MSK Flashcards
What nerves supply pectoralis major and minor?
Medial pectoral nerve (C8 - T1)
Pectoralis major also supplied by lateral pectoral nerve (C5-C7)
What nerve supplies serratus anterior?
Long thoracic nerve (C5 - C7)
What happens if serratus anterior is paralysed?
Normally due to damaged long thoracic nerve. Medial scapula is rotated laterally and posteriorly - winged scapula
Upper limb can’t abduct beyond 90 degrees
What are the boundaries of the axilla?
Apex - cervicoaxillary canal formed by first rib, clavicle and superior edge of scapula
Base - Concave skin, subcutaneous tissue and axillary fascia
Anterior border - Pectoralis major underlying fascia
Posterior border - scapula and subscapularis
Medial border - Thoracic wall and ribs 1-4, intercostals and serratus anterior
Lateral border - Coracobrachialis and intertubecular groove of humerus
What are the contents of the axilla?
Axillary artery and vein
Axillary lymph nodes
Cords and branches of brachial plexus
What can an axillary artery aneurysm cause?
Compression of brachial plexus causing pain and anaesthesia of supplied skin
What are some complications of axillary clearance?
Lymphoedema in arm as lymph can’t drain
Can damage thoracodorsal or long thoracic nerve causing weakened medial rotation of upper limb and winged scapula
In limb development, what is the function of the Apical Ectodermal Ridge?
Induces underlying mesenchyme to stay undifferentiated and also induces development of digits
In limb development, what is the purpose of the Zone of Polarising Activity?
Maintains AER and also separates dorsal from ventral to generate asymmetry
What is the difference between syndactyly and polydactyly?
Syndactyly is fusion of digits, either by just connective tissue or by bone
Polydactyly is where extra digits form
What is ameila?
Complete absence of a limb
What is meromelia?
Partial absence of one or more limb structures
May be due to dysfunction AER
(eg phocomelia, associated with thalidomide exposure
In embryonic development, what does limb rotation achieve?
Originally, thumbs and big toes face up with elbows and knees out.
Upper limbs rotate laterally so thumbs are facing out and elbows face backwards
Lower limbs rotate medially so knees face up/forwards and soles face down
What forms the coracoacromial arch and why is it important?
Coracoacromial ligament, acromion, coracoid process and humeral capsule
Prevents upper displacement of humerus but is very tight space so inflammation quickly causes problems - painful arc syndrome
What are the 4 rotator cuff muscles and what are they innervated by?
Suprapinatus - suprascapular nerve (C4-6)
Infraspinatus - suprascapular nerve
Teres minor - Axillary nerve (C5, 6)
Subscapularis - Upper and lower subscapular nerves (C5 - 7)
What is frozen shoulder?
Adhesive fibrosis and scarring between subacromial bursa, deltoid, capsule and rotator cuff muscles, due to dislocation, muscle tears or tendinitis. Can only abduct shoulder above 45 degrees by elevating and rotating scapula
What nerves supply the muscles of the anterior forearm?
All muscles innervated by median nerve (c5-t1) except flexor carpi ulnaris and median half of flexor digitorum profundus - ulnar nerve (C7 -T1)
What are the boundaries of the cubital fossa?
Superior is imaginary line between two epicondyles
Medial is Pronator teres
Lateral is Brachioradialis
What are the contents of the cubital fossa lateral to medial?
Radial nerve
Biceps Tendon
Brachial artery
Median nerve
What are the three stages of development of osteoarthritis?
Extensive proteolytic breakdown of cartilage matrix
Fibrillation and erosion of cartilage and breakdown products are released into the synovium.
Products are taken up by synovial cells and this stimulates an inflammatory response
What causes septic arthritis?
Bacteria gets into joint space and damages articular cartilage. Bacteria/virus then releases chondrocyte proteases which stimulates a host immune inflammatory process
What is the process behind rheumatoid arthritis?
Ideopathic but there’s hyperplasia of synovium, forming a pannus which stimulates endothelial cells and triggers an immune response, destroying cartilage, bone, tendons, ligaments and blood vessels
What nerves innervate the muscles of the hand?
All innervated by ulnar nerve apart form Lateral 2 lumbricals, opponens pollicis, Abductor pollicis brevis and flexor pollicis brevis (LOAF)
What are the contents of the carpal tunnel?
4 tendons of flexor digitorum profundus
4 tendons of flexor digitorum superficialis
1 tendon of flexor pollicis longus
1 median nerve