Ch._18_Shoulder_Joint_Complex--2024

Shoulder Joint Complex

Overview

• Author: Marlene Carmona, DPT, MSPT

• Chapter: 18

• Copyright: 2005, Elsevier Ltd.

Bones Involved in the Shoulder Joint Complex

• Humerus

• Scapula

• Clavicle

• Sternum

Joints of the Shoulder Joint Complex

• Sternoclavicular (SC) Joint

• Acromioclavicular (AC) Joint

• Glenohumeral (GH) Joint

Sternoclavicular (SC) Joint

• Type: Saddle Synovial Joint

• Features:

  • Thick fibrous capsule

  • Reinforced by anterior and posterior sternoclavicular ligaments

  • Contains articular disk in joint space

• Connection: Proximal end of clavicle with the manubrium

Acromioclavicular (AC) Joint

• Connection: Distal end of clavicle with the acromion of the scapula

• Type: Plane synovial joint with articular disk

• Features: Fibrous joint capsule, reinforced by ligaments

AC Joint Ligaments

• Superior Acromioclavicular Ligament: Reinforces AC joint superiorly

• Inferior Acromioclavicular Ligament: Reinforces AC joint inferiorly

• Coracoclavicular Ligament: Contains two parts:

  • Trapezoid (lateral)

  • Conoid (medial)

Glenohumeral (GH) Joint

• Type: Ball and Socket Synovial Joint

• Connection: Humeral head with glenoid fossa/cavity

• Key Features:

  • Glenoid is shallow, deepened by the glenoid labrum

  • Labrum is fibrocartilaginous

GH Joint Ligaments

• Joint Capsule: Surrounded by a loose fibrous tissue

• Glenohumeral Ligaments: Includes three thickened areas forming a "Z" shape on the anterior wall of the joint capsule:

  • Superior GH ligament

  • Middle GH ligament

  • Inferior GH ligament

• Function: Prevent extreme external rotation

Additional GH Joint Ligaments

• Coracohumeral Ligament: Connects coracoid to the superior part of the joint capsule and the anatomical neck of the humerus

• Transverse Humeral Ligament: Thicken joint capsule, prevents bowing of the long head of the biceps tendon

• Coraco-Acromial Ligament: Protects GH joint superiorly

Clinical Correlations

• Reading Recommendations: Rotator cuff tears and AC joint injuries

• Clarifications: Mistake noted in mnemonics in Tables 18.1 on pages 194 and 206

• Exam Note: Movement measurements not tested in this course, important for summer mobilizations

Review and Study Tips

• Lab Handouts: Review and create outlines for Chapters 17 and 18, helpful for exam preparation

• Folders: Available for further practice and reference

Types of Joints Overview

• Synarthrosis (None): Fibrous Suture, e.g., bones in skull

• Syndesmosis (Slight): Fibrous Ligamentous, e.g., distal tibiofibular joint

• Amphiarthrosis (Little): Cartilaginous, e.g., symphysis pubis

• Diarthrosis (Free): Synovial, e.g., hip, elbow, knee

Joint Types by Motion

• Nonaxial: Linear movement; example: intercarpal joints

• Uniaxial: One plane; e.g., elbow, knee

• Biaxial: Two planes; e.g., wrist

• Triaxial: Three planes; e.g., shoulder

Synovial Joint Structure

• Components:

  • Bones

  • Ligaments

  • Joint Capsule

  • Synovial Fluid

  • Cartilage

  • Muscles

  • Bursae

Synovial Joint Structure Details

• Capsules: Protective layers surrounding joints; two layers (outer for support, inner with synovial membrane)

• Synovial Fluid: Lubricates cartilage, reduces friction, provides nutrients

• Cartilage Types:

  • Hyaline (articular)

  • Fibrocartilage (shock absorption)

  • Elastic (flexibility)

• Muscles: Attach via tendons, provide movement

• Bursa: Sacs reducing friction in areas of high stress

Quote of the Day

• "Tis better to have loved and lost than never to have loved at all." -- Alfred Lord Tennyson (1809-1892)

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