Anatomy - Exam 2

• clavicle
• scapula
• humerus

• scapulothoracic
• sternoclavicular
• acromioclavicular
• glenohumeral

sternoclavicular

provides mobility and stability for the UE

• connects manubrium and rib one to the acromion of scapula
• acts as a strut to hold UE free of trunk
• shaped like an "s" to improve strength
• transmits force from UE to axial skeleton

• medial 2/3 and lateral 1/3 meet (where clavicle starts to flatten)
• falls directly onto shoulder or onto outstretched hand
• lateral fragments tend to drop down
• medial piece help up by SCM

• covers about ribs 2-7
• concave anteriorly
• convex posteriorly
• connects to clavicle at AC joint and humerus at GH joint

AC joint

GH joint

• head articulates at the glenoid fossa of the scapula
• greater and lesser tubercles are separated by the bicipital groove
• has anatomical and surgical neck

• occur around the surgical neck
• children may fracture epipheseal plate
• neres and circumflex artery are at risk when Fx

• apex: convergence of clavicle, scapula and rib 1
• base: fascia and skin of armpit
• anterior wall: pectoral muscles, anterior axillary fold - pec major
• posterior wall: scapula and subscapularis muscle, posterior axillary fold - latissimus dorsi and teres major
• lateral wall: humerus
• medial wall: ribcage
• neurovascular bundle: brachial plexus runs through the axilla

• brachiocepahlic: neck (big arch)
• subclavian: under clavicle
• axillary: into armpit
• superior thoracic: towards ribs
• thoracoacromial: towards acromion
• lateral thoracic: outside of ribs
• subscapular: between superior and lateral thoracic
• ant/post humeral circumflex: blood to head of humerus

• scapulothoracic joint
• articulations of scapula and thorax
• not a true anatomic joint
• movments are linked to SC and AC joint
• movment available at ST joint
• --elevation/depression
• --abduction/adduction (protract/retract)
• --upward/downward rotation
• glenoid is source of reference
• protected by muscle
• --keep scapula following the contour of thorax as it moves

60 degrees

to keep glenoid fossa and head of humerus aligned and provide stability

• coordinated movment of the GH and ST joint
• rhythm occurs at a 1:2 ratio
• --for every 3^o of movement, 1^o is generated by ST joing and 2^o by the GH joint
• GH joint always moves first
• --1st 60^o in flexion
• --1st 30^o in abduction
• whether it is in the 1st 30^o of GH abduction or its the fors 60^o in flexion, the scapula is fixating itself in that it will proide a good BoS for furthuer motion

• winging: lateral tilt
• movement of the vertebral border of the scapula away from the thorax
• tipping: upwards tilt
• movement of the inferior angle of scapula away from the thorax

• sternoclavicular joint
• only bony attachment of the shoulder girdle to the axial skeleton
• plane synovial joint with 3 DoF
• --elevation/depression
• --protraction/retraction
• --rotation
• has sternoclavicular disc (fibrocartilage) to increase the contact of fairly inconfruent surfaces and acts as pivot point for movement and also help with force absorption
• convex and concave joint surfaces allow for elevation/depression and protraction/retraction

• anterior sternoclavicular
• posterior sternoclavicular - check ant/post movment of head of clavicle
• costalclavicular - check elevation and superior glide
• interclavicular ligament - check depression and downward glide

• acromioclavicular joint
• lateral end of clavicle and acromion process of scapula
• plane synovial joint with 3 DoF
• --small gliding and rotating movements
• maintains connection between clavicle and scapula
• helps scapula respond to movment and tild the glenoid cavity up or down
• also allows for winging or tipping

• helps maintain stability
• superior acromioclavicular
• inferior acromioclavicular: controls horizontal stability
• coraclavicular: connects clavicle and coracoid process
• --divided into 2 parts - trapizoid (lateral) and coronoid (medial)
• coracoacromial ligament

• glenohumeral joint
• ball and socket joint with 3 DoF
• --flexion/extention
• --rotation in horizontal plane
• --rotation in the sagittal plane
• humeral head is at an angle to shaft of bone (angle of inclination) and points slightly posterior (angle of torsion)
• capsule is taut superiourly and slack inferiorly and is reinforced to most on the anterior side
• capsule is tighet when arm is down
• anterior capsule is arranged in a "z" pattern
• --superior, middle, inferior
• coracohumeral ligament: connects coracoid process with greater tubercle and help support humerus against pull of gravity

glenoid labrum is a connective tissue attached to edges of the glenoid cavity that serves to deepend to articular surface

seperates supraspinatus tendon and head of humerus from the acromion process

seperates scapula from ribcage

• formed by acromion andcoracoacromial ligament
• protects the trop of humeral head, the muscles, tendons, and bursae from trauma from above like the strap of a bookbag
• also helps prevent the head of the humerus from slidingg superiorly if pushed upward
• aka: 5th joint of shoulder

• pectorialis major
• pectorialis minor
• subclavius
• serratus anterior

• origin: outersurface of upper margin of ribs 3-5
• insertion: coracoid process
• action: lowers lateral angle of scapula, pulls shoulder forward
• innervation: medial pectoral
• blood supply: thoracoacromial

• origin: sternal half of clavicle, sternume to 7th rib, cartilages of the true ribs, aponeurosis of external obliques
• insertion: lateral lip of bicipital groove of humerus
• action: adducts shoulder, flexes and medially rotates
• innervation: medial and lateral pectoral
• blood supply: thoracoacromial

• origin: upper border of 1st rib and its cartilage
• insertion: groove on under surface of clavicle
• action: draws clavicle down and forward
• innervation: nerve to subclavius
• blood supply: thoracoacromial

• origin: outersurface of upper 8 or 9 ribs
• insertion: costal surface of vertebral border of scapula
• action: abducts and upwardly rotates scapula and raises ribs when scapula is fixed
• innervation and blood supply: long thoracic

• trapezius
• latissimus dorsi
• levator scapulae
• rhomboid major
• rhomboid minor

• upper fibers elevate scapula
• middle bifers retract scapula
• lower fibers upwardly rotate the scapula
• origin: external occipital protuberance, superior nuchal line, nuchal ligament from spines of C7-12
• insertion: lateral 1/3 of clavicle, spine of scapula, acromion
• action: adducts scapula, tilts chin
• innervation: spinal accessory
• blood supply: descending scapula

• orgin: spines of T6-16, lumbodorsal fascia, crest of ilium, muscular slips of lower 3 or 4 ribs
• insertion: floor of bicipital groove or humerus
• action: adducts, extends, and medially rotates shoulder
• innervation: thoracodorsal
• blood supply: descending scapula, subscapular

• origin: transverse process of C1-C4
• insertion: vertebral border of scapula between superior angle and root of spine of scapula
• action: elevates scapula, ipsilateral lateral neck flexion if scapula is fixed
• innervation: sorsal scapula
• blood supply: descending scapula

• origin: spinous process of T2-T5
• insertion: medial border of scapula between spine and inferior angle
• action: adduction and downward rotation of scpula
• innervation: dorsal scapular
• blood supply: descending scapula

• origin: ligamentum nuchae, sping of C7-T1
• insertion: root of spine of scapula
• action: adduction and downward rotation of scapula
• innervation: dorsal scapular
• blood supply: descending scapular

traps and rhomboids combine to stabilize the scapula

• deltoids
• teremes major

• origin: lateral 1/3 of clavicle
• insertion: deltoid tuberosity
• action: flexion and medial rotation of arm

• origin: acromion
• insertion: deltoid tuberosity
• action: abduction of the GH joint

• origin: spine of the scapula
• insertion: deltoid tuberosity
• action: extension and lateral rotation of humerus

• origin: dorsal surface of inferior angle of the humerus
• insertion: medial lip of bicipital groove
• action:adductss, medially rotates and extends arm
• innervation: lower subscapular
• blood supply: scapular circumflex

• teres minor
• supraspinatus
• infraspinatus
• subscapularis

• origin: upper 2/3 lateral border of scapula
• insertion: lowest facet of greater tuberosity below infraspinatus
• action: lateral rotation of GH joint
• innervation: lower subscapular
• blood supply: scapular circumflex

• origin: supraspinous fossa of scapula
• insertion: superior facet of greater tuberosity
• action: assist deltoid in abducting upper arm, fixates head of humerus in glenoid cavity, secondary external rotation of head of humerus
• innervation: suprascapular

• origin: infraspinous fossa of scapula
• insertion: middle facet of greater tuberosity
• action: ER
• innervation: suprascapular
• blood supply: suprascapular and scapular circumflex

• origin: subscapular fossa
• insertion: lesser tuberosity and capsule of shoulder joint
• action: medially rotates humerus, draws if forward and down when raised
• innervation: upper and lower subscapularis
• blood supply: lateral thoracic and subscapularis

• flexion/extension
• abduction/adduction
• internal/external rotation

• upward and downward rotation
• rotation in horizontal plane
• reotation in sagittal plane

• elevation/depression
• protraction/retraction
• upward and downward rotation

• elevation/depression
• protraction/retraction
• rotation

circumflex artery