MHS1101 Lecture 7 Upper Limb 2 PDF

MHS1101: LECTURE 7 UPPER LIMB 2 LEARNING OUTCOMES By the end of this lecture you should be able to:  Describe the origins, insertions & actions of the flexor muscles of the forearm  Describe the origins, insertions & actions of the extensor muscles of the forearm  Describe the nerve and blood su...

MHS1101: LECTURE 7 UPPER LIMB 2 LEARNING OUTCOMES By the end of this lecture you should be able to:  Describe the origins, insertions & actions of the flexor muscles of the forearm  Describe the origins, insertions & actions of the extensor muscles of the forearm  Describe the nerve and blood supply to the upper limb FLEXOR COMPARTMENT OF THE FOREARM ▪ superficial & deep compartments [fascia] ▪ superficial muscles share a common origin - medial epicondyle of humerus [+] ▪ deep muscles arise from the radius & ulna & interosseous membrane (I-O) FLEXOR COMPARTMENT OF THE FOREARM Superficial compartment ▪ palmaris longus ▪ pronator teres ▪ flexor carpi radialis ▪ flexor carpi ulnaris ▪ flexor digitorum superficialis FLEXOR COMPARTMENT OF THE FOREARM Palmaris longus ▪ origin: medial epicondyle of humerus ▪ insertion: palmar aponeurosis [tendon degenerated] ▪ action: flexion of forearm (v. weak) & wrist; tendinous insertions to MPJ – weak ▪ nerve supply: median nerve ▪ ?flexion of proximal phalanges ▪ may assist with thumb flexion ▪ missing in +/- 13% - variable - population or sex differences ▪ present in orangs (?climbing), variable in chimps & gorillas ▪ tendon used in graft surgical repair FLEXOR COMPARTMENT OF THE FOREARM Pronator teres ▪ origin: medial epicondyle of humerus, coronoid process of ulna ▪ insertion: radial shaft – lateral aspect ▪ action: flexion of elbow & forearm pronation ▪ nerve supply: median nerve FOREARM ROTATION ▪ proximal & distal radio-ulnar joints ▪ rotation of radius over ulna ▪ pronation & supination ▪ full supination – anatomical position ▪ adaptation to brachiation (c) Pronation (a) Supination FIG. 10.26 Copyright © McGraw-Hill Education. Permission required for reproduction or display. FLEXOR COMPARTMENT OF THE FOREARM Flexor carpi radialis ▪ origin: medial epicondyle of humerus ▪ insertion: bases of 2nd & 3rd metacarpals ▪ action: flexion forearm & wrist, & radial deviation (abduction) of wrist ▪ nerve supply: median nerve FLEXOR COMPARTMENT OF THE FOREARM Flexor carpi ulnaris ▪ origin: medial epicondyle of humerus, upper posterior border of ulna ▪ insertion: pisiform, hook of hamate & base of 5th metacarpal ▪ action: flexion forearm & wrist, ulnar (medial) deviation/adduction of wrist ▪ nerve supply: ulnar nerve FLEXOR COMPARTMENT OF THE FOREARM Flexor digitorum superficialis ▪ origin: medial epicondyle, radius ▪ insertion: split to insert on middle phalanges of 4 fingers ▪ actions: flexion of elbow, wrist, proximal I-P joints ▪ nerve supply: median nerve ▪ strongest when wrist extended ▪ extensors act as antagonists to reduce excess movement at wrist ▪ act as synergists in finger flexion FLEXOR COMPARTMENT OF THE FOREARM Deep Compartment ▪ flexor digitorum profundus ▪ flexor pollicis longus ▪ pronator quadratus FLEXOR COMPARTMENT OF THE FOREARM Flexor digitorum profundus ▪ origin: upper anterior & medial ulna & interosseous membrane ▪ insertion: distal phalanges of 4 fingers ▪ actions: flexion of elbow, wrist, distal I-P joints ▪ nerve supply: median & ulnar nerve ▪ bulkiest, essential for gripping, strongest when wrist extended FLEXOR COMPARTMENT OF THE FOREARM Flexor pollicis longus ▪ origin: anterior radius & interosseous membrane ▪ insertion: distal phalanx of thumb ▪ actions: flexion of thumb (& wrist, when thumb fixed) ▪ nerve supply: median nerve FLEXOR COMPARTMENT OF THE FOREARM Pronator quadratus ▪ origin: distal anterior ulna ▪ insertion: distal anterior radius ▪ actions: pronation of forearm ▪ nerve supply: median nerve NERVE SUPPLY TO THE FOREARM ▪ flexor compartment - median & ulnar nerves NERVE SUPPLY TO THE FOREARM ▪ median nerve: enters forearm through 2 heads of pronator teres ▪ ulnar nerve: grooves the medial epicondyle & passes into flexor carpi ulnaris ▪ radial nerve: pierces supinator ▪ sites of nerve compression NERVE SUPPLY TO THE FOREARM median nerve: all anterior compartment muscles except flexor carpi ulnaris & medial 1/2 flexor digitorum profundus ulnar nerve: medial 1/2 flexor digitorum profundus & flexor carpi ulnaris BLOOD SUPPLY TO THE FOREARM o ▪ brachial artery – divides into radial & ulnar arteries [cubital fossa] ▪ anastomotic branches supply elbow joint BLOOD SUPPLY TO THE FOREARM radial artery ▪ lateral side of forearm, covered by skin, superficial & deep fasciae ▪ at wrist, runs dorsally to enter anatomical snuff-box ▪ passes through 1st dorsal interosseous muscle to enter palm BLOOD SUPPLY TO THE FOREARM ulnar artery ▪ larger; initially lies deep to superficial compartment muscles ▪ gives rise to common interosseous [I-O] artery just below radial tuberosity ▪ divides into anterior & posterior I-O arteries on either side of membrane ▪ crosses over flexor retinaculum – accompanied by ulnar nerve ▪ distally becomes more superficial – pulse palpated deep to flexor carpi ulnaris INTRODUCTION TO THE WRIST & HAND FASCIA OF WRIST & HAND ▪ tough bands fibrous tissue across wrist - thickenings of deep forearm fascia flexor and extensor retinaculae across the wrist ▪ attach to bones of the proximal and distal rows of carpal bones ▪ lined by synovial sheath ▪ bind long tendons at wrist, prevent bow-stringing ▪ attachment for intrinsic muscles of hand FLEXOR & EXTENSOR RETINACULAE Flexor Photos © McGraw-Hill Education Extensor FASCIA OF WRIST & HAND Palmar aponeurosis ▪ thin triangular sheet ▪ tough connective tissue ▪ apex attached to flexor retinaculum ▪ central, covers tendons in palm ▪ forms insertion of palmaris longus FIBROUS FLEXOR SHEATHS ▪ tendons at wrist in ‘tunnels’ surrounded by synovial membrane ▪ synovium ensures that tendons ‘glide’ freely in fibrous sheaths CARPAL TUNNEL ▪ flexor surface at wrist ▪ flexor retinaculum attached to carpal bones - creates osseo-fibrous tunnel ▪ non-elastic, non-distensible ▪ contains long tendons to fingers & median nerve www.homecast.net CARPAL TUNNEL SYNDROME ▪ median nerve compression ▪ females > males, middle-age, bilateral – 50% Causes ▪ synovial inflammation (RA) ▪ fluid retention (pregnancy) ▪ fractures, osteophytes ▪ hypothyroidism – oedema in connective tissues ▪ impaired kidney function CARPAL TUNNEL SYNDROME Symptoms ▪ tingling, burning sensation, numbness ?night ▪ impaired cutaneous sensation to fingers, palm & thumb ▪ thenar muscle weakness EXTENSOR COMPARTMENT OF THE FOREARM EXTENSOR COMPARTMENT OF THE FOREARM ▪ superficial & deep compartments ▪ superficial: common extensor origin (lateral epicondyle of humerus) ▪ deep: radius & ulna EXTENSOR COMPARTMENT OF THE FOREARM Superficial Group ▪ brachioradialis ▪ anconeus ▪ extensor carpi radialis longus ▪ extensor carpi radialis brevis ▪ extensor carpi ulnaris ▪ extensor digitorum communis ▪ extensor digiti minimi EXTENSOR COMPARTMENT OF THE FOREARM Deep Group ▪ supinator ▪ extensor indicis ▪ extensor pollicis longus ▪ extensor pollicis brevis ▪ abductor pollicis longus EXTENSOR COMPARTMENT OF THE FOREARM Brachioradialis ▪ origin: lateral supracondylar line of humerus ▪ insertion: distal radius, above styloid process ▪ actions: flexion of forearm ▪ nerve supply: radial nerve EXTENSOR COMPARTMENT OF THE FOREARM Anconeus ▪ origin: lateral epicondyle of humerus ▪ insertion: posterior ulna, olecronon process ▪ actions: extension of forearm ▪ nerve supply: radial nerve EXTENSOR COMPARTMENT OF THE FOREARM Extensor carpi radialis longus ▪ origin: supracondylar line of humerus ▪ insertion: base of 2nd metacarpal ▪ actions: extension & abduction of wrist Extensor carpi radialis brevis ▪ origin: lateral epicondyle of humerus ▪ insertion: base of 3rd metacarpal ▪ action: extension of wrist Extensor carpi ulnaris ▪ origin: lateral epicondyle of humerus, posterior border ulna ▪ insertion: base of 5th metacarpal ▪ actions: extension & adduction of wrist ▪ nerve supply: radial nerve EXTENSOR COMPARTMENT OF THE FOREARM Extensor digitorum communis ▪ origin: lateral epicondyle of humerus ▪ insertion: middle & distal phalanges of medial 4 fingers ▪ actions: extension of digits & wrist ▪ nerve supply: radial nerve DORSAL EXTENSOR EXPANSIONS ▪ insertions of extensor digitorum ▪ tendons cross dorsum of hand ▪ ▪ ▪ ▪ ▪ spread over MCP joints - hood slips to proximal phalanges central slip passes to middle phalanges lateral slips to distal phalanges – tension extends DIPJ slips to adjacent fingers www.home.comcast.net EXTENSOR COMPARTMENT OF THE FOREARM Extensor digiti minimi ▪ origin: lateral epicondyle of humerus ▪ insertion: all phalanges of 5th digit ▪ actions: extension of 5th digit ▪ nerve supply: radial nerve EXTENSOR COMPARTMENT OF THE FOREARM Supinator ▪ origin: lateral epicondyle of humerus, supinator crest of ulna ▪ insertion: lateral aspect of radius (mid region) ▪ actions: supination of forearm ▪ nerve supply: radial nerve ▪ unopposed supination – usually acts alone ▪ fast/forceful supination – works with biceps [lifting heavy objects – start in pronated position – move to supination accompanied by flexion] EXTENSOR COMPARTMENT OF THE FOREARM Extensor indicis ▪ origin: ulna & I-O membrane ▪ insertion: phalanges 2&3 of index finger ▪ actions: extension of index finger & wrist ▪ nerve supply: radial nerve EXTENSOR COMPARTMENT OF THE FOREARM Extensor pollicis longus ▪ origin: lateral, middle 1/3, posterior ulna & I-O membrane ▪ insertion: base of distal phalanx of thumb ▪ actions: extension distal phalanx of thumb ▪ nerve supply: radial nerve EXTENSOR COMPARTMENT OF THE FOREARM Extensor pollicis brevis ▪ origin: posterior radius & I-O membrane ▪ insertion: proximal phalanx of thumb ▪ actions: extension of thumb & abduction of wrist Abductor pollicis longus ▪ origin: posterior ulna & I-O membrane ▪ insertion: base of 1st metacarpal lateral ▪ actions: abduction of thumb & wrist ▪ nerve supply: radial nerve ANATOMICAL SNUFF-BOX ▪ Formed by tendons of EPL, EPB & APL ▪ dorsal, radial side ▪ scaphoid & trapezium form floor Contains: ▪ tendons of extensor carpi radialis long & brevis [cross floor of snuff-box] ▪ radial artery - radial pulse can be palpated in snuffbox [between radius & FCR] ▪ cephalic vein NERVE SUPPLY TO THE FOREARM ▪ posterior compartment - radial nerve ▪ radial nerve - pierces supinator ▪ site of nerve compression NEXT LECTURE: UPPER LIMB 3 & LOWER LIMB 1