Anatomy Lesson: Clavicle and Scapula

Overview

• Topic: Clavicle and Scapula bones
• Relevance: Part of the appendicular skeleton, forming the pectoral girdle (shoulder girdle)
• Function: Attaches the upper arm to the axial skeleton

Clavicle (Collarbone)

• Classification: Long bone
• Location: Sits horizontally on each side of the superior thorax
• Joints:
  • Acromioclavicular joint (lateral): Articulates with the scapula
  • Sternoclavicular joint (medial): Articulates with the sternum
• Landmarks:
  • Midclavicular line: Imaginary line for apical pulse assessment
  • Acromial end: Lateral, flattened, articulates with scapula (acromioclavicular joint)
  • Trapezoid line: Ridge for trapezoid ligament attachment
  • Conoid tubercle: For conoid ligament attachment
  • Costoclavicular ligament impression: For attachment to the first rib's cartilage
  • Sternal end: Medial, articulates with sternum's manubrium

Clinical Relevance

• Common fracture site for athletes

Scapula (Shoulder Blade)

• Classification: Flat bone
• Location: Posterior side, part of the posterior pectoral girdle
• Articulations:
  • Humerus (arm)
  • Clavicle
• Notable features:
  • Coracoid process: Hook-like structure for muscle and ligament attachments
  • Glenoid cavity: Depression for glenohumeral joint (ball-and-socket with humerus)
  • Tubercles:
    • Supraglenoid (above) for biceps brachii
    • Infraglenoid (below) for triceps brachii
  • Subscapular fossa: For subscapularis muscle attachment

Three Key Characteristics

• Depressions: Three fossae
• Borders:
  • Superior: Shortest, sharpest
  • Medial: Longest, toward midline
  • Lateral: Thickest, near glenoid cavity
• Angles:
  • Lateral (head of scapula)
  • Inferior: For teres major muscle
  • Superior: For levator scapulae

Posterior View of Scapula

• Spine: Ridge for trapezius and deltoid muscles
• Acromion:
  • Projects from the spine
  • Articulates with clavicle (acromioclavicular joint)
• Fossae:
  • Supraspinous fossa: Above spine, for supraspinatus muscle
  • Infraspinous fossa: Below spine, for infraspinatus muscle

Additional Resources

• Quiz: Available online for testing knowledge
• Further Learning: More videos on anatomy and physiology available