Lecture - MSK (Pectoral girdle) Flashcards
What are the functions of the upper limb? How does it differ to hip joint?
- Reaching, grasping
- Lifting, carrying
- Throwing, hitting
- Delicate Manipulaions (mainly fingers of the hand) aka on top of heavy duty movements, can delicate ones - possible bc can steer our joints with our shoulder joint
Shoulder vs hip:
- should joint way more moveable than hip - additional moevement in shoulder bc hip built for stability and less movement so can get the stability
- can dislocate shoulder easier than hip bc of the additional movement (it has less stability)
- so: hip joint more stable and less moveable (vice cersa for shoulder)
What are the two bones comprising the shoulder girdle?
Scapula and clavicle
These two provide contact of upper extremity to the rest of the trunk
Scapula:
- What type of bone is it?
- How many borders and how many angles?
- What is the anterior surface known as?
- What is the posterior surface of scapula divided by and into what?
- What does the acromion end in?
- Where does the coracoid process project?
- What 5 are attachments for muslces?
Label this image with where these things are: the three angles and borders, subsxapular fossa, supraspinous fossa, infraspinous fossa, acromion, spine and coracoid process
Yozza
Clavicle:
- Acts a as a ____, joining the scapla to the sternum
- How would you describe its two ends and its shaft?
- Medially, what fraction of that part convex forward? Laterally?
- The upper side of it is smooth or nah? What about the lower side? Why?
- On the diagram, label the two ends with their actual names and the line, tubercule, attachment and ligmanet attachment in the bottom image
- The trapezoid line and tubercule: help to laterally connect clavicle to scapula
- Costoclavicular ligament attachment: connects clavicle to 1st rib
Movements of shoulder girdle and joints involved:
So the scapula is a _____ bone, it can _____ relative to rib cage; in conjuction with clavicle and what two joints?
In the diagram - what’re the six notes about?
Go to lecture lol
What’s the actual name of the different movements you can do at the shoulder joint? What are the movements limited by?
- Elevation = abduction (except elevation goes beyond angle of 90)
- Depression. = adduction
- Protraction = flexion, antiversion
- Retraction = extension, retroversion
- Medial and lateral rotation
All these movements aren’t limited by bones - they are limited by ligamnets and muscles of shoulder joint (the ones that provide stability at the shoulder joint)
Sternoclavicular joint
- Connects clavicle to what?
- What does the fibrous/fibrocartilaginous articular disc do?
- What sort of joint is this?
- You need the disc because the axis of motion is where?
- What ligaments connect the clavical to first rib?
Sticky note 1: Sternal end of the clavical has an articular disc - imp for providing a pliable movement of the clavical in front of the menubrium - stablised by anterior and posterior capsular ligamnets of the joint
Sticky note 2: More important than the sternoclavicular ligamnets
These connect clavical to the first rib
These are serving as a pivot or lever where the clavical moves
Need disc bc the axis motion is (pink line
Acromioclavicular joint
- Small _____ joint (what further type?) between what two things?
- What projects into the joint?
- Supported by what ligament? What are its two parts?
- What is the ligament at the roof of the shoulder joint and what does it connect?
- Coracocromial ligament
Roof of shoulder joint
Connects the caroid to clavical
Stick note on top: Acromial and acromial extremity of clavical = acromialclavicular joint (pliable joint capsule)
Sticky note on bottom: Connect clavical to coracoid process
Now moving onto the actual connection of shoulder girdlewith humerus at the shoulder joint: glenohumeral (shoulder)
Label this and tell me about the tendon of biceps brachii, hyaline cartialge of the glenuoid fossa, the joint capsule and its 2 dense ligaments
- Long tendon of biceps brachii muscle
Tendon extends both anteriorly and posteirorly to another set of fibrocartialge that extends the glenuioid cartialge to provide more stable joint surface
- Hyaline cartialge of the shoulder joint foss (glenuoid fossa)
This joint surface is only 20% of the head of humerus so need 5x as much caetialge on head of humerus so it is pretty moveable since small socket and large no-bone (BC is 20%)
- Joint capsule - reinforeced by 2 dense ligaments
- glenohumeral ligaments (connect to head of jhumerus and scapula)
- corachumeral ligament
——both originate of coracoid porcess and off the glenuoid orcess and insert bw line bw greter and less tuberal - reaches all the way around head and towards anatomical neck of humerus
Label this
Identify the tendon of biceps brachii
What can you tell about the joint surface on the x-ray?
Very small joint surface
SO have huge range of motion
Shoulder joint
- Stabalised by ____ _____ muscles - what are the 4?
- What two bursae should you know?
- What is the coracoacromial arch?
Label and what can you tell me about the subscapular recess?
Adiitional bit of CT strucute to allow elevation/abd of arm
If you leave your arm to trunk when fractured - this recess sticks together and then you wont be able to move your shoulder so humeral bone injury that is being treated non-surgically then need to have the cast at elevation
Muscles - what’s the difference between extrinsic and intrinsic muscles?
Extrinsic - come from outside of shoulder joint and insert close to shoulder joint
Intrinsic -insert eg scpaula to humerus
What can you tell me about the deltoid muscle in terms of its three parts and what movement each part does?
What nerve supplies the deloid?
Like a cap - three parts:
Has centra part - originate proximally from spine of scapula and cromion inserts to tuberoisty of humerus: abduction of shoulder joint
Posterior part/head: originates from spine of scapaula
Anterior head: originates from acromion and most later part of clavical and acromial head
Both ant and post go with central to get to tuberioisty of humerus
Post and ant - help in abduction but also help adduction of arm and if only anterior rotating then helps with internal rotation (posterior contracting then external rotation)
The intrinsic muscles comprising the rotator cuff - what are each of these and what are the nerves that supply?
Supraspinatus:
From supraspinatous fossa off scapula and inserts to suprior rpole of humeris
- serves as abduction and also helps in external rotation
- innervated by that suprrascapular nerve
Infraspinatus
-interal rotater and in supplied by the same sub nerve
Teres minor muscle is innervated by axxilary nerve
:
Intrinsic muscles at the shoulder joint - what is shown in these pictures?
“Scapula sits posteriorly behind ribs but still provides both internal and external ______ as well as interior/posterior movement at joint
This muscle helps to carry out _____ rotation - sits ))))) at fossa of scapula (___ fossa) and innervated by ______ nerve”
“Joint capsule reinforced by ______ muscle and _______ muscele, infraspinous muscle and of _____ ______ muscles
- supraspinarius
- subscapulairs
- infra spinaris
- teres minor
= rotator cuff muscles
Scapula sits posteriorly behind ribs but still provides both internal and external rotation as well as interior/posterior movement at joint
This muscle helps to carry out internal rotation - sits anteriorly at fossa of scapula (subscapula fossa) and innervated by subscapular nerve
Joint capsule reinforced by subscapular muscle and supraspinatus muscele, infraspinous muscle and of teres minor muscles
- supraspinarius
- subscapulairs
- infra spinaris
- teres minor
= rotator cuff muscles
Extrinsic muslces of the shoulder joint:
- Why is it called extrinsic?
- What are the two and what nerves?
- Can originate from other bones, not just scpula
- Pectoralis major:
Helps in both adduction but also helps in forceful internal rotation
Off clavical/menbrium of sternum and ribs - innervated by that nerves
These fibres coming off have a little twist when interseting. This twist is pre important
Pectoralis minor:
Orignites of 3rd, 4th and 5th rib and at the coracoid porcess
More extrinsic muscles at the shoulder joint- what are these three (or four) and what nerves?
- Trapezius:
All spinous process of cervial and thoracic spine - insert to clavical and. at the acromial so help retraction posteriorly towards trunk
Accesory nerve - 11th of the cranial nerves
- Latissimus dorsi:
Just inferior to trap - this muscle
Orinigates off thoracoo spinous process and illium - go to humerus and can help to depress and internally rotate the shoulder joint
- Levator scapulae and rhomboids:
Help to lift anf medially retract scapula
All three muscle innercated by that enrve
Second to last extrinsic muscles of the shoulder joint - what is this one and what is the nerve?
7-8 muscle bellies/heads and they jointly insert at the medial border/margin of scapula and can move scapula towards trunk but also to locate/move scapula ventrally
This nerve is running down its anterior surface
Okay, now last extrinsic muslce - biceps brachii
- What does it looks like?
- What nerve?
- What movements?
Long head is more lateral
Medial is short - off coracoid process
Both insert at tuberoistiy of radius
Both have epineurotic sheath at which the muscle also inserts at the fascia/CT of forearm
Flexion at elbow joint and extension at shoulder joint and BICEPS BRACHII MUSCLE IS KEY MUSCLE THAT HELPS TO SUPINATE - KEY SUPINATOR AT a flexion degree of 90 DEGREES AT ELBOW JOINT
Label this:
