Upper Limb Flashcards
What is the medial wall of the axilla?
The thoracic wall
What is the anterior wall of the axilla?
Pectoralis major and Pectoralis minor
What is the posterior wall of the axilla?
The anterior surface of the scapula and latissimus Doris and teres major (inferiorly)
What forms the base of the axilla?
Subcutaneous tissue and axillary fascia
What forms the posterior axillary fold of the axilla?
Latissimus Doris and Teres major
What forms the anterior axillary fold of the axilla?
Pec major
What forms the apex of the axilla?
The cervicoaxillary canal
What are the contents of the axilla?
Axillary artery Axillary vein Cords of the brachial plexus Biceps brachial and coracobrachialis tendons Axillary lymph nodes
What are the 3 parts of the axillary artery?
1st part = medial to pec minor
2nd part = posterior to pec minor
3rd part = lateral to pec minor
What is axillary clearance and what damage can it cause?
The removal of axillary lymph nodes, used as a treatment in breast cancer.
Possible damage to the long thoracic nerve
What is the medial border of the cubital fossa?
Pronator teres
What is the lateral border of the cubital fossa?
Brachioradialis
What is the superior border of the cubital fossa?
An imaginary line between the two epicondyles
What forms the floor of the cubital fossa?
The brachialis muscle and supinator muscle
What forms the roof of the cubital fossa?
Brachial and antebrachial fascia, subcutaneous tissue and skin
What are the contents of the cubital fossa (lateral to medial)?
Radial nerve
Biceps brachii tendon
Brachial artery
Median nerve
Where can the brachial pulse be felt?
By palpating it immediately medial to the biceps brachii tendon in the cubital fossa?
What is thoracic outlet syndrome?
Compression of the vessels and nerves between the bones at the apex of the axilla.
Occurs in trauma (eg fractured clavicle) and in repetition.
Presents with pain, tingling, muscle weakness, discolouration
Why is the glenohumeral joint the most mobile but least stable joint?
The glenoid cavity is very shallow
The articulating surfaces have disproportionate surface area (humeral head much larger)
It allows multiplanar movements
It has a lax capsule
What ligaments stabilise the shoulder joint?
Intra-capsular: 3 Glenohumeral ligaments (superior, middle and inferior)
Extra-capsular: coracoacromial, coracohumeral, transverse humeral (holds tendon of long head of biceps in place) coracoclavicular
What is the Coracoacromial Arch?
The arch made by the coracoid process, the coracoacromial ligament and the acromion.
Stabilises the shoulder joint superiorly and prevents upper displacement of the humerus.
What stabilises the shoulder joint?
Tendons of the rotator cuff muscles Coracoacromial Arch Capsule Ligaments Glenoid labrum The splinting effect of the long head of the biceps and triceps
Name 2 bursa in the shoulder joint and explain their location and why they are important
Subscapular bursa between the subscapularis tendon and the scapular. Reduces wear and tear on the tendon during movement at the shoulder joint.
Subacromial bursa inferior to the deltoid and acromion, superior to the supraspinatus tendon and joint capsule. Facilitates movement of the supraspinatus tendon under the CAA & deltoid.
What is the blood supply to the shoulder joint?
Anterior and posterior circumflex humeral arteries and the suprascapular artery
What structures are vulnerable to injury during an intramuscular injection in the deltoid?
The axillary nerve
The posterior circumflex artery
How and in which direction does dislocation of the shoulder joint usually occur? What structure could it damage?
Usually caused by trauma on an abducted arm.
Occurs in an inferior direction, humeral head locates anteriorly (below the coracoid process) due to the pull of powerful abductors.
Capsule and rotator cuff muscles may tear.
Possible axillary nerve damage
How is axillary nerve damage indicated?
Paralysis of the deltoid - loss of abduction over 15 degrees
Loss of sensation in the regimental badge area.
What is the lateral wall of the axilla?
The intertubercular sinus of the humerus
What is painful arc syndrome?
The supraspinatus tendon rubbing under the CAA, causes irritation and inflammation of the tendon and subacromial bursa (bursitis). Causes pain during 50-130 degrees of abduction due to impingement of tendon & bursa between acromion and head of humerus.
Caused by repetitive overuse, age, avascularity of the tendon.
Why does the shoulder dislocate inferiorly?
It it the least supported. No tendons etc.
Supported superiorly by the CAA
What type of joint is the acromioclavicular joint?
Plane joint
What ligaments strengthen the acromioclavicular joint?
Acromioclavicular ligament Coracoclavicular ligament (conoid and trapezoid parts)
How may damage to the musculocutaneous nerve occur and how is it detected?
Can occur because of compression due to muscle hypertrophy/entrapment between the biceps aponeurosis and brachialis fascia.
Causes weakness of flexion at the elbow and shoulder, and of supination of the forearm
How may damage to the radial nerve occur and how is it detected?
Can during a mid-shaft fracture of the humerus, sleeping with arm in awkward position, pressure from leaning arm over the back of a chair, using crutches.
Causes loss of extension of the wrist and fingers “wrist drop”, weakness of supination, weakness in hand grip