Anatomy of the Limbs Flashcards
What are the bones in the region of the shoulder?
- scapula
- clavicle
- humerus
What are the muscular compartments of the shoulder and arm?
- anterior pectoral girdle muscles
- posterior pectoral girdle muscles
- intrinsic shoulder muscles
- anterior compartment of the upper arm
- posterior compartment of the upper arm
What are the 4 muscles of the pectoral girlde?
- pectoralis major
- pectoralis minor
- subclavius
- serratus anterior -> runs between the anterior and posterior
Where is the pec major attached?
o PROXIMAL ATTACHMENTS -> broad attachment at the medial third of the clavicle, the sternum ad the costal cartilages
o DISTAL ATTACHMENT -> branches to the lateral lip of the intertubercular sulcus
What is the role of the pec major?
- adduction and medially rotation of the humerus -> punching muscle
Where does the pec minor originate and attach to?
- originates -> coracoid process of the scapula
- attaches to ribs 2, 3, 4 and 5
Where does the the subclavius attach?
- first rib
- under surface of the clavicle
What is the role of the subclavius?
- stabilising the clavicle
Where does the serratus anterior attach?
- ribs 1-9 coming posteriorly from the medial edge of the scapula
- runs around the side of the chest wall and divides into its different, finger-like parts
What is the role of the serratus anterior?
- holding and stabilisng the scapula
What muscles make up the anterior pectoral girdle?
- Trapezius
- Latissimus dorsi
- Levator scapulae
- Rhomboids
Where does the trapezius attach?
- proximal attachment = spinous processes
- distal attachment = scapula and clavicle
What is the motor supply of the trapezius?
- spinal accessory nerve -> cranial nerve XI
What is the major action of the trapezius?
- stabilise, hold and movement of the scapula
Where does the latissimus dorsi attach?
- attaches from T8, right down to the connective tissue in the posterior pelvic region
- fibres coming from the broad, distal attachment converge to form a strap, with an attachment to the floor of the intertubercular groove
What is the role of the latissimus dorsi, naming some activities in which it is heavily involved?
- extends, adducts and rotates the humerus
- pulling yourself up, climbing, rowing
What are the components of the rhomboids and where do they attach?
- two muscles -> minor and major -> combine to form a single strap muscle
- medial border of the scapula, the spinous processes at the lower end of the neck and the upper part of the thorax
Where does the levator scapulae attach?
- originates from C1-4 and attaches to the scapula
What is the role of the levator scapulae?
- elevates and rotates the scapula
What muscles make up the intrinsic shoulder muscle compartment?
- deltoid
- teres major
- rotator cuff muscles
Where does the deltoid muscle attach?
- posteriorly attaches to the scapular spine, acromial region and the clavicle
- fibres converge onto the deltoid tuberosity (of the humerus)
What are the actions of the deltoid?
- muscle of adduction
- when different parts are working separately, it contributes to other movements of the shoulder joint
What nerve supplies the deltoid?
- axillary nerve
What are the muscles of the rotator cuff?
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
Where are the rotator cuff muscles attached?
- come off of the scapula at various places and cross the shoulder joint to attach around the head of the scapula
What is the role of the rotator cuff?
- holding the head of humerus into the socket -> the socket is very shallow, so a lot of muscular activity is required to stabilise this joint
Where is the teres minor attached?
- comes off the inferior angle of the scapula and into the floor and medial lip of the intertubercular sulcus of the humerus
What nerve supplies the teres major?
- lower subscapular nerve
What muscles make up the anterior compartment of the arm?
- biceps
- brachialis
- coracobrachialis
What muscles does the musculocutaneous nerve supply?
- biceps
- brachialis
- coracobrachialis
Describe the structure of the bicep and where it attaches?
o two-headed muscle of the arm
- the short head proximal attachments is the coracoid process
- the long head tendon also crosses over the shoulder joint (through the intertubercule groove) and it attaches to the supraglenoid tubercule of the scapula
- the two heads converge to form a single tendon, part of which attaches to a tuberosity on the radius while some of the tendon splays out into a fan-shaped tendinous structure called an aponeurosis
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Where are the attachments of the brachialis?
- middle and distal parts of the humeral shaft
- coronoid process of the ulna
What is the role of the brachialis?
- major contributor to the flexion of the elbow joint -> along with the bicep
Where does the coracobrachialis attach?
- comes from the coracoid process and attaches to the shaft of the humerus
What is the role of the coracobrachialis?
- flexion of the shoulder joint
What muslces make up the posterior compartment of the arm?
- triceps
- anconeus
What nerve supplies the posterior compartment of the arm?
- radial nerve
Describe the structure of the tricep and where it attaches?
o have a long head, a lateral head and a medial head
- long head covers the other heads -> crosses the shoulder group, towards the infraglenoid tubercle -> other proximal attachments are posterior to the shaft of the humerus
- the heads converge to form the triceps tendon, which crosses over the elbow joint and attaches to the olecranon process of the ulna
Where does the anconeus attach?
- a small muscle that attaches from the lateral epicondyle of the humerus to the upper part of the posterior of the ulna bone
What are joints of the shoulder and arm?
- sternoclavicular joint
- acromioclavicular joint
- gleno-humeral joint (shoulder joint)
- scapulothoracic joint (“physiological” joint)
- elbow joint
What joints make up the pectoral girdle?
- sternoclavicular joint
- acromioclavicular joint
- gleno-humeral joint
- scapulothoracic joint
What makes up the sternoclavicular joint?
- medial end of the clavicle articulating with a disc at the manubrium
What forms the acromioclavicular joint?
- lateral end of the scapula articulating with the acromion process of the scapula
Which is the only joint to have direct bone attachment in the upper limb?
- sternoclavicular joint -> pivot point of the upper limb to the trunk
What kind of joint is the gleno-humeral joint?
- ball and socket synovial joint
Describe reason for lots of muscle being required for the shoulder joint.
- the glenoid fossa of the scapula is very shallow -> unstable, so you need lots of ligaments and muscles for stabilisation
- it is deepened slightly with a small rim of cartilage called the glenoid labrum or lip
What are bursae?
- are found around many joints where there are lots of movements going on
- act to lubricate joints and have a cushioning effect
- can become inflamed and this can be very problematic and painful
Which direction is dislocation of the shoulder most likely to be?
- downwards -> up is prevented by bone and sideways by muscles of the rotator cuff
What are the arteries of the shoulder and arm?
- subclavian -> axillary -> brachial -> ulnar and radial arteries
Describe the venous drainage of the shoulder and arm.
- in limbs, venous return is via superficial and deep vessels
- deep return essentially mirrors the arterial supply
- COMPLICATION: veins in the deep return are not single veins (often a pair, sometimes more) -> are closely opposed to the artery, sometimes with communicating branches (venae communicantes)
- cephalic vein (superficial) runs up lateral border of arm
- basilic vein (superficial) runs up the medial border of arm
- axillary vein becomes the subclavian vein at the level of the first rib
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Which lympathic vessels are important in breast cancer?
- axillary lymph nodes
Which lympathic vessels are at risk of damage in surgery?
- long thoracic nerve and thoracodorsal nerve
What are the 5 largest nerves of the brachial plexus?
- axillary nerve
- musculocutaneous nerve
- ulnar nerve
- median nerve
- radial nerve
What nerve supplies the pectoral muscles?
- pectoral nerves
Which nerve do you hit when you bang your elbow?
- ulna nerve -> wraps around the medial epicondyle of the humerus
Which nerve is at most risk of damage when the shoulder is dislocated?
- axillary
Name the bones in the elbow, forearm and wrist.
o Humerus
o Radius
o Ulna
o Carpal Bones
- proximal row: scaphoid, lunate, triquetrum, pisiform
- distal row: trapezium, trapezoid, capitate, hamate
Where does the radius join with the humerus?
- anterior border of the head of radius is received by the radial fossa in forearm flexion
Where does the ulna join with the humerus?
- coronoid process of the ulna fits into the coronoid fossa
- olecranon fossa – it receives the olecranon process of the ulna
Which area of the radius is linked with the bicep?
- tuberosity of the radius is an important attachment for biceps brachii
What connects the ulna to the radius?
- a fibrous membrane called the interosseous membrane
What is the function of the interosseous membrane?
o forces are transmitted between the ulna and radius so is mechanical support
o acts as a partial or complete attachment site for muscles
- seperates the anterior and posterior compartments of the forearm
What is the annular ligament?
- a strong band of fibres that encircles the head of the radius, and retains it in contact with the radial notch of the ulna
Which proximal bone does not articulate with the ulna and radius row?
- pisiform
What is the pisiform?
- a sesamoid bone -> a bone that forms within a tendon -> another example of a sesamoid bone is the patella
Which of the anterior arm muscles cross in the forearm?
- both the biceps and brachialis BUT NOT the coracobrachialis
- are powerful flexors of the forearm at the elbow joint
- biceps are an important supinator (acts on the radial tuberosity)
Which nerve supplies the anterior compartment of the arm?
- musculocutaneous nerve (C5, 6)
Which posterior arm muscles extend to the elbow?
- both the tricep and anconeus
- 3 heads of the tricep converge to form a triceps tendon, which crosses the elbow joint posteriorly and attach to the olecranon process of the ulna
- anconeus attaches to the lateral epicondyle of the humerus and the lateral and upper part of the ulna shaft -> small muscle that is involved in stabilisation during certain movements
What nerve supplies the posterior compartment of the arm?
- radial nerve
What are the compartments of the forearm?
- anterior superficial -> flexors
- anterior deep -> flexors
- posterior -> extensors
What is the purpose of the forearm muscles?
- remote control of the hand and wrist
- whole purpose of the upper limb revolves around hand movement control
What are the 5 muscles of superficial anterior compartment of the forearm?
- pronator teres (PT)
- flexor carpi radialis (FCR)
- palmaris longus (PL)
- flexor digitorum superficialis (FDS)
- flexor carpi ulnaris (FCU)
What muscles are in deep anterior compartment of the forearm?
- flexor digitorum profundus (FDP)
- flexor pollicis longus (FPL)
- pronator quadratus (PQ)
What is the medial epicondyle?
- a point on the distal humerus -> the COMMON FLEXOR TENDON -> many muscles, particularly the superficial region, these muscles fan out from the common flexor to attach to different points
What does the pronator teres do?
- wraps around the radius -> when it contracts it pulls it to pronate (turn the limb so that the palm is facing downwards or inwards) the arm
What are the roles of the flexor carpi radialis and the flexor carpi ulnaris?
- flexor of the wrist on the radial and ulnar side respectively
What does the pronator quadratus do?
- a small quadrate muscle that attaches at the anterior surfaces of the distal part of the shafts of radius and ulna -> contraction causes bones to close over on one another
What is the common way to emphasise the position of the common flexor origin?
What is the the deep fascia of the forearm?
- the antebrachial fascia -> is continuous with the brachial fascia
- is a dense, membranous investment, which forms a general sheath for the muscles in this region
Where is the antebrachial fascia attached?
- to the olecranon and dorsal border of the ulna
What emerges with the antebrachial fascia?
- the bicipital aponeurosis merges with the antebrachial fascia
What is the retinaculum?
- tough band of connective tissue found close/at the joints -> holds down lots of tendons
What muscles move the wrist joint?
- extensor carpi radialis longus (ECRL)
- extensor carpi radialis brevis (ECRB)
- extensor carpi ulnaris (ECU)
What are the mucles that move the digits?
- extensor digitorum (ED)
- extensor indicis (EI)
- extensor digit minimi (EDM)
What muscles move the thumb?
- abductor pollicis longus (APL)
- extensor pollicis brevis (EPB)
- extensor pollicis longus (EPL)
What are the muscles of the posterior/extensor compartment of the forearm?
- extensor carpi radialis longus (ECRL)
- extensor carpi radialis brevis (ECRB)
- extensor carpi ulnaris (ECU)
- extensor digitorum (ED)
- extensor indicis (EI)
- extensor digit minimi (EDM)
- abductor pollicis longus (APL)
- extensor pollicis brevis (EPB)
- extensor pollicis longus (EPL)
- brachioradialis
- supinator
Where is the most common sites of proximal attachments of posterior muscles?
- shaft of the ulnar or radius and interosseous membrane
What is the supinator muscle?
- wraps around the radius -> when the forearm is pronated its action supinates it
What bone is most commonly broken in a fall?
- the scaphoid
How can the scaphoid be located/assessed?
- in the anatomical snuff box
- tendons of extensor pollicis longus and extensor pollicis brevis -> if you extend the thumb, there is a small depression
Describe the elbow joint.
- the joint between the capitulum and trochlea of the distal humerus, and the head of radius and proximal part of ulna -> the radius articulates with the capitulum (lateral) and the ulna with the trochlea
- a synovial joint
What ligaments are assocaited with the elbow joint?
- collateral ligaments (both ulnar and radial) -> prevent deviation (adduction and abduction)
- radial annular ligament wraps around the neck of radius -> allows for rotation
What movements are possible with the elbow joint?
- flexion
- extension
What is the difference between the carrying angle at the elbow when comparing the sexes?
- women = >15 degrees
- men = 10-15 degrees
- obvious reason being the relative width of the pelvis
Describe the proximal radio-ulnar joint.
- the head of radius is held close to the proximal part of ulna -> it has an articular surface that articulates with the capitulum as part of the elbow joint (head of radius)
- the JOINT also has a trochlear articulating surface (proximal part of ulna)
- on the joint is a rim, allowing the head of radius to also articulate with the radial notch of ulna
Why is there a bigger gap between the ulna and the carpal bones than the radius?
- there is an intervening articular disc -> it articulates with the disc which articulates with the carpal bones
What muscles are involved in flexion of the elbow?
- brachialis
- biceps
- (brachioradialis)
- (pronator teres)
What muscles are involved in extension of the elbow?
- tricep
- (anconeus)
What muscles are involved in supination of the radio-ulnar joint?
- supinator
- bicep
- (EPL)
- (ECRL)
What muscles are involved in pronation of the radio-ulnar joint?
- pronator quadratus
- pronator teres
- (FCR)
- (PL)
- (brachioradialis)
Describe the position of the pronator teres and the supinator in the supine/anatomical and prone position?
- in the supine position: the pronator teres is stretched around the bone, pronator quadratus is stretched into its approximately quadrate shape and the supinator has contracted here, and has pulled the radius round so that the bones are parallel
- in the prone position, the pronator teres has contracted and has rotated the radius round, as has pronator quadratus
Where is the pronator teres attached?
- lateral side of the shaft of the radius and the medial head of the humerus
What muscles are important in the flexion of the wrist?
- flexor carpi radialis
- flexor carpi ulnaris
What muscles are important in the extension of the wrist?
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor carpi ulnaris
What muscles are important in the radial deviation (abduction) of the wrist?
- abductor pollicis longus
- flexor carpi radialis
- extensor carpi radialis longus
- extensor carpi radialis brevis
What muscles are important in the ulnar deviation (adduction) of the wrist?
- extensor carpi ulnaris
- flexor carpi ulnaris
What are the arteries of the forearm?
- at the elbow, the brachial artery divides into the ulnar and radial arteries
- ulnar artery branches almost immediately to give a common interosseous branch -> common interosseous branch immediately branches to give anterior (supplies deep structures) & posterior (posterior compartment) interosseous arteries
Where does the cephalic vein run?
- a superficial vein which runs up the lateral border of the arm
What forms the subclavian vein?
- basilic veins joins venae comitantes to form the axillary vein in the arm -> cephalic vein joins axillary vein in the axilla -> axillary vein becomes the subclavian vein at the level of the first rib
Where does the basilic vein run?
- superficially along the medial border of the arm
Where does the cephalic and basilic veins arise from?
- the dorsal venous arch of the hand
What commonly joins the cephalic and basilic veins?
- connected at the cubital fossa by the median cubital vein -> not always present or prominent
What is the clinical significance of the median cubital vein?
- commonly used in phlebotomy -> if it is absent the cephalic or basilic vein is used instead
How similar are veins and arteries paths in the arm?
- deep drainage by veins follows that of arteries -> especially in the distal regions
Describe the lympathic drainage of the forearm?
- superficial and deep systems, running with veins
- cubital lymph nodes drain the forearm (usually 3 or 4 lymph nodes, often on the medial side) -> enlargements may indicate HIV status or syphilis
- axillary nodes are also draining nodes for the distal parts of the upper limb
Describe the musculocutaneous nerve.
- C5, 6, 7
- supplies all the anterior compartment of the upper arm
- sensory to the lateral forearm as the lateral cutaneous nerve of the forearm -> terminal branch
Describe the median nerve.
- C6, C7, C8, T1
- courses through the anterior compartment of the arm (no significant branches) -> lies anterior to the elbow, with the brachial artery (easily damaged) – found in cubital fossa
- main nerve to the muscles of the forearm -> supplies LOADS of the flexors, but only HALF of the flexor digitorum profundus -> ulnar supplies the other half of the flexor digitorum profundus
Describe the ulnar nerve.
- C8, T1
- courses via the posterior compartment of the upper arm (no significant branches in the upper arm) -> lies behind the medial epicondyle at the elbow (easily damaged)
- main nerve of the hand
Describe the radial nerve.
- C5, 6, 7, 8, T1
- supplies all the muscles of the posterior compartments of the upper arm and forearm
- passes around the body of the humerus at its mid-shaft in the radial groove -> easily damaged
- divides just above the level of the elbow -> deep branch supplying the posterior interosseous nerve and the superficial branch supplying the superficial radial nerve (sensory)
Summarise the motor supply in the forearm.
- Radial Nerve supplies all posterior muscles
- Ulnar Nerve supplies only FCU and the Ulnar half of FDP
- Median Nerve supplies all of the remaining anterior muscles