Musculoskeletal SystemAppendicular System: Upper LimbLecture 3: Pectoral Region, Back &

Shoulder muscles & Axilla

Dr. Ashraf RamzyProfessor of Anatomy & Embryology

ash-ramzy@hotmail.com

Dr Ashraf Ramzy

Movements of shoulder joint

* Includes:

1. Abduction & adduction.

2. Flexion & extension.

3. Med. Rotation & lateral rotation.

* Produced by: muscles inserted

in humerus.

Dr Ashraf Ramzy

Movements of shoulder girdle* Includes:

1. Elevation & depression.

2. Protraction & retraction.

3. Rotation up & rotation down of scapula.

* Produced by: muscles inserted

in shoulder girdle (clavicle

or scapula).

Dr Ashraf Ramzy

Pectoral Region

Dr Ashraf Ramzy

Pectoralis major

▪ Origin:

It takes origin by 2 heads;

1. Clavicular head:

Anterior surface of the medial ½ of the clavicle.

2. Sternocostal head:

Front of the sternum, upper 7 costal cartilages & aponeurosis of the external abdominal oblique.

▪ Insertion: By a flat bilaminartendon into the lateral lip of the bicipital groove of the humerus.

P. M.

Clav.

Dr Ashraf Ramzy

▪ N. supply: Lateral pectoral N. & Medial pectoral N.

▪ Action:

1. Adduction, flexion & medial rotation of the arm.

2. The clavicular head brings the extended arm to the resting position.

3. The sternocostal head brings the flexed arm to the resting position.

4. With the insertion fixed & the arm raised, the whole muscle draws the trunk upwards towards the arm as in swimming, playing gymnastics & climbing.

Dr Ashraf Ramzy

Pectoralis minor

▪ Origin: From 3rd , 4th & 5th

ribs just lateral to their costal cartilages.

▪ Insertion: Into upper surface of the coracoid process of the scapula.

▪ Nerve supply: Medial pectoral nerve.

▪ Action: Protraction & depression of the shoulder.

Dr Ashraf Ramzy

Subclavius

▪ Origin: From the junction between the 1st rib & its costal cartilage.

▪ Insertion: Into the groove for subclavius muscle (subclavian groove) on the lower surface of the middle 1/3 of the clavicle.

▪ Nerve supply: N. to subclavius.

▪ Action: Stabilizes & fixes the clavicle.

Dr Ashraf Ramzy

Clavipectoral fascia▪ This is a well defined membranous

fascia that extends between subclavius & pectoralis minor muscles deep to pectoralis major muscle.

▪ Attachments:

- Above: It splits to enclose the subclavius muscle & gets attached to the clavicle (margins of the groove for subclavius).

- Below: It splits to enclose the pectoralis minor muscle & then the 2 layers fuse together to form the suspensory lig. of the axilla which gets attached to axillary fascia.

Clavipect. F.

Sub.

P. min.

Dr Ashraf Ramzy

Clavipectoral fascia

Dr Ashraf Ramzy

- Medially: The clavipectoral fascia is attached to 1st

costal cartilage.

- Laterally: It is attached to the coracoid process of the scapula.

- Therefore, it could be called the costocoracoidmembrane.

Dr Ashraf Ramzy

Serratus anterior

■ Origin: By 8 fleshy slips from the middle of the outer

surface of the upper 8 ribs, interdigitating with the slips of the external abdominal oblique muscle.

Dr Ashraf Ramzy

■ Insertion: Into the ventral surface of the medial border of the scapula;

- 1st digitation opposite the superior angle.

- 2nd & 3rd digitations along the whole length of the medial border.

- Lower 5 digitations opposite the inferior angle.

■ Nerve supply: Long thoracic nerve (N. to serratus anterior).

Dr Ashraf Ramzy

■ Action:

1. Protraction & depression of the shoulder.

2. The lower 5 digitations help in the rotation up (lateral rotation) of the scapula to raise the arm above the head.

■ Applied anatomy:

1. Since the long thoracic nerve runs on outer surface of serratus anterior, therefore it is liable to injury.

2. Injury of long thoracic nerve

Paralysis of serratus anterior

muscle causing winging of the

scapula (prominence of medial

border & inferior angle of the

scapula).

Dr Ashraf Ramzy

Back Muscles

Dr Ashraf Ramzy

1st layer

* 5 muscles connecting the upper limbs to the vertebral column.

•* Arranged in 2 layers

Trapezius Latissimus dorsi

2nd layer

Levator scapulae Rhomboideus minor Rhomboideus major

Trapezius

Dr Ashraf Ramzy

1. Trapezius

* Origin (3):1. External occipital protuberance + medial ⅓ of the superior nuchal line.2. Ligamentum nuchae + C7 spine.3. All thoracic vertebral spines (T1 – T12) + Supraspinous ligaments. Dr Ashraf Ramzy

Lig.

nu

chae

7th

Dr Ashraf Ramzy

Insertion (3):1. Posterior border of the lateral ⅓ of clavicle. (Upper fibers).2. Medial border of the acromion + upper lip of crest of spine of scapula (Middle fibers).3. Tubercle at the medial end of the scapular spine. (Lower fibers).

Dr Ashraf Ramzy

Dr Ashraf Ramzy

* Nerve supply:

1. Motor: spinal accessory nerve (11th cranial N.).

2. Sensory (Proprioceptive): C3 & C4.

* Action (3):

1. Upper fibers → elevate the scapula.

2. Middle fibers → retract the scapula.

3. Upper and lower fibers (with lower (5) digitations of serratus anterior) → upward rotation of the scapula from (90° - 180°).

Dr Ashraf Ramzy

2. Latissimus dorsi* The only muscle of the upper limb which has pelvic attachment.

* Origin:

1. Pelvic: Posterior ⅓ of the outer lip of the iliac crest of the hip bone.

2. Vertebrel: Lumbar fascia + spine of lower 6 thoracic vertebrae.

3. Costal: back of the lower 3 or 4 ribs.

4. Scapular: back of the inferior angle of the scapula.

Dr Ashraf Ramzy

* Insertion:* The floor of the bicipital groove of thehumerus.

* Nerve supply:

* Nerve to latissimus dorsi (C 6,7,8).

* Action:

* Adduction, medial rotation and extension of the arm.

Dr Ashraf Ramzy

3. Levator scapulae

* Origin: the transverse processes of the upper (4) cervical vertebrae.

* Insertion: Back of the medial border of the scapula between the superior angle and the scapular spine.

* Nerve supply: Nerve to rhomboides (Dorsal scapular nerve).

* Action: Elevation & rotation down of scapula.

Dr Ashraf Ramzy

Dr Ashraf Ramzy

4. Rhomboideus Minor

* Origin: Lower part of ligamemtum nuchae, 7th

cervical & 1st thoracic spines.

* Insertion: root of the scapular spine.

* Nerve supply: Nerve to rhomboides (Dorsal scapular nerve).

* Action: Retraction & rotation down of scapula.

Dr Ashraf Ramzy

5. Rhomboideus Major* Origin: Spines of T 2, 3, 4, 5 and their supraspinousligaments.

* Insertion: Back of the medial border of the scapula between the root of the scapular spine and the inferior angle of the scapula.

* Nerve supply: Nerve to rhomboides (Dorsal scapular nerve).

* Action: Retraction & rotation down of scapula. Dr Ashraf Ramzy

Levator scapulae

Rhomboideus minor

Rhomboideus major

Dr Ashraf Ramzy

* Triangle of auscultation: Bounded by Trapezius, latissimus

dorsi & medial border of scapula. (Rhomboideus major in floor).

* Used to hear breath

sounds.

Ausc.

Dr Ashraf Ramzy

Shoulder Muscles

Dr Ashraf Ramzy

6 Muscles

* 2 teres: Major & Minor.

* 2 Spinatus: Supra & infra.

* 2 large: Deltoid & Subscapularis.

* General rules:

1. All originate from the scapula.

2. All are inserted into the humerus.

3. All supplied by nerves with root value C5,6.

4. All act on the shoulder joint.

Dr Ashraf Ramzy

* Origin:-Medial ⅔ of supraspinousfossa of scapula.

* Insertion:Upper impression of greater tuberosity of the humerus.* Nerve supply: Suprascapular nerve.* Action: Initiation of abduction of shoulder (0-18

Dr Ashraf Ramzy

* Origin:-Medial ⅔ of infraspinous fossa of scapula.

* Insertion:Middle impression of greater tuberosity of the humerus.* Nerve supply: Suprascapular nerve.* Action: Adduction & lateral rotation of shoulder joint.

Dr Ashraf Ramzy

* Origin:-Upper ⅔ of the dorsal aspect of the lateral border of the scapula.

* Insertion:Lowest impression of greater tuberosity of the humerus.* Nerve supply: Axillary N. * Action: Adduction & lateral rotation of shoulder joint.

Dr Ashraf Ramzy

* Origin:-Lower 1/3 of the dorsal aspect of the lateral border of the scapula.

* Insertion:Medial lip of bicipital groove of the humerus.* Nerve supply: Lower subscapular nerve.* Action: Adduction, extension & medial rotation of shoulder joint. Dr Ashraf Ramzy

* Origin:-Medial ⅔ of subscapular fossa.

* Insertion:Lesser tuberosity of the humerus.* Nerve supply: Upper & Lower subscapular nerves.* Action: Adduction & medial rotation of shoulder joint. Dr Ashraf Ramzy

* Origin:-1. Anterior fibers: from

anterior & upper surface of lateral ⅓ of clavicle.2. Middle fibers: from lateral border of the acromion process.3. Posterior fibers: from inferior lip of the crest of the scapular spine.* Insertion:Deltoid tuberosity of the humerus.

Dr Ashraf Ramzy

Deltoid is a Multipennate muscle

* Nerve supply:

Axillary nerve.

* Action:

1. Anterior fibers: Flexion & medial rotation of shoulder joint.

2. Middle fibers: Abduction of shoulder joint (18-90

3. Posterior fibers: Extension & lateral rotation of shoulder joint.

Dr Ashraf Ramzy

Rotator Cuff* Is formed by:1- Subscapularis.2- Supraspinatus.3- Infraspinatus.

4- Teres Minor.* These muscles are

inserted partially in capsule of shoulder joint.

* They help in stability of shoulder joint.

Dr Ashraf Ramzy

Abduction at Shoulder* 0-90º take place at shoulder joint:1- 0-18º → by supraspinatus.

2- 18-90º → by middle fibers of deltoid.

* 90-180º take place at shoulder girdle: by the rotation up (lateral rotation) of scapula → by action of lower 5 digitations of serratus anterior & upper & lower fibers of trapezius.

Dr Ashraf Ramzy

Quadrangular space

Upper triangular space

Lower triangular space

Intermuscular Axillary spaces

Dr Ashraf Ramzy

Boundaries & Contents of Intermuscular Spaces

Upper triangular space

Quadrangular space

Lower triangular space

1. Superiorboundary:

Teres minor. Teres minor. Teres major.

2. Inferior boundary:

Teres major. Teres major.

3. Medial boundary:

Long head of triceps.

Long head of triceps.

4. Lateral boundary:

Long head of triceps.

Surgical head of humerus.

Shaft of humerus.

5. Contents: Circumflex scapular artery.

1. Axillary nerve.2. Posterior circumflex humeral artery.

1. Radial nerve.2. Profunda brachii artery.

Dr Ashraf Ramzy

Dr Ashraf Ramzy

Axilla

Dr Ashraf Ramzy

AXILLA● It is a pyramidal space between the upper part of the arm (laterally) and the side of the chest wall (medially).

● Forms an important passage for nerves, blood and lymphatic vessels from the root of the neck to the upper limb.

● Has an apex directed upwards into the root of the neck, lower end or base, and 4 walls (anterior, posterior, medial and lateral).

Dr Ashraf Ramzy

Dr Ashraf Ramzy

Dr Ashraf Ramzy

Walls of the axilla

1. Anterior wall : formed of :

a.Pectoralis major (superficial layer).

b.Pectoralis minor, Subclavius & clavipectoral

fascia (deep layer).

● Anterior fold of axilla: This is the lower border of

the anterior wall of the axilla. It is formed by the

lower border of pectoralis major only.

Dr Ashraf Ramzy

Dr Ashraf Ramzy

2. Posterior wall of axilla: formed by :

a. Subscapularis (above).

b. Latissimus dorsi & Teres major (below).

● Posterior fold of axilla: This is the lower

border of the posterior wall of the axilla. It

is formed by Latissimus dorsi &Teres

major. It is lower than the anterior fold of the axilla.

Dr Ashraf Ramzy

Dr Ashraf Ramzy

Dr Ashraf Ramzy

3.Medial wall of axilla: formed of :

a. Upper 5 ribs & intercostal spaces in between.

b. Upper digitations of Serratus anterior which

arise from upper 5 ribs.

Dr Ashraf Ramzy

4.Lateral wall of axilla: formed of :

a. Bicipital groove of the humerus.

b. coracobrachialis & short head of biceps.

Dr Ashraf Ramzy

5. Apex of axilla (upper end) :

It is a triangular bony space which connects the neck with the upper limb.

It is called cervico-axillary canal.

It gives passage to arteries & nerves to enter the upper limb & veins & lymphatics to leave the upper limb.

It is bounded by:

* Front: Lateral half of clavicle.

* Behind: Upper border of scapula.

* Medial: Outer border of 1st rib.

Dr Ashraf Ramzy

Dr Ashraf Ramzy

Dr Ashraf Ramzy

6.Base (lower end) of axilla:

It is formed by axillary fascia & skin stretching between anterior and posterior axillary walls.

It is bounded by :

* Front: Anterior axillary fold (pectoralis major).

* Behind: Posterior axillary fold (tendon of latissimus dorsi and teres major).

* Medial: Chest wall.

Dr Ashraf Ramzy

Dr Ashraf Ramzy

1. Axillary artery and its branches.

2. Axillary vein and its tributaries.

3. Brachial plexus; the cords and its branches.

4. Axillary lymph vessels and nodes.

5. Axillary fat.

6. Axillary tail of the breast.

7. Axillary sheath.

CONTENTS OF AXILLA

Dr Ashraf Ramzy

Dr Ashraf Ramzy

Dr Ashraf Ramzy

Dr Ashraf Ramzy