Clavicular Head (from med. ½ of clavicle) ® ant. lamina of insertion into bicipital groove
Sternocostal Head (from manubrium & body of sternum) ® intermediate lamina
Posterior fibres of S-C head ® posterior lamina inserting into capsule of shoulder jt.
Med pectoral n pierces (and supplies) pec minor --> enters deep surface of pec major.
Lat pectoral nerve (C5,6,7) pierces clavipectoral fascia medial to med pect nerve ® deep surface of PM
Only upper limb muscle supplied by all five segments of brachial plexus.
Arises from 3rd-5th ribs ® coracoid process
Impt landmark for axillary artery and brachial plexus
medial pectoral nerve C8,T1
Passing inwards: cephalic vein and lymphatics
Passing outwards: thoracoacromial vessels and lateral pectoral nerve.
Costochondral junct of 1st rib ® inf surface of clavicle. Enclosed by clavipectoral fascia.
Upper trunk of brachial plexus ® n to subclavius C5, C6
Not derived from limb bud myotomes so
not supplied by brachial plexus.
Origin from sup nuchal line ® all cervical and thoracic vertebrae. Insertion: lat 1/3 of clavicle, acromion and spine of scapula.
Spinal part of CN XI, = C1-5, + branches of
cervical plexus; enters from posterior triangle of neck
Wide origin: spines of T7 ® T12 and lumbar fascia (hence all lumbar & sacral spines and iliac crest)
upper edge runs horizontally under lower trapezius, over inferior angle of scapula (may get slips from here)
reinforced by fibres from lower four ribs (interdigitate with EO); forms lumbar triangle.
Converges as lower border of axillary fold; spirals around lower border of teres major (397)
Narrow insertion: 3cm wide, inter intertubercular sulcus
because of spiral, lowest fibres insert highest and vice-versa (like pec major)
Thoracodorsal n C6-8 from post cord of BP, runs down medial-posterior wall of axilla ® med surface of LD; vulnerable in axillary clearance.
Extends shoulder joint, medially rotates humerus (fold arms behind back)
Powerful adductor with pec major (major climbing muscle)
Assists in deep inspiration
Compresses lower thorax eg in sneezing
Only upper limb to have pelvic attachment, \ useful in spinal patients
Test: abduct arm to right angle, then adduct against resistance; feel bulk below post axillary fold.
Minor: C7+T1 (spines) ® medial scapula at level of spine.
Major: T2-5 (spines) and intervening supraspinous ligaments ® medial scapula b/n spine and inf angle.
Draw scapula medially and upwards (retract / square shoulders)
Hands on hips, push elbows back against resistance; palpate, observe for symmetry.
Strap on floor of posterior triangle.
Arises: C1-2 (transverse processes) and C3-4 (posterior tubercles)
Inserts: medial border of scapula superior to spine
Supply: C3-4 (cervical plexus muscle), reinforced from dorsal scapula n.
Action: elevates scapula (with upper trapezius), and can laterally rotate neck.
= med wall of axilla; clothes sidewall of
thorax; covered by pec major anteirorly.
Arises: digitations from upper 8 ribs, over its 1st digitation runs the neurovascular bundle to axilla.
Inserts: costal angle of scapula, ® 1st & 2nd digitations to upper angle, next 2 along vertebral border, lowest 4 at inferior angle
C5-7 roots of BP ® long thoracic n, runs in mid-axillary line on surface of SA (ant to thoracodorsal)
Protracts the scapula, elongating the upper limb
Rotates scapula laterally, (more than trapezius), raising the arm above the shoulder
Apposition of scapula surface to the chest wall.
Outstretched hand pushed against wall ®
Commonly divided in thoracotomy incisions but is the lower portion of it; so little denervation usually recognized.
Manubrium meets medial clavicle (and adjoining first costal cartilage below is attached, though this is a simple firm primary cartilaginous attachment to manubrium).
Intervening disc of fibrocartilage separates the joint into two cavities
a capsule invests the joint like a sleeve; the disc attaches to this, to clavicle ends and to 1st CC.
Ant and post sternoclavicular ligs thicken the capsule.
synovial but not hyaline cartilage; atypical as is fibrocartilage.
Only the lower half of the clavicle meets the joint
interclavicular ligament joins two clavicle ends across the jugular notch
costoclavicular ligament binds clavicle to 1st rib and 1st CC in 2 laminae: anterior lamina run upwards and laterally posterior run upwards and medially (like EO / IO)
very strong: the major stabilising factor of the SC jt ; transfers strain instead to below.
Nerve supply: C3,C4 from cervical plexus via medial supraclavicular nerve.
Reciprocal (opposite) movement to acromial end of clavicle and to forward and backward shoulder movement (typically occur between manubrium and the disc, ie disc moves with clavicle)
- in rotary movement of arm, also moves reciprocally at this point, passively secondary to transferred force from coracoclavicular ligaments
Synovial (but again atypical as covered in fibrocartilage)
Encapsulated by a fibrous sleeve, thickened on top as the acromioclavicular ligament.
an incomplete disc of fibrocartilage hangs down into the upper half of the cavity
conoid: inverted cone, coracoid to conoid tubercle under clavicle
trapezoid: coracoid to trapezoid ridge under clavicle
Nerve supply: suprascapular nerve C5-6 (and maybe C4)
Movements: passive. Three groups of movement combined in varying proportions, each transmitted through ligaments to clavicle at both ends:
protraction and retraction: acromion tip glides to-and-fro on tip of clavicle
rotation: scapular can rotate 60o. 20o from scapula, rest from clavicle rotation.
elevation and depression: medial end of clavicle moves but AC jt moves little.
Stability: coracoclavicular ligament.
the upper limb simply hangs off from conoid assisted by deltoid, triceps, biceps
forces ® glenoid ® clavicle via trapezoid ligament ® 1st rib via costoclavicular ligament
hence in FOOSH, no strain occurs at either end of the clavicle, rather in the middle.
Triangle of Auscultation
Upper horizontal border of Lat dorsi, lat trapezius, vertebral border of scapula (floored by fascia)
- deep to here is cardiac orifice of stomach, where succussion splash heard