Sem 1 - R - Pectoral Girdle and Shoulder Joint - Scapula, humerus, clavicle, Muscles, Rotator cuff,ligaments, arteries, spaces

Question 1

Need to know the osteology of the scapula Firstly label the boxes pointing to features of the anterior aspect of the scapula

Answer 1

Black box - coracoid process Red box - acromion Orange box - superior angle Blue box - subscapular fossa Brown box - Medial border Green box - Lateral border

Question 2

Now label the bony features of the posterior scapula

Answer 2

Yellow box - suprascapular notch White box - acromion Red box - lateral border Orange box - medial border Green box - infraspinous fossa Blue box - spine of scapula Purple box - supraspinous fossa Brown box -superior angle

Question 3

What is the order of the three muscles attaching to the greater tubercle form superior to inferior? Which muscle attaches to the lesser tubercle? Which musces attach to the bicipital groove?

Answer 3

• Greater tubercle
  
  • * Supraspinatus
  • * Infraspinatus
  • * Teres minor
• Lesser tubercle
  
  • * Subcapularis
• Bicipital groove -
  
  • * Pectoralis major
  • * Lattismus dorsi
  • * Teres major

Question 4

What is the general rule for the movements of the upper limb if you are a muscle crossing the joint?

Answer 4

* If you cross the anterior surface of the joint you will flex (and possibly medially rotate) the joint * If you cross the posterior surface of the joint you will extend (and possibly laterally rotate) the joint * If you cross the outer surface of the joint you will abduct the joint * If you cross the inner surface of the joint you will adduct the joint

Question 5

What is the attachments of the pectoralis major?

Answer 5

Medial clavicle, sternum and costal cartilages of ribs 1-6 To the outer lip of the bicipital groove of the humerus

Question 6

What is the function of the pectoralis major? (think of the parts of the joint it crosses to help) What is the nerve supply?

Answer 6

Pectoralis major Acts to flex and adduct the arm as well as medially rotate the humerus Its nerve supply - Medial pectoal nerve and Lateral pectoral nerve

Question 7

What are the medial and lateral pectoral nerve roots? What part of the brachial plexus do they arise from?

Answer 7

Medial pectoral nerve - C8, T1

• Arises from the medial cord of the brachial plexus

Lateral pectoral nerve - C5,6,7

• Arises from the lateral cord of the brachial plexus

Question 8

State the attachments of the pec major, its function and nerve supply (with roots)

Answer 8

• Attaches from medial clavicle, sternum and ribs 1-6 costal cartilages to the outer lip of the bicipital groove of the humerus
• Function is to flex & adduct the arm, and medially rotate the humerus
• Nerves - Medial pectoral (C8-T1) and Lateral pectoral nerve (C5-7) from medial & lateral cords respectively

Question 9

The pectoralis minor lies underneath its larger counterpart muscle, pectoralis major. Both of these muscles form part of the anterior wall of the axilla region. What are its attachments?

Answer 9

The pec minor originates form ribs 3-5 an inserts at the coracoid process of the scapula

Question 10

What is the function of the pectoralis minor?

Answer 10

It helps to stbailise the shoulder by pulling it anterior and inferiorly - to be precise it stabilises the scapula by pulling it anteroinferiorly against the body wall It can elevate the ribs if the shoulder is fixed - accessory muscle of inspiration

Question 11

What is the nerve supply and the roots of the pec minor?

Answer 11

Nerve supply - medial pectoral nerve from the medial cord of the brachial plexus (C8,T1)

Question 12

What is the attachment, function and nerve supply to the pectoralis minor?

Answer 12

• Attachment Originates at ribs 3-5 and inserts at the coracoid process of the scapula
• Function - stabilises the scapula by drawing it anteroinferiorly against the body wall Elevates the ribs when the shoulder is fixed
• Nerve - Medial pectoral nerve (C8, T1) from medial cord of brahcial plexus

Question 13

What is the attachment of the serratus anterior?

Answer 13

It originates from the outer surface of ribs 1 to 8 to curve round the anterior surface of the scapula to the medial border of the scapula

Question 14

What is the function of the serratus anterior and its nerve supply?

Answer 14

Function - protraction of the scapula Nerve supply - Long thoracic nerve (C5,6,7) (bracnhes from the root of the brahcial plexus)

Question 15

What is the attachment, function and nerve supply of the serratus anterior? Which rib is atypical due to its tuberosity for the serratus anterior muscle?

Answer 15

• Attachment Outer surface of upper 8 ribs to the anterior surface of the medial border of the scapula
• Function is to protract the scapula
• Nerve supply - long thoracic nerve (C5,6,7)

Rib 2 has a tuberosity for the serratus anterior

Question 16

What are the attachment sites of the trapezius muscle?

Answer 16

Medial 1/3rd of the superior nuchal line, nucal ligament, spinous processes of C7-T12 Inserts to the lateral clavicle, acromion and spine of scapula

Question 17

What is the innervation to the trapezius muscle?

Answer 17

Motor inervation form the spinal accessory nevre (CN XI) Pain and proproception from C3,4 spinal nerves

Question 18

What is the fucntion of the trapezius muscle?

Answer 18

• Upper (descending) part - elevates the scapula and rotates the glenoid cavity
• Middle (transverse) part -retracts the scapula
• Lower (ascending) part - depresses the scapula

Question 19

What is the attachments, function and innervation of the trapezius?

Answer 19

Medial 1/3rd superior nuchal line, nuchal ligament & spinous processes of C7 - T12 vertebra to lateral clavicle, acromion&spine of scapula

Innervation - Spinal accessory nerve (CN XI for motor) and C3,4 spinal nerve(pain/proprioception)

Function - Upper part - elevates scapula and rotates glenoid cavity, middle part retracts scapula, lower part depresses scapula

Question 20

The bigger the muscle bulk the more difficult it is to move the joint in that area With trapezius and latttimus dorsi – muscle tries to be very thin over a large surface area to give a lot of muscle area without limiting joint movement What are the attachments of the lattisumus dorsi?

Answer 20

Originates at the spinous processes T7-12, thoracolumbar fascia, iliac crests and lower 3-4 ribs Inserts at the floor of the bicipital groove of the humerus

Question 21

What is the function and nerve supply of the lattismus dorsi?

Answer 21

Function - allows for adduction and extension of the arm and medial rotation of the humerus Nerve supply - thoracodorsal nerve (C6,7,8)

Question 22

What can the thoracodorsal nerve also be known as and why? What exercises is lattismus dorsi helpful in? Also what muscle allows a person to shrug their shoulders?

Answer 22

Thoracordal nerve is also known as the middle subscapular nerve or the long subscapular nerve as it comes from the posterior cord between the upper & lower subscapular nerves Upper fibres of trapezius allows a person to shrug their shoulder Lattismus dorsi useful in climbing and chin ups

Question 23

State the attachment, function and nerve supply of the latismus dorsi muscle

Answer 23

• Spinous process of T7-T12 vertebrae , thoracolumbar fascia, iliac crest and lower 3/4 ribs
• Inserts at the floor of the biciptal groove of the humerus
• Function - extend & adduct the arm, medially rotate the humerus (useful in climbing and chin ups)
• Innervation-Thoracodorsal nerve (C6,7,8)

Question 24

Talked about pec major, minor and serratus anterior Now also talked about trapezius and lattismus dorsi (superficial extrinsic muscles of the back), time to talk about the other superficial extrinsic muscles of the back What are they? In these set of cards however we are talking in relation about the pec girdle

Answer 24

Levator sacpulae Rhomboid minor Rhomboid major

Question 25

What is the attachents of the levator scapulae muscle?

Answer 25

Origins - posterior tubercles of transverse processes C1-4 vertebrae and attaches to the medial border of the scapula above the spine

Question 26

What is the function of the levator scapulae? What can it do if the shoulder is fixed? What is the nerve supply to the levator scapulae?

Answer 26

It elevates the scapulae (along with the trapezius) If the shoulder is fixed it can laterally flex the neck to the same side Direct from C3,4 cervical spinal nerves as well as C5 from the dorsal scapula nerve (which also supplies the rhomboids)

Question 27

State the attachments, function and nerve supply of the levator scapulae

Answer 27

Attachments - Posterior tubercles of transverse process of C1-4 vertebrae to the medial border of the scapua above the spine Function - elevate the scapula and if the shoulder is fixed can laterally flex the neck to the same side Nerve supply - C3,4 spinal nerves and the Dorsal Scapula nerve

Question 28

What are the attachments of the rhomboid minor and major?

Answer 28

Rhomboid minor - attaches from nuchal ligament, spinous process of C7 and T1 o medial end of the scapulae spine Rhomboid major - attaches from spinous processes T2 to T5 to the medial border of the scapula (from spine to inferior angle)

Question 29

What is the function of the rhomboids and their nerve supply?

Answer 29

Functions - Retarction and rotation of the scapula Nerve supply - Dorsal Scapular nerve (C4, 5)

Question 30

What is the attachments of rhomboid minor and major and their nerve supply?

Answer 30

• Rhomboid minor - Nuchal ligament , spinous processes C7 & T1 to medial end of spine of scapulae
• Rhomboid major - spinous processes T2-T5 to medial border of scapula (spine to inferior angle)
• Functions - Retraction and rotate the scapula
• Nerve supply - Dorsal scapular nerve (C4,5)

Question 31

Deltoid is said to be multipennate. What does this mean? What are the attachments of the deltoid muscle?

Answer 31

Multipennate - a muscle with several central tendons toward which the muscle fibers converge

Attachments - Lateral 1/3rd of clavicle, acromion and scapula spine to the deltoid tuberosity of the humerus

Question 32

What is the function of the deltoid muscle? (state the fibres exacting each function) State the nerve supply of the deltoid muscle

Answer 32

Extension and lateral rotation of the arm from posterior fibres Flexion and medial rotation of the arm from anterior fibres Abduction of the arm from mostly middle fibres - 10 to 110 degrees Nerve supply to deltoid - Axillary nerve from the posterior cord (C5,6)

Question 33

Where is most of the detloid muscle bulk and therefore what is its main action? What carries out abudction for the first 10 to 15 degrees? What happens when 100 degrees of abduction is reach?

Answer 33

Most of the deltoid bulk is its middle fibres and therefore abduction is its main action Supraspinatus muscle carris out abduction for the 1st 10-15 degrees At about 100 degrees of abduction the humerus will begin to hit the scapula, so the trapezius muscle tilts the scapula to allow abduction to continue

Question 34

State the attachments, function and nerve supply of the deltoids again

Answer 34

Attachments - Lateral 1/3rd clavicle, acromion and spine of scapula to deltoid tuberosity on humerus Middle fibres - abduction 10-110 degrees Posterior fibres - extension and lateral rotation Anterior fibres - flexion and medial rotation Nerve supply -Axillary nerve (C5,6)

Question 35

Betweent he pec major and deltoid is a little fatty stripe which if opened contains what vein? What is this fatty strip known as?

Answer 35

The vein running within the deltopectoral groove is the cephalic vein The fatty strip is known as the deltopectoral groove The cephalic vein starts on the lateral aspect of the hand running all this way

Question 36

Teres major sits slightly below the rotator cuff muscles (will discuss later) What is its attachment?

Answer 36

The teres major attaches from the lateral border of the scapula (posterior lower 1/3rd) to the medial lip of the bicipital groove of the humerus

Question 37

What is the function of the teres major and what is its nerve supply?

Answer 37

Function - Adduction and medial rotation of the arm Nerve supply - lower subscapular nerve (C5,6) from the posterior cord of the brachial plexus

Question 38

State the attachment, function and nerve supply to the teres major?

Answer 38

Attachment LAteral border of scapular (poster 1/3rd) to the medial lip of the bicipital groove of the humerus Function - adduction and medial rotation of the arm and nerve supply from the lower subscapular nerve (C5,6)

Question 39

What is another name for the bicipital groove? Where does it run?

Answer 39

Bicipital groove - also known as the intertubercular groove is a deep groove in the humerus separating the greater and lessser tubercles (pec major (outer lip) lattisimus dorsi (floor) and teres major (medial lip) attach here)

Question 40

State the attachment of the subclavius, its function and its nerve supply

Answer 40

It attaches from the sternal end of the 1st rib to the underside of the clavicle Stabilises the clavicle by drawing it down and slightly forwards during abduction Nerve supply - nerve to subclavius (C5,6)

Question 41

Rotator cuff helps prevent the potential dislocation of the shoulder joint Why is there an increased risk of dislocation from the shoulder joint? Upper limb – made for mobility rather than stability What are the rotator cuff muscles?

Answer 41

Subscapularis Supraspinatus Infrapsinatus Teres minor Shoulder joint is a very shallow joint and therefore dislocations are not uncommon - rotator cuff helps stabilize the joint

Question 42

What is the only rotator cuff muscle to attach to the lesser tubercle off the humerus? Where does it lie?

Answer 42

This is the subscapularis It lies in the subscapular fossa (anterior scapula) and attaches to the lesser tubercle

Question 43

The subcapularis is the only rotator cuff muscle to attach to the lesser tubercle of the humerus It runs from subscapular (fossa) (anterior scapula) What is its action and what is its nerve supply? What part of the joint capsule does it help to protect?

Answer 43

It acts to medially rotate the arm Nerve supply - Upper and lower subscapular nerves (C5,6,7) (from the posterior cord of the brachial plexus) It helps to protect the anterior aspect of the joint capsule

Question 44

Describe the attachments of the supraspinatus muscle and its function?

Answer 44

The suprapsinatus muscle goes from the supraspinous fossa to the upper facet of the greater tubercle It abducts the arm for the first 10-15 degrees

Question 45

The supraspinatus attaches from the surpasinatus fossa to the upper facet of the greater tubercle abducting the arm for the first 10 to 15 degrees. What is its nerve supply? What part of the joint capsule does it help to protect?

Answer 45

It is supplied by the suprascapular nerve from the superior trunk of the brachial plexus (C5,6) The supraspinatus helps to protect the superior aspect of the joint capsule

Question 46

State the attachment of the infraspinatus muscle, its function, its nerve supply and the part of the joint capsule it helps protect?

Answer 46

It attaches from the infraspinatus fossa to the middle facet of the greater tubercle cause lateral rotation of the arm It is supplied by the suprascaplar nerve (C5,6) from the superior trunk of the brachial plexus It helps to protect the bulk of the posterior aspect of the joint capsule

Question 47

What is the attachment of the teres minor? What its function and what is its nerve supply? What part of the joint capusle does it help protect?

Answer 47

Upper 2/3rds of the lateral border of the scapula to the lower facet of the greater tubercle Its function is for lateral rotation of the arm Supplied by the axillary nerve Helps protect the lower posterior aspect of the joint capsule

Question 48

State the attachments, movement allowed by the muscle and nerve supply of the rotator cuff muscles State which part of the joint capsule it protects

Answer 48

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Question 49

Subscpularis protects front of the joint Supraspinatus protects it superiorly Infrapsinatus and teres minor protect it posteriorly What protects the inferior apsect of the joint?

Answer 49

The inferior aspect of the joint is not protected and is therefore prone to dislocations

Question 50

Ligaments in the shoulder joint, the ligaments play a key role in stabilising the bony structures. * Glenohumeral ligaments * Coracohumeral ligament * Transverse humeral ligament * Acromioclavicular ligament * Coracoacromial ligament * (for pectoral girdle - also have sternoclavicular and costoclavicular and interclavicular ligaments) What are the glenohumeral ligaments?

Answer 50

There is a superior middle and inferior glenohumeral ligament They are a group of ligaments connecting the glenoid fossa to the lesser tubercle of the humerus and stabilise the anterior aspect of the shoulder joint

Question 51

Ligaments in the shoulder joint, the ligaments play a key role in stabilising the bony structures. * Glenohumeral ligaments * Coracohumeral ligament * Transverse humeral ligament * Acromioclavicular ligament * Coracoacromial ligament * (for pectoral girdle - also have sternoclavicular and costoclavicular and interclavicular ligaments) What is the coracohumeral & tranvserse humeral ligament?

Answer 51

Coracohumeral ligament attaches from coracoid process to greater tubercle of the humerus strengthening the superior apsect of the joint capsule

Transverse humeral ligament - attaches between greater and lesser tubercle holding the biceps tendon in place in the bicipital groove

Question 52

Bursae = synovial pockets – may or may not be in communication with shoulder joint What is the only bone fixing the upper limb to the body?

Answer 52

This would be the clavicle

Question 53

Ligaments in the shoulder joint, the ligaments play a key role in stabilising the bony structures. * Glenohumeral ligaments * Coracohumeral ligament * Transverse humeral ligament * Acromioclavicular ligament * Coracoacromial and coracoclavicular ligament * (for pectoral girdle - also have sternoclavicular and costoclavicular and interclavicular ligaments) What is the acromioclavicular and coracoacromial ligament?

Answer 53

Acromioclavicular ligament attaches the acromion of the scapula to the distal end of the clavicle Coracoacromial ligament attaches between the coracoid process and acromion of the scapula - reinforces top of shoulder joint preventing superior dislocation

Question 54

The coracoclavicular ligament can be split into conoid and trapezoid parts. Which is more medial and what do they work with to maintain the alignment of the clavicle in relation to the scpaula?

Answer 54

It runs from the coracoid process of the scapula to the clavicle Conoid ligament is the more medial of the two coracoclavicular ligament parts They work alongside the acromioclavicular ligament to maintain the alignment of the clavicle in relation to the scapula

Question 55

Ligaments in the shoulder joint, the ligaments play a key role in stabilising the bony structures. * Glenohumeral ligaments * Coracohumeral ligament * Transverse humeral ligament * Acromioclavicular ligament * Coracoacromial ligament * (for pectoral girdle - also have sternoclavicular and costoclavicular and interclavicular ligaments) Describe sterno, cost and inter - clavicular ligaments?

Answer 55

Sternoclavicular ligaments - anterior & posterior ligaments (joint between sternum and clavicle is a synovial saddle joint)

Costoclavicular ligaments - between 1st rib &clavicles

Interclavicular ligaments - between both clavicles All three of these strengthen the clavicle attachment to the body

Question 56

Which branch of the subclavian artery gives the the suprascapular arteries? What does the suprascapular artery anastamose with to supply the scapula?

Answer 56

The thyrocervical trunk is a branch of the subclavian artery which gives off the suprascapular The dorsal artery (from the subclavian artery) and the suprascapular artery have a high level of anastamoses

Question 57

Anatomical spaces are small spaces with things passing through them The axillary space is an anatomic space. It is further subdivided into quadrangular space, triangular space, and triangular hiatus (interval). It is bounded by teres major, teres minor, medial border of the humerus, and long head of triceps brachii. We are not getting taught about the triangular space. What are the boundaries of the quadrangular space and the trinagular hiatus?

Answer 57

• Quadrangualar space
• * Superiorly - teres minor, Inferiorly - teres major * Medially - long head of the triceps * Laterally - humerus
• Triangular hiatus * Superiorly - teres major * Medially - long head of the triceps * Laterally - humerus
• Trinagular space - Superiorly - teres minor, inferiorly - teres major, laterally - long head of triceps (DONT NEED TO KNOW)

Question 58

What passes throught he quadranagular space, trinagular hiatus and triangular space?

Answer 58

Quadrangular space - The axillary nerve and posterior circumflex humeral artery Triangular hiatus (interval) - The radial nerve and profunda brachii (deep artery of the arm) Triangular space - Curcmflex scapular branch of subscapular artery (DONT NEED TO KNOW)

Question 59

State again the boundaries of the quadrangular space and trinagular interval/hiatus and what passes through them

Answer 59

Quadrangular space

• Superiorly - teres minor, inferiorly - teres major, medially - long head of biceps, laterally - humerus
• Axillary nerve and posterior circumflex humeral artery

Triangular interval/hiatus

• Superiorly - teres major, medially - long head of biceps, laterally - humerus
• Radial nerve and profunda brachii artery