Upper Limb Anatomy 1 & 2 Flashcards
What is the axilla?
The pyramidal space below the shoulder joint - provides passage for the vessels and nerves going to and from the upper limb
Which muscles make up the anterior wall of the axilla?
Pectoralis major and minor
Which muscles make up the posterior wall of the axilla?
Subscapularis
Which structures make up the medial wall of the axilla?
Thoracic wall and serratus anterior
Which structure forms the lateral wall of the axilla?
Intertubercular groove of the humerus
The axillary artery is a continuation of which artery?
Subclavian
At which anatomical point does the axillary artery begin?
The lateral border of the 1st rib
The axillary artery continues beyond the axilla as which vessel?
Brachial artery
At what anatomical point does the axillary artery become the brachial artery?
Lower border of teres major
Name the roots of the brachial plexus?
Anterior rami of C5-T1
Which nerve roots form the upper trunk of the brachial plexus?
C5 and C6
What is Erb’s point?
The site of the upper trunk of the brachial plexus (2-3cm above the clavicle
What is the clinical relevence of Erbs point?
Injury to the upper trunk results in Erb’s palsy in which the upper limb becomes medially rotated with the wrist flexed
What is the cause of Erb’s palsy?
Hyper-extension of the head from the shoulder: fall on the shoulder, birth injury or during anaesthesia
Which roots of the brachial plexus contribute to the lower trunk?
C8 and T1
What happens when the lower trunk of the brachial plexus is damaged?
Klumpke’s Palsy - affects the intrinsic muscles of the hand and ulnar flexors of the wrist and fingers - caused by undue abduction of the arm
List the branches of the lateral cord of the brachial plexus
- Lateral pectoral
- Lateral root of the median n.
- Musculocutaneous
- Median
List the branches of the medial cord of the brachial plexus
- Medial pectoral
- Ulnar
- Radial root of the median n.
- Medial cutaneous nerve of the arm
- Medial cutaneous nerve of the forearm
List the branches of the posterior cord of the brachial plexus
- Thoracodorsal n.
- Axillary
- Radial
- Upper/lower subscapular n.
Which venous plexus lies on the back of the hand>
Dorsal venous arch
Which vein arises at the lateral end of the dorsal venous arch?
Basilic vein
Which vein arises from the medial end of the dorsal venous arch?
Cephalic vein
Which vein shunts blood between the cephalic vein and basilic vein?
Median cubital vein
What are the five groups of axillary nodes?
- Anterior or pectoral
- Posterior or subscapular
- Apical
- Central
- Lateral
Where do all the lymphatic vessels from the upper limb drain?
Axillary nodes
Which bones make up the pectoral girdle?
- Humerus
- Scapula
- Clavicle
Which part of the clavicle is most prone to breakages?
Middle 3rd - most prominent and it changes to concave from convex at this point
What type of synovial joint is the acromioclavicular joint?
Plane
What type of synovial joint is the sternoclavicular?
Saddle
Which muscles are involved in elevation of the scapula?
Trapezius and levator scapulae
Which muscle is involved in depression of the scapula?
Lower trapezius
Which muscle is involved in protraction (movement forward) of the scapula?
Serratus anterior
Which muscles are involved in retraction of the scapula?
Trapezius (middle fibres) and rhomboids
Which muscles are involved in lateral rotation (elevating the glenoid cavity) of the scapula?
Upper and middle trapezius
Which muscles are involved in medial rotation (downward) of the scapula?
Gravity, levator scapulae, rhomboids and pectoralis minor
List the scapular muscles
- Transverse trapezius
- Levator scapulae
- Rhomboid minor
- Rhomboid major
- Supraspinatus
- Infraspinatus
- Teres minor
- Latissimus dorsi
What is the name of the cartilage that surrounds the glenoid cavity?
Glenoid labrum
What is the function of the glenoid labrum?
Keeps the head of the humerus in place and reduces friction
Which structures make up the coraco-acromial arch and what does it do?
- Acromial process and coracoid process of the scapula
- Coraco-acromial ligament
- Prevents superior displacement of the humeral head
Which part of the shoulder joint capsule is the weakest?
Inferior - not protected by muscles or ligaments
Which bursa communicates with the shoulder joint cavity?
Subscapular
Name the rotator cuff muscles
Subscapularis, supraspinatus, infraspinatus and teres minor
What is the function of the rotator cuff muscles?
- Abduction and medial + lateral rotation
- Stabilisation and support of the shoulder joint
What are the actions of the deltoid muscle on the shoulder?
- Anterior fibres: medial rotation and flexion
- Middle fibres: abduction
- Posterior fibres: lateral rotation and extension
What is the nerve supply to the deltoid muscle?
Axillary n.
Where do you test for axillary nerve sensation?
C5/6 - regimental badge area
What is the action of pectoralis major on the shoulder joint?
Adduction and medial rotation of the humerus
Which structures make up the border of the deltopectoral triangle?
- Clavicle
- Deltoid muscle
- Pectoralis major
Which vein is found in the deltopectoral triangle?
Cephalic vein
What are the functions of serratus anterior?
- Protraction of the scapula
- Stabilisation of the scapula during limb movements
- Holding the scapula against the thoracic cage
What is the innervation of serratus anterior?
Long thoracic (C5-7)
What are the actions of trapezius muscle?
- Superior fibres: elevation of the scapula
- Middle fibres: retract the scapula
- Inferior fibres: depress the scapula
What is the innervation of the trapezius muscle?
Accessory (CrN XI)
What are the actions of teres major on the shoulder joint?
Adduction, medial rotation and extension
What are the actions of latissimus dorsi on the shoulder joint?
Adduction, extension and internal rotation
What are the two heads of the biceps brachii?
Long and short
What is the action of biceps brachii ?
- Flexes elbow and shoulder joints
- Supinates the radio-ular joint
What is the innervation of biceps brachii?
Musculocutaneous (C5/6)
What are the actions of coracobrachialis?
Flexion, adduction and stabilising of the shoulder joint
What is the nerve supply of coracobrachialis?
Musculocutaneous
What is the main action of brachialis?
Flexion of the elbow
What is the innervation of brachialis?
Musculocutaneous
Describe the path of the musculocutaneous nerve
- Arises from the lateral cord of the brachial plexus
- Enters the arm by perforating the coraco-brachialis muscle and descends between biceps and brachialis
- Continues as lateral cutaneous nerve of the foreaem
What is the root value of musculocutaneous nerve?
C5-7
Which artery is a continuation of the axillary artery?
Brachial artery
What are the roots of the median nerve?
Medial and lateral cord of the brachial plexus
What is the root of the ulnar nerve?
Medial cord of the brachial plexus
Name the three common sites on the humerus where nerves can be damaged
- Radial groove: radial nerve
- Medial epicondyle: ulnar nerve
- Surgical neck: axillary nerve
List the structures that make up the borders of the cubital fossa
- Base: line between the medial and lateral epicondyles
- Medial border: pronator teres muscle
- Lateral border: brachioradialis
Name the contents of the cubital fossa
Radial nerve, biceps tendon, brachial artery and median nerve
Which muscle occupies the entire posterior compartment of the arm?
Triceps
What is the main action of the triceps muscle?
Extension
What is the action of the aconeus muscle and what is its innervation?
- Extension of the forearm
- Radial n.
What are the nerve roots of the radial nerve?
C6-8 and T1
What is the characteristic clinical sign of a radial n. injury?
Wrist drop of the forearm
Name the three ligaments of the elbow joint
- Ulnar collateral ligament
- Radial collateral ligament
- Anular ligament
Name the flexors of the elbow joint
- Brachialis
- Biceps brachii
- Coracobrachialis
Name the extensors of the elbow joint
Triceps and acroneus
What is the function of the annular ligament
It holds the head of the radius in place
Name the muscles with supinate the forearm
- Supinator
- Biceps brachii
Name the muscles which pronate the forearm
- Pronator quadratus
- Pronator teres
Which muscle is the most powerful supinator of the forearm?
Biceps brachii
Which muscle is the most powerful pronator of the forearm?
Pronator quadratus