BIOM2020 Notes: Origins and Insertions of Upper Body Muscles + past-exam worked answer. PDF

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BIOM2020 Notes: Origins and Insertions of Upper Body Muscles + past-exam worked answer. Osteology and pelvic girdle included too....

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BIOM2020 Notes Lecture 8; Myology of shoulder and arm Appendicular skeleton; Proximal origins, Distal insertions Pectoralis Major External structure: fan/convergent Origin: body of sternum, costocartilages 2-6, inferomedial portion of clavicle Insertion: Greater tubercule and lateral lip of intertubercular groove of humerus Function: flexion, adduction, medial (inward) rotation Pectoralis Minor (more internal underneath the major one) External structure: fan or convergent Origin: Anterosup. surfaces of ribs 3-5 Insertion: coracoid process of scapula Function: depress and protract shoulder, downward rotation of scapula, elevate ribs. Serratus Anterior External structure: serrated Origin: anterosuperior margins of ribs 1-8 or 9 Insertion: anterior surface of vertebral border of the scapula Function: protract shoulder, upward rotation of scapula (glenoid cavity points superiorly) Trapezius External structure: trapezoid Origin: occipital bone, ligamentum nuchae, spinous processes of thoracic vertebrae Insertion: clavicle, acromion, spine of scapula Function: elevate, retract, depress or rotate scapula (upward) and/or clavicle, extend the neck - Connected by a joint to the clavicle so moves acromion with the clavicle *** Muscle where it is/where the insertion sites/size of attachments are does not determine how much force it can produce – length of fibres and how *** Rhomboideus Major – rotation of scapula Trapezius Levator scapulae - All help to shrug the shoulders Latissimus Dorsi External structure: convergent Origin: spinous processes of the inferior thoracic and all lumbar vertebrae, ribs 8-12, lumbodorsal fascia Insertion: floor of intertubercular groove of humerus Function: medial rotation of humerus at shoulder joing, extension, adduction and rotation at shoulder joint

Teres Major External structure: fusiform Origin: inferior angle of scapula Insertion: medial lip of intertubercular groove of humerus Function: extension, medial rotation at the shoulder of the arm, adduct the arm Deltoid External structure: ‘Triangular’ Origin: lateral clavicle, acromion of spine of scapula (3 main points of origin) Insertion: deltoid tuberosity of humerus Function: shoulder abduction, flexion (insertion is below the origin) and medial rotation, extension and lateral rotation – visualise where muscle fibres pass Rotator Cuff - Regulate movement at the shoulder, articulation between humerus and glenoid cavity - 4 muscles; subscapularis, supraspinatus, infraspinatus, teres minor - Subscapularis; originates at the subscapular fossa of the anterior scapula, insertion at lesser tubercule of humerus - Supra/Infraspinatus and teres minor originate at the greater tubercule of the scapula - Form a set of dynamic ligaments – they wrap around the humeral head – highly mobile shoulder joint - Subscapularis – medial rotation of shoulder - Supraspinatis – abduction of shoulder - Infraspinatus – lateral rotation of shoulder - Teres minor – lateral rotation, adduction Compartments of arm - Divided by connective tissue - Flexor/extensor Biceps Brachii External structure: Fusiform, 2 heads Origin: short head = coracoid process, long head = supraglenoid tubercule Insertion: radial tuberosity and bicipital aponeurosis Function: flexion of shoulder and elbow, supination of flexed forearm Bracioradialis Origin: lateral supracondylar ridge of distal humerus Insertion: Base of styloid process of the radius Function: flexion of the elbow NOTE****Forms part of the posterolateral compartment of the forearm which is the wrist’s extensor compartment. Note however that this muscle is a FLEXOR of the ELBOW Coracobrachialis Origin: coracoid process Insertion: medial margins of humeral shaft Function: adduction and flexion of shoulder Bracialis Origin: anterior distal surface of humerus

Insertion: coronoid process of ulna Function: flexion of elbow Triceps Brachii External structure: fusiform, three heads Origin: long head=infraglenoid tubercule of scapula, lateral head = sup. Lateral margin of humerus, medial = posterior surface of humerus inferior to radial groove Insertion: olecranon process of ulna Function: extension of elbow, LONG HEAD ONLY; extension and adduction at shoulder Abductors - Supraspinatus (initiates movement) – tendon passes through a skinny space before it reaches the lateral deltoid - Lateral deltoid (contributes to the movement after initiation by the supraspinatus) - Greater tubercule swings around as you abduct Adductors (arm closer to midline) - Posterior deltoid - Long head of triceps - Teres major - Latissimus dorsi - Coracobrachialis - Pectoralis major - Anterior deltoid Shoulder flexors - Anterior deltoid - Clavicular head of pectoralis major - Coracobrachialis - Biceps brachii Shoulder extensors - Posterior deltoid - Teres major - Latissimus dorsi - Long head of triceps - Sternocostal portion of pectoralis major Scapula protractors - Pec minor – originate from axial skeleton and then to scapula - Pec major - Serratus anterior Scapula retractors - Rhomboid minor - Middle fibres of trapezius - Rhomboid major - Upper fibres of latissimus dorsi

Medial rotators (anterior) – closer to lesser tubercule - Pec major - Anterior deltoid - Subscapularis - Latissimus dorsi - Teres major Lateral rotators (lateral) – closer to greater tubercule - Teres minor - Posterior deltoid - Infraspinatus Elbow flexors - Biceps brachii - Brachialis - Pronator teres - Brachioradialis - Extensor carpi radialis longus Elbow extensors - Triceps brachii – all 3 heads - Anconeus Lecture 9; Myology of forearm and hand Compartments (brachial region) - Anterior fascial compartment – Flexor for elbow joint - FLEXION - Posterior fascial compartment – Extensor containing triceps brachii - EXTENSION - These are divided by connective tissue - Either side of humerus Compartments of forearm - Have interosseous membrane - Flexor pronator compartment - Extensor-supinator compartment - Interosseous membrane Flexor compartment - Superficial; pronator teres, palmaris longus, flexor carpi radialis, flexor carpi ulnaris - Intermediate; flexor digitorum superficialis - Deep; flexor digitorum profundus, flexor pollicis longus, pronator quadratus - Median nerve = flexor nerve

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Flexors affect any and all of joints and tendons that it runs past until where it inserts

Forearm radius and ulna ****main features**** - Olecranon - Trochlear notch - Coronoid process - Radial tuberosity - Radial notch of ulna - Ulnar notch of radius - Styloid processes Superficial flexor layer Common origin; medial epicondyle of humerus; PT also coronoid process of ulna, FCU also olecranon process Pronator teres; insertion= lateral midshaft radius (short muscle) Flexor carpi radialis; insertion= bases of metacarpal 2 + 3 Palmaris longus; insertion= palmar aponeurosis and flexor retinaculum Flexor carpi ulnaris; insertion=pisiform bone, hamate bone, base of metacarpal 5 ^^^^in order from thumb to pinky finger^^^^ Palmaris longus - Weak flexor of wrist - Tense skin of hand, proximal phalanx - Missing in 11-14% of population - Disappearing from the population Intermediate flexor layer - Flexor digitorum superficialis - Structure; gives rise to four tendons that pass through the carpal tunnel in two pairs, one superficial to the other - Origin; medial epicondyle of humerus and adjacent anterior surfaces of the ulna and the radius - Insertion; medial-lateral surfaces of the middle phalanges of fingers 2-5 - Pass beneath flexor retinaculum Deep flexor layer Flexor digitorum profundus Structure; gives rise to 4 tendons that pass through carpal tunnel side by side Origin; medial and posterior surfaces of the ulna, medial surface of coronoid process, interosseous membrane Insertion; bases of distal phalanges of fingers 2-5 - Must cross the FD superficialis on its journey to the distal phalanx Flexor pollicis longus Structure; unipennate Origin; anterior shaft of radius and interosseous membrane Insertion; base of distal phalanx of thumb

Flexors in the carpal tunnel - Pass into the hand - Tendons stacked 2 upon 2 through the carpal tunnel - Formed by; medial wall=pisiform (proximal) and hamate (distal), lateral wall=trapezium and scaphoid tubercules, floor=other carpal bones, roof=flexor retinaculum - CT syndrome; median nerve compression due to swelling of the tendon sheathes due to repetitive flexion-extension - Compartment is unyielding

Deep flexor layer (continued) Pronator quadratus Structure; square and flat Origin; anterior and medial surfaces of the distal ulna Insertion; anterolateral surface of distal portion of radius - Connects from radius to ulna - Involved in pronation Forearm pronators - Pronator teres (superficial layer) – shortened, causes radius to cross over the ulna and causes rotation along longitudinal axis - Pronator quadratus (deep layer) - Some help; brachioradialis, flexor carpi radialis Pronator quadratus - Pronates forearm - Quadrilateral shape - Arises from anterior and medial surface of distal ulna and inserts on anterolateral surface of distal radius - When fibres shorten, the radius is pulled/rotated towards/around the fixed ulna - They are antagonistic muscles

Extensor Muscle Compartment Superficial layer - Brachioradialis - Extensor carpi radialis longus - Extensor carpi radialis brevis - Extensor digitorum - Extensor digiti minimi - Extensor carpi ulnaris Deep layer - Supinator (proximal muscle) - Extensor indicis - 3 thumb muscles (abd. Pollicis longus, abd. Pollicis brevis, ext. pollicis longus)

Superficial extensor layer Brachioradialis (An EXCEPTION) Origin= lateral supracondylar ridge of distal humerus Insertion; styloid process of radius ** forms part of the posterolateral compartment of forearm which is the wrists extensor compartment. Note however that this muscle is a FLEXOR of the ELBOW - Radial nerve ~ extensor nerve Common origin; lateral epicondyle of humerus - Extensor carpi ulnaris; inserts at base of fifth metacarpal - Extensor digitorum; inserts at 4 tendons into extensor expansions and distal phalanges of digits 2-5 - Extensor digiti minimi; inserts at posterior surface of proximal phalanx of little finger Tendons (see image below)

1. Extensor retinaculum 2. Connexus intertendineus 3. Extensor expansion (hoods of material on fingers)

RADIAL SIDE 1. Extensor carpi radialis longus - Origin; lateral supracondylar ridge of humerus - Insertion; base of metacarpal 2 2. Extensor carpi radialis longus - Origin; lateral epicondyle of humerus - Insertion; base of metacarpal 3 ***These 2 muscles start off superficial but travel deep distally*** - Both muscles together; extension of wrist and some radial deviation - Both muscles and extensor carpi ulnaris – we get pure wrist extension - Circumduction – activate a combination of them - Note; corresponding insertions of FCR Deep extensor layer Supinator - Origin; lateral epicondyle of humerus and proximal ulna - Insertion; proximal radius **** the other supinator of the forearm/hand is the biceps brachii – worth noting that it inserts on to radial tuberosity, can be a useful supinator – insertion of biceps brachii can wrap around radius when supinated when the arm is flexed (not extended because not in the correct anatomical position for it to occur)**** - Acts to supinate the forearm - ‘wraps’ around radius when the hand is moved into pronated position, thus lengthening its fibres - Concentric contraction (shortening) of the fibres reverses the movement drawing it back into a supinated position - Articulations; head of radius and capitulum, proximal and distal radius and ulna joints 3 pollicis muscles (THUMB) 1. Abductor pollicis longus (abduct – away from plane of the palm) - Origin; dorsal shaft of radius and ulna

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Insertion; lateral Metacarpal 1 (& trapezium) Extensor pollicis longus Origin; dorsal shaft or radius/ulna and interosseous membrane (more distal) Insertion; base of distal phalanx of thumb Extensor pollicis brevis Origin; dorsal shaft or radius/ulna and interosseous membrane Insertion; base of proximal phalanx of the thumb

2 + 3 = form anatomical snuff box - Lateral wall = extensor pollicis brevis - Medial wall = extensor pollicis longus - Floor = mostly scaphoid, but also styloid process of the radius (proximally) and trapezium (distally) 4. Extensor indicis (index finger – more independence of movement on this finger) - Origin; posterior surface of distal ulna and interosseous membrane - Insertion; extensor expansion of index finger (joins tendon of extensor digitorum) Lack of independence of movement of the middle fingers - 3rd and 4th - They are joined by tendons – don’t have their own tendons – so they tend to sort of move eachother - Limited by connexus intertendineus Extensors of the digits and the extensor expansion Lumbricals = earthworm - Origin; tendon of flexor digitorum profundus - Insertion; lateral edge of extensor expansion on first phalanx of digits 2-5 - Function; FLEXES metacarpophalangeal joints but EXTENDS interphalangeal joints - Nerve supply; ULNAR Nerve = claw hand -

Extensor tendon joins extensor expansion

The Interossei (intrinsic muscles of the hand) Palmar Interossei (touch fingers) - Origin; side of metacarpals facing digit 3 (absent from this bone) - Insertion; extensor expansion of first phalanx (except 3) on the same side - Function; ADDUCTORS OF DIGITS (= PAD) Dorsal Interossei (spread fingers) - Origin; sides of metacarpals - Insertion; extensor expansion over first phalanx of digits 2-4, on both sides of no. 3 but opposite sides for other digits - Function; ABDUCTORS OF DIGITS (= DAB) Motor control of digits - Extrinsic and intrinsic muscles = good for precision - Extrinsic = big movements - Intrinsic = specific stuff

Extension via extensor apparatus - Metacarpophalangeal flexion

Lecture 10; Osteology and Arthrology of the Pelvic Girdle and Lower Limb Functions of pelvic limb - Weight bearing/transfer (load bearing structure – supports body weight) - Locomotion - Balance - Squatting & lifting Terminology - Pelvic girdle and pelvis - Thigh - Leg/crus region - Foot Components… Bones - Hip bones - Femur - Patella - Tibia - Fibula - Tarsals - Metatarsals - Phalanges Joints - Sacroiliac - Pubic symphysis - Hip - Tibiofemoral - Patellofemoral - Proximal tibiofibular - Distal tibiofibular - Ankle - Subtalar - Intertarsal - Tarsometatarsal - Metatarsophalangeal - Interphalangeal Pelvic girdle – does not include sacrum and coccyx Hip bones – ilium, ischium, pubis

Pelvic Girdle - 2 hip bones - Ischial tuberosity (see the star in the picture on next page) – will not be seen on specimens but can assist in orienting the bone - Big upper part = ilium - Internal part = pubis (near pubic region) - External point = ischium (contains the ischial tuberosity)

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Acetabulum/acetabula fossa = lateral view (helps to determine it) Cartilaginous joins between the 3 bones Full skeletal maturity – 25 years old Pubis and ischium fuse at 7 years of life

Hip bone features (lateral view) - Iliac crest - Posterior side = deep notches - 4 iliac spines = anterior side; anterior superior iliac spine (ASIS), anterior inferior iliac spine (AIIS) – posterior side; posterior superior iliac spine (PSIS), posterior inferior iliac spine (PIIS) – most common protuberances on iliac - Ischial spine – point on ischium bone - Ischial tuberosity - Large opening = obturator foramen - 3 lines; anterior gluteal line and inferior gluteal line – limit extent of muscle attachment Medial view

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Iliac tuberosity – rough Auricular surface – ear shape – synovial joint Greater sciatic notch – in ilium, sciatic nerve passes here Ischial spine Lesser sciatic notch – nerves for genitalia Obturator foramen is bound by the superior pubic ramus, the inferior pubic ramus and the ischial ramus (sub sects) Arcuate line and pectineal line – archaeological landmarks

The pelvis - 2 hip bones + sacrum + coccyx - 2 parts; greater (false) and lesser (true) pelvis - Greater; area superior to pelvic inlet = forms inferior part of abdominal cavity (more external near iliac bone) - Lesser; area inferior to the pelvic inlet which houses the pelvic organs (internal) - Pelvic brim is circle of lesser pelvis Male vs female - Pubic angle is 100º (larger = female) - Robust/heavy vs light/smooth - Pelvic inlet heart shaped vs round - Pelvic inlet narrow vs wide - Ilia less splayed vs laterally spread - Ilia extend superior to sacrum versus little extension - These do not always ring true - Most female features due to childbirth Sacroiliac joints - Iliac tuberosity-sacral tuberosity = sacroiliac interosseous (between bones) ligament = fibrous syndesmosis - Auricular surfaces = synovial plane joint – smooth surface that allows for free movement, a small degree of movement before interosseous ligament prevents movement Pelvic joints - Sacroiliac joints = synovial gliding and fibrous syndesmosis - Pubic symphysis = fibrocartilage symphysis - Many ligaments around the pelvis due to needing to support the entire body weight - Axial and appendicular connections - Sacrospinous ligament - Sacrotuberous ligament – ischial tuberosity - ^ above 2 ligaments prevent the sacrum from tilting anteriorly Femur - Greater trochanter and lesser trochanter – linked by intertrochanteric crest (posteriorly) - Anterior; intertrochanteric line, patellar surface, epicondyles vs condyles

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Posterior; gluteal line, linea aspera (lines the entire bone basically), intercondylar fossa Both; fovea, GT, LT, pectineal line, supracondylar ridges, adductor tubercule

Pectoral vs pelvic girdle - Articular cartilage is pearly smooth when healthy at femur, develops osteoarthritis later in life (progressive disease) – more so than pectoral - Hip joint; Synovial ball and socket; multiaxial diarthrosis - The shoulder joint has more movement I think Leg bones; tibia and fibula (paired) - Fibula always sits laterally - Proximal portion of tibia; condyles and intercondylar eminence (raised tubercules) - Tibia; medial and lateral articular surfaces (not as curved), soleal line - Distally; Medial (tibia) and lateral malleolus (fibula) - Proximal and distal joints between both bones – do not allow movement of the forearm - Tibia supports 80% of the body weight Bones of knee joint - Femur, patella, tibia, fibula - Tibial plateau (articular surface) - A synovial modified hinge joint; uniaxial diarthrosis – femur slides relative to tibia – patella plays no role in articulation - Medial femoral condyle > lateral femoral condyle; results in some rotation about long axis of bone during flexion-extension of the knee - Tibiofemoral joint; results in twisting and stretching of ligaments to lock the knee in extension - Meniscus between lateral and medial epicondyles – ligaments maintain the joint - Fibular and tibular collateral ligaments; prevent leg from deviating in adduction or abduction ways – stabilises knee - Cruciate ligaments – cross like – stabilise and control – connect with medial meniscus (bad thing for injury – stretching forces – tears the meniscus as well as the ACL)

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Fibrocartilaginous menisci act as ‘space-fillers’ to improve joint congruency and thus reduce joint stress… often torn in knee injuries Medial is fixed, lateral is mobile Both menisci are crescent shaped – where the condyles sit – bathed in synovial fluid Functional role of patella; centre of rotation for flexion and extension of knee joint, moves tendon away from centre of rotation and increases the moment arm, less strength needed – a sesamoid bone – effective knee extension mechanism Patellofemoral joint; synovial gliding joint: non-axial diarthrosis, articulates with anterior femur, held in place with many ligaments, 2 facets and a large lateral facet and a large medial facet (articulate with the femur)

Tibiofibular joints - Proximal – synovial gliding joint, non-axial diarthrosis (compare to elbow joint) - Distal – fibrous syndesmosis, amphiarthrosis (compare to distal radioulnar joint) - Tibiofibular interosseous membrane Bones of foot (7 tarsals) - Calcaneus (hee...