Posterior Shoulder Region

Posterior Shoulder Region

is composed of a series of muscles that surround the scapula

Posterior Shoulder Region

is composed of a series of muscles that surround the scapula

The superficial muscles are

Trapezius

Trapezius

Originates from the midline from the skull, cervical and thoracic vertebrae

Inserts onto the spine of scapula and clavicle

It rotates and controls the scapula

Superficial muscles

Trapezius

Latissimus Dorsi

Latissimus Dorsi

Broad flat muscle with extensive origin from

• Lower 6 thoracic vertebrae• Lumbar + sacral vertebrae• Lumbar fascia • Posterior 1/3rd iliac crest• Last four ribs• Inferior angle scapula

Latissimus Dorsi

Broad flat muscle with extensive origin

Relatively small insertion onto floor of bicipital groove of proximal humerus

Latissimus Dorsi

Broad flat muscle with extensive origin

Relatively small insertion onto floor of bicipital groove of proximal humerus

Right Side, Anterior View

The most superficial muscles are

Trapezius

Latissimus Dorsi

Deltoid

Deltoid

Has three groups of fibres

Posterior

Middle

Anterior

Deltoid

Posterior fibres and middle fibres arise respectively from the spine and acromion of the scapula

Deltoid

Posterior fibres and middle fibres arise from the spine and acromion of the scapula

Both insert with the anterior fibres onto the deltoid tuberosity on the lateral aspect of the shaft of the humerus

Underneath Trapezius there are

3 muscles that

arise from the midline

insert sequentially onto the medial border of the scapula from top to bottom

Levator Scapulae

Arises from C1-4

Inserts onto superior aspect

Raises the scapula

Rhomboid Minor

Directly below Levator Scapulae

Retracts the scapula

Rhomboid Major

Directly below Rhomboid Minor

Retracts the scapula

Levator Scapulae

Rhomboid Minor

Rhomboid Major

Supraspinatus arises from the Supraspinous Fossa of the scapula

It attaches to the upper part of the Greater Tuberosity of the Humerus

It abducts the arm

Infraspinatus arises from the Infraspinous Fossa of the scapula

It attaches to the posterior part of the Greater Tuberosity of the Humerus

It externally rotates the arm

Teres Minor arises from the upper part of the Lateral Border of the Scapula

It attaches to the Inferior part of the Greater Tuberosity of the Proximal Humerus

It externally rotates the arm

Posterior View

Teres Major arises from the inferior angle of the scapula and adjacent lateral border

There are three spaces in the

posterior aspect of the Shoulder

Region

3 spaces Posterior Shoulder Region

Quadrangular Space

Triangular Space

Triangular Interval

Teres minor superiorly

The Quadrangular Space is an area bounded by

Teres Minor superiorly

Teres Major inferiorly

The Quadrangular Space is an area bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps medially

The Quadrangular Space is an area bounded by

The Quadrangular Space is an area bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps medially

Shaft of the Humerus Laterally

The Quadrangular Space is an area bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps medially

Shaft of the Humerus Laterally

ContentsAxillary nerve

The Quadrangular Space is an area bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps medially

Shaft of the Humerus Laterally

ContentsAxillary nerve Posterior circumflex humeral artery

The Quadrangular Space is an area bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps medially

Shaft of the Humerus laterally

The Triangular Space is an area medial to the quadrangular space bounded by

Teres Minor superiorly

The Triangular Space is an area medial to the quadrangular space bounded by

Teres Minor superiorly

Teres Major inferiorly

The Triangular Space is an area medial to the quadrangular space bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps laterally

The Triangular Space is an area medial to the quadrangular space bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps laterally

The Triangular Space is an area medial to the quadrangular space bounded by

Teres Minor superiorly

Teres Major inferiorly

Long head of Triceps laterally

The Triangular Space is an area medial to the quadrangular space bounded by

ContentsCircumflex Scapular Artery

The Triangular Interval is an area just below the quadrangular space bounded by

Teres Major superiorly

The Triangular Interval is an area just below the quadrangular space bounded by

Teres Major superiorly

Long head of Triceps medially

The Triangular Interval is an area just below the quadrangular space bounded by

Teres Major superiorly

Long head of Triceps medially

Shaft of the Humerus laterally

The Triangular Interval is an area just below the quadrangular space bounded by

ContentsRadial nerve

Teres Major superiorly

Long head of Triceps medially

Shaft of the Humerus laterally

The Triangular Interval is an area just below the quadrangular space bounded by

ContentsRadial nerve Profunda Brachii artery

Teres Major superiorly

Long head of Triceps medially

Shaft of the Humerus laterally

The Triangular Interval is an area just below the quadrangular space bounded by

Quadrangular SpaceAxillary NervePosterior circumflex humeral artery

Summary of Spaces and contents around the Posterior Shoulder Region

Quadrangular SpaceAxillary NervePosterior circumflex humeral artery

Triangular SpaceCircumflex scapular artery

Summary of Spaces and contents around the Posterior Shoulder Region

Quadrangular SpaceAxillary NervePosterior circumflex humeral artery

Triangular SpaceCircumflex scapular artery

Triangular IntervalRadial NerveProfunda Brachii

Summary of Spaces and contents around the Posterior Shoulder Region

Quadrangular SpaceAxillary NervePosterior circumflex humeral artery

Triangular SpaceCircumflex scapularartery

Triangular IntervalRadial NerveProfunda Brachii

Summary of Spaces and contents around the Posterior Shoulder Region

Summary of Muscles

Posterior Shoulder Region

Posterior Chest Wall

TrapeziusOrigin Medial third of superior nuchal

line; external occipital spinous processes of C7 - T12 vertebrae

Insertion Upper fibres to lateral third of clavicle, lower fibres to acromio and spine of scapula

Action Superior fibers elevate, middle fibers retract, and inferior fibers depress scapula

Nerve Supply Spinal root of accessory nerve (CN XI) (motor) and cervical nerves (C3 and C4) (pain and proprioception)

Blood Supply Transverse cervical artery

Posterior Chest Wall

Latissimus DorsiOrigin Spinous processes of lower 6

thoracic, all lumbar and sacral vertebrae, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs, inferior angle of scapula

Insertion Floor of intertubercular groove of humerus

Action Extends, adducts, and internally rotates humerus; pulls body up toward arms during climbing

Nerve Supply Thoracodorsal nerve (C6, C7, and C8)

Blood Supply Thoracodorsal artery

DeltoidOrigin Lateral third of clavicle,

acromion, and spine of scapulaInsertion Deltoid tuberosity on middle

of lateral shaft of humerusAction Anterior part: flexes and

internally rotates arm; Middle part: abducts arm; Posterior part: extends and externally rotates arm

Nerve Supply Axillary nerve (C5 and C6)Blood Supply Deltoid branch of

thoracoacromial artery

Posterior Chest Wall

Posterior Chest Wall

Levator ScapulaeOrigin Posterior tubercles of

transverse processes of C1 - C4 vertebrae

Insertion Superior part of medial border of scapula

Action Elevates scapula and tilts glenoid inferiorly by rotating scapula

Nerve Supply Dorsal scapular (C5) and anterior rami of cervical (C3 and C4) nerves

Blood Supply Dorsal scapular artery

Posterior Chest Wall

Rhomboid MinorOrigin Lower part of nuchal ligament

and spinous processes of C7 T1 vertebrae

Insertion Medial border of scapula at level of spine

Action Retracts and rotates scapula to move glenoid inferiorly; fixes scapula to thoracic wall

Nerve Supply Dorsal scapular nerve ( C4 and C5)

Blood Supply Dorsal scapular artery

Posterior Chest Wall

Rhomboid MajorOrigin Spinous processes of T2 - T5

vertebraeInsertion Lower part of medial border of

scapulaAction Retracts and rotates scapula to

move glenoid inferiorly; fixes scapula to thoracic wall

Nerve Supply Dorsal scapular nerve ( C4 and C5)

Blood Supply Dorsal scapular artery

Posterior Chest Wall

SupraspinatusOrigin Supraspinous fossa of scapula

Insertion Superior facet on greater tuberosity of humerus

Action Abduction of armNerve Supply Suprascapular nerve (C4, C5

and C6)Blood Supply Suprascapular artery

Posterior Chest Wall

InfraspinatusOrigin Infraspinous fossa of scapulaInsertion Middle facet on greater

tuberosity of humerusAction Externally rotates armNerve Supply Suprascapular nerve (C5 and

C6)Blood Supply Suprascapular and circumflex

scapular arteries

Posterior Chest Wall

Teres MinorOrigin Superior part of lateral border

of scapulaInsertion Inferior facet on greater

tuberosity of humerusAction External rotation of the armNerve Supply Axillary nerve (C5 and C6)Blood Supply Subscapular and circumflex

scapular arteries

Posterior Chest Wall

Teres MajorOrigin Lower third of lateral border of

scapula near the inferior angleInsertion Medial lip of bicipital groove of

humerusAction Adducts and internally rotates

armNerve Supply Lower subscapular nerve (C6

and C7)Blood Supply Subscapular and circumflex

scapular arteries