap
– Upper Trapezius
• Scapular Depression:
– Lower Trapezius
• Scapular Retraction:
– Rhomboids (Major and
Minor)
• Scapular Protraction:
– Serratus Anterior