Block 4 Study Guide

Know the parts of the scapula, clavicle, humerus, ulna, and radius.

arm: shoulder to elbow

  • shoulder dislocation: head of the humerus is displaced from the scapula

  • shoulder separation: torn ligaments

forearm/ antebrachial region : elbow to wrist

hand: wrist to fingers

  • scapula:

    • weirdly shaped

    • no posterior articulation

  • clavicle (collarbone)

  • humerus

  • ulna

    • c - shaped proximal end

    • the head is on the distal end

  • radius

Know the names and locations of the carpals, metacarpals, and phalanges. 

  • carpals (wrist):

    • hamate

    • capitate

    • pisiform

    • triquetrum

    • lunate (most dislocated)

    • trapezium

    • trapezoid

    • scaphoid (most frequent to fracture)

  • metacarpals (palm):

    • head, shaft, and base; numbered I-IV starting with the thumb

  • phalanges (finger):

    • distal

    • middle

    • proximal

Know the Clinical significance with fractures of the humerus.

  • surgical neck:

    • injury to axillary nerve

  • middle of shaft:

    • may cause injury to the radial nerve = wrist drop

  • distal end of humerus:

    • injury to median nerve

  • medial epicondyle:

    • injury to ulnar nerve

  • traumatic separation of the proximal epiphysis under 18-20 years old

  • dislocation of the shoulder joint

What are the four joints of the shoulder and where are each located?

  • acromioclavicular joint

    • location: where the clavicle meets the acromion of the scapula

  • scapulothoracic joint

    • location: where the scapula glides on the rib cage

  • sternoclavicular joint

    • location: where clavicle meets sternum

  • glenohumeral joint

    • location: where humerus meets scapula

Know the locations, function, and innervations of the following: all rotator cuff muscles, teres major, latissimus dorsi, trapezius, levator scapulae, rhomboid major, rhomboid minor, deltoid, coracobrachialis, pectoralis major, pectoralis minor, serratus anterior, subscapularis, biceps brachii, brachialis, triceps brachii, and aconeus.

rotator cuff muscles

  • supraspinatus

    • origin: scapula, supraspinatus fossa

    • insertion: humerus, greater tuberosity

    • innervation: suprascapular n (C4-C6)

    • action: abduction

  • infraspinatus

    • origin: scapula, infraspinous fossa

    • insertion: humerus, greater tuberosity

    • innervation: suprascapular n (C4-C6)

    • action: external rotation

  • teres minor

    • origin: scapula, lateral border

    • insertion: humerus, greater tuberosity

    • innervation: axillary n (C5,C6)

    • action: external rotation, weak adduction

  • subscapularis

    • origin: scapula, subscapular fossa

    • insertion: humerus, lesser tuberosity

    • innervation: suprascapular n (C5,C6)

    • action: internal rotation

teres major

origin: scapula (inferior angle)

insertion: crest of less tuberosity of the humerus (anterior angle)

innervation: lower subscapular nerve (C5-C7)

action: internal rotation, extension

latissimus dorsi (coughing muscles)

  • vertebral

    • origin: spinous process T7-T12 vertebrae; thoracolumbar fascia

    • insertion: crest of less tuberosity of the humerus (anterior angle)

    • innervation: thoracodorsal nerve (C6,C7,C8)

    • action: internal rotation, adduction, extension, respiration (cough muscle )

  • scapular

    • origin: scapula (inferior angle)

    • insertion: crest of less tuberosity of the humerus (anterior angle)

    • innervation: thoracodorsal nerve (C6,C7,C8)

    • action: internal rotation, adduction, extension, respiration (cough muscle )

  • costal

    • origin: 9th to 12th rib

    • insertion: crest of less tuberosity of the humerus (anterior angle)

    • innervation: thoracodorsal nerve (C6,C7,C8)

    • action: internal rotation, adduction, extension, respiration (cough muscle )

  • iliac

    • origin: iliac crest (posterior one third )

    • insertion: crest of less tuberosity of the humerus (anterior angle)

    • innervation: thoracodorsal nerve (C6,C7,C8)

    • action: internal rotation, adduction, and extension

trapezius:

  • descending part:

    • origin: occipital bone; spinous process C1-C7

    • insertion: clavicle (lateral 1/3)

    • innervation: accessory n (CN XI); cervical plexus (C3-C4)

    • action: draws scapula obliquely upward; rotates gleniod cavity superiorly; tilts head to same side and rotates it to opposite

  • transverse part:

    • origin: aponeurosis at T1-T4 spinous processes

    • insertion: acromion

    • innervation: accessory n (CN XI); cervical plexus (C3-C4)

    • action: draws scapula medially

  • ascending part:

    • origin: spinous process T5-T12

    • insertion: scapular spine

    • innervation: accessory n (CN XI); cervical plexus (C3-C4)

    • action: draws scapula medially downward, entire muscles; steadies scapula on thorax

levator scapula

origin: transverse process of C1-C4

insertion: scapula (superior angle )

innervation: dorsal scapular

action: draws scapula medially upwards while moving inferior angle ,medially; inclines neck to same side

rhomboid minor

origin: spinous process of C6,C7

insertion: medial border of scapula above (minor) and below (major) scapular spine

innervation: dorsal scapular n (C3,C4)

action: steadies scapula; draws scapula medially upward

rhomboid major

origin: spinous process of T1-T4 vertebrae

insertion: medial border of scapula above (minor) and below (major) scapular spine

innervation: dorsal scapular n (C3,C4)

action: steadies scapula; draws scapula medially upward

deltoid

function: most important abductor of the arm 90 degree

innervation: axillary nerve C5-C6

anterior part: flexes the arm (anteversion) + medial rotation of the arm

middle part: abducts the arm

posterior part: extends (retroversion) + lateral rotation

coracobrachialis

origin: scapula (coracoid process)

insertion: humerus

innervation: musculocutaneous n. C6,C7

action: flexion, adduction, internal rotation

pectoralis major

  • clavicular:

    • origin: clavicale

    • insertion: humerus

    • innervation: C5-T1

    • action: entire muscle: adduction, internal rotation, clavicular and sternocostal parts: flexion; assist in respiration when shoulder is fixed

  • sternocostal:

    • origin: sternum and coastal cartiale

    • insertion: humerus

    • innervation: C5-T1

    • action: adduction, internal rotation, clavicular and sternocostal parts: flexion; assist in respiration when shoulder is fixed

  • abdominal:

    • origin: rectus sheath

    • insertion: humerus

    • innervation: C5-T1

    • action: adduction, internal rotation, clavicular and sternocostal parts: flexion; assist in respiration when shoulder is fixed

pectoralis minor

orgin: 3rd-5th rib

insertion: coracoid process

innervation: medial and lateral pectoral n C6-T1

action: draws scapula downward, causing inferior angle to move posteromedially; rotates glenoid inferiorly; assists is respiration

serratus anterior

  • superior

    • origin: 1st - 9th rib

    • insertion: scapula

    • innervation: long thoracic n C5-C7

    • action: lowers raised arm

  • intermediate

    • origin: 1st - 9th rib

    • insertion: scapula

    • innervation: long thoracic n C5-C7

    • action: entire muscle draws scapula laterally forward; elevates ribs when shoulder is fixed

  • inferior

    • origin: 1st - 9th rib

    • insertion: scapula

    • innervation: long thoracic n C5-C7

    • action: rotates scapula laterally

subscapularis

origin:

insertion:

innervation: upper/lower subscapular nerves C5-C6-C7

action: arm adduction and medial roataion

biceps brachii

  • long head

    • origin: supraglenois tubercle of scapula

    • insertion: radial tuberosity

    • innervation: musculocutaneous C5-C7

    • action:

      • elbow join: flexion, supination

      • shoulder joint: flexion, stabilization of humeral head during deltiod contraction; abduction and internal rotation of the humerus

  • short head

    • origin: coracoid process of scapula

    • insertion: radial tuberosity

    • innervation: musculocutaneous C5-C7

    • action: flexion, stabilization of humeral head during deltiod contraction; abduction and internal rotation of the humeru

brachialis

origin: humerus

insertion: ulnar tuberosity

innervation: musculocutaneous n. C5-C7 and radian n. C7,minor

action: flexion at the elbow joint

triceps brachii

origin:

insertion:

innervation: olecranon of the ulna

action: elbow joint extension, shoulder joint long head extension and adduction

anconeus

origin: lateral epicondyle of humerus

insertion: olecranon of ulna

innervation: radial n. C6-C8

action: extends the elbow and tightens the joint

Know the Clinical significance of a “winged scapula.” How are two ways this could happen, i.e., what muscles and corresponding nerves would be damaged? How would you determine which muscles are compromised?

  • clin sig:

    • someone with a winged scapula would not be able to lift the arm beyond 90 degrees. It causes weakness in the muscles of your neck, shoulders, and arms

  • muscles damaged

    • 1) Serratus Anterior (long thoracic)

      2) Rhomboids (dorsal scapular)

  • if patient can lift arm over head; serratus anterior is fine and rhomboids are damaged. if they can only lift 90 degrees; serratus anterior is damaged.

Which veins are utilized during a venipuncture, and why?

  • veins of the (ante)cubital fossa (cephalic, median cubital, basilic) are frequently used due to the cross sectional area and visibility

Know all nerves of the brachial plexus and the roots from where the plexus originates.

  • musculocutaneous nerve- roots C5-C7

  • axillary nerve- roots C5 and C6

  • median nerve- roots C6-T1

  • radial nerve- roots C5-T1

  • ulnar nerve- roots C8-T1

additional brachial plexus nerves- dorsal scapular, suprascapular, subclavius, lateral pectoral, medial pectoral, upper subscapular (USS), thoracodorsal (TD), lower subscapular (LSS), medial brachial cutaneous (MBC), medial antebrachial cutaneous (MABC), lon thoracic

Know the Clinical significance of all brachial plexus injuries.

  • brachial plexus neuropraxia (stretch):

    • Root compression usually by rotation of the head; commonly seen in older individuals

    • Nerve traction is a result of a downward pull; common among adolescents and young adults

    • Both characterized as "burners" or "stingers" depending on the sensation felt with each injury

  • Brachial Plexus Rupture:

    • A forceful stretch resulting in the partial or complete tear of a nerve

    • Associated with muscle weakness and pain, severity depends on location and extent of injury

    • Often require surgery to repair

  • Brachial Plexus Neuroma:

    • Commonly occurs when a nerve is cut during surgery

    • Scar tissue forms a painful knot on the nerve, preventing it from healing itself

    • Surgery often required to remove scar tissue

  • Brachial Plexus Avulsion:

    • Nerve root is completely separated from spinal cord

    • Common injury during childbirth (2/1000 births), among athletes, and blunt trauma

    • Two types depending on nerves involved

    • Treatment depends on severity

What are the lymph node groups in the axillary region, and how are they involved in lymph drainage of the breast and upper limb?

  • groups:

    • pectoral, lateral, apical, central, and posterior

  • Drainage:

    • subclavian lymphatic trunk to right lymphatic duct to right venous angle

    • 75% of breast lymphatics drain to the lymph nodes of the axillary region

What is the Clinical significance of Colle’s fracture?

  • clin sig:

    • fracture of the radial styloid process; posterior displacement forces the process into the shaf

    • this can happen by falling on the hand while the arm is extend and may be accompained by avulsion of ulnar styloid process

Know the locations, innervations, and origins/insertions of the following muscles of the Forearm:

Anterior Compartment-Superficial

  • Pronator teres

    • innervated: by the median nerve

    • origin: Humeral head: medial supracondylar ridge of humerus Ulnar head: Coronoid process of ulna

  • insertion: Lateral surface of radius (distal to supinator)

  • Flexor carpi radialis

    • innervated: by the median nerve

    • inserts: at the bases of the 2nd and 3rd metacarpal bones

  • Palmaris longus

    • innervated by the median nerve

    • originates: at the medial epicondyle of the humerus and inserts: a bit, at the flexor retinaculum

  • Flexor carpi ulnaris

    • innervated: by the ulnar nerve (C7-T1)

    • inserts: at the base of the metacarpal bone 5

    • originates: from the Lateral epicondyle of humerus, posterior border of ulna

Anterior Compartment- Intermediate

  • Flexor digitorum superficialis

    • innervated: by the median nerve

    • origin/ insertion divided into two heads; a humeroulnar head and radial head.

    • its large muscular belly courses distally towards the wrist,

    • where it splits into four tendons and attaches to the middle phalanges of the second through fifth digits of the hand

Anterior Compartment- Deep

  • Flexor digitorum profundus

    • innervation: median n and median n

    • origin: ulna and interosseous membrane

    • insertion: distal phalanges 2nd and 5th digits

  • Flexor pollicis longus

    • innervation: median n

    • origin: radius and adjacent interosseous

    • insertion: distal phalanax of thumb

  • Pronator quadratus

    • innervation: median n

    • origin: distal quarter of ulna

    • insertion: distal quarter or radius

Posterior Compartment- Superficialis

  • Extensor digitorum

    • innervation: posterior interosseous nerve, which is a branch of the radial nerve

    • origin: common head

    • insertion: dorsal digit expansion of 2nd to 5th digits

  • Extensor digiti minimi

    • innervation: radial n

    • origin: common head

    • insertion: dorsal digit of 5th digit

  • Extensor carpi ulnaris

    • innervation: radianl n

    • origin: comon head and ulnar head

    • insertion: base of the 5th metacarpal

Posterior Compartment- Deep

  • Supinator

    • innervation: radianl n.

    • origin: olecranon, lateral epicondyle of humerus, radial collateral ligament annular ligament of radius

    • insertion: radius (b/w radial tuberosity and insertion of pronator teres)

  • Abductor pollicis longus

    • innervation: radial n

    • origin: radius and ulna

    • insertion: base of 1st metacarpal

  • Extensor pollicis brevis

    • innervation: radial n

    • origin: radius and interosseous membrane

    • insertion: base of proximal phalanx of thumb

  • Extensor pollicis longus

    • innervation: radial n

    • origin: ulna and interosseous membrane

    • insertion: base of distal phalanx thumb

  • Extensor indicis

    • innervation: radial n

    • origin: ulna and interosseous membrane

    • insertion: posterior digital extension of 2nd digit

Radialis Group

  • Brachioradialis

    • innervation: radial n

    • origin: dital humerus

    • insertion: radial styloid process

  • Extensor carpi radialis longus

    • innervation: radial n

    • origin: lateral supracondylar and ridge of distal humerus

    • insertion: 2nd metacarpal base

  • Extensor carpi radialis brevis

    • innervation: radial n

    • origin: lateral epicondyle of humerus

    • insertion: 3rd metacrapal base

Know the Clinical significance of carpal tunnel, including the associated tendons.

  • two rows of the carpal bones produce the carpal groove which is concave anteriorly

  • flexor retinaculum which is a Double layer of membrane covering the carpal groove anteriorly and produces the carpal tunnel for of flexor muscles and median nerve to pass through this tunnel

  • carpal tunnel syndrome:

    • compression to the median nerve in the tunnel due to hypothyroidism, rheumatoid arthritis, pregnancy, and amyloidosis

  • the structures that pass through this tunnel are

    • flexor digitorum superficialis and profundus

    • flexor pollicis longus

    • median nerve

Know the Clinical significance of scaphoid and lunate fractures and/or dislocations

  • ccaphoid fractures are the most common carpal bone fractures, generally occurring at the narrowed waist between the proximal and distal poles (A, right scaphoid)

  • bc blood supply to the scaphoid is transmitted via the distal segment, fractures at the waist can compromise the supply to the proximal segment, often resulting in nonunion and avascular necrosis (meaning the scaphoid bone can die)

Know the locations, functions, and innervation of the following:

Thenar muscles

  • Adductor pollicis

    • innervation: ulnar n

    • function: carpometacarpal joint of thumb; adduction and metacarpophalangeal joint of thumb: flexion

  • Abductor pollicis brevis

    • innervation: median n

    • function:carpometacarpal joint of thumb; adbuction

  • Flexor pollicis brevis

    • innervation: median n and ulnar n

    • function: carpometacarpal joint of thumb flexion

  • Opponens pollicis

    • innervation: median n

    • function: carpometacarpal joint of thumb; opposition

Hypothenar muscles

  • Opponens digiti minimi

    • innervation: ulnar n

    • function: draws metacarpals in palmar direction (opposition)

  • Flexor digiti minimi

    • innervation: ulnar n

    • function: metacarpophalangeal joint little fingers; flexion

  • Abductor digiti minimi

    • innervation: ulnar n

    • function: metacarpophalangeal joint little fingers; flexion and abduction of little fingers and helps in extension of little fingers

  • Palmaris brevis

    • innervation: ulnar n

    • function: Tightens the palmar aponeurosis (protective function)

Know the Clinical significance of the “anatomical snuffbox.0”

  • snuffbox borders:

    • tendon of extensor pollicis longus (superior), tendons of the extensor pollicis brevis, and abductor pollicis longus (inferiorly)

    • contents of snuffbox:

      • radial artery (gives blood to all of digit 1) and superficial radial nerve

    • this is significant b/c if you have a fracture at your scaphoid bone or a dislocation here, the scaphoid can be pushed in to that anatomical snuffbox

Know all Clinical symptoms regarding damage to the radial, median, and ulnar nerves.

  • radial nerve injury:

    • injury proximal to the origin of triceps

      • no extension of elbow

      • no triceps reflex

      • wrist drop, thumb is flexed and adducted

      • sensory loss: dorsolateral lower brachial region, posterior surface of forearm, dorsum of the hand and radial side of proximal phalanges

    • injury to the nerve on rdial grove:

      • fractures of humerus

      • triceps muscle is usally functioning

      • wrist drop and sensory loss in dorsolateral aspect of teh forearm and hand

  • nerve injury in foramen:

    • deep radial nerve is injured

    • extension of teh thumb and metacarpal joints is disturebed

    • sensation is usally preserved

  • median nerve injury: opponens splint, C-bar or thumb post splint

    • injury above the elbow:

      • only muscles in the forearm and hand muscles are affected

      • all flexors of the wrist are paralyzed except flexor carpi ulnaris and the ulnar part of flexor digitorum profundus

      • thumb flexors and abductor paralyzed but not the adductor (ulnar nerve)

      • flexion at metacarpophalangeal joints possible (intact interossei muscles innervation by ulnar nerve)

      • 1st and 2nd Lumbricals lost function and are unable to fully flex index and middle finger -- hand of benediction

      • pronation of forearm paralyzed and sensory loss over the median nerve area

    • injury at wrist joint:

      • short muscles of the thumb paralyzed, not adductor

      • thenar muscles atrophy; flexor polliicis longus functioning

      • sensory loss over medial nerve area

  • ulnar nerve injury:

    • at wrist:

      • claw hand

    • injury at elbow:

    • paralysis of dlexor capri and medial portion of flexor digitorum profundus

    • ulnar deviation of teh wrist is weakened

LAB