Week 2 - The Shoulder Flashcards
What is the shoulder complex composed of?
Sternoclavicular Joint, Acromioclavicular Joint, Glenohumeral Joint, Scapulothoracic Joint
What type of joint is the sternoclavicular joint?
Saddle synovial joint
What structures form the sternoclavicular joint?
Clavicular notch of manubrium of sternum, Sternal end of clavicle, 1st costal cartilage
What is the function of the articular disc in the sternoclavicular joint?
Splits the cavity in 2, allowing for two different movements
Which ligaments are associated with the sternoclavicular joint?
- Anterior & posterior sternoclavicular ligaments
- Interclavicular ligament
- Costoclavicular ligament
What will break before the ligaments in the sternoclavicular joint?
Clavicle
What type of joint is the acromioclavicular joint?
Plane synovial joint
What structures form the acromioclavicular joint?
Acromion process of scapula & acromial end of clavicle
What ligaments are associated with the acromioclavicular joint?
- Acromioclavicular ligament
- Coracoclavicular ligaments (Conoid, Trapezoid)
What does dislocation of the acromioclavicular joint indicate?
Shoulder separation due to rupture of acromioclavicular or coracoclavicular ligaments
What type of joint is the glenohumeral joint?
Ball & Socket synovial joint
What structures form the glenohumeral joint?
Glenoid cavity & anatomical head of humerus
What is the characteristic of the glenohumeral joint?
Shallow socket provides mobility but reduced stability
What deepens the cavity of the glenohumeral joint?
Fibrocartilage labrum
Which muscles are part of the rotator cuff?
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
What ligaments are associated with the glenohumeral joint?
- Glenohumeral ligaments (Superior, Middle, Inferior)
- Coracoacromial ligament
- Coracohumeral ligament
- Transverse humeral ligament
What is the most commonly dislocated joint in the body?
Glenohumeral joint
What occurs during anterior dislocation of the glenohumeral joint?
Head of the humerus is forced anteriorly
What is the function of the subscapular bursa?
Located between scapula and subscapularis tendon
What prevents friction in the subacromial/subdeltoid bursa?
Prevents friction between acromion, coracoacromial arch and other structures
What type of joint is the humeroradial joint?
Plane synovial joint
What structures form the humeroradial joint?
Capitulum of humerus & head of radius
What type of joint is the humeroulnar joint?
Hinge synovial joint
What structures form the humeroulnar joint?
Trochlea of humerus & trochlear notch of ulna
What movements does the humeroulnar joint allow?
Flexion & extension
What type of joint is the proximal radioulnar joint?
Pivot synovial joint
What structures form the proximal radioulnar joint?
Head of radius & radial notch of ulna
What ligaments are associated with the elbow complex?
- Medial (ulnar) collateral ligament
- Lateral (radial) collateral ligament
- Annular ligament
What can cause subluxation or dislocation of the radial head?
Child’s arm is forced up
What type of joint is the interosseous membrane?
Syndesmosis (fibrous) joint
What is the function of the interosseous membrane?
Binds radius & ulna together, distributes forces, and divides forearm into compartments
What type of joint is the distal radioulnar joint?
Pivot synovial joint
What structures form the distal radioulnar joint?
Head of ulna & ulnar notch of radius
What occurs at the distal radioulnar joint during pronation and supination?
Radius pivots around the fixed ulna
What type of joint is the radiocarpal (wrist) joint?
Condyloid synovial joint
What structures form the radiocarpal joint?
Radius, scaphoid & lunate
What ligaments are associated with the radiocarpal joint?
- Palmar radiocarpal ligament
- Dorsal radiocarpal ligament
What type of joint is the carpometacarpal joint?
Saddle synovial joint (1st), Plane synovial joint (2nd-5th)
Which carpals are involved in the carpometacarpal joint?
- Trapezium
- Trapezoid
- Capitate
- Hamate
What type of joint is the metacarpophalangeal joint?
Condyloid synovial joint
What structures form the metacarpophalangeal joint?
Head of metacarpal & base of proximal phalanx
What are the types of interphalangeal joints?
- 1st Interphalangeal joint (only 1)
- 2nd – 5th Interphalangeal joints (2 each)
What structures form the first interphalangeal joint?
Proximal phalanx & distal phalanx
What structures form the proximal interphalangeal joint?
Proximal phalanx & intermediate phalanx
What structures form the distal interphalangeal joint?
Intermediate phalanx & distal phalanx
What are the superficial muscles of the posterior axioappendicular group?
Trapezius; latissimus dorsi
These muscles are primarily responsible for movements of the shoulder girdle.
What are the deep muscles of the posterior axioappendicular group?
Levator scapulae; rhomboids
These muscles assist in stabilizing and moving the scapula.
Which muscles are included in the scapulohumeral group?
Deltoid; teres major; rotator cuff muscles (RCs) x4
The rotator cuff consists of supraspinatus, infraspinatus, teres minor, and subscapularis.
What are the muscles of the anterior appendicular group?
Pectoralis major; pectoralis minor; serratus anterior
These muscles are involved in movements such as flexion and protraction of the shoulder.
Which muscles are involved in the anterior compartment of the arm?
Biceps brachii; coracobrachialis; brachialis
These muscles primarily flex the elbow and shoulder.
Which muscle is found in the posterior compartment of the arm?
Triceps brachii
This muscle is responsible for extension of the elbow.
What are the primary muscles involved in shoulder abduction?
Deltoid (all parts), Supraspinatus
Shoulder abduction involves moving the arm away from the body.
Which muscles are responsible for shoulder adduction?
Latissimus dorsi, Pectoralis major, Teres major, Teres minor, Subscapularis, Triceps (long head), Coracobrachialis
Shoulder adduction brings the arm closer to the body.
Name the muscles that facilitate shoulder flexion.
Anterior deltoid, Coracobrachialis, Pectoralis major, Biceps brachii
Shoulder flexion is the movement of raising the arm forward.
Which muscle is primarily responsible for shoulder extension?
Posterior deltoid
Shoulder extension is the backward movement of the arm.
Identify the muscles involved in medial rotation of the shoulder.
Anterior deltoid, Latissimus dorsi, Pectoralis major, Teres major, Subscapularis
Medial rotation turns the arm inward toward the body.
What muscles are responsible for lateral rotation of the shoulder?
Posterior deltoid, Teres minor, Infraspinatus
Lateral rotation turns the arm outward, away from the body.
Which muscles contribute to the superior rotation of the scapula?
Upper part of trapezius, Serratus anterior, Lower part of trapezius
Superior rotation of the scapula involves the upward movement of the scapula.
What is the primary function of the muscles involved in inferior rotation of the scapula?
Facilitate downward movement of the scapula
Inferior rotation of the scapula helps in lowering the arm.
What is the initial degree of abduction of the humerus at the GHJ?
30°
This is the first phase of scapulohumeral rhythm.
What occurs after the initial 30° of abduction at the GHJ?
> 30° - Abduction at the GHJ & superior rotation of scapula
This indicates the coordination between humeral abduction and scapular movement.
At approximately how many degrees does lateral rotation of the humerus occur?
120°
This is part of the scapulohumeral rhythm.
By what degree has the scapula rotated when the GHJ has abducted to 150°?
40°
This reflects the relationship between scapular rotation and humeral abduction.
What artery is divided into three parts by the pectoralis minor?
Axillary artery
The axillary artery supplies blood to the shoulder region.
What is the largest branch of the third part of the axillary artery?
Subscapular artery
The subscapular artery has important branches supplying the scapular region.
List the branches of the second part of the axillary artery.
- Thoracoacromial trunk
- Lateral thoracic artery
These branches supply various regions around the shoulder and chest.
Which nerve innervates the shoulder joint and is from the upper trunk of the brachial plexus?
Suprascapular nerve
This nerve provides sensory and motor innervation to the shoulder.
What is the function of the axillary nerve?
Innervates deltoid and teres minor
The axillary nerve also provides sensation to the skin over the shoulder.
What is a common cause of anterior shoulder dislocation?
Violent external rotation in abduction
This is especially prevalent in young men.
What percentage of shoulder dislocations are anterior?
95%
Most shoulder dislocations occur in the anterior direction due to the anatomy of the joint.
What is a Bankart lesion?
Avulsion of anterior labrum & inferior GH ligament
This injury is often associated with shoulder dislocations.
What is the primary cause of subacromial impingement?
Compression of supraspinatus tendon
This condition is the most common cause of shoulder pain.
What is the typical duration of a frozen shoulder condition?
18-24 months
This condition is self-limiting but can significantly restrict movement.
Fill in the blank: The long head of the biceps brachii originates from the _______.
supraglenoid tubercle of scapula
This anatomical origin is crucial for understanding biceps function.
True or False: A Hill Sachs lesion occurs in 90% of shoulder dislocations.
True
This type of injury is often seen in conjunction with dislocations.
What is the typical conservative treatment duration for axillary nerve injury?
6-8 weeks
This allows for myelin sheath regrowth and recovery.
What is the common mechanism for rotator cuff tears?
Degeneration of tendon due to repetitive stress
This is prevalent among individuals involved in overhead work or sports.
What is the scapular region?
The posterior aspect of the shoulder.
Which muscles are mentioned as part of the scapular region?
- Trapezius
- Latissimus dorsi
What is the quadrangular space?
An intermuscular space located below the glenohumeral joint.
What structures bound the quadrangular space?
- Above: Subscapularis, teres minor muscles, shoulder joint capsule
- Below: Teres major muscle
- Medially: Long head of the triceps
- Laterally: Surgical neck of the humerus
True or False: The axillary nerve and posterior circumflex humeral vessels pass through the quadrangular space.
True
What is the axilla?
A pyramid-shaped space between the upper arm and side of the chest.
What forms the apex of the axilla?
- Clavicle (anterior)
- Upper border of the scapula (posterior)
- Outer border of the first rib (medially)
What forms the base of the axilla?
- Anterior axillary fold (pectoralis major)
- Posterior axillary fold (latissimus dorsi and teres major)
- Chest wall (medially)
List the four walls of the axilla.
- Anterior wall: Pectoralis major, subclavius, pectoralis minor
- Posterior wall: Subscapularis, latissimus dorsi, teres major
- Medial wall: Upper ribs and intercostal spaces covered by serratus anterior
- Lateral wall: Coracobrachialis and biceps brachii
What important structures are contained within the axilla?
- Axillary artery and its branches
- Axillary vein and its tributaries
- Lymph vessels and lymph nodes
- Brachial plexus
What is the pectoralis minor?
A thin triangular muscle that lies deep to the pectoralis major.
Where does the pectoralis minor insert?
Coracoid process of the scapula.
What is the clavipectoral fascia?
A strong sheet of connective tissue lying deep to the pectoralis major.
What structures pierce the clavipectoral fascia?
- Lateral pectoral nerve
- Cephalic vein
- Branches of the thoracoacromial artery
- Lymphatic channels from infraclavicular nodes
Fill in the blank: The axilla contains the axillary artery, axillary vein, lymph vessels, and _______.
[Brachial plexus]
