Clavicle and Scapula
Shoulder girdle = clavicle + scapula (pectoral girdle)
Clavicle: the big idea
- The only bony attachment between the trunk and the upper limb
- Palpable along its whole length
- Gentle S-shape
Clavicle: two ends
Acromial (lateral) end
- Flat
- Small oval facet for the acromion of the scapula
- Concave part, faces forward
Sternal (medial) end
- Robust, somewhat quadrangular
- Much larger facet: mainly manubrium of sternum, lesser extent first costal cartilage
- Convex part, faces forward
Surfaces
- Inferior surface, lateral third: conoid tubercle + trapezoid line, for the coracoclavicular ligament
- Surfaces and margins are roughened by muscles linking clavicle to thorax, neck and upper limb
- Superior surface is smoother than the inferior
Scapula: large, flat, triangular
3Angles
lateral, superior, inferior
lateral, superior, inferior
3Borders
superior, lateral, medial
superior, lateral, medial
2Surfaces
costal, posterior
costal, posterior
3Processes
acromion, spine, coracoid
acromion, spine, coracoid
Parts and what they do
Lateral angle
- Shallow, comma-shaped glenoid cavity
- Meets head of humerus: glenohumeral joint
Tubercles (round the glenoid)
- Supraglenoid (above): long head of biceps brachii
- Infraglenoid (below): long head of triceps brachii
Spine
- Divides the posterior surface
- Supraspinous fossa: small, superior
- Infraspinous fossa: much larger, inferior
Acromion
- Anterolateral projection of the spine
- Arches over the glenohumeral joint
- Small oval facet on its distal end meets the clavicle
Coracoid process
- Hook-like, projects anterolaterally
- Directly inferior to the lateral part of the clavicle
Notches
- Suprascapular: small, just medial to the root of the coracoid, on the superior border
- Greater scapular (spinoglenoid): between lateral angle and where the spine attaches
Surfaces and borders
| Part | Feature |
|---|---|
| Costal surface | Unremarkable; shallow concave subscapular fossa. Muscle: subscapularis. Moves freely over the thoracic wall |
| Posterior surface | Spine, supraspinous and infraspinous fossae |
| Lateral border | Strong and thick for muscle attachment |
| Medial border and most of superior border | Thin and sharp |
Flow: clavicle to scapula
Sternum (manubrium) + 1st costal cartilage
⇄
Sternal end of clavicle
Acromial end of clavicle
⇄
Acromion of scapula
Glenoid cavity
⇄
Head of humerus
Palpable on a patient
- Spine and acromion
- Tip of the coracoid process
- Inferior angle
- Much of the medial border
Remember
- Clavicle = only bony link: trunk to upper limb
- Medial end convex, lateral end concave (both forward)
- Conoid tubercle + trapezoid line → coracoclavicular ligament
- Scapula: 3 · 3 · 2 · 3 (angles, borders, surfaces, processes)
- Supra = biceps (above), Infra = triceps (below)
Made only from your textbook pages. Check labels against your book before exams.