pectoral girdle, elbow and shoulder Flashcards
pectoral girdle attachment
- attachment to axial
- only 1 p.o.a to the axial skeleton at the sternoclavicular joint- medial end of the clavicle articulates w manubrium of the sternum
- scapula doesn’t directly attach to the axial skeleton via joint but connects to back of the thorax by muscles- allows 4 large range of movement
- ligs provide stability and support to joints in pec girds
what is pec gird
clavicle n scapula
clavicle
- long bone
- lies horizontally between scapula n sternum
- 2 joint- ACJ (acromioclavular joint) and SCJ (sternoclaviculr joint)
- articulates medially with the sternum at SCJ
- articulates laterally with acromion at ACJ
- serves as muscular attachment point
- one of the most fractured bones in body
scapula
- large, triangular flat bone that connects the trunk to the upper limb
- the posterior bone of pectoral girdle sitting across the back of the thoracic cage, superiorly
- major features= spine, coracoid process, acromion process and glenoid cavity
- got 3 borders n angles (it triangle): superior, medial n lateral and superior, inferior and lateral
- 3 fossas= supraspinous, infraspinous, subscapular
- has a suprascapular notch
acromion process
a continuation of the scapula spine which passes laterally over the shoulder (Glenohumeral) joint
- ACROMION: of the scapula extends from the scapular spine to articulate with the clavicle to form the Acromio-clavicular joint
spine of scapula
oblique ridge of bone that passes across the upper posterior part of the scapula
coracoid process
small hook-like structure which points laterally forward, on the edge of the superior anterior portion of the scapula
- for muscle attachments
glenoid cavity
- a very shallow articular surface that articulates with the humeral head
sternoclavicular joint
- where pec girdle joins to the axial skeleton
- Strong synovial saddle joint
- Contains a fibrocartilaginous articular disc
- Robust ligamentous and muscular support
-sternoclavicular ligament= reinforces the joint capsule and prevents forward/ backward movement - costoclavicular ligament= connects the clavicle to the first rib and prevent elevation of clavicle
- interclavicular ligament= runs along top of sternum, connects the 2 clavicle to prervnt excessive downward movement
Acromioclavicular joint
Small synovial plane joint
Allows scapula and clavicle to move together during arm movement
Strong ligamentous support
Can have a small fibrocartilaginous disc
Relatively prone to injury
- acromioclavicular ligament: keeps joint capsule together and connects acromion n clavicle together
- coracoclavicular ligament: connect coracoid process to the clavicle to prevent displacement
labrum of the shoulder
labrum: fibrous cartilage and deepens the socket and provides additional stability = different movement allowed
glenohumeral joint
- synovial joint of the shoulder has a fibrous articular capsule that completely encloses the joint and extends from the glenoid cavity to the neck of the humerus
- on surface, joint is lined with synovial membrane= provide synovial fluid= lubricates joint and reduce friction
- it has 5 ligaments, a glenoid labrum, and four bursae (act as cushions) to alleviate friction
humerus
- largest and longest bone in upper limb
- articulates with scapula at glenohumeral joint + radius and ulna at the elbow joint
major features of humerus
head:
- rounded part at the proximal end
- fits into the glenoid fossa of scapula
anatomical neck:
- separates the head of the humerus from the greater and lesser tubercles
tubercles (greater and lesser):
- greater is more lateral and larger
intertubercular groove:
- dep groove between tubercles
- houses the tendon of long head of bicep brachii, provides poa for major muscle groups of shoulder
surgical neck:
- site of fractures that require surgery
shaft:
- cylindrical at proximal end but becomes more triangular as it flattens and broadens at the distal end
- contains a central medullary cavity filled with bone marrow
deltoid tuberosity:
- attachment for deltoid muscles
- on posterior side there is radial groove that contain the radial nerve
distal end of humerus
capitulum:
- rounded notch that articulates with radius at the elbow joint
trochlea:
- articulates with the ulna allowing for flexion and extension of elbow
median and lateral epicondyle:
- bony protrusions
- attachment point for muscles n ligaments
olecranon fossa:
- deep indentation on posterior aspect that accommodates the olecranon (bony prominence of the ulna when elbow is extended)
coronoid fossa:
- small indentation on anterior aspect that receives the coronoid process of the ulna during flexion
- large depression on back of humerus
the elbow
Essential for bending the arm and rotating the forarm
3 points of articulation:
Humeroradial joint:
Capitulum with radial head
Humeroulnar joint:
Trochlear with trochlear notch
Proximal radioulnar joint:
Head of the radius with the radial notch
ligaments of elbow joint
median collateral ligament:
- extends from the medial epicondyle of the humerus to the coronoid process and the olecranon of the ulna
- thick triangular ligament
lateral collateral ligament:
- strong triangular ligament
- extends from lateral epicondyle of the humerus to the annular ligament of the radius and the radial notch of the ulna
- annular ligament completely encircles the head of the radius and hold it into eh radial notch of the ulna
ligaments of shoulder joint
5 ligaments:
Coracohumeral
(to greater tubercle)
- extends from coracoid process in scapula to greater tubercle of humerus= split into anterior and posterior divisions by the biceps tendon
S, M, I glenohumeral
(to lesser tubercle)
- mobile and least stable joint- commonly dislocated synovial joint
- extend from the glenoid cavity to the lesser tubercle and anatomical neck of humerus
Transverse humeral:
- connects greater to lesser tubercle
-keeps the tendon of the long head of the bicep in the bicipital groove
acromioclaviclaular ligament:
- connects acromion to clavicle
coracoclavilcuar ligament:
- connects coracoid process to clavicle
coracoacreomion ligament:
- connects coracoid to acromion
labrum:
- fibrous ring around the glenoid cavity
muscles of shoulder
- there are superficial and deep muscles that connect the scapula and clavicle to the trunk
- also superficial and deep muscles connect the clavicle, scapula and trunk to the proximal end of the humerus
- four rotator cuff muscles which connect
the scapula to the humerus (most important)
muscles that connect the scapula and clavicle to the trunk
function by controlling the movement of the scapula and the humerus:
trapezius:
- superficial, flat and broad
- covers the upper back and part of neck and shoulders
- inserts on the lateral third of the clavicle, the acromion and scapula spine
levator scapulae:
- deep
- lies in posterior triangle of neck
- attaches to medial surface of the scapula and elevates
rhomboid (major and minor):
- deep
- attached to medial border of the scapula
- retract and stabilise the scapula, pulling it towards the spine
muscles that connect the clavicle, scapula, and trunk to the proximal end of the humerus
3 superficial and 2 deep
superficial:
pectoralis major
deltoids
latissimus dorsi
deep:
pectoralis minor
teres major
superficial muscles that connects c,s and t to proximal end of h
pectoralis major:
- provide movement and support in the anterior part of the shoulder
- 2 heads: originates from midline of clavicle and sternum
- inserts into humerus and ribs
- allow 4 shoulder flexion (horizontal, upward diag and downward diag
latissimus dorsi:
- originate from lumbar vertebrae and pelvis
- inserts into the Intertubercular groove groove of humerus
- allow 4 shoulder adduction and extension
- keeps the inferior angle of scapula against the chest
deltoid:
- provides the characteristic shape of the shoulder
- originates in 3 portions, anterior, middle, and posterior
- anterior portion originates from anterior superior surface of the clavicle
- middle from the acromion process
- posterior from the lower border of crest of spine of scapula
- these 3 insert into deltoid tuberosity of the humerus
deep muscles that connect c,s and t to the proximal end of the h
pectoralis minor:
- small deep triangular muscle that passes as 3 muscular slips from the thoracic wall to the coracoid process
- draws scapula forwards and downwards and raises the ribs in inspiration (draw air in lungs)
teres major:
- originate from posterior surface of inferior angle of scapula
- attaches medial lip to the middle lip of the intertubercular groove
- extends and medially rotates the humerus
rotator cuff muscles
- muscles that connect the scapula to the humerus
- muscles and associated tendons surround the shoulder joint and all originate from the scapula and attach either to the greater or lesser tubercle of the humerus
- stabilises point and allow 4 wide range of movement
- work together to keep head of humerus within the shoulder socket of the glenoid fossa
- rotator cuff tendons attach 2 deep rotator cuff muscles
describe rotator cuff muscles
supraspinatus- originates in supraspinous fossa of scapula/ inserts on the superior facet of the greater tubercle of the humerus / initiates abduction of the arm and stabilises the joint while helping to hold head of humerus in place
infraspinatus- originates and sits in the infraspinatus fossa of scapula (below spine of scapula) / inserts on middle facet of greater tubercle / externally rotates the arms and helps stabilise shoulder joint
teres minor - originates from lateral border of the scapula / inserts into lower facet of the greater tubercle / externally rotates the arm / assists in adduction and stabilisation
subscapularis- originates in subscapularis fossa of scapula (front surface of scapula) / inserts onto lesser tubercle / internally rotates the arm and help w stabilisation
vascular supply to pectoral gridle summary
intricate network of blood vessels ensures that the shoulder girdle has the necessary blood flow for proper function and muscle activity
Arteries:
- blood supply to the shoulder girdle primarily comes from the subclavian and axillary arteries and their branches, which supply the bones, muscles, and joints of the shoulder
Veins:
- subclavian and axillary veins, along with their tributaries, drain the blood from the shoulder region back to the heart
major arties of the shoulder
- oxygenated blood delivered via SUBCLAVIAN (primary source)
- run under clavicle
- becomes AXILLARY ARTERY AT THE OUTER BORDER OF THE FIRST RIB
- continues until the lower border of the teres major muscle where it becomes the BRACHIAL ARTERY
key branches of axillary artery that supply shoulder are: thoracoacromial artery, lateral thoracic artery, subscapular artery, circumflex scapular artery and the thoracodorsal artery
major veins of the shoulder
veins of the shoulder follow the path of the arteries and drain into larger veins that eventually return blood to the heart.
Subclavian Vein:
- subclavian vein runs parallel to the subclavian artery, draining blood from the arm, shoulder, and neck
- It joins the internal jugular vein to form the brachiocephalic vein, which drains into the superior vena cava.
Axillary Vein:
- primary vein draining the shoulder area
- It is a continuation of the brachial vein, and it runs alongside the axillary artery.
It receives blood from various tributaries, including:
Cephalic vein, Basilic vein and branches from the circumflex humeral veins
major arteries of the elbow summary
- provided mostly by the brachial artery (with branches), radial artery, and ulnar artery (forms extensive network of arteries around the joint)
- blood vessels join together to ensure that the elbow joint receives an adequate blood supply during movement
description of major artery of elbow
MEDIAL SIDE:
- superior ulnar collateral artery from brachial artery joins with the posterior recurrent artery from the ulnar artery
- inferior ulnar collateral artery joins with the anterior ulnar recurrent artery
LATERAL SIDE:
- radial collateral artery meets with radial recurrent
- medial collateral artery joins with the interosseous recurrent artery
major veins in elbow
return deoxygenated blood from elbow to heart & drain muscles, bones and other structures around the elbow joint & closely accompany the arteries
SUPERFICIAL:
- cephalic, basilic, median cubital
- join superficial tissue of the elbow
- visible under skin (cannulation)
DEEP:
- brachial, radial, ulnar and interosseous
- join deeper structures
- from primary root venous= drain back to the heart
major innervation of the shoulder
BRACHIAL PLEXUS
- supply motor and sensory function to the shoulder joint and surrounding structures (forearm and hand)
- gives rise to 7 important nerves
description of the major innervation of shoulder
- suprascapular innervates the supraspinatus and the infraspinatus
- dorsal scapula innervates the rhomboids and levator scapulae
- long thoracic nerve innervates the serratus anterior muscle
- thoracodorsal nerve innervates the latissimus dorsi muscle, scapula nerves and the medial and lateral pectoral nerves
- musculocutaneous nerve innervates the anterior compartment of the arms at the biceps and provides sensory info to the lateral forearm
- axillary nerve innervates the deltoid
- radial nerve innervates the extensor muscles
- median nerve innervates most of the flexor muscles
- ulnar nerve innervates some of the forearm muscles and most intrinsic hand muscles 2 provide sensation
fat pads
- small protective cushions made of adipose tissue located within elbow joint
- fibrous joint capsule at the side of your membrane
- reduce friction and assist w smooth movement
3 fat pads in elbow:
- anterior, located in coronoid fossa of humerus
- posterior fat pad located in the olecranon
- supinator fat pad located near the supine muscle in the lateral part of elbow
shoulder- dislocation
- 90% of dislocations are anterior
- Common sports injury
- Causes lots of soft tissue injury
- Lots of vulnerable structures nearby including main blood vessels and nerves
shoulder- fracture
- can be caused by fall from height/ traffic accident
- involves humeral head, the greater tuberosity and the lesser tubercle of the humeral shaft
clavicle - fracture
- normally treated without surgery dependent on displacement
- “cyclists” fracture
calcific tendonitis
- calcium salts deposited in the tendons, most commonly in rotator cuff
- ## causes pain and inflammation and can limit range of movement
labral tear
- labrum of glenoid cavity can have a tear
- joint stability can be comprised
- there are different classifications of labral tear:
SLAP ; Bankart; Posterior
MRI Arthrogram (contrast injected into the joint) to image the labrum and detect tears
