Pectoral and Scapular Regions Flashcards
What is the pectoral girdle ?
An incomplete ring of bone
Scapula and clavicle
What is the axilla ?
Gateway to the upper limb
What is the pectoral region ?
Anterior chest
How many muscles are in the pectoral region and what do they do ?
4 muscles:
1 moves clavicle
1 moves humerus
2 move scapula
Name the muscles that supply the pectoral region
Muscle that moves :
Clavicle - Subclavius
Humerus - Pectoralis Major
Scapula - Pectoralis Minor, Serratus Anterior
What nerve supplies the subclavian muscle ?
Nerve to subclavius (C5,6) : C6 more important
Which nerve(s) supply the pectoralis major muscle ?
Medial Pectoral Nerve (C8, T1) +
Lateral Pectoral Nerves (C5,6,7) : C6 more important
Which nerve supplies the pectoralis minor muscle ?
Medial pectoral (C8,T1)
Which nerve supplies the serratus anterior muscle ?
Long Thoracic nerve (C5,6,7) : C5 + 6 are important
Function of the Subclavian muscle
Fixator / Synergist rather than prime mover
Stabilises/ Depresses the clavicle
Function of the Pectoralis Major muscle
2 HEADS :
Sternocostal head
Clavicular head
Movements :
Adduction
Medially rotates humerus
(Minor action - Flexion and Extension)
Function of the Pectoralis Minor muscle
Attaches to the coracoid process of the scapula
Origins from ribs 2,3,4 / 3,4,5
Stabilises/ Depresses scapula
Function of the Serratus Anterior muscle
Inserts into ribs 2-9,
Inserts into medial border of the scapula
Each digitation attaches to a different rib
Protracts the scapula
Prevents “Winging”
Scapular rotation
How many extrinsic back muscles are there and what so they do ?
4 muscles (sort of)
1 moves humerus
3 move scapula
Name the muscles of the extrinsic back
Muscle that moves
Humerus - Latissimus Dorsi
Scapula :
Trapezius
Rhomboids
Levator Scapula
Which nerve supplies the latissimus dorsi muscle ?
Thoracodorsal nerve (C6,7,8) - C6,7 important nerves
Which nerve supplies the trapezius muscle ?
Spinal Accessory nerve (CN 11 - afferent C3,4)
Which nerve supplies the rhomboid muscles ?
Dorsal Scapular nerve (C4,5) - C5 important
Which nerve(s) supply the levator scapula muscle ?
Cervical Nerves (C3,4)
Dorsal Scapular (C4,5)
Function of Latissimus dosi
Action is at the GH joint
Extends
Adducts
Medially Rotates the humerus
What muscle is related with the elevation of the scapula ?
MAIN - prime mover : Upper trapezius
What muscle is related with the depression of the scapula ?
MAIN - prime mover : Gravity
(also pec. major/minor, lat. dorsi, lower trapezius)
What muscle is related with protraction of the scapula ?
MAIN - prime mover : Serratus anterior
(also pec. major and minor)
What muscle is related with retraction of the scapula ?
MAIN - prime mover : Middle Trapezius
(also - rhomboids and lat. dorsi)
What muscle is related with Lateral rotation (upwards rotation) of the scapula ?
MAIN - prime mover : Upper trapezius + Inferior Serratus Anterior
(also : lower trapezius)
What muscle is related with Medial rotation (downwards rotation) of the scapula ?
MAIN - prime mover : Latissimus Dorsi
(also: rhomboids, levator scapulae, gravity)
What is an intrinsic shoulder muscle ?
One that extends from the scapula to the humerus in order to move the glenohumeral joint.
Name the 2 muscles involved in GH movement but are not intrinsic muscles
Latissimus dorsi
Pectoralis Major
State some intrinsic shoulder muscles
Deltoid
Teres Major
Rotator cuff (S.I.T.S)
Which nerve supplies the deltoid muscle ?
Axillary Nerve (C5,6)
Which nerve supplies the teres major muscle ?
Lower Subscapular Nerve (C5,6)
Structure of deltoid
Multipenate muscle
State the 3 parts of the deltoid muscle
Anterior (Clavicular)
Middle (Acromial)
Posterior (Spinal)
State the function of the anterior part of the deltoid muscle
Anterior part - aka Clavicular part
- Flexion
- (Medial Rotation)
State the function of the middle part of the deltoid muscle
Middle part - aka Acromial part
- Abduction
State the function of the posterior part of the deltoid muscle
Posterior part - aka Spinal part
- Extension
- Lateral Rotation
What movement do you get when all 3 parts of the deltoid work together ?
Abduction
Function of teres major muscle
Arises from the inferior angle of the scapula
Inserts into the medial lip of the intertibercular sulcus
ACTION :
- Adduction @ GH joint
- Medial rotation @ GH joint
State the muscles in the rotator cuff
Supraspinatus - Above spine of scapula
Infraspinatus - Below spine of Scapula
Teres Minor - Beside infraspinatus
Subscapularis - Anterior side of scapula
What nerve supplies the supraspinatus muscle ?
Supracapular nerve (C4,5,6) : C5 imp.
What nerve supplies the infraspinatus muscle ?
Supracapular nerve (C5,6) : C5 imp.
What nerve supplies the teres minor muscle ?
Axillary nerve (C5,6) : C6 imp.
What nerve supplies the subscapularis muscle ?
U and L Subscapular nerves (C5,6,7) : C6 imp.
Describe the significance of the rotator cuff
Very important for CH joint stability
- Holds the humeral head in the glenoid fossa
Where do the rotator cuff muscles insert ?
Head of the humerus and fuse with the joint capsule of the humerus.
3 insert on GREATER TUBEROSITY
-Supraspinatus
-Infraspinatus
- Teres minor
1 onto the LESSER TUBEROSITY
-Subscapularis
Location of rotator cuff muscles
Surround the humeral head
Supraspinatus runs beneath acromion
- Subacromial bursa
- Inflation
- Impingement
What is the most common appearance for a dislocated shoulder ?
Anterior dislocation
What muscle is responsible for the 1st 15degrees of GH abduction ?
Supraspinatus muscle
Initiates abduction
Function of Supraspinatus muscle
Initiates the first 15 degrees of abduction
Function of Infraspinatus muscle
External rotation
Function of Teres minor muscle
External rotation
Function of Subscapularis muscle
Internal rotation
Describe fascia of the pectoral and scapular regions
Deep fascia for each muscle
Clavipectoral fascia
Pectoral fascia
Axillary fascia
Brachial fascia - sock
Infraspinatus and Supraspinatus fascia
Describe the fascia around pectoralis minor
Clavipectoral fascia
Describe the fascia around pectoralis major
Pectoral fascia
What is the axillary fascia ?
The blending of the clavipectoral fascia and the pectoral fascia.
Axillary fascia
- Floor of the axilla
- Axillary fossa
Features of infraspinatus and supraspinatus fascia
Really dense
Origin of the muscles
Describe the walls and contents of the axilla
The axilla has 4 walls :
Anterior
Posterior
Medial
Lateral
Describe the anterior wall of the axilla
Pectoralis Major
Pectoralis Minor
Fascia
Describe the posterior wall of the axilla
Scapula
Subscapularis
Teres Major
Latissimus Dorsi
Describe the medial wall of the axilla
Ribs 1-4
Serratus Anterior
Describe the lateral wall of the axilla
Humerus
(inter-tubercular groove)
Describe the floor of the axilla
Skin and Axillary Fascia
What is the axilla ?
Pyramidal shaped conduit between the root of the limb and the upper neck.
Bounded anteriorly, posteriorly, medially and laterally
Describe the extent of the axilla
Continuous above
- Cervico-axillary canal
- 1st rib, scapula, clavicle
Continuous below
- Medially : thoracic wall
- Laterally : upper limb
Anterior Fold : formed by
- pec. major
Posterior fold : formed by
- teres major, lat. dorsi
Describe the contents of the axilla
Axillary vessels
Brachial plexus
- cords and branches
Axillary sheath
- from pre vertebral fascia
Describe the “gateways”
2 gateways :
- Axilla
- Scapular Region
Lymphatics of the axilla
Drains the upper limb and thoracic wall
Axillary tail of the breast
5 groups :
- Anterior
- Lateral
- Posterior
- Central
- Apical
Go to the subclavian trunk
And onto respective lymph trunks
Gateways to the posterior limb
Upper triangular
Quadrangular
Lower Triangular
Describe the contents of the quadrangular space of the scapular region
Posterior circumflex humeral artery
Axillary nerve
State the borders of the quadrangular space of the scapular region
Teres Minor
Teres Major
Humerus
Long head of triceps
Describe the contents of the upper triangular space of the scapular region
Circumflex Scapular artery
Leads to scapular anastomosis
State the borders of the upper triangular space of the scapular region
Teres Minor
Teres Major
Long Head of Triceps
Describe the contents of the lower triangular space of the scapular region
Radial nerve
Profunda Brachii artery
Leads to spiral groove
State the borders of the lower triangular space (TRIANGULAR INTERVAL) of the scapular region
Lateral head of triceps
Long head of triceps
Teres major