Scapular and Pectoral Regions Flashcards
Anatomical Neck of humerus
Marks the differentiation between the bony epiphysis and diaphysis
Surgical Neck of humerus
Thinnest part of the proximal shaft Often injured or fractured
Three important joints of/in the shoulder
Sternoclavicular, acromioclavicular, and glenohumeral joints
Three ligaments of the acromioclavicular joint. What happens if these ligaments are ruptured?
Acromiolclavicular ligament (1) Coracoclavicular ligaments (2) *Connection between upper limb and clavicle are lost
What is the actual term for “separated shoulder”? The clavicle and scapula are pulled in different directions…why?
Acromioclavicular dislocation *Weight of upper limb is pulling the scapula down and away from the clavicle. Trapezius is pulling the clavicle up
What are two common ways to separate the shoulder or fracture the clavicle? How will patient present with a clavicle fracture?
- Fall on outstretched arm 2. Fall on shoulder *Patient will hold arm up because clavicle fracture makes it painful to let weight of arm pull down on fracture
What 3 ligaments make up the joint capsule?
Glenohumeral ligaments (superior, middle, and inferior)
What ligament reinforces the shoulder joint superiorly
Coracoacromial ligament
Structural integrity of the glenohumeral joint is held together by which muscles? (4)
Held together by rotator cuff muscles: supraspinatus, infraspinatus, teres MINOR, and subscapularis
What is the most common type of humerus dislocation?
Anterior and inferior dislocation
Anterior EXTRINSIC muscles (4) (Take a piss)
Pectoralis major Pectoralis minor Subclavius Serratus anterior
Posterior EXTRINSIC muscles (5) (TRL)
Trapezius Latissimus dorsi Levator scapulae Rhomboid major Rhomboid minor
INTRINSIC muscles of upper limb (6) 4 of these are the rotator cuff muscles
Deltoid Teres major Teres minor Supraspinatus Infraspinatus Subscapularis
Pectoralis Major: Innervation Actions (2)
Innervation: medial and lateral pectoral nerve Actions: primarily an adductor of arm. Whole muscle activation will adduct and medially rotate arm
Pectoralis Minor: Innervation Actions (2)
Innervation: medial pectoral nerve Actions: stabilizes scapula against rib cage and elevates rib cage when scapula is fixed. *Accessory muscle of respiration
Subclavius Innervation Action (1)
Innervation: nerve to subclavius (seriously…that’s its name) Action: depresses clavicle
Serratus Anterior Innervation Actions (2)
Innervation: long thoracic nerve Actions: 1. protracts and stabilizes scapula 2. rotates scapula
Long thoracic nerve injury- two things to look for
- Winged scapula on affected side 2. Patient unable to abduct arm above 90º
Trapezius Innervation Actions (4) What is special about trapezius innervation?
Innervation: Accessory nerve Actions: 1. Elevates (superior bit) scapula 2. Retracts (medial) scapula 3. Rotates scapula 4. Depresses (lower) scapula *Only muscle of upper limb NOT innervated by brachial plexus
Latissimus dorsi Innervation Actions (3)
Innervation: Thoracodorsal nerve Actions: Adducts, extends, and internally rotates humerus
Muscles responsible for ELEVATION of shoulder (4)
- Trapezius
- Levator scapulae
3 and 4. Rhomboids
DEPRESSION of shoulder
5 muscles and 1 force
- Gravity
- Pectoralis major and minor
- Latissimus dorsi
- Trapezius
- Serratus anterior
PROTRACTION of shoulder (3)
- Serratus anterior
- Pectoralis Major
- Pectoralis Minor
RETRACTION of shoulder (4)
- Trapezius
- Rhomboid major and minor
- Latissimus dorsi
SUPERIOR ROTATION of shoulder (2)
1. Trapezius
2. Serratus anterior
INFERIOR ROTATION of shoulder
6 muscles and 1 force
- Latissimus dorsi
- Gravity
- Levator scapulae
- Rhomboids
- Pectoralis major and minor
Deltoid
Innervation
Actions
Innervation: axillary nerve
Actions: flexes (anterior fibers), abducts (lateral), and extends (posterior) arm at shoulder
Teres Major
Innervation
Actions (3)
Innervation: Lower subscapular nerve
Actions: 1. Adducts humerus
- Internally rotates humerus
- Assists latissimus dorsi
Rotator Cuff:
Innervation of supraspinatus and infraspinatus
Innervation of teres minor
Innervation of subscapularis
Supraspinatus and infraspinatus- suprascapular nerve
Teres minor- axillary nerve
Subscapularis- upper and lower subscapular nerves
Rotator Cuff
Actions of supraspinatus-
Actions of infraspinatus and teres minor-
Actions of Subscapularis-
Supraspinatus- initiates abduction of humerus
Infraspinatus and teres minor- laterally/externally rotate humerus
Subscapularis- medially/internally rotate humerus
How will a patient with supraspinatus injury abduct arm?
The patient will swing arm up until deltoid takes over because the swinging takes pressure off the supraspinatus
Why do most arm dislocations occur inferiorly?
Because there is nothing to resist humerus being pulled down except for joint capsule which is weak
Branch from 1st part of axillary artery
Superior thoracic artery
Branches off 2nd part of axillary artery
- Thoracroacromial trunk
- Lateral thoracic artery
Branches of thoracoacromial trunk (4)
- Pectoral br
- Deltoid
- Acromial
- Clavicular
Branches of 3rd part of axillary artery
- Anterior circumflex humeral a.
- Posterior circumflex humeral a.
- Subscapular a
Branches of subscapular artery (2)
- Thoracodorsal artery
- Circumflex artery
Triangular Space
Borders- lateral, superior, and inferior
Contents
Lateral: long head of triceps brachii
Superior: teres minor
Inferior: teres major
Contents: circumflex scapular artery
Quadrangular Space
Borders- lateral, medial, superior, and inferior
Contents (2)
Lateral- surgical neck of humerus
Medial: long head of triceps brachii
Superior: teres minor
Inferior: teres major
Contents: axillary nerve and posterior circumflex humeral artery
Damage to axillary nerve causes what?
Atrophy of deltoid. Patient will have difficult time elevating arm
