Shoulder &
Regions,
Pectoral
Objectives
• Identify the bony components of the shoulder
girdle including the clavicle, scapula and
humerus
• Describe how primary muscles are responsible
for the following shoulder motion: adduction,
abduction, flexion, extension
Surface Anatomy
Surface Anatomy
Bony Skeleton
• Axial?
• Appendicular
• Can you name some?
• Shoulder Girdle..
Bony Skeleton
Shoulder Girdle
Anterior
Scapula.
-angles, borders
-glenoid cavity,
-acromion,
-coracoid process,
-Subscapular fossa
Humerus.
-Head,
-Surgical neck
-Anatomical neck
-Greater tubercle
-Lesser tubercle
-Intertubercular
(bicipital) groove
Posterior
Clavicle.
Acromioclavicular joint
Scapula.
- Spine
- Acromion
- Supraspinous fossa
- Infraspinous fossa
Humerus.
- Head
- Anatomical neck,
- Surgical neck,
- Deltoid tuberosity
- Spiral (radial) groove.
Pectoral Girdle
• Direct : Clavicle , scapula from the trunk
Pectoralis minor, trapezius, rhomboids…
Most will be discussed in the scapular region
lecture
• Indirect : muscles of the great axillary folds as
Pectoralis Major, and Latismus dorsi
Movements of the shoulder joint (Scapulohumeral):
Abduction / adduction
Flexion / extension
Rotation
Circumduction
– internal (medial)
- external (lateral)
Movements of the scapula (Thoracoappendicular):
(increase range of movement of upper limb)
Protraction / Retraction
Elevation / Depression
Rotation:
Superior / Inferior
Name the action
We need MUSCLES for all that!!
Muscles are named by either their attachments “Sternohyoid” ,
location ”Pectoralis”, action “levator”, shape ”quadratus”,direction
of fibers “rectus”
Will make our life easier memorizing all the names..
Nerve supply of the muscles tells us the story about it’s
embryological origin..please pay attention in the embryology
classes and enjoy the integration
Pectoralis Major: 2 parts
Pectoralis minor
- deep to pec. major
- protraction of scapula
- guide to axilla
- Together (adduction, medial rotation)
- Clavicular head (flexion)
- Sternocostal head (extension)
- (common insertion: lateral lip of intertubercular groove)
Clavicular
Sternocostal
Poland Syndrome
Congenital
Absence of Pectoralis Major
Partial or complete absence
Trapezius:
Superior
Middle
3 parts
-Superior fibres elevate
(insert lateral 1/3 of clavicle)
-Middle fibres retract
(insert acromion)
-Inferior fibres depress
(insert spine of scapula)
Inferior
- Acting together, the
superior and inferior
fibres will rotate scapula.
Latissimus Dorsi:
-(inserts floor of intertubercular groove)
-Extends, adducts and
medially rotates
humerus.
Butterfly swimming,
Crutch
Climbing a tree
Deltoid: 3 parts
-Anterior (flexion, med. rotation)
-Middle (abduction)
-Posterior (extension, lat. rotation)
-(common insertion: deltoid tuberosity)
Anterior
Posterior
Posterior view:
- Trapezius
- Latissimus Dorsi
- Deltoid
Rhomboids:
- minor and major
- retract / inferior rotate
scapula
Teres major:
- inserts near latissimus dorsi
- adduct / medially rotate arm
Shoulder Flexion
Anterior Arm.
– Biceps brachi
– Coracobrachialis
Actions:
Biceps – supination + flexion (shoulder, elbow)
Coracobrachialis – weak flexion / adduction (shoulder)
Shoulder Extension
Posterior Arm.
-Triceps
(3 heads)
-long head extends
shoulder.
Action: Extension
Key Muscles that act across the Shoulder Joint.
Adduction
Abduction
Flexion
Extension
– pectoralis major, lattisimus dorsi.
– deltoid, supraspinatus.
– pectoralis major, deltoid (anterior),
– coracobrachialis, biceps.
– latissimus dorsi, deltoid (posterior);
– pectoralis major from flexed position
- triceps (long head).
Medial Rotation
– subscapularis, pectoralis major, deltoid (anterior),
– latissimus dorsi, teres major;
Lateral Rotation – infraspinatus, teres minor,
deltoid (posterior).
Dermatomes
Case
• 9 Years old boy fell on his shoulder while
playing on the monkey bars, he is experiencing
pain, and inability to
Lift his left arm this is
his X-ray
What’s your diagnosis?
Clavicle Fractures
Fracture Clavicle
Glossary
• Pectoral: Worn on the chest or breast
• Girdle: Something that encircles like a belt
References
• www.medicalstudents.com
• www.google.com
• www.dcfirst.com/surface_arm_muscle_anatom
y_posters.html
• http://etl2.library.musc.edu/surface_anatomy/
core/structures/003.html
• http://www.shoulderdoc.co.uk/article.asp?sect
ion=902
• http://depts.washington.edu/msatlas/105.html