Pectoral Girdle and Shoulder Joint Flashcards
What bones make up the glenohumeral joint and pectoral girdle?
Scapula
Humerus
Clavicle
What is highlighted?
Corocoid process of the scapula
What is highlighted?
Acromion process of scapula
What is shown and what makes this groove?
The bicipital groove of the humerus
Created by the tendon of the long head of biceps brachii
What is highlighted and what muscle attaches here?
Deltoid tuberosity
Deltoid muscle inserts here
Within the upper limb, what are some basic rules for movements at a joint depending on where the muscle passes over?
- If a muscle/tendon passes over anterior surface it will flex the joint, but if it crosses posterior it will extend
- If it crosses the medial surface it will adduct it whereas if it crosses the lateral surface it will abduct
What structures are highlighted here?
Glenohumeral ligaments
Superior, middle and inferior ligaments
Pass from lesser tubercle of humerus to the edges of the glenoid cavity
Where does the coracohumeral ligament run?
Passes from the greater tubercle of the humerus to the coracoid process of the scapula
What is A highlighting and what does it do?
Transverse humeral ligament
Hold the tendon of the long head of biceps brachii in place as it passes through the bicepital groove
What ligament is highlighted?
Acromioclavicular
What ligament is highlighted?
Coracoacromial ligament
What ligament is shown and what 2 parts does it have?
Coracoclavicular ligament
Conoid and trapezoid parts
What are the 2 anatomical spaces associated with the muscles attached to posterior aspect of scapula?
Quadrangular space
Triangular space
Describe the quadrangular space and what passes through it
Superior border - Teres minor
Inferior border - Terese major
Medial - Long head of triceps brachii
Lateral - Humerus
Axillary nerve and posterior circumflex humeral artery pass through
Describe the triangular space and what passes through it?
Superior border - Teres major
Medial - Long head of triceps brachii
Lateral - Humerus
Radial nerve and deep brachiial artery run through
What is the blood supply for the scapular anastamosis?
Branches of the subclavian
Describe the origins of the subclavian arteries
Right subclavian is a branch of brachiocephalic trunk
Left subclavian is a direct branch of aorta
What does the subclavian artery become?
Becomes axillary artery as it passes under the clavicle and over the surface of the first rib
What is this muscle and its innervation?
Pectoralis major
Medial (C8-T1) and Lateral (C5-7) pectoral nerves
What are the attachments of pectoralis major?
Clavicle, costal cartilage of ribs 1-6, and sternum to the outer lip of the bicepital groove of the humerus
What are the actions of pectoralis major?
Flexion and adduction of the arm and medial rotation of the humerus
What is this muscle and its innervation?
Pectoralis minor
Medial pectoral nerve (C8, T1)
What are the attachments of pectoralis minor?
Ribs 3,4,5 to the coracoid process of scapula
What are the actions of pectoralis minor?
Pulls shoulder anterior and inferior, or can elevate ribs if shoulder is fixed
What is this muscle and its innervation?
Serratus anterior
Long thoracic nerve (C5,6,7)
What are the attachments of serratus anterior?
Outer surface of upper 8 ribs to the medial border of scapula
What is the action of serratus anterior?
Protraction of scapula
What is this muscle and its innervation?
Trapezius
Spinal accessory nerve (CN XI) for motor
Cervical plexus C3,4 for sensory
What are the attachments of the trapzius?
Superior nuchal line, nuchal ligament, spinous process C7-T12, to the lateral third of clavicle, acromion and spine of scapula
What are the actions of the trapezius?
Ascending part- depresses scapula
Transverse part - retracts scapula
Descending part - elevates scapula and rotates the glenoid cavity
What is this muscle and its innervation?
Latissimus Dorsi Thoracodorsal nerve (C6-8)
What is the action of latissimus dorsi?
Extension, medial rotation and abduction of the arm
Climbing and chin ups
What are the attachments of latisimus dorsi?
Iliac crest, thoracolumbar fascia, spinous process of lower 6 thoracic vertebrae to the floor of the bicepital groove of the humerus
What is this muscle and its innervation?
Levator scapulae
Direct C3, 4 and 5 via the dorsal scapular nerve
What are the attachments of levator scapuli?
Transverse process of atlas and axis, C3 and 4 to the medial scapular border between the superior angle and medial end of scapular line
What is the actions of levator scapulae?
Helps to control scapular position, elvates shoulder with the trapezius, and with the shoulder fixed it can laterally flex the neck to the same side
What are the attachments of the rhomboids?
Major- thoracic spines 2-5 to the medial border of the scapula
Minor - nuchal ligament and C7-T1 spines to the medial end of the scapula
What is the role of the rhomboids?
Retraction of the scapula
What is the innervation of the rhomboids?
Dorsal scapular nerve C4-5
What muscle is this and what is its innervation?
Deltoid Axillary nerve (C5,6) from posterior cord of brachial plexus
What are the attachments of the deltoid?
Lateral 1/3 of clavicle, acromion, spine of scapula to the deltoid tuberosity of humerus
What is the actions of the deltoid?
Abduction of arm from 10-110, mostly middle fibres
Extension and lateral rotation of arms from posterior fibres
Flexion and medial rotation of arms from anterior fibres
What muscle is this and what is its innervation?
Teres major
Subscapular branch of posterior cord of brachial plexus (lower C5-6)
What is the action of teres major?
Adduction and medial rotation of arm
What are the attachments of teres major?
Lateral border of scapula (lower 1/3 posterior) to the medial lip of bicepital groove of humerus
What muscle is this and what is its innervation?
Subclavius
Nerve to subclavius (C5,6)
What is the action of the subclavius?
Draws clavicle down and slightly forwards during abduction
What are the attachments of the of the subclavius?
Sternal end of 1st rib to the middle third of the underside of clavicle
What is the rotator cuff?
A group of 4 muscles that help to keep the humerus in the glenoid fossa of the scapula
Helps to prevent dislocation
What is the most common direction for shoulder dislocation?
Antero-inferior direction
What muscle is highlighted and what is its innervation?
Subscapularis
Upper and lower subscapular nerves (C5,6,7) from posterior cord of brachial plexus
What is the action of the subscapularis?
Medially rotates the arm
What are the attachments of the subscapularis?
Subscapular fossa on the anterior fossa to the lesser tubercle of the humerus
What is the muscle shown and what is its innervation?
Supraspinatous Suprascapular nerve (C5,6) from superior trunk of brachial plexus
What is the action of the supraspinatous?
Abducts the arm the first 10-15 degrees
Where does the supraspinatous attach?
Supraspinatous fossa on the posterior aspect of the scapula to the greater tubercle of humerus (upper facet)
What muscle is highlighted and what is its innervation?
Infraspinatous Suprascapular nerves (C5,6) from superior branch of the brachial plexus
What is the action of the infraspinatous?
Lateral rotation of the arm
What are the attachments of the infraspinatus?
Infraspinous fossa of posterior scapula to the greater tubercle of humerus (middle facet)
What is the muscle shown and what is its innervation?
Teres minor Axillary nerve (C5,6) branch of posterior cord of brachial plexus
What is the action of the teres minor?
Lateral rotation of the arm
What are the attachments of teres minor?
Upper 2/3rds lateral border of scapula to the greater tubercle of humerus (lower facet)
What are the muscles of the rotator cuff?
Subscapularis
Supraspinatous
Infraspinatous
Teres minor
