chapter 14 the shoulder complex. overview the shoulder is a complex set of articulations that work...

Download Chapter 14 The Shoulder Complex. Overview The shoulder is a complex set of articulations that work together toward the common goal of positioning the

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  • Slide 1
  • Chapter 14 The Shoulder Complex
  • Slide 2
  • Overview The shoulder is a complex set of articulations that work together toward the common goal of positioning the hand in space, which allows an individual to interact with the environment and to perform fine motor functions The shoulder is a complex set of articulations that work together toward the common goal of positioning the hand in space, which allows an individual to interact with the environment and to perform fine motor functions
  • Slide 3
  • Anatomy Although the entire shoulder complex functions as an integrated unit, it is anatomically simpler to describe each joint separately. The shoulder joint complex consists of: Although the entire shoulder complex functions as an integrated unit, it is anatomically simpler to describe each joint separately. The shoulder joint complex consists of: Three bones (the humerus, the clavicle, and the scapula) Three joints (the sternoclavicular (S-C), the acromioclavicular (A-C), and the glenohumeral (G-H) joints) One pseudojoint One physiological area
  • Slide 4
  • Anatomy Glenohumeral Joint Glenohumeral Joint The glenohumeral (G-H) joint is a true synovial-lined diathrodial joint that connects the upper extremity to the trunk, as part of a kinetic chain The GH joint is formed by the humeral head and the glenoid fossa of the scapula
  • Slide 5
  • Anatomy Glenoid fossa Glenoid fossa The glenoid fossa is flat, but is made approximately 50% deeper and more concave by a ring of fibrocartilage called a labrum The labrum, which forms part of the articular surface, is attached to the margin of the glenoid cavity and the joint capsule, and contributes to joint stability
  • Slide 6
  • Anatomy Scapula Scapula The scapula forms the base of the G-H joint It is a flat blade of bone that lies along the thoracic cage at 30 to the frontal plane, 3 superiorly relative to the transverse plane, and 20 forward in the sagittal plane The scapulas wide and thin configuration allows for its smooth gliding along the thoracic wall, and provides a large surface area for muscle attachments both distally and proximally
  • Slide 7
  • Anatomy Scapula Scapula A prominent feature of the scapula in man is the large overhanging acromion, which, along with the coracoacromial ligament functionally enlarges the glenohumeral socket The position of the acromion also places the deltoid muscle in a dominant position to provide strength during elevation of the arm Although the acromion appears to be flat, three types of acromion morphology have been described, of which the hooked is associated with an increase in rotator cuff pathology
  • Slide 8
  • Anatomy Joint capsule Joint capsule The voluminous joint capsule of the glenohumeral joint allows for large amounts of motion to occur at the G-H joint The lateral attachment of the glenohumeral joint capsule attaches to the anatomical neck. Medially, the capsule is attached to the periphery of the glenoid and its labrum The overall strength of the joint capsule bears an inverse relationship to the patients age: the older the patient, the weaker the joint capsule
  • Slide 9
  • Anatomy The greater and lesser tuberosities The greater and lesser tuberosities Located on the lateral aspect of the anatomical neck of the humerus Serve as attachment sites for the tendons of the rotator cuff muscles The greater tuberosity serves as the attachment for the supraspinatus, infraspinatus and teres minor The lesser tuberosity serves as the attachment for the subscapularis The greater and lesser tuberosities are separated by the intertubercular groove, through which passes the tendon of the long head of the biceps on its route to attach on the superior rim of the glenoid fossa
  • Slide 10
  • Anatomy The glenohumeral ligaments The glenohumeral ligaments At the anterior portion of the outer fibers of the joint capsule, three local reinforcements are present: the superior, middle and inferior G-H ligaments ( > Z = ligaments) Superior - serves to limit external rotation and inferior translation of the humeral head with the arm at the side Superior - serves to limit external rotation and inferior translation of the humeral head with the arm at the side Middle - serves to limit external rotation (Table 14-5) and anterior translation of the humeral head with the arm in 0 and 45 of abduction Middle - serves to limit external rotation (Table 14-5) and anterior translation of the humeral head with the arm in 0 and 45 of abduction Inferior - consists of an anterior band, a posterior band, and an axillary pouch with varying functions Inferior - consists of an anterior band, a posterior band, and an axillary pouch with varying functions
  • Slide 11
  • Anatomy The coracohumeral ligament The coracohumeral ligament Covers the superior G-H ligament anterior-superiorly, and fills the space between the tendons of the supraspinatus and subscapularis muscle; uniting these tendons to complete the rotator cuff in this area
  • Slide 12
  • Anatomy The coracoacromial ligament The coracoacromial ligament Consists of two bands that join near the acromion and is ideally suited, both anatomically and morphologically, to prevent separation of the A-C joint surfaces
  • Slide 13
  • Anatomy Coracoacromial Arch Coracoacromial Arch Formed by the anterior-inferior aspect of the acromion process, coracoacromial ligament, and inferior surface of the A-C joint During overhead motion in the plane of the scapula, the supraspinatus tendon, the region of the cuff most involved in the degenerative process, can pass directly underneath the coracoacromial arch During overhead motion in the plane of the scapula, the supraspinatus tendon, the region of the cuff most involved in the degenerative process, can pass directly underneath the coracoacromial arch If the arm is elevated while internally rotated, the supraspinatus tendon passes under the coracoacromial ligament, whereas if the arm is externally rotated, the tendon passes under the acromion itself If the arm is elevated while internally rotated, the supraspinatus tendon passes under the coracoacromial ligament, whereas if the arm is externally rotated, the tendon passes under the acromion itself
  • Slide 14
  • Anatomy Suprahumeral/subacromial space Suprahumeral/subacromial space An area located on the superior aspect of the G-H joint Contents include the long head of biceps tendon, supraspinatus and upper margins of subscapularis and infraspinatus, subdeltoid-subacromial bursa The space is at its narrowest between 60 and 120 of scaption
  • Slide 15
  • Anatomy The subacromial bursa The subacromial bursa One of the largest bursa in the body Provides two smooth serosal layers; one of which adheres to the overlying deltoid muscle and the other to the rotator cuff lying beneath
  • Slide 16
  • Anatomy Neurology Neurology The shoulder complex is embryologically derived from C 5-8, except the A-C joint, which is derived from C 4. The sympathetic nerve supply to the shoulder originates primarily in the thoracic region from T 2 down as far as T 8
  • Slide 17
  • Anatomy Vascularization Vascularization The vascular supply to the rotator cuff muscles of the shoulder consists of three main sources: the thoracoacromial, suprahumeral, and subscapular arteries The brachial artery provides the dominant arterial supply to each of the two heads of the biceps
  • Slide 18
  • Anatomy Glenohumeral joint Glenohumeral joint Close packed position The close packed position for the G-H joint is 90 of glenohumeral abduction and full external rotation; or full abduction and external rotation, depending on the source The close packed position for the G-H joint is 90 of glenohumeral abduction and full external rotation; or full abduction and external rotation, depending on the source Open packed position Without internal or external rotation occurring, the open packed, or rest position of the G-H joint has traditionally been cited as 55 of semi-abduction and 30 of horizontal adduction Without internal or external rotation occurring, the open packed, or rest position of the G-H joint has traditionally been cited as 55 of semi-abduction and 30 of horizontal adduction
  • Slide 19
  • Anatomy Glenohumeral joint Glenohumeral joint Capsular pattern According to Cyriax, the capsular pattern for the shoulder is external rotation the most limited, abduction the next most limited, and internal rotation the least limited in a 3:2:1 ratio respectively According to Cyriax, the capsular pattern for the shoulder is external rotation the most limited, abduction the next most limited, and internal rotation the least limited in a 3:2:1 ratio respectively
  • Slide 20
  • Anatomy The acromioclavicular joint The acromioclavicular joint The acromioclavicular (A-C) joint is a diarthrodial joint, formed by the acromion and the lateral end of the clavicle The joint serves as the main articulation suspending the upper extremity from the trunk, and it is at this joint about which the scapular moves
  • Slide 21
  • Anatomy Acromioclavicular joint Acromioclavicular joint The articulating surface of the lateral end of the clavicle can be either convex or concave and corresponds with the articulating surface of the acromion. Consequently, although the joint is described as a planar joint, there is often a male-female relationship, with 3 degrees of freedom
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