2- Bones and the Skeleton Flashcards
How are the upper limbs attached to the axial skeleton?
Sternoclavicular joint attaches medial aspect of clavicle to the manubrium of the sternum.
What is apposition, reposition, and opposition?
Apposition- touching of 5th digit to thumb
Reposition- Release of fingers
Opposition- gripping with fingers
What are some roles/facts of the clavicle?
Joins axial skeleton to upper limbs
Sternoclavicular ligaments are so strong, bone will break before disjoining
Transmits weight
Acts as a strut
Slight sigmoid curves (concave laterally, convex medially)
What are key features of the scapula?
Acromion- lateral, articulates with clavicle to form acromioclavicular joint.
Coracoid process- Used for muscular/ligament attachments
Spine- sharp ridge, posterior, splits scapula into supraspinous and infraspinous fossa
Glenoid Cavity- Lateral, articulates with humerus
Subscapular Fossa- Anterior surface where muscles pass over.
What muscles hold the scapula in place?
Trapezius Levator Scapula Rhomboid Major/Minor Serratus Anterior Pectoralis Minor
What is protraction/retraction of the scapula?
Protraction- pushing a door open, separating the scapula
Retraction- pulling scapulae together.
What muscles make up the posterior wall of the axilla?
Subscapularis, Teres major, Latissimus Dorsi, and long head of triceps brachii
What muscles make up the anterior wall of the axilla?
Pectoral Muscles
What landmarks form the lateral and medial borders of the axilla?
Medial- Upper thoracic wall and Serratus Anterior
Lateral- Intertubercular sulcus of humerus and muscles
What is the origin and insertion of pectoralis major?
Origin- Anterior, medial clavicle, sternum, upper 6 costal cartilage, aponeurosis of external oblique (fibrous tissue, takes place of tendon in flat muscle)
Insertion- Crest of greater tubercle and lateral lip of intertubercle groove (lower fibres form U-shaped tendon)
What action does pectoralis major cause?
Protracts and depresses scapula
Adducts and medially rotates humerus
Clavicular head can flex humerus
Sternocostal head can extend humerus
What nerve(s) innervate pectoralis major?
Medial and Lateral pectoral nerves coming from brachial plexus
What is the origin and insertion of pectoralis minor?
Origin- 3-5th ribs near costochondral junction
Insertion- Medial border and superior surface of the coracoid process of the scapula
What are the actions caused by pectoralis minor?
Depresses shoulder
Scapular protraction
Raises ribs when scapula is fixed
What nerve(s) innervate pectoralis minor?
medial pectoral nerve
What nerves form the brachial plexus?
Ventral rami of C5-T1 spinal nerve roots
C4 and T2 have minor contributions
What nerve fibres form the superior trunk of the brachial plexus?
C5 and C6
What nerve fibres form the middle trunk of the brachial plexus?
C7
What nerve fibres form the inferior trunk of the brachial plexus?
C8 and T1
What divisions form the lateral cord of the brachial plexus?
Anterior divisions of the superior (C5/6) and middle (C7) trunks
What divisions form the posterior cord of the brachial plexus?
Posterior divisions of the superior (C5/6), middle (C7), and inferior (C8/T1) trunks
What divisions form the medial cord of the brachial plexus?
Anterior division of the inferior (C8/T1) trunk
What cords and roots form the musculocutaneous terminal root of the brachial plexus?
Lateral cord of anterior divisions of the superior (C5/6) and middle (C7) trunks
What nerve roots form the musculocutaneous terminal root of the brachial plexus?
C5/6/7
What nerve roots form the axillary terminal root of the brachial plexus?
C5/6
What nerve roots form the median terminal root of the brachial plexus?
C5*/C6/7/8/T1
What nerve roots form the radial terminal root of the brachial plexus?
C5/6/7/8/T1
What nerve roots form the ulnar terminal root of the brachial plexus?
C8/T1
What muscles and skin does the anterior division of the brachial plexus supply?
Flexor muscles of upper limb
Skin on anterior surface of the upper limb
What muscles and skin does the posterior division of the brachial plexus supply?
Extensor muscles and skin on the back of the upper limb
Where do the divisions of the brachial plexus lay, and how many are there?
6 divisions (3 anterior, 3 posterior) Pass deep to middle 1/3rd of clavicle into the apex of the axilla
Where do the cords of the brachial plexus lay, and how many are there?
3 cords (named based on location to axillary artery) Initially lie posterior to axillary artery
Where are the terminal branches of the brachial plexus found?
At the lower border of pectoralis minor
What muscles does the musculocutaneous nerve supply?
Corachobrachialis muscle, biceps brachii, brachialis
What muscles does the lateral and median roots of the median nerve supply?
forearm flexor muscles and thenar eminence (muscles of the thumb on the anterior surface)
What muscles does the ulnar nerve supply?
intrinsic muscles of the hand
What muscles does the radial nerve supply?
All extensors (it is the largest) Medial and Lateral heads of triceps
What muscles does the axillary nerve supply?
Teres minor and deltoid
What are the main supraclavicular branches of the brachial plexus as well as their origin and the muscle they innervate?
Dorsal Scapular- ramus of C5, supplies rhomboids and levator scapula
Long thoracic- ventral rami of C5/6/7, supplies serratus anterior
Suprascapular- superior trunk, supplies supraspinatus and infraspinatus
What are the main infraclavicular branches of the brachial plexus as well as their origin and the muscle they innervate?
Medial and Lateral Pectoral- From medial and lateral cords, pectoral major for both, and minor for medial nerve
Upper and Lower Subscapular- From posterior cord, supplies subscapularis and teres major
Thoracodorsal- From posterior cord, supplies latissumus dorsi
What are some injuries to the brachial plexus?
Crutch Palsy- Impacts radial nerve impacting extensor muscles
Radial Nerve Damage- error when performing intramuscular injections to deltoid causing drop wrist (can’t extend hand)
Carpel Tunnel- Median nerve damage caused by overuse of wrist (repetition) causing swelling of carpel, numbness, tingling, pain in palm and fingers
What type of joint is the sternoclavicular joint?
Saddle Joint, although acts more like a Ball and socket synovial joint
What ligaments are found at the sternoclavicular joint?
Sternoclavicular ligament bonding medial clavicle to manubrium
Interclavicular ligament attaches the medial aspects of the clavicles
Costoclavicular ligament joins clavicle to 1st costal cartilage
What ligaments help form the acromioclavicular joint?
Coracoclavicular ligament
Acromioclavicular ligament
Coracoacromial ligament
What type of joint is the acromioclavicular joint?
Gliding synovial joint
What type of joint is the glenohumeral joint?
Multiaxial ball and socket joint
Limited stability as it is a poor fit
What is the purpose of the rotator cuff muscles?
Stabilize glenohumeral joint while allowing for free movement (as opposed to ligaments)
The humerus is 4x too large for the glenoid cavity
What is the glenoid labrum
fibrocartilage ring that runs around perimeter of glenoid cavity helping to extend it and increase hold on humerus
What side of the humerus are the greater and lesser tubercles found, and which is most lateral?
Anterior
Greater is more lateral
Where is the glenohumeral capsule attached, and what factor impacts injury of it?
Proximally at scapula beyond the supraglenoid tubercle as well as the margin of the labrum and distally at the anatomical neck of the humerus
The inferior aspect is quite loose and thus a common sight of dislocation
What are bursae?
They reduce friction where one structure commonly moves over another
What bursae are found at the glenohumeral joint?
Subacromial
Subscapular
Subdeltoid
Subcoracoid
What is the pectoral girdle?
Scapula and clavicle
What muscles aid in flexion of the upper limb?
Pectoralis Major (clavicular part) Anterior fibres of Deltoid, assisted by biceps brachii and coracobrachialis
What muscles aid in extension of the upper limb?
Posterior fibres of Lat Dorsi and Deltoid
Aided by scapular rotation by trapezius and levator scapula
What muscles aid in the upper limb return extension to anatomical position following flexion?
Latissimus Dorsi, Teres Major, Pectoralis Major (sternal head)
Aided by rhomboid major and pectoralis minor
What muscles aid in the abduction of the upper limb?
First 15-30- Supraspinatus
30-horizontal- Deltoid (it cannot initiate abduction though)
Horizontal to over head- Serratus anterior (lower fibres) and trapezius (upper fibres)
What muscles aid in the adduction of the upper limbs?
Gravity
Latissimus Dorsi
Lowest sternocostal fibres of Pec Major (until arm is horizontal)
What muscles aid in medial rotation of the upper limbs?
Pectoralis Major
Latissimus Dorsi
Subscapularis
Teres Major
What muscles aid in the lateral rotation of the upper limbs?
Infraspinatus
Deltoid (posterior fibres)
Teres minor
What muscles form the rotator cuff?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
What is the origin, insertion, action, and innervation of teres minor?
Origin-Lateral margin of scapula
Insertion- Posterior greater tubercle of humerus
Action- lateral rotation of humerus and stabilisation
Innervation- Axillary nerve
What is the origin, insertion, action, and innervation of infraspinatus?
Origin- Infraspinatus fossa of medial scapula
Insertion- Posterior superior greater tubercle of humerus
Action- Lateral rotation of humerus and stabilization
Innervation- suprascapular nerve
What is the origin, insertion, action, and innervation of supraspinatus?
Origin- Supraspinatus fossa of scapula
Insertion- superior greater tubercle of humerus
Action- abduction (first 15 degrees), and stabilization
Innervation- suprascapular nerve (upper trunk)
What is the origin, insertion, action, and innervation of subscapularis?
Origin- Subscapular fossa of scapula
Insertion- Lesser tubercle of humerus
Action- Medial rotation of humerus, stabilization
Innervation- upper/lower subscapular nerves (posterior cord)
What is the origin, insertion, action, and innervation of serratus anterior?
Origin- Lateral aspect of ribs 1-8th
Insertion- Anterior length of medial border of scapula
Action- Protraction of scapula
Innervation- Long thoracic nerve (of C5/6/7)
What are common shoulder injuries?
Dislocation- Most frequent (tears ligaments and articular capsule)
Rotator Cuff Injury- Tear supraspinatus tendon, common when using limb above horizontal (swimming)
Axillary Nerve Injury- Injured with dislocations of humeral head. Paralysis of deltoid and loss of sensation in small area of skin over deltoid
Which nerve travels close to the shaft of the humerus between the lateral and medial heads of the triceps?
Radial
What is the name of the gap located between teres major and minor, humerus, and long head of the triceps, through which the axillary nerve travels?
Quadrangular space
Which muscles can rotate the arm laterally?
Infraspinatus and teres minor
What part of the trapezius has a role in rotating (tilting) the scapula so that the inferior angle swings laterally, and, what is it needed for?
Superior (descending) fibres
Aids in elevation of upper limb above head
Where on the scapula does the levator scapulae attach?
Superior angle at medial aspect of scapula
Which muscle is needed for starting arm abduction from the anatomical position?
Supraspinatus
What actions does the latissimus dorsi muscle effect on the shoulder joint?
Adduction, extension, and medial rotation
What is the name of the fascial layer that envelops the muscles which are part of the erector spinae?
Thoraco-lumbar fascia
Which muscle(s) are (is) located immediately deep to the trapezius and connects vertebral spinous processes to the medial margins of the scapulae?
Rhomboids
What factors control osteoblastic proliferation and differentiation?
Wnt, Hedgehog, BMP (Specialization into osteoprogenitor)
BMP, Transforming Growth Factor-beta (differentiation into pre-osteoblast, and later for matrix maturation into mature osteoblast)
Fibroblast Growth Factor, IGF
CBFA1- activation of osteoblast
What factors regulate osteoclast formation and activity?
E2, glucocorticoids, PTH, 1.25 D3, IL-1, TNFa, IFNy, RANKL
What factor(s) does an osteoblastic cell release that lead to or prevent differentiation of a pre-fusion osteoclast into a mature osteoclast?
RANKL has activating effect
OPG has suppressing effect
We can regulate this to cause more or less bone resorption via osteoclast activity
What hormone do osteocytes release in quiescent bone surfaces, and what does this hormone act on?
Sclerostin is released to inhibit Wnt signalling, preventing osteoblast proliferation
How does a bone fracture change osteocyte activity?
Osteocyte near crack undergo apoptosis and stop releasing sclerostin, which then allows for Wnt signalling to pre-osteoblasts for proliferation and differentiation into mature osteoblasts
How are stromal cells impacted in terms of sclerostin levels following a fracture?
Sclerostin release is inhibited and IL-1 factors stimulate the stromal cells to secrete Macrophage Colony-Stimulating Factor which helps generate pre-osteoclasts.
What hormone regulates osteoclast lifespan?
Oestrogen
How is osteoclast activation stopped following the 2 week period of bone resorption during fracture repair?
Pre-osteoblasts mature into osteoblasts that stop expressing RANKL and secrete Osteoprotegrin which binds RANKL of existing pre-osteoblasts, blocking the binding/activation of other pre-osteoclasts
How do pre-osteoblasts aid in healing of a fracture, start with RANKL expression?
Pre-osteoblasts express RANKL which binds RANK on pre-osteoclasts, causing pre-osteoclast to enlarge and fuse with mature osteoclasts.
Osteoclast binds bone matrix using integrins and secrete acid/cathepsin K to resorb the bone (takes about 2 weeks), followed by osteoclast apoptosis.
Pre-osteoblasts mature into osteoblasts (RANKL expression stops), that line the resorbed cavity and secrete osteoid which becomes mineralized and reforms bone in 3-4 months.
Some osteoblasts differentiate into osteocytes and some into lining cells.
What are some systemic modulators inhibiting bone remodeling?
Oestrogens, androgens, progesterone, calcitonin.
During adolescent ageing, how does bone geometry change in the spine and long bones?
Spine- increased size and trabecular thickness
Long Bone- increased length and diameter
How does menopause impact bone remodelling?
Loss of oestrogen results in lack of inhibition of bone remodelling.
More remodelling occurs, however resorption rates increase while deposition rates decline, resulting in a net loss of bone mass, and reaching the fracture threshold.
How does oestrogen impact bone acquisition?
It aids in terminally differentiating chondrocytes and mineralizing bones
How do androgens and oestrogens impact bone acquisition?
Androgens- Largely aids in proliferation of chondrocytes and periosteum formation
Oestrogens- Reduce bone remodelling by reducing osteoclast differentiation via increased osteoblast release of osteoprotegrin (OPG)
What secretion is under control of oestrogen, impacting osteoclast activity?
Osteoprotegrin
Less oestrogen results in less OPG, meaning less blocking of the RANK receptor on osteoclasts.
This causes increased activation of pre-osteoclasts into mature osteoclasts, meaning more bone resorption and less apoptosis of inactive osteoclasts
What is osteoporosis?
Compromised bone strength
Increased risk of fracture
Reduction of bone density and quality
What are common fractures that occurs with osteoporosis?
Colle’s Fracture of the wrist (common in elderly who fall forward)
Compression fractures of Lumbar vertebrae
Femoral neck fracture (most common in elderly)
Subcapital fracture of hip
Proximal Humerus fracture
In terms of ageing women, which fractures are most common from 50-85?
Wrist at 50, but plateaus around 60
Vertebral fracture constantly increasing (in line with wrist, than incidence rises above all types)
Hip fractures less common but constantly increasing (surpass wrist at around 75 years)
What are major risk factors for osteoporosis?
Age Vertebral compression Family history Malabsorption syndrome Fragility fracture after 40yo Primary hyperparathyroidism Early menopause Hypogonadism Propensity to fall Osteopenia
What are minor risk factors for osteoporosis?
Rheumatoid arthritis Past history of clinical Hyperthyroidism Chronic anticonvulsant therapy Low dietary calcium Smoking High alcohol/caffeine intake Weight <57kg Weight loss >10% of weight Long-term heparin therapy
What factors determine fracture risk?
Bone strength and extra-skeletal conditions (propensity to fall, fall-related conditions)
What fractures cost the most (from most expensive to least)?
Hip
Other
Wrist
Vertebral
How is fracture risk assessed?
Dual X-Ray Assessment (DXA)
T-score is calculated
Allows for fractue risk and diagnosis of osteoporosis
What values for the T-score help determine diagnosis of osteoporosis?
Normal (> -1),
Osteopenia (-1 to -2.5), Osteoporosis (less than -2.5)
What are some non-pharmacological approaches to prevention of postmenopausal osteoporosis?
Calcium intake Healthy weight/muscle strength Smoking cessation Safe alcohol levels Minimize risk of fall (avoid sedative, treat stressors, treat neurological/rheumatologic conditions, balance training)
What are some pharmacological treatments for osteoporosis prevention?
Vitamin D (calcitriol and/or alphacalcidol) Calcium
What is a type of pharmacological treatment for osteoporosis that is no longer used in prevention in asymptomatic women?
Oestrogen Hormone replacement (also shown to improve women with declines)
Increases risks of cancer, stroke, heart attack, DVT and thus not used in prevention
It showed no evidence of net benefit
What medication can help reduce vertebral fractures (but not shown to reduce any other fractures)?
Raloxifene
What drug is used in the management of osteoporosis?
Bisphosphonates
Binds hydroxyapatite
Both nitrogen and non-nitrogen bisphosphonates
How do nitrogen and non-nitrogen bisphosphonates differ?
Non-nitrogen containing produces cytotoxic analogues of ATP which increase osteoclast death reducing bone remodelling
Nitrogen containing inhibit enzymes in the 3H3MG coenzyme A pathway which reduces protein phenylation which in turn reduces recruitment of osteoclast precursors, osteoclast activity and osteoclast death, reducing bone remodelling
What is the impact of bisphosphate on fracture risk?
Reduces vertebral, wrist and hip incidence.
What are side effects of bisphosphonates?
GI problems, malabsorption,
peptic ulcer
Injection of zoledronic acid reduces morphometric fractures and may carry less side affects than weekly pill (alendronate)
How do bisphosphonates treat osteoporosis?
By reducing osteoclast activity and therefore reducing bone remodelling, increasing bone density
How does Teriparatide work in the treatment of osteoporosis?
PTH analogue that works to increase bone deposition
How does Denosumab work to reduce osteoporosis fractures?
Monoclonal antibody that binds ligand blocking RANKL binding, preventing formation of mature osteoclast, reducing bone resorption
How does Romosozumab work to treat osteoporosis?
Recently approved injected monoclonal antibody
Binds and inhibits sclerostin
Less sclerostin means increased Wnt activity and more maturation of mature osteoblasts
Reduces vertebral fractures but increases cardiovascular event risk (therefore second use drug)
How do glucocorticoids impact osteoporosis risk?
They decrease functioning of remaining osteoblasts via inhibition of insulin-like growth factor 1 expression (IGF1 increases osteoblast differentiation/maturation)
IGF1 also works to increase kidney reuptake of Vit D at the proximal tubules, increasing calcitriol, and increasing Ca absorption in the gut.
They also cause reductions in Wnt and osteoprotegrin, while increasing RANKL
What are the borders of the quadrangle space?
Laterally: surgical neck of humerus
Medially: Lateral border of the long head of triceps brachii
Superiorly: teres minor
Inferiorly: teres major
What fascia covers the posterior upper limb (arm specifically)?
Brachial fascia
What are the borders of the triangular space?
Superiorly: inferior border of teres minor
Inferiorly: superior border of teres major
Laterally: Medial surface of long head of triceps brachii
What anatomical structures are found in the triangular space?
Circumflex scapular artery and vein
What are the borders of the triangular interval?
- Sup: Teres Major
- Med: Long Head Triceps
- Lat: Lateral Head Triceps
What anatomical structures are found in the triangular interval?
Radial nerve Profunda Brachii (deep brachial) artery
What anatomical structures are found within the quadrangle space?
- Axillary nerve
* Posterior Circumflex Humeral Artery (from axillary a)
How does trabeculae arrangement in cancellous bone differ at the proximal vs distal epiphysis of the femur and why?
At the proximal end, the trabeculae are trying to force compression out to the compact bone, so trabeculae converge on the cortical bone at the medial and lateral sides.
At the distal end, distribution of weight is more important so trabecula are arranged in a more regular lattice pattern.
How does growth differ in bones vs cartilage?
Bone- apposition growth- new bone laid on pre-existing surface
Cartilage- appositional and interstitial- cells within cartilage can proliferate and divide. This is how the epiphyseal growth plate develops
What are the zones of the growth plate?
R -(Rest/Replicate) Layer of resting or reserve cartilage cells (chondrocytes), these cells replicate slowly.
P - (Proliferation) Cells here divide more rapidly and line up in rows along the long axis of the bone.
H - (hypertrophy) The chondrocytes then mature and expand in size.
C - (calcification) The expanded cells then become calcified and die via apoptosis. The calcified matrix forms the structure for bone to be laid down.
O - (osteoblast invasion) Blood vessels and bone cells invade the calcified cartilage and begin to replace the structure with bone.
What type of cartilage forms the epiphyseal growth plate?
Hyaline cartilage
What is intramembranous ossification and where does it typically occur?
Bone deposition occurs directly by mesenchyme as opposed to cartilage formation.
Mesenchyme form template for bone, then differentiate into osteoblasts which secrete ECM and deposit calcium.
Occurs in skull and clavicle
What are the gaps between the bones of the skull called and what is their purpose?
Fontanelles
Allow for brain and skull growth during development
What is periostitus?
Inflammation of the periosteum
Caused by: inflammation, infection (staphylococcus, syphilis, blood born cancers), trauma, stress, Osgood-Schlatter disease (inflammation around tibial tuberosity typically in adolescents as growing)
Types: acute (infection) or chronic (shin-splints, inflammation)
What is the origin, insertion, action, and innervation of coracobrachialis?
Origin: Coracoid process
Insertion: Proximal 3rd of anterior humerus
Action: Flexion, weak adductor, medial rotation
Innervation: Musculocutaneous nerve
What is the origin, insertion, action, and innervation of biceps brachii?
Origin: LH- supraglenoid tubercle of scapula (passes through greater and lesser tubercle of humerus), SH- coracoid process
Insertion: Radial tuberosity (medial aspect)
Action: Elbow flexion, supination, abduction, and internal rotation of humerus
Innervation: Musculocutaneous nerve
What could damage to the long thoracic nerve cause?
Winging of the scapula Serratus anterior (supplied by the LTN) helps hold the scapula to the thoracic wall (along with the rhomboids), so lack of innervation can result in winging
What joining allows for pronation and supination of the forearm?
The radius with the capitulum
What bones/joints form the wrist?
Bones: Radius, Ulna, Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate
Joints: Radiocarpal joint (condyloid synovial)
The styloid process of the distal radius with the carpal bones.
Head of ulna will articulate with the radius via radioulnar joint (pivot synovial)
What prevents the ulna from articulating with the carpals?
Fibrocartilage
What is the radial tuberosity?
Important attachment site for biceps brachii
What are important proximal landmarks of the ulna?
Trochlear notch- portion of olecranon process where articulation with trochlea occurs
Coronoid process- more anterior
Olecranon process- posterior protuberance
Radial notch of ulna- lateral
What joints are included within the synovial capsule of the elbow?
Humeroulnar
Humeroradial
Proximal radioulnar
How does biceps brachii attach to the ulna?
Bicipital aponeousis creates indirect binding from the insertion of the biceps brachii tendon (onto the radial tuberosity of the ulna) to the posterior ulna.
This aids in supination, reinforces the cubital fossa, and protects the brachial artery and the median nerve running underneath.
What action does the short head of the biceps brachii perform?
Flexes shoulder
Also supination minorly
What action does the long head of the biceps brachii perform?
Holds humerus against glenoid cavity, particularly during abduction
What is the origin, insertion, action, and innervation of brachialis?
Origin: Anterior distal humerus (deep)
Insertion: Across elbow to coronoid process of ulna
Action: flexes elbow
Innervation: Musculocutaneous
What is the origin, insertion, action, and innervation of triceps?
Origin: Long Head - infraglenoid tubercle of scapula, Lateral Head- Superior, posterior humerus, MH- posterior humerus distal to groove for radial nerve
Insertion: superior aspect of olecranon process of ulna
Action: Main extensor of elbow, long head also acts on shoulder
Innervation: Radial nerve
What is the origin, insertion, action, and innervation of anconeus?
Origin: Posterior, lateral epicondyle of humerus
Insertion: Lateral, posterior olecranon of ulna
Action: extensor of elbow and role in pronation
Innervation: radial nerve
How much pronation is available from just the forarm?
About 140 degrees
What ligament encircles the head of the radius and maintains contact between the radial notch of the ulna and the radius?
Radio annular ligament
Maintain the pivot joint
What joint is found at the distal portion of the forearm and allows for pronation/supination?
Distal Radioulnar Joint- pivot joint Articular disc (fibrocartilage plate) and interosseous membrane (fibrous tissue) aid in the movement
What joint is formed by the interrosseus membrane?
Syndesmosis joint- contains fibrous tissue
What muscles allow for supination?
Biceps Brachii
Supinator
What is the origin and insertion of the supinator muscle?
Origin: Deep head- supinator crest of ulna, superficial- lateral epicondyle of humerus
Insertion: lateral proximal radius
What is the origin and insertion of pronator teres?
Origin: Superficial head- medial epicondyle humerus, Deep Head- medial coronoid process of ulna
Insertion: crosses forearm and attaches to middle of shaft of radius
What is the origin and insertion of the pronator quadratus muscle?
Origin: distal shaft of ulna
Insertion: distal shaft of radius
What muscles aid in pronation of the forearm?
Pronator teres
Pronator quadratus
What is the cubital fossa?
Triangular depression of the elbow, where we transition for arm to forearm
What are the borders of the cubital fossa?
Lateral: brachioradialis
Medial: Pronator teres
What structures enter and leave the cubital fossa?
Vessels: Brachial artery enters at base and bifurcates to leave as radial and ulnar arteries
Nerves: Median runs through, radial nerve laterally if the brachioradialis is retracted
What are the anterior muscles of the forarm?
Superficial: Pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis
Deep: Flexor pollicis longus, flexor digitorum profundus, pronator quadratus
What are the posterior muscles of the forearm?
Superficial: Extensor carpi brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, brachioradialis, extensor carpi radialis longus, anconeus
Deep: Extensor indicis, extensor pollici longus, extensor pollici brevis, abductor pollicis longus
What forms tendons?
Parallel fibres of collagen 1 give strength
Cellular (fibroblasts and tenocytes) 20%
Extracellular matrix 80% (70% water, 30% solids (Collagen 1, ground substances, elastin, collagen 4)
How do tendons heal?
Extrinsically- cells from outside the tendon come in to heal
Intrinsically- Cells within healing
3 stages: Inflammation (days 0-7), Repair (3-60- c3 laid down first, unorganized), Organization and remodelling (28-180, changing to type 1 collagen)
What cytokines aid in tendon healing?
PDGF for chemotaxis
Transforming GF beta (decides subtype of collagen to make)
Also ILG-1 and VEGF
What is the function of tendons?
To transmit force
What are treatment for rotator cuff tears?
Non-operative (physio, injection of steroid)
Surgery (repair tendon to bone, arthroscopic/open surgery)
Platelet rich plasma injection
What are the most common sites of tendinopathy?
Shoulder Hip Ankle Knee Elbow
What are some theories in the pathophysiology of tendinopathy?
Mechanical Theory (Increased demand-> improper healing -> degenerative changes)
Inflammation (inflammatory mediators found)
Apoptosis (Cyclic strain (repetitive use) leads to oxidative stress/acquisition of cartilage/activations of MMPs)
Vascular/Neurogenic (Increased vascular ingrowth into tendons causes weakening)
Continuum Model (Clinical symptoms with lab-based research to guide treatment)
What form of dysregulation can lead to early tendinopathy?
Dysregulation of ECM, immune response, and stromal response.
Failed homeostasis leads to influx of immune cells, stromal cell dysfunction, apoptosis, oxidative stress, and matrix dysfunction.
What pre-disposing factors and external exposures can lead to pre-clinical tendinopathy?
Epidemiology
Environmental factors (metabolic disease, smoking, drugs (fluoroquinolones, steroids, statins)
Genetics (COL5A1, MMP3, TIMP2, TNC)
Adaptive and abnormal response to load
What cellular factors can lead to early tendinopathy?
ECM Dysregulation (Abnormal collagen turnover, MMPs, matrix dysfunction, small-leucine rich proteoglycans) Immune Cell Dysfunction (chemokines, cytokines, alarmins) Oxidative stress of Mitochondrial Dysfunction (Nitric oxide, BNIP3) Apoptosis
What factors can lead to chronic tendinopathy?
Oxidative stress of Mitochondrial Dysfunction (Nitric oxide, BNIP3)
Stromal Cell Dysfunction
Apoptosis
Auto-Amplicatory Loops (Abnormal collagen, MMP dysfunction, Matrix dysfunction)- dysregulated repair
What muscle(s) does median nerve pass through?
The two heads (superficial and intermediate) of pronator teres within the forearm.
What forms the pelvic girdle?
Left and right hip bones and the sacrum
What is the acetabulum of the hip?
The joint surface for the head of the femur
What forms the hip joint?
Acetabulum of the innominate bone
Head of femur
Acetabular labrum (cartilaginous extension helping to deepen joint and increase stability)
What structures and found within the hip joint?
Articular cartilage
Transverse acetabular ligament (bridges the ends of the acetabular notch)
Ligament of head of the femur (or round ligament, ligament of teres)
Artery to head of femur (main supply when young)
What ligaments are found in the hip joint?
Iliofemoral ligament- anterior inferior spine of ileum to greater trochanter and intertrochanteric line of femur, strongest and most superficial, prevents hip hyperextension while standing
Pubofemoral- inferiorly from pubic bone to the femur. Prevents excessive abduction
Ischiofemoral- posterior, weakest, protects from hip hyperflexion
How do ligaments in the hip and upper limb differ?
In the upper limb, ligaments help with mobility (and stability), in the hip joint they are primarily for stability.
What is the sacrotuberous ligament, and what does it help form?
Fan shaped ligament
Connects spine of posterior superior iliac spine to ischial tuberosity, sacrum (sacral tuberosity and lower, lateral margins), and coccyx (upper, lateral margins).
Helps form the greater sciatic foramen
What is the sacrospinous ligament, and what does it help form?
Attaches the ischial spine to the sacrum and coccyx
Helps form lesser sciatic notch
Where does the inguinal ligament pass?
From the anterior superior iliac spine to the pubic tubercle
What plexus’ are found at the lower limbs?
Sacral Plexus and Lumbar plexus
Form the lumbosacral plexus (L1-S4)
What are the 3 important nerves of the lower limbs being focused on, as well as their roots?
Femoral nerve from L2-L4
Obturator nerve from roots L2-L4
Sciatic Nerve L4-S3 (largest nerve in body)
What are the 4 main hip extensors/abductors?
Gluteus maximus
Gluteus Medius
Gluteus Minimus
Piriformis
What is the origin, insertion, action, and innervation of gluteus maximus?
Origin: Iliac bone (outer surface of ala thoracolumbal aponeurosis), sacrum (posterior), sacrotuberal ligament
Insertion: cranial portion -> ilio-tibial tract (fascia), caudal portion -> femur via gluteal tuberosity
Action: Thigh extension, resisting gravity
Innervation: superior and inferior gluteal nerves.
What is the origin, insertion, action, and innervation of gluteus medius?
Origin: iliac bone (posterior)
Insertion: Greater trochanter of femur
Action: Abductor, and part for medial rotation
Innervation: Inferior gluteal nerve
What is the origin, insertion, action, and innervation of piriformis?
Origin: Sacrum, pelvic (anterior) surface
Insertion: Greater trochanter (medial)
Action: abductor/lateral rotator
Innervation: Superior and inferior gluteal nerves.
What is the origin and insertion of obturator internus?
Origin: Obturator membrane
Insertion: Trochanteric fossa
Where does the sciatic nerve pass in relation to muscles, and how does this relate to clinical pain and injections?
Inferior to piriformis
If piriformis is swollen, it can compress the nerve.
Injections should be in upper, outer quadrant of glut to avoid hitting sciatic nerve
What is the origin, insertion, action, and innervation of tensor fasciae latae?
Origin: anterior portion of iliac crest
Insertion: iliotibial tract (which extends to the tibia)
Action: Abduction, tightens fasciae latae, also tenses to aid in blood circulation
Innervation: superior and inferior gluteal nerve
What gluteal muscles aid in medial/ lateral hip rotation?
Medial: Gluteus medius & tensor fasciae latae
Lateral: Gluteus maximus, piriformis, obturator internus
How does the hip rotate as you walk?
Medial rotation of limb fixed to ground
Advancing limb will have lateral rotation
What are the compartments of the thighs?
Anterior- flexion of hip and knee extension
Posterior- thigh extension, knee flexion
Medial- adduction
What nerves supply the compartments of the thigh?
Anterior- femoral
Medial- obturator
posterior- sciatic
pectineus and adductor magnus are in 2 diff compartments and have 2 nerve supplies each
What is the origin, insertion, action, and innervation of rectus femoris?
Origin: anterior iliac spine
insertion: patella, tibial tuberosity via the patellar ligament and retinacula
Innervation: femoral nerve
Action: hip flexion (it is the only quadricep muscle that crosses the hip), knee extension
What is the origin, insertion, action, and innervation of iliopsoas?
Origin: Iliac fossa (iliacus) and lumbar vertebrae (psoas)
Insertion: unite at inguinal ligament and insert onto lesser trochanter of femur
Innervation: lumbar spinal nerves L1-3 (psoas) and parts of the femoral nerve (iliacus).
Action: Hip flexion
What compartments are within the thigh?
Anterior (hip flexion, knee extension)
Medial (adductors)
Posterior (hip extensors, knee flexors
What nerves supply the different compartments of the thigh?
Anterior- Femoral
Medial- Obturator
Posterior- Sciatic
What are the hip flexor muscles found within the anterior compartment of the thigh?
Pectineus
Sartorius,
Quadriceps: Rectus Femoris
Also Iliopsoas (not technically in thigh)
What are the knee extensor muscles found within the anterior compartment of the thigh?
Quadriceps
What are the adductor muscles found within the medial compartment of the thigh?
Pectineus
Gracillis
Adductors (adductor magnus (anterior portion), brevis, longus)
What are the hip extensors muscles found within the posterior compartment of the thigh?
Hamstrings Adductor magnus (posterior portion)
What are the knee flexor muscles found within the posterior compartment of the thigh?
Hamstrings
What two muscles in the thigh are found in multiple compartments?
Pectineus- anterior part for hip flexion, medial part for adduction
Adductor Magnus- anterior part for adduction, Posterior part for hip extension
What nerve(s) supply the muscles below the knee?
Branches of sciatic nerve
What is the adductor hiatus?
A space found at the insertion point of adductor magnus
Where femoral artery passes through to the back of the knee to become the popliteal artery
What pathologies are associated with the sciatic nerve?
Piriformis Syndrome - compression of nerve by piriformis
Hamstring Syndrome- insertional tendinopathy at ischium possibly involving sciatic compression
Hip Dislocation
What form the borders of the Femoral Triangle?
Lateral Border- Sartorius
Medial- Adductus Longus
Superior Border- Inguinal Ligament
What structures are found within the Femoral Triangle, moving lateral to medial?
Femoral Nerve
Femoral Artrery
Femoral Vein
Lymphatics
Which muscles form the pes anserinus?
Tendons of the sartorius, gracilis, and semitendinosus muscles
What ligaments of the knee are most commonly injured?
Anterior Cruciate Ligament
Medial Collateral Ligament
Which meniscus is most commonly torn?
Medial
Of the muscles forming the pes anserinus, which act on both the hip and the knee joints?
Semitendinosus and Sartorius
Which part of the leg does not receive its sensory innervation from a branch of the sciatic nerve?
Medial Saphenous nerve (branch of femoral nerve)
Where does the sciatic nerve arise from, and what does it supply?
Lumbar and sacral plexuses (L4-S3)
Supplies sensory innervation to leg and foot (not medial cutaneous supply as this is the saphenous nerve (from femoral))
Motor innervation to the anterior, lateral and posterior compartments of the leg.
Motor innervation of posterior compartment of thigh
Which nerve(s) pass(es) through the adductor canal?
Saphenous nerve (femoral) and nerve to vastus medialis
What are SERMs and what is their mechanism of action?
Selective Estrogen Receptor Modifiers
Can act as a corepressor or coactivator depending on type of tissue (agonistic effect in bone and lipid, antagonist effect in endometrial lining/breast tissue- therefore not contributing to oestrogen-induced cancers)
Raloxifene downregulates osteoclast activity by binding intracellular oestrogen receptors causing dimerization, and impacting transcription and translation of factors needed for resorption. Raloxifene can also modulate osteoblast activity by impacting OPG expression, also controlling osteoclast activity
When are Hormone Replacement Therapies typically utilized in osteoporosis?
For treatment and secondary prevention of fracture in post-menopausal women
When are SERMs used as treatment for osteoporosis?
Treatment and secondary prevention of fracture for vertebral fracture.
