MSK: upper limb Flashcards
palmaris longus muscle: origin, insert, action
- originates from the medial epicondyle of the humerus
- inserts into the flexor retinaculum and palmar aponeurosis of the hand.
- Its main action is flexion of the wrist/hand.
Describe the brachial plexus
- (5)Root -> (3)Trunk -> (6)Divisions -> (3)Cords -> (5)branches
mnemonic = Read That Damn Cadaver Book
- The brachial plexus is formed by the anterior rami of C5, C6, C7, C8 and T1 (roots).
- These roots form 3 trunks: upper, middle, lower
- These trunks become 6 divisions (anterior and posterior for each trunk).
- These form 3 cords: lateral, posterior, medial
- These five terminal branches (in order MAMRU): musculocutaneous, axillary, median, radial, ulnar.
Anatomical borders of the axilla (anterior, posterior, lateral, medial, apex)
(1. ) Anterior = pec.major and minor
(2. ) Posterior = subscapularis, teres major, latissimus dorsi
(3. ) Lateral = humerus, bicep brachii, coracobrachialis
(4. ) Medial = serratus anterior, ribcage
(5. ) Apex = 1st rib, clavicle, scapula
Name the four rotator cuff muscles and their origin, insertion, action
(1. ) Supraspinatus
- origin = supraspinatus fossa
- inserts = greater tuberosity of humerus.
- action = abduction of the humerus
(2. ) Infraspinatus
- origin = infraspinatus fossa
- inserts = greater tuberosity of humerus.
- action = lateral rotation
(3. ) Teres minor
- origin = lateral border of scapula
- inserts = greater tuberosity of humerus.
- action = lateral rotation
(4. ) Subscapularis
- origin = subscapularis fossa
- inserts = lesser tuberosity of humerus.
- action = medial rotation and adduct
Whats parts of the scapula articulates with humerus and clavicle
(1. ) Head of humerus articulates with coracoid process and glenoid fossa
(2. ) Clavicle articulates with acromion process
Whats muscles elevate and retract the scapula (3.)
(1. ) Levator scapulae
(2. ) Rhomboid major and minor
Deltoid: origin, insertion, action, innervation
- Origin = clavicle, acromion process, spine of scapula
- Inserts = deltoid tuberosity on humerus
- action = flex, abduct, extend arm
- innervation = axillary nerve
What is a frozen shoulder?
(1. ) Inflamed tendon of supraspinatus that causes pain when it passes through the gap between humerus and acromion.
(2. ) Pain is felt when raising arm to a certain height and after that it is pain free
What causes an axillary nerve palsy? and what sensory and motor loss is seen?
(1. ) Axillary nerve runs along the neck of the humerus
(2. ) Posterior dislocation or fracture to humerus neck can damage nerve
(3. ) This causes paralysis of deltoid and patch of numb skin on lateral arm
What causes a radial nerve palsy?
(1. ) Radial nerve run in the groove of the humerus
(2. ) This can be easily damaged by fracture or direct pressure
What causes an ulnar nerve palsy?
(1. ) Bang to the funny bone/medial epicondyle where the ulnar nerve passes behind it
(2. ) Leads to severe pins and needle in skin supplied by nerve.
What is found within the axilla?
(1. ) Fat and lymph nodes
(2. ) Axillary artery and vein
(3. ) Brachial plexus
Tricep brachii: origin, insertion, innervation, blood supply
Origin
- Infragrlenoid tubercle of scapula (Long head)
- Posterior humerus below radial groove (Medial head)
- Posterior humerus above radial groove (Lateral head)
Insert
- Olecranon process of ulna
Innervation
- Radial Nerve
Blood supply
- brachial artery
Name 3 branches that come off the posterior cord? and what do they supply?
(1. ) Axillary nerve = deltoid
(2. ) Radial nerve = extensors of arm and forearm
(3. ) Thoracodorsal nerve = lats
Name 2 branches that come off the lateral cord?
(1. ) Musculocutaneous
2. ) Median nerve (both lateral + medial cord
Name 2 branches that come off the medial cord?
(1. ) Median nerve (both lateral + medial cord)
(2. ) Ulnar nerve
Describe the relationship between the brachial plexus’ cords and axillary artery
(1. ) Lateral cord is found lateral to the axillary artery
(2. ) Medial cord is found medial to the axillary artery
What provides stability to the shoulder joint?
(1. ) Rotator cuff muscles
(2. ) Glenoid labrum
(3. ) Ligaments
What borders make up the cubital fossa
(1. ) Medial border = pronator teres
(2. ) Lateral border = brachioradialis
(3. ) Superior border = line between epicondyles
What is found in the cubital fossa
(1. ) Tendon of bicep
(2. ) Brachial artery
(3. ) Median nerve
(4. ) Superficial veins (basilic v = medially, cephalic v = laterally)
What is the blood supply and innervation of the coracobrachialis, bicep brachii, brachialis?
(1. ) Brachial A
(2. ) Musculocutaneous N
What drains into the axillary lymph node
(1. ) Upper limb
(2. ) Thorax
(3. ) Abdominal wall above the umbilicus
What would you see if the there was damage to the upper trunk of the brachial plexus (C5 + C6)
(1. ) Erb’s palsy
(2. ) Humerus internally rotated (due to paralysis of shoulder’s extensors), hands are flexed (due to paralysis of extensors) -> this can be described as a ‘waiter’s tip’
What would you see if the there was damage to the lower trunk of the brachial plexus (T1 + C8)
(1. ) Klumpke palsy due to excessive pull of upper limb e.g. hanging off tree
(2. ) ‘Claw’ appearance i.e. wrist and MCP is extended but DIP and PIP are in flexed position due to damage to MN and UN.
(3. ) Involvement of T1 may result in Horner’s syndrome,
What would you see if there was damage to T1?
(1. ) Horner’s Syndrome
(2. ) This is a triad of:
- Miosis (constriction of pupils)
- Ptosis
- Anhidrosis (inability to sweat)
(3. ) This is because T1 carries sympathetic fibres.
Most commonly injured bones
(1. ) Scaphoid
(2. ) 5th metacarpal (boxer’s fracture, result of a closed fist striking a hard object)
(3. ) Distal radius bone - in menopausal or osteoporosis