Lecture 21 - Pectorial Girdle and Shoulder Flashcards
Upper limb functions
Proximal (larger) muscles position hand - for example bringing closer to body when eating or for when throwing a ball
Note how mobile the upper limb is as compared to the lower limb
Distal (smaller) muscles for fine motor movements
Locomotion - when you are younger this is crawling, as you are older this is for climbing for example
Upper limb
shoulder
arm
forearm
hand
Area between shoulder joint and elbow joint is
the arm
Are between the elbow joint and the wrist joint is
the forearm
Muscles anterior in the upper limb do
flexion
Muscles posterior in the upper limb do
extension
Arteries of the upper limb
Aorta to subclavian to axillary (which passes through the medial part of the arm) to brachial (brachial means arm) and goes through the cubital fossa and the brachial artery divides into 2 to form the radial and ulnar artery
Deep veins run parallel with the arteries, and have the same name as the arteries
Superificial palmar arch and deep palmar arch
Superficial palmer arch is formed by ulnar artery and superficial branch of radial artery
Deep palmar arch is formed by the radial artery and deep branch of the ulnar artery
Superficial veins of the upper limb
Located at the superficial fascia
Dorsal venous arch to basilic (on the medial side) to cephalic (runs along lateral part of arm and forearm)
Cephalic and basilic connection at the median cubital vein (blood test common place for it)
Supinated =
palm up
Pronated =
palm down
Venepuncture
- Often done for blood collection or intravenous fluid/drug administration
- Commonly done through the median cubital vein (MCV)
- MCV connects the basilic vein to the cephalic vein
Pulse locations for upper limb…
Axillary pulse Brachial pulse in midarm Brachial pulse in the cubital fossa (needs extension of elbow because it means that the tendon moves out of the way, tendon is in the way during flexion) Radial pulse in distal forearm Ulnar pulse in distal forearm Radial pulse in the anatomical snuffbox
3 Plexuses in the body …
Cervical – supplying the neck
Brachial – supplying upper limb
Lumbosacral – supplying lower limb (lumbar plexus and sacral plexus grouped together)
Brachial plexus innervates
the upper limb
Brachial plexus is formed from
the anterior rami of C5-T1 spinal nerves
Main branches of the brachial plexus
- Axillary
- Radial
- Musculocutaneous
- Median
- Ulnar
Axillary branch of brachial plexus
Axillary: supplies deltoid + teres minor
Radial branch of brachial plexus
Radial: supplies posterior arm and forearm muscles
Musculocutaneous branch of brachial plexus
Musculocutaneous: supplies biceps
brachii, brachialis, coracobrachialis (BBC)
MC supplies BBC
On the anterior side
Median + Ulnar branch of brachial plexus
Median+Ulnar:supply anterior forearm and hand muscles
Both run on medial side
Median - supplies most of the forearm muscles and some of the hand muscles (runs under the carpal tunnel)
Ulnar - supplies some of the forearm and most of the hand muscles (pinched when you hit your ‘funny bone’
Pectoral girdle made of
scapula and clavicle
Function of the pectoral girdle
Connect axial skeleton to the appendicular skeleton //Attach the upper limb to axial skeleton
Ligaments of the pectoral girdle
Limit movement
Provide stability
Pectoral girdle provides
protection for deep structures - VAN
Sternal end of clavical
medial
attaches to the sternum which is a bone in the middle of the rib cage
Subclavian groove
for muscle called subclavius
Conoid tubercle
For conoid ligament
Trapezoid line
Trapezoid ligament attaches here
Clavicle fracture
- Commonly due to force from falling onto outstretched limb
- (usually) Medial fragment is pulled superiorly by sternocleidomastoid (muscle)
- Lateral fragment drops because of gravity (may also be pulled medially by pectoralis major)
Glenoid fossa
Comes in contact with the humerus to form the shoulder joint
Subcapsular fossa
For subscapularis
SMooth surface
Superior angle
for levator scapulae
Function of this muscle is to help elevate the scapula
Spine of scapula
splits scapula into 2 regions - supraspinous fosaa and infraspinous fossa
Supraspinous fossa
for supraspinatus
Above spine of scapula
Infraspinous fossa
For infraspinatus
Below the spine of the scapula
Medial border
for rhomboids which is a muscle that is involved with retraction of the scapula
Scapula movement =
Elevation
Depression
Upward rotation - inferior angle is moving up
Downward rotation - moving back to the medial side
Protraction - move scapula forward
Retraction - move scapula back
When do we protract scapula?
Protraction is when you are moving the scapula forward
Push ups, pushing against something/someone you are protracting your scapula
Joints of the pectoral girdle
Sternoclavicular joint
Sternoclavicular joint
- Saddle synovial joint, allowing biaxial movement (saddle shaped heads allows movement in two different planes)
- Has an articular disc
Inflammation at this joint will impact on arm movements
Sternoclavicular joint
Synovial joint with a fibrocartilage disc that seperates the joint into 2 compartments
Sternal angle
Important landmark for clinicians
Acromioclavicular joint
- Synovial plane joint, allowing sliding movement
- Has an incomplete articular disc
- Extrinsic ligaments help stabilize the joint - lots of ligament support - acromioclavicular, coracoclavicular (coronid and trapezoid), coracoacromial
Plane joints usually uniaxial permit gliding or sliding movements
Key ligaments of pectoral girdle
Coracoclavicular
Acromioclavicular
Coracoacromial
Dislocation of the acromioclavicular joint
Common in contact sports (e.g., hockey, martial arts) or fall on shoulders
Ligament can rupture
Glenohumeral joint
Synovial ball and socket joint
• Head of the humerus
• Glenoid fossa of the scapula
Wide range of movement - flexion, extension, adduction, abduction, circumduction, medial rotation, lateral rotation
Relatively unstable and requires external stabilization from:
• Ligaments and muscles
• Glenoid labrum ( increases concavity) - helps increase concavity of joint, increase surface area so it can help to stabilise the humerus in this area
• Capsule (taut superiorly)
Dislocation of glenohumeral joint
Dislocation mostly happens inferiorly
Tends to because …
1 - Bony structures above humerus (acromion and clavicle, therefore easier to occur inferiorly), tendon of the biceps is also above the humerus
2 - Muscles anteriorly, muscles and bone (scapula) posteriorly
3 - thinner and weaker capsule inferiorly
This prevents the humerus from going anteriorly and posteriorly so therefore dislocaiton happens inferiorly
