Pectoral and Scapular Regions Flashcards
Name the 4 muscles of the pectoral region - anterior chest
Subclavius
Pectoralis Major
Pectoralis Minor
Serratus Anterior
What is the purpose of the subcalvius and what nerves supply it?
Moves clavivle
Nerve to Subcalvius (C5,6)
What is the purpose of the pectoralis major and what nerves supply it?
Moves Humerus
Med. (C8,T1) And Lat. Pectoral (C5,6,7) Nerves
What is the purpose of the pectoralis minor and what nerves supply it?
Moves scapula Medial pectoral (C8,T1)
What is the purpose of the serratus anterior and what nerves supply it?
Moves scapula
Long thoracic nerve (C5,6,7)
How many heads does the pectoralis major have and what does it do to the arm?
- 2 heads (clavicular and sternocostal)
- Adducts
- Medially rotates
How many heads does the pectoralis minor have and what does it do?
- 3 heads
- Comes from the 3rd-5th rib give or take a bit idk
- Stabilises / depresses Scapula
What does the subclavius do?
•Stabilises /
depresses
Clavicle
What does the serratus anterior do?
- Protracts
- Prevents “Winging”
- Scapular rotation
Where is the origin of the serratus anterior?
2nd - 9th rib
What are the two heads of the pectoralis major and what major fascia helps define its shape?
The clavicular and sternocostal head
The abdominal part (literally that)
What are the 5 extrinsic back muscles?
Latissimus dorsi Trapezius Rhomboids Major Rhomboids Minor Levator scapula
What nerves supply the Latissimus dorsi?
Thoracodorsal nerve (C6,7,8)
What nerves supply the Trapezius?
Spinal Accessory (Cn XI - afferent C3,4)
What nerves supply the Rhomboids Major?
Dorsal Scapular nerve (C4,5)
What nerves supply the Rhomboids Minor?
Dorsal Scapular nerve (C4,5)
What nerves supply the Levator scapula?
Cervical nerves (c3,4) Dorsal Scapular (c4,5)
What actions occur and where due to the extrinsic back muscles Latissimus dorsi and Teres major?
- Action at GH joint
- Extends
- Adducts
- Medially rotates
What 3 sets of movements may the scapular undergo?
Elevation/depression
Protraction/retraction
Lateral(upwards) and Medial(downwards) Rotation
What causes depression of the scapula?
Prime mover first
Gravity Pec major (inferior fibres) Lat. dorsi Lower Trapezius Serratus ant. (Inf. Part) Pec. Minor
What causes elevation of the scapula?
Prime mover first
Upper Trapezius
Lev. Scapula
Rhomboids
What causes protraction of the scapula?
Prime mover first
Serratus Ant.
Pec. Minor
Pec. minor
What causes retraction of the scapula?
Prime mover first
Middle Trapezius
Rhomboids
Lat. Dorsi
What causes Lateral (upwards) rotation of the scapula?
Prime mover first
Upper Trapezius
Serratus Ant. (inf. part)
Lower Trapezius
What causes medial (downwards) rotation of the scapula?
Prime mover first
Lat. Dorsi Lev. Scapula Rhomboids Pec. Major (inf. fibres) Pec. Minor Gravity
What are the intrinsic shoulder muscles?
Deltiod
Teres Major
Rotator Cuff muscles
What is the location and purpose of the extrinsic shoulder muscles?
From Scapula to Humerus
- Move GH joint
What nerve innervates the deltoid and what roots make up said nerve?
Axillary Nerve (C5,6)
What nerve innervates Teres Major and what roots make up said nerve?
Lower Subscapular Nerve (C5,6)
What are the three functional parts of the deltoid?
literally every meathead knows this
Anterior (Clavicular)
Middle (Acromial)
Posterior (Spinal)
What is the anterior deltoid responsible for?
• Flexion
•Medial Rotation
at the glenohumeral joint
What is the middle deltoid responsible for?
Abduction (After first 15 degrees and until 90 degrees)
At the glenohumeral joint
What is the posterior deltoid responsible for?
• Extension
•Lateral Rotation
at the glenohumeral joint
What may be found between the deltoid and the pectorals major?
The deltopectoral groove
What may be found in the deltopectoral groove?
The cephalic vein
Where do trees major and latissimus dorsi attach to?
The floor and medial lip of intertubecular sulcus of humerus
What are terms major and latissimus dorsi responsible for?
• Adduction
•Medial rotation
at glenohumeral joint
What are the 4 rotator cuff muscles?
SITS (think Sonia) – Supraspinatus – Infraspinatus – Teres Minor – Subscapularis
What nerve innervates supscapularis and what nerve roots make up this nerve?
U and L Subscapular nerves (C5,6,7)
What nerve innervates Teres Minor and what nerve roots make up this nerve?
Axillary nerve (C5,6)
What nerve innervates Infraspinatus and what nerve roots make up this nerve?
Suprascapular Nerve (C5,6)
What nerve innervates Supraspinatus and what nerve roots make up this nerve?
Suprascapular Nerve (C4,5,6)
What is the purpose of the rotator cuff muscles?
• Very important for GH joint stability – Hold the Humeral head in the Glenoid fossa
What movement is the supraspinatus responsible for?
First 15 degrees of abduction
- initiates abduction to be continued by deltoid then scapular movement
at glenohumeral joint
What movement is the infraspinatus responsible for?
External rotation
at glenohumeral joint
What movement is the trees minor responsible for?
External rotation
at glenohumeral joint
What movement is the subscapularis responsible for?
Internal rotation
at glenohumeral joint
Whats a good way to remember the insertion of the rotator cuff muscles on the humerus?
Place the first 4 digits of the hand on the head of the humerus with the thumb on the anterior surface and the palm facing the medial aspect
Digits 2,3 and 4 represent SIT with the thumb representing the final S: subscapularis
Where do the rotator cuff muscles actually insert?
Supraspinatus, infraspinatus and teres minor all insert on the greater tuberosity of the head of the humerus.
Subscapularis inserts on the lesser tuberosity
Where does the supraspinatus run and what problems can this cause?
Beneath the acromion.
This can cause issues with rubbing on the subacromial bursa and inflammation can lead to impingement
Excessive rubbing on the bone can cause bony spurs to form also
What muscles from the arm cross the glenohumeral joint?
– Long head of Biceps Brachii
– Corocobrachialis
– Long head of triceps
Discuss the deep fascia of the pectoral and scapular regions
There are associated deep fascia for every muscle, some of the epimysium will come off of the muscle and blend with other deep fascias, eg clavipectoral fascia
What fascia does the pectoral fascia epimysium blend into?
The axillary fascia
What does the axillary fascia form?
The floor of the axilla
When the upper limbs are abducted what structure is formed by the floor of the axilla?
The axillary fossa
armpit
What article of clothing does the structure of the brachial fascia resemble
A sock
What is special about the Infraspinatus and
Supraspinatus fascia?
- Origin of the muscles
* Really dense
What two gateways are present in the upper limb?
The axilla and scapular region
What does the axilla gateway connect?
Connects neck to upper limb
What does the Scapular Region connect?
– Connect axilla to posterior of limb
– Quadrangualr space
– Triangular Space (Upper Triangular Space)
– Triangular Interval (Lower Triangular Space)
Discuss the structure of the axilla?
• Pyramidal shape • 4 walls: Anterior Posterior Medial Lateral • Floor
What is the anterior wall of the axilla made up of?
Pec major, Minor and fascia
What is the posterior wall of the axilla made up of?
Scapula, Subscapularis
Teres Maj, Lat. Dorsi
What is the medial wall of the axilla made up of?
Ribs1-4, Serratus ant.
What is the lateral wall of the axilla made up of?
Humerus (intertubercular groove)
What is the floor of the axilla made up of?
Skin and axillary fascia
What is the axilla continuous above (open to)?
- Cervico-axillary canal - root of neck
* 1st rib, scapula, clavicle
What is the axilla continuous below (open to)?
- Medially –thoracic wall
* Lateraly – upper limb
What makes up the anterior fold of the axilla?
pectoralis major
What makes up the posterior fold of the axilla?
Teres major, Lat. dorsi
What are the contents of the axilla?
- Axillary vessels
- Brachial Plexus
- Cords and branches
- Axillary Sheath
- From prevertebral fascia
Where do the lymphatics of the axilla drain?
The upper limb and thoracic wall
And axillary tail of the breast
What are the 5 nodes of the lymphatics of the axilla
Lateral (Humeral) Anterior (Pectoral) Posterior (Subscapular) Central Apical
What lymph nodes found in the axilla are palpable?
Lateral (Humeral)
Anterior (Pectoral)
Posterior (Subscapular)
Central
What lymph node(s) found in the axilla are not palpable?
Apical
What is the pathway of lymph in the axilla?
Lateral (Humeral), Anterior (Pectoral), Posterior (Subscapular), Central nodes -> Apical node -> Superclavicular nodes -> Subclavian lymph trunks -> Thoracic duct (L) Right lymphatic duct (R)
What are the gateways of the posterior limb?
upper triangular
quadrangular
lower triangular
What are the borders of the quadrangular space?
- Teres Minor
- Teres Major
- Humerus
- Long Head of Triceps
What are the contents of the quadrangular space?
• Posterior Circumflex
Humeral Artery
• Axillary nerve
• (Surgical neck of Humerus)
What are the borders of the upper triangular space?
- Teres Minor
- Teres Major
- Long Head of Triceps
What are the contents of the upper triangular space?
- Circumflex Scapular artery
* Leads to scapular anastomosis
What are the borders of the lower triangular space (triangular interval)?
- Lateral head of Triceps
- Long Head of Triceps
- Teres Major
What are the contents of the lower triangular space (triangular interval)?
- Radial nerve
- Profunda Brachii artery
- Leads to spiral groove