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Back and Upper Limb - Written Examination October 3rd, 2008: Part V - Essay

Note: This is an outline of topics to be covered. It is not the "answer key." It is an answer guide.

Brachial Plexus and Nerve Injury

Review the anatomy of the brachial plexus. Include relationships within the axilla. For each terminal nerve, discuss the effects of nerve injury on muscle movements and joint position. Discuss compensation for lost or weakened movements. (12 pts)
  • The brachial plexus is derived from the ventral rami of spinal nerves C5 - T1. There may be contributions from C4 and T2. The three cords of the brachial plexus are within the axilla. They surround the axillary artery and are named accordingly; the medial, lateral, and posterior cords.
  • Structure
    • Roots - ventral rami C5 - T1
    • Trunks - upper (C5 - C6), middle (C7), lower (C8 - T1)
    • Divisions - anterior (mostly flexors), posterior (mostly extensors)
    • Cords - medial, lateral, and posterior named for relationship to axillary artery
  • Relationships within the axilla (boundaries of the axilla)
    • Superior: clavical and thoracic outlet
    • Inferior: skin of the axilla; teres minor and serratus anterior
    • Anterior: pectoralis major and minor
    • Posterior: latissimus dorsi and teres major
    • Medial: serratus anterior
    • Lateral: humerus
  • Dorsal scapular nerve
    • Rhomboids and levator scapulae
    • Weakened retraction and elevation of the scapula
    • Compensation by trapezius
  • Long thoracic nerve
    • Serratus anterior
    • Lost protraction of the scapula - "winging" of the scapula
    • Pectoralis major and minor may compensate for some loss of stability
  • Suprascapular nerve
    • Supraspinatus
      • Lost first 15 degrees abduction
      • Compensation by "hip bump" and leaning to side of lesion
    • Infraspinatus and teres minor
      • Weakened lateral rotation at glenohumeral joint
      • Compensation by deltoid
  • Lateral and medial pectoral nerves - weakened adduction and medial rotation
    • Pectoralis major
      • Adduction compensation by deltoid, teres major, lattissimus dorsi, coracobrachialis, short head biceps
      • Medial rotation compensated by subscapularis and adductors
  • Upper subscapular nerve - weakened medial rotation
    • Subscapularis
      • Medial rotation compensation by subscapularis, deltoid, teres major, lattissimus dorsi, coracobrachialis, short head biceps
  • Middle subscapular nerve (thoracodorsal nerve) - weakened extension/flexion, adduction, and medial rotation
    • Latissimus dorsi
      • Extension compensated by deltoid, teres major, pectoralis major, coracobrachialis, short head biceps
      • Medial rotation compensated by deltoid, teres major, pectoralis major, coracobrachialis, short head biceps
    • Superficial epigastric and superficial circumflex iliac arteries and veins
  • Lower subscapular nerve
    • Subscapularis
      • See upper subscapular nerve
    • Teres major
      • Medial rotation compensation by subscapularis, deltoid, lattissimus dorsi, coracobrachialis, short head biceps
  • Axillary nerve
    • Deltoid
      • Rotation compensation by rotator cuff
      • Abduction from 15 -90 degrees at the glenohumeral joint not compensated
      • Some compensation for lost abduction at the glenohumeral joint by scapular rotation - trapezius and serratus anterior
      • Adduction compensated by pectoralis major, coracobrachialis, and latissimus dorsi
    • Teres minor * Lateral rotation compensated by infraspinatus
  • Ulnar nerve
    • Flexor carpi ulnaris
      • Flexion compensated by long flexors of the forearm
      • Adduction compensated by extensor carpi ulnaris
    • Flexor digitorum profundus
      • No compensation of flexion of distal IP for the the ring and little fingers
      • Compensation for flexion at joints proximal to DIP by long flexors
      • Compensation for flexion at MP joints by intrinsic muscles of the hand
    • Intrinsic muscles of the hand
      • Clinical: claw hand
        • Hyperextension at MP joints and tethering at the IP joints
      • Loss of adduction at the MP joints
        • Minor compensation by lumbricals
      • Loss of abduction at the MP joints
        • Minor compensation by lumbricals
      • Loss of extending IPs while flexing MP
        • No compensation
  • Median Nerve
    • Flexor carpi radialis
      • Abduction compensated by extensor carpi radialis
      • Flexion at wrist compensated by flexor carpi ulnaris
    • Flexor digitorum profundus
      • No compensation of flexion of distal IP for the the index and middle fingers
      • Compensation for flexion at joints proximal to DIP for the ring and little fingers by ulnar part of FDP
      • Compensation for flexion at MP joints by intrinsic muscles of the hand
    • Flexor digitorum superficialis
      • No compensation of flexion of proximal IP for the the index and middle fingers
      • Compensation for flexion at joints proximal to DIP for the ring and little fingers by ulnar part of FDP
      • Compensation for flexion at MP joints by intrinsic muscles of the hand
    • Flexor pollicis brevis
      • No compensation for lost flexion of the thumb
    • Pronator teres
      • Compensation for weakened elbow flexion by muscles of anterior compartment of the arm
    • Intrinsic muscles of the hand
      • Radial two lumbricals compensated for by interossei
      • Flexor pollicis brevis compensated by ulnar head
      • Opponens pollicis not compensated
    • Clinical
      • Ape hand due to atrophy of thenar eminence and loss of opposition (pronation)
  • Radial Nerve
    • Brachioradialis
      • Elbow flexion compensated by anterior compartment of arm
      • Pronation compensated by pronator teres and pronator quadratus
      • Supination compensated by supinator and biceps
    • Extensor carpi radialis longus/brevis
      • No compensation for wrist drop (loss of flexion)
      • Abduction compensated by flexor carpi radialis
    • Extensor carpi ulnaris
      • No compensation for wrist drop (loss of flexion)
      • Adduction compensated by flexor carpi ulnaris
    • Extensor digitorum, indicis, and digiti minimi
      • No compensation for loss of extension from the distal IP and joints proximal
    • Extensor policis longus and brevis
      • No compensation
    • Abductor pollicis longus
      • Compensation by abductor pollicis brevis
    • Clinical
      • Wrist drop

Elbow Joint

Review the anatomy of the elbow joint. Include bones, articular surfaces, cavities, capsules, ligaments, contents, muscles, movements and limitations of movement, vasculature, innervation, relationships to surrounding structures, and lymphatic drainage. (12 pts).
  • General
    • Humero-radial and humero-ulnar
    • Synovial joint - synovial membrane continuous with elbow and radioulnar joint
    • Hinge joint
  • Bones and articular surfaces
    • Humeral trochlea and ulnar trochlear notch - elbow joint
    • Capitulum and radial head - radioulnar joint
    • Olecranon and olecranon fossa
  • Capsules, cavities, ligaments
    • Ulnar collateral ligament - medial epicondyle to olecranon and coronoid process
      • triangular, anterior, intermediate, and posterior fibers
    • radial collateral ligament - lateral epicondyle to annular ligament and to supinator crest
    • Annular ligament - secures radial head to the ulnar notch, blends with radial collateral ligament
  • Muscles, movements, and limitations of movement
    • Flexion
      • Anterior compartment of arm - biceps, brachialis, and brachioradialis
      • Flexor origin from medial humeral epicondyle
    • Extension
      • Posterior compartment of arm - triceps and anconeus
      • Flexor origin from medial humeral epicondyle
  • Vasculature and Innervation
    • elbow anastomosis
    • Hilton's law - musculocutaneous, median, ulnar, and radial nerves
    • Cutaneous
      • Lower lateral cutaneous of arm, posterior cutaneous nerve of arm, posterior cutaneous nerve of forearm
      • Medial and lateral cutaneous nerves of the forearm
  • Relationships
    • cubital fossa and contents - medial to lateral: median nerve, brachial artery and vein, radial and ulnar arteries, tendon of biceps, radial nerve
    • biceps aponeurosis
    • median cubital vein
    • elbow (cubital) anastomosis
    • lateral cutaneous nerve of forearm
    • ulnar groove and nerve
  • Lymphatic drainage
    • Supratrochlear nodes

Scapular Region and Shoulder Joint

Review the anatomy of the scapular region and shoulder joint. Include bones, articular surfaces, cavities, capsules, ligaments, contents, muscles, movements and limitations of movement, vasculature, innervation, relationships to surrounding structures, and lymphatic drainage. (12 pts) Scapular Region
    • The scapula is a highly movable structure that makes up the bulk of the pectoral girdle.
    • Abduction from approximately 90 degrees to 180 degrees is largely accounted for by scapular movement (upward rotation).
    • A rich anastomotic network centered in the infraspinous fossa provides an arterial shunt across much of the axillary artery.
    • The scapula hosts the proximal component of the glenohumeral joint.
    • Positioning of the upper limb is largely dependent upon the anatomy of the scapular region
  • Bones, Muscles and Movements
    • Medial border *Rhomboideus minor
      • Rhomboideus major
      • Serratus anterior
    • Superior Angle
      • levator scapulae
    • Inferior Angle
      • Serratus anterior
    • Lateral border
      • Teres major
    • Supraspinous fossa
      • Supraspinatous
    • Infraspinous fossa
      • Infraspinatous
      • Teres minor
    • Spine of the scapula
      • Upper fibers of trapezius
      • Lower fibers of trapezius
    • Acromion
      • Trapezius
      • Deltoid
      • Coracoacromial ligament and arch
    • Subscapular fossa
      • Subscapularis
    • Corocoid Process
      • Pectoralis minor
      • Coracobrachialis
      • Short head of biceps
    • Glenoid fossa
      • Proximal articulation for glenohumeral joint
    • Supraglenoid tubercle
      • Long head biceps
    • Infraglenoid tubercle
      • Long head triceps
  • Vascularization and Scapular anastomosis
    • Transverse cervical artery
    • Suprascapular artery
    • Dorsal scapular artery
    • Posterior intercostal arteries
    • Circumflex scapular artery
  • Innervation
    • Suprascapular nerve
    • Accessory nerve
    • Axillary nerve
    • Dorsal scapular nerve
    • Medial and Lateral pectoral nerves
    • Upper, middle, and lower subscapular nerves
    • Musculocutaneous nerve
    • Long thoracic nerve - winging
  • Relationships
    • Superior transverse scapular ligament and scapular notch
      • Suprascapular nerve passes through osseofibrous foramen
      • Suprascapular artery passes superior to the superior transverse scapular ligament
      • Circumflex scapular artery in the triangular space
      • Posterior cord anterior to subscapularis
      • Subscapular fossa is part of posterior wall of axilla
      • Coracoacromial arch is superior support for glenohumeral joint
  • Lymphatic drainage
      • Posterior - intercostal nodes
      • Anterior - axillary nodes
Rotator Cuff
    • The rotator cuff, celebrated for its role in lateral rotation, mediates lateral rotation, medial rotation, 15 deg of abduction, and weak adduction.
    • The tendon of supraspinatus is particularly vulnerability to tearing due to the restricted space between it and the acromion.
  • Bones: Scapula and Humerus
    • Glenoid fossa
    • Acromion
    • Corocoid process
  • Muslces
    • Supraspinatus
    • Infraspinatus
    • Teres minor
    • Subscapularis
  • Movements
    • Abduction: 15 deg by supraspinatus
    • Adduction: weak by teres minor
    • Lateral rotation: infraspinatus and teres minor
    • Medial rotation: subscapularis
  • Vascularization
    • Scapular anastomosis av
    • Shoulder anastomosis av
    • Anterior humeral circumflex av
    • Posterior humeral curcumflex av
    • Subscapular av
  • Innervation
    • Suprascapular nerve
    • Axillary nerve
    • Upper and lower subscapular nerves
  • Relationships *Subacromial bursa and arch
    • Tendon of the long head of the biceps
  • Lymphatic drainage
    • Axillary nodes
    • Cervical nodes
  • Clinical Significance
    • Rotator cuff tear - supraspinatus
Shoulder Joint
  • Extremely Unstable - "Golf ball and Tee"
  • Bones
    • Glenoid Fossa and Humerus
  • Articular surfaces
    • Glenoid fossa - cartilage
    • Head of humerus - cartilage
    • Glenoid labrum
  • Cavities
    • Synovial joint cavity
    • Subacromial Bursa
  • Capsules and ligaments
    • Fibrous joint capsule
    • Glenohumeral ligaments
    • Musculocutaneous Cuff (rotator Cuff)
  • Contents
    • Biceps tendon
  • Muscles
    • Rotator Cuff, Deltoid
    • Pectoralis major, teres major, latissimus dorsi
    • coracobrachialis, long and short head of biceps, long head of triceps
  • Movements
    • Medial rotation
    • Lateral rotation
    • Abduction
    • Adduction
    • Flexion
    • Extension
  • Limitations of movement
    • Glenohumeral ligaments
    • Antagonistic muscles
  • Vascularization
    • Anterior and Posterior humeral circumflex arteries
    • Deltoid and acromial branches of thoracoacromial trunk
    • Suprascapular artery and Circumflex scapular artery
    • Ascending branch of profunda brachii
  • Innervation
    • Axillary Nerve
    • Upper lateral cutaneous nerve of arm
    • Hilton's law - Axillary, suprascapular, and lower subscapular nerves
    • Hilton's law continued - musculocutaneous, radial, median, and ulnar nerves
  • Relationships
    • Coracoacromial arch
    • Long head biceps tendon
    • Clavical
    • Coracoid process
  • Lymphatic drainage o
  • Shoulder injury and dislocation
    • Traction injury of axillary nerve
    • Clinical test for upper lateral cutaneous nerve

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-- LorenEvey - 19 Oct 2008

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Topic revision: r1 - 05 Jan 2009, UnknownUser
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