Lecture 7 - Shoulder, arm and chest wall Flashcards
What makes up the Pectoral girdle?
- Clavicle & scapula
What does the Pectoral girdle connect?
Pectoral girdle connects thorax (thoracic cage) to upper limb
What are the chest & shoulder muscles?
- anterior thoracic walls
- posterior thoracic walls
What are the arm muscles?
- Humerus
- Anterior & posterior compartment
What are key bones in the scapula?
- Acromion
- Spines
- Coracoid process
What are articulations of the clavicle?
articulates with the scapula at the acromion
What are the 2 ends of the right clavicle?
- Sternal (medial) end
- Acromial (lateral) end
What are the joints found in the clavicle?
- Sternoclavicular
- Arcomio-clavicular
What are parts of the humerus?
- Head, anatomical neck, greater and less tubercles, intertubercular sulcus, deltoid tuberosity, shaft, trochlea, capitulum
What joint is found in the humerus?
- Glenohumeral
Describe the arterial supply of arm
Arch of the aorta –> L/R subclavian artery –> axillary artery (changes name after first rib) –> brachial artery –> deep brachial artery
(deep artery of the arm/ profunda brachii artery)
What is the venous supply from the forearm/elbow?
brachial vein (deep) + cephalic and basilic veins (superficial) –> axillary vein –> L/R subclavian vein –> L/R brachiocephalic vein –> SVC (superior vena cava)
Where does the roots of brachial plexus comes from?
Spinal cord, from the spinal nerves in the neck, from C5 to T1 (C5, C6, C7, C8, T1)
What are the divisions of the nerves?
- Roots
- Trunks
- Divisions
- Cords
- Nerves
What are the different nerves in the arm?
- Axillary nerve
- Musculocutaneous nerve
- Radial nerve
- Median nerve
- Ulnar nerve
How many muscles are in the rotator cuff?
4:
1 - anterior
3 - posterior
What are the 3 posterior muscles in the rotator cuff?
- Supraspinatus
- Infraspinatus
- Teres minor
What is the anterior muscle in the rotator cuff?
Subscapularis
Describe features of the supraspinous?
Origin: supraspinous fossa
Insertion: greater tubercle of humerus
Innervation: suprascapular nerve
Describe features of the infraspinatus?
Origin: infraspinous fossa
Insertion: greater tubercle of humerus
Innervation: suprascapular nerve
Describe features of teres minor
Origin: lower border scapula
Insertion: greater tubercle of humerus
innervation: axillary nerve
Describe the features of the subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Innervation: upper/lower subscapular nerve
What are features of the deltoid muscle?
Origin: Spine of scapula, acromion & lateral third of clavicle
Insertion: Deltoid tuberosity of humerus
Innervation: axillary nerve
What are the 2 muscles of the anterior thoracic wall?
- Pectoralis major
- Pectoralis minor
What are features of the Pectoralis major?
Origin: medial half of clavicle, anterior surface sternum, upper 6 costal cartilage
Insertion: Intertubercular sulcus of humerus
Innervation: medial and lateral pectoral nerves
What are features of the Pectoralis minor?
Origin: anterior surface of ribs 3-5
Insertion: coracoid process of scapula
Innervation: medial and lateral pectoral nerves
What muscles are superficial and posterior on the thoracic wall?
- Latissimus dorsi
- Trapezius
What are features of the Latissimus dorsi?
Origin: iliac crest, lower 6 spinous process of the thoracic vertebrae, thoracolumbar fascia and lower 3-4 ribs
Insertion: intertubercular sulcus of humerus
Innervation: thoracodorsal nerves
What are features of the Trapezius?
Origin: superior nuchal line, external occipital protuberance and spinous process of C7-T12
Insertion: spine of scapula, acromion and lateral third of the clavicle
Innervation: accessory nerves
What are the muscles found deep and posterior in the thoracic wall?
- Teres major
- Levator scapulae
- Rhomboid minor
- Rhomboid minor
What are features of Teres major?
Origin: inferior angle of scapula
Insertion: intertubercular sulcus of humerus
Innervation: lower subscapular nerve
What are features of the levator scapulae?
Origin: transverse process of C1-C6 vertebrae
Insertion: medial border of the scapula from the superior angle of the root of the spine
Innervation: Dorsal scapular nerve
What are features of the Rhomboid minor?
Origin: Spinous process of C7-T1 vertebrae
Insertion: Medial border of scapula at the root of the spine
Innervation: Dorsal scapular nerve
What are features of the Rhomboid major?
Origin: Spinous process of T2-T5 vertebrae
Insertion: Medial border of scapula from the root of the spine to the inferior angle
Innervation: Dorsal scapular nerve
What is the arm?
- From shoulder (glenohumeral joint) to elbow
- Humerus
- Muscles act on shoulder & elbow joint
- Two compartments
What are the 3 anterior (flexor) muscles?
- Biceps branchii
- Brachialis
- Coracobrachialis
What is the anterior (extensor) muscle?
Triceps brachii
Describe the features of the biceps branchii
Origin: 2 heads
Long head - supraglenoid tubercle of the scapula
Short head - coracoid process of the scapula
Insertion: Radial tuberosity (via bicipital tendon)
What is the action of the biceps branchii?
- Flexes arm at shoulder joint
- Flexes forearm at elbow joint
What is the blood supply and innervation of the biceps branchii?
Blood supply - Brachial artery
Innervation - Musculocutaneous nerve
What are features of the brachialis?
Origin: midshaft of the humerus
Insertion: Coronoid process and tuberosity of the ulna
Action: Powerful flexor of the forearm at the elbow joint
What are features of the coracobrachialis?
Origin: Coracoid process of scapula
Insertion: Midshaft of humerus
Action: Flexes arm at shoulder joint
What are features of the Triceps branchii?
Origin: 3 heads
Long head - infraglenoid tubercle of the scapula
Medial & Lateral heads - posterior surface of the humerus
Insertion: ilecranon process of the ulna (via triceps tendon)
What is the action of the Triceps branchii?
- Extends arm at shoulder joint
- Extends forearm at elbow joint
What is the blood supply and innervation of the Triceps branchii?
Blood supply - deep brachial artery
Innervation - radial nerve
What is a summary of the shoulder, arm and chest wall?
- The pectoral girdle connects the trunk to the upper limb via the glenohumeral joint. It consists of 2 bones - the scapula and the clavicle, it interacts with the humerus.
- The thoracic wall muscles are divided into anterior & posterior. All are innervated by branches of the brachial plexus, exception trapezius (innervated by the accessory nerve - a cranial nerve).
- The shoulder muscles include the rotator cuff and the deltoid. All are innervated by branches of the brachial plexus.
- The glenohumeral (shoulder) joint is a multiaxial joint with a wide range of movements (flexion, extension, abduction, adduction, medial rotation, lateral rotation and circumduction).
- The arm muscles are divided into anterior (flexor) and posterior (extensor) compartments.
- The flexor compartment of the arm has 3 muscles (biceps brachii, brachialis, coracobrachialis). They’re innervated by the musculocutaneous nerve & supplied by the brachial artery
- The extensor compartment of the arm has 1 muscle (triceps brachii). It is innervated by the radial nerve and supplied by the deep brachial artery
