upper limbs (shoulder girdle and humerus)

• Humerus


  Largest and longest bone in the upper limbs
• Humerus

  • Articulates with the scapula (shoulder blade) at the shoulder joint
• Proximal humerus


  Part of the upper arm that articulates with the scapula; makes up the shoulder joint
• Head of the humerus


  • Rounded; most proximal part
• Anatomic neck


  • Slightly constricted area; below and lateral to the head; appears as a line of demarcation between the rounded head and greater and lesser tubercles
• Lesser tubercle


  • Process below the anatomic neck on the anterior surface
• Greater tubercle


  • Larger lateral process; where the pectoralis major and supraspinatus muscles attach
• Intertubercular groove (bicipital groove)


  Deep groove between two tubercles
• Surgical neck


  • Tapered area below head and tubercles; site of frequent fractures
• Body (shaft) of the humerus


  Long; distal to the surgical neck
• Deltoid tuberosity


  • Roughened raised triangular elevation along the anterolateral surface of the body; where deltoid muscle is attached
• Shoulder girdle


  Consist of two bones - clavicle and scapula; function is to connect each upper limb to the trunk or axial skeleton
• Clavicle


  • Long bone with a double curvature; has three main parts: lateral or acromial extremity, medial or sternal extremity, and body (shaft)
• Scapula


  • Flat triangular bone with 3 borders, 3 angles, 2 surfaces
• Borders of the scapula


  • Medial border - long edge near the vertebrae
  • Superior border - uppermost margin of the scapula
  • Lateral (axillary) border - nearest the axilla (armpit)
• Lateral angle (head) of the scapula


  • Thickest part; ends laterally in the glenoid cavity (fossa)
• Scapulohumeral joint (glenohumeral joint or shoulder joint)


  Humeral head articulates with the glenoid cavity of the scapula
• Neck of the scapula


  • Constricted area between head and body of the scapula
• Body (blade) of the scapula


  Arched for greater strength
• Wing or ala of the scapula


  Thin, flat lower part of the body of the scapula
• Ventral (costal) surface of the scapula


  • Anterior surface; has a large concavity of depression called the subscapular fossa
• Spine of the scapula


  • Prominent structure on the dorsal/posterior surface; starts at the vertebral border as a smooth triangular area and continues laterally to end at the acromion
• Crest of the spine of the scapula


  • Thickened; posterior border or ridge of the spine
• Infraspinous and supraspinous fossa


  Separates the posterior surface of the scapula; serve as surfaces of attachment for shoulder muscles
• Lateral view of the scapula


  • Thin scapula looks like the letter "Y"; the upper parts of the "Y" are the acromion and coracoid process, the bottom leg is the body
• Acromion


  • Expanded distal end of the spine; extends superiorly and posteriorly to the glenoid cavity
• Coracoid process


  • Located more anteriorly in relationship to the glenoid cavity/shoulder joint
• Lateral (axillary) border of the scapula


  Thicker edge or border that extends from the glenoid cavity to the inferior angle
• Joints/articulations involved in the shoulder girdle


  • Sternoclavicular joint
  • Acromioclavicular joint
  • Scapulohumeral joint (glenohumeral/shoulder joint)
• Synovial joints


  Characterized by a fibrous capsule that contains synovial fluid
• Freely movable or diarthrodial joints


  All freely movable
• Scapulohumeral (glenohumeral) or shoulder joint


  • Articulation between the head of the humerus and the glenoid cavity of the scapula; spheroidal (ball-and-socket) joint with movements including flexion, extension, abduction, adduction, circumduction and medial (internal) and lateral (external) rotation
• Glenoid cavity


  • Very shallow, allowing freedom in mobility of the shoulder joint
• Sternoclavicular joint


  • Double plane or gliding joint; the sternal end of the clavicle articulates with the manubrium and the cartilage of the first rib
• Acromioclavicular joint


  • Small synovial joint of the plane, or gliding type; between the acromial end of the clavicle and the medial aspect of the acromion of the scapula
• Movements at the acromioclavicular joint


  1. Primary movement - gliding action between the end of clavicle and acromion

  2. Secondary movement - the scapula moves forward and backward with the clavicle