Phase 2 - Week 2 (Tendons, Shoulder), Phase 1 - Week 6 (Muscles, Muscle/Nerve Excitation), Phase 2 - Week 3 (Muscle, Elbow + Forearm, Nervous Control) Flashcards
List the bones of the shoulder
- Scapula
- Clavicle
- Humerus
Describe the position of the scapula
Lies obliquely on the back/side of the thorax
What type of bone is the scapula
Flat
Describe the articulations made by the scapula
- Acromioclavicular joint - acromial end of of the clavicle and acromion of the scapula
- Glenohumeral joint - glenoid fossa of the scapula and head of the humerus
List the distinct structural features of the scapula
- Acromion
- Coracoid process
- Glenoid fossa
- Inferior angle
- Infraspinous fossa
- Lateral Border
- Medial Border
- Neck of the glenoid
- Spine
- Superior border
- Subscapular fossa
- Supraspinous fossa
- Suprascapular notch
Acromion
Large projection forming point of the shoulder, articulates with the clavicle
Coracoid Process
Large anterior projection, provides insertion point for pectoralis minor and point of origin for short head of the biceps brachii and corcacobrachialis
Glenoid Fossa
Shallow socket that articulates with the head of the humerus to form the shoulder joint
Inferior angle
Junction between the medial and lateral borders, typically overlies 7th rib
Infraspinous fossa
Large depression on the back of the scapula, below the spine, provides point of origin for the infraspinatus
Lateral border
Thick border, runs from infraglenoid tubercle to inferior angle
Medial border
Thin border between superior and inferior angles
Neck of the glenoid
Constriction between glenoid + body of the scapula
Spine of the scapula
Triangular ridge of bone that crosses the back of the scapula , from acromion to medial border
Superior Angle
Junction between lateral + medial borders
Superior Border
Thin, sharp border, separated from coracoid process by supraglenoid notch
Subscapular fossa
Slightly ridged fossa on inner surface of the scapula. Point of origin for subscapularis muscle
Supraspinous fossa
Deep fossa on back of scapula, above spine. Point of origin for supraspinatus muscle
Subscapular notch
Dip in superior border, just medial to coracoid process
Describe the shape and postition of the clavicle
Slightly S-shaped bone, lies at the base of the neck, in front of the first rib
Describe the articulations made by the clavicle
- Acromioclavicular joint with the acromion of the scapula
2. Sternoclavicular joint with the manubrium of the sternum
Describe the ends of the clavicle
- Sternal end = medial end of clavicle, articulates with the manubrium of the sternum
- Acromial end = lateral end of the clavicle, articulates with the acromion of the scapula
Conoid tubercle of the clavicle
Small projection from posterior edge, gives attachment to the conoid part of the coracoclavicular ligament
Describe the articulations made by the humerus
- Glenohumeral joint - head of the humerus with the glenoid fossa of the scapula
- Humeroulnar joint - trochlea of the humerus with the trochlear notch of the ulna
- Humeroradial joint - capitulum of the humerus with the head of the radius
List the distinct structural features of the humerus
- Head
- Anatomical neck
- Greater tubercle
- Lesser tubercle
- Surgical neck
- Intertubercular groove
- Shaft
- Deltoid tuberosity
- Capitulum
- Trochlea
- Coronoid fossa
- Radial fossa
- Olecranon fossa
- Medial epicondyle
- Lateral epicondyle
Head of the humerus
Forms 1/3 of a sphere that articulates with the glenoid fossa of the scapula
Anatomical neck of the humerus
Constricted area that joins head to greater and lesser tubercles
Greater tubercle
Large projection from the lateral side of the proximal humerus
Lesser tubercle
Projection that provides an insertion point for the subscapularis muscle
Surgical neck
Junction between the tubercles and the shaft. Common site for fractures
Intertubercular groove
Located anteriorly between the tubercles, holds the tendon of the biceps brachii muscle. Sometimes called bicipital groove.
Shaft of the humerus
Long + thick shaft that connects the two extremities
Deltoid tuberosity
Roughened area, halfway down shaft. For the insertion of the deltoid muscle
Capitulum
Lateral of the two distal condyles, articulates with the radius
Trochlea
Medial of the two distal condyles, articulates with the ulna
Coronoid fossa
Anterior fossa above the capitulum for the head of the radius
Radial fossa
Anterior fossa above the capitulum for the head of the radius
Olecranon fossa
Large posterior fossa for the olecranon of the ulna
Medial epicondyle
Prominence medial to the trochlea, gives origin to the superficial flexor muscles in the forearm
Lateral epicondyle
Prominence located lateral to the capitulum gives origin to the extensor muscle in the forearm
List the muscles acting on the scapula
- Pectoralis minor
- Rhomboid major
- Rhomboid minor
- Trapezius
- Serratus anterior
Give the origin, insertion and action of pectoralis minor
Origin = Ribs 3-5 Insertion = Coracoid process of the scapula Action = Pulls shoulder girdle forwards + downwards
Give the origin, insertion and action of rhomboid major
Origin = T2-T5 spinous processes Insertion = Medial border of the scapula Action = Medially rotates + retracts the scapula
Give the origin, insertion and action of rhomboid minor
Origin = C7-T1 spinous processes Insertion = Spine of the scapula Action = Medially rotates the scapula and retracts the scapula
Give the origin, insertion and action of the trapezius
Origin = External protuberance of the occipital bone, nuchal ligament, C7-T2 Insertion = Clavicle, scapula Action = Elevates + retracts the scapula and depresses its medial aspect, extends and laterally flexes the head and neck
Give the origin, insertion and action of serratus anterior
Origin = Ribs 1-9 Insertion = Costal surface of the medial border of the scapula Action = Protracts the scapula and pectoral girdle
List the shoulder muscles acting on the humerus
- Latissimus dorsi
2. Pectoralis major
Give the origin, insertion and action of latissimus dorsi
Origin = T7-T12 spinous processes, iliac crest of hip bone, ribs 9-12 Insertion = Intertubercular groove of the humerus Action = Extends, adducts and medially rotates the arm at the shoulder joint
Give the origin, insertion and action of pectoralis major
Origin = Medial end of the clavicle, sternum, costal cartilages 1-6 Insertion = Intertubercular groove of the humerus Action = Adducts and internally rotates the humerus, extends shoulder joint from flexed + flexes it from extended
List the rotator cuff muscles
- Supraspinatus
- Infraspinatus
- Subscapularis
- Teres minor
Give the origin, insertion and action of the supraspinatus
Origin = Supraspinous fossa of the scapula Insertion = Greater tubercle of the humerus Action = Initiates abduction of the arm
Give the origin, insertion and action of the infraspinatus
Origin = Infraspinous fossa of the scapula Insertion = Greater tubercle of the humerus Action = Laterally rotates the arm
Give the origin, insertion and action of the subscapularis
Origin = Subscapular fossa of the scapula Insertion = Lesser tubercle of the humerus Action = Medially rotates the arm
Give the origin, insertion and action of teres minor
Origin = Lateral border of the scapula Insertion = Greater tubercle of the humerus Action = Laterally rotates the arm, contributes to abduction of the arm
Give the origin, insertion and action of the deltoid
Origin = Clavicle, spine of the scapula, acromion of the scapula Insertion = Deltoid tubersity of the humerus Action = Adbucts the shoulder
Give the origin, insertion and action of the teres major
Origin = Inferior angle of the scapula Insertion = Intertrabecular Groove of the humerus Action = Extends the shoulder, adducts and medially rotates the humerus
Give the origin, insertion and action of the coracobrachialis
Origin = Coracoid process of the scapula Insertion = Humerus Action = Flexes the shoulder and adducts the arm
How are the upper limbs innervated
The brachial plexus supplies the entire upper limb with motor and sensory innervation
Describe the structure of the brachial plexus
- Roots - C5-T1 spinal nerves
- Trunks - superior, middle and inferior
- Divisions - anterior and posterior
- Cord - posterior, lateral and medial
- Branches
Superior trunk of the brachial plexus
- Formed from roots of C5 + C6
- Splits into anterior and posterior divisons
Middle trunk of the brachial plexus
- Formed from root of C7
- Splits into anterior and posterior divisions
Inferior trunk of the brachial plexus
- Formed from the roots of C8 + T1
- Splits into anterior + posterior divisons
Anterior divisions of the brachial plexus
The upper and middle anterior divisions form the lateral cord and the lower anterior division forms the medial cord
Posterior divisions of the brachial plexus
The posterior divisions of all three trunks combine to form the posterior cord
Posterior cord of the brachial plexus
- Formed by the posterior divisions of all three trunks
- Gives off branches:
1. Subscapular nerves
2. Thoracodorsal Nerve
3. Axillary nerve
4. Continues as radial nerve
Lateral Cord of the brachial plexus
- Formed by the anterior division of the inferior trunk
- Gives of branches:
1. Musculocutaneous nerve
2. Lateral pectoral nerve
3. Joins with the medial cord to form the median nerve
Medial cord of the brachial plexus
- Formed by the anterior divisions of the superior and middle trunks
- Gives off branches:
1. Medial pectoral nerve
2. Medial cutaneous nerve of the forearm
3. Medial cutaneous nerve of the arm
4. Ulnar nerve
5. Joins with the lateral cord to form the median nerve
List the terminal branches of the brachial plexus
- Axillary nerve
- Radial nerve
- Musculocutaneous nerve
- Ulnar nerve
- Median nerve
Axillary nerve
Origin = C5/6, posterior cord Course = descends behind the axillary artery + winds around the surgical neck of the humerus Innervates = motor = deltoid + teres minor, sensory = shoulder joint, cutaneous = skin over the shoulder + lateral arm
Radial nerve
Origin = C5-T1 posterior cord of the brachial plexus Course = exits axillae under teres minor, runs around back of humerus in the radial groove with the arteria profunda brachii. Passes down the lateral side of the forearm to the wrist Innervates = motor = extensors of elbow, wrist + hand, sensory = elbow, wrist + hand joints, cutaneous = skin over the posterior surface of the upper limb
Musculocutaneous nerve
Origin = C5-7, lateral cord Course = descends between biceps + brachialis to the elbow where it becomes the lateral cutaneous nerve of the forearm Innervates = motor = flexors of the elbow joint, cutaneous = skin over the lateral border of the forearm
Ulnar nerve
Origin = C7-T1, medial cord Course = descends the medial side of the arm in front of the medial head of triceps to reach the elbow. Enters the flexor compartment of the forearm + travels to the wrist Innervates = motor = majority of the muscles of the hand, sensory = hand joints, cutaneous = skin of the medial aspect of the hand
Median nerve
Origin = C5-T1, medial + lateral cords
Course = leaves axillae with brachial artery, travels to the elbow. In the forearm, it travels to the wrist where it enters the carpal tunnel and divides into medial and lateral branches
- Innervates = motor = most of the flexor muscles in the forearm, cutaneous = skin of the elbow, wrist and radial aspect of the palm of the hand
List the 3 major arteries in the posterior scapular region
- Suprascapular artery
- Posterior circumflex artery
- Circumflex scapular artery
Describe the function of tendons
Tough, fibrous structures that provide attachment for muscles to bones. Transmit the muscles’ contractile force to bone, producing movement at joints.
Describe the arrangement of fibres in tendons
Collgen fibril –> Collagen fibre –> Primary collagen fibre bundle (sub-fascicle) –> Secondary fibre bundle (fascicle) –> Tertiary fibre bundle –> Tendon
Describe the connective tissue layers that surround tendons
Endotenineum = Surrounds primary, secondary and tertiary bundles to facilitate gliding Epiteon = fine layer of connective tissue that sheathes tendon Paratenon = loose elastice connective tissue layer, allows tendon to more against neighbouring tissues
How are tendons attached to bones?
By collagenous fibres (Sharpey fibres) that continue into the matrix of the bone
What type of collagen is found in tendons?
Type 1
List the cell types found in tendons
- Tenocytes (fibrocytes)
2. Tenoblasts (fibroblasts)
Explain the role of tenocytes in tendons
Mature tendon cells - lay down type 1 collagen fibres.
Explain the role of tenoblasts in tendons
Immature tendon cells, give rise to tendons. Highly proliferative, involved in synthesis of collagen and other components of the ECM.
What aspect of tendon structure gives their tensile strength?
Collagen bundles in parallel arrangements gives tensile strength and elasticity in one direction.
Describe the components of the ECM of tendons
Elastin, proteoglycans, type 1 collagen
List the stages of tendon healing
- Inflammation
- Regeneration
- Remodelling
How long does each stage of tendon healing last?
Inflammation lasts a week, regeneration lasts a month, remodelling lasts a year
Describe the pain felt during each stage of tendon healing
Pain occurs during:
- Inflammation even when at rest
- Regeneration under normal load bearing
- Remodelling with extreme load bearing
Describe the inflammation stage of tendon healing
- Tendon ruptures/tears
- BVs are also damaged, platelets in the blood become activated
- Platelets release growth factors, trigger surrounding inflammatory cells - e.g. macrophages
- OR - molecules from interior of cells that are ruptured from injury are released and recognised as foreign by the immune system, triggers the inflammatory response
- Inflammation is initially non-specific
Describe the regeneration stage of tendon healing
- Macrophages stimulate reconstruction - summon endothelial cells that form new BVs + mesenchymal stem cells that start forming new ground substance with collagen
- At first, type 3 collagen is laid down (rather than type 1) and is haphazardly organised (not in parallel bundles)
- new material looks like watery gel - pink coloured granulation - Becomes large nodule (tendon callus) which encloses the old injury site
Compare type 1 and type 3 collagen
Type 3 collagen can be quickly produced but is of a lower quality than type 1 - weaker and less elastic. Type 1 has a more complex structure which takes longer to synthesise but is stronger and more elastic.
Describe the remodelling stage of tendon healing
- For the new tissue to perform like the old tendon did the collagen needs to be higher quality + be organised in neat parallel bundles aligned in the direction of strain
- To know which way the direction of force is the cells detect the deformation cycle which occurs when muscles pull the damaged tendon - why load bearing/movement is important during healing
- Cells break down the callus and replace it with a better, more functionally adapted material - primarily collagen type 1, in parallel arrangement
- Callus decreases in size, tissue left resembles original tendon
Tendinitis
Inflammation of the tendon (acute)
Treatment of tenditis
- Rest joint
- Take NSAIDs
- Physiotherapy
- Steroid injections, surgery, shock wave therapy (if more long-term)
Diagnosis of tendinitis
Physical examination
List the symptoms of tendinitis
- Pain - worse with movement
- Difficulty moving joint
- Feeling grating/crackling sensation when moving joint
- Swelling, sometimes w/ heat or redness
Describe methods of prevention of tendinitis
- Warm up before exercising, stretch afterwards
- Wear suitable shoes for exercise
- Take regular breaks from repetitive exercise
- Don’t over-exercise tired muscles
- Don’t do repetitive exercises
Tendinosis
Non-inflammatory degeneration of the tendon caused by micro-tears due to overuse
Complete tendon rupture
Tear of the tendon in which none remains intact
Partial tendon rupture
Tear of the tendon in which some remains intact
List the symptoms of tendon ruptures
- Swelling around joint
- Inability to bear weight
- Bruising
- Sudden, sharp pain at time of injury which develops into a dull ache
- Stiffness
- Snapping/popping sound at time of injury
Diagnosis of tendon ruptures
- Physical examination
- Check for range of movement/weight bearing etc.
- Ultrasound/MRI to show rupture
Describe the treatment of tendon ruptures
- Depends on partial or complete tear, age, health etc.
- All will have physiotherapy
- Non-surgical or surgical treatment options
Describe non-surgical treatment of tendon ruptures
- Plaster cast, brace on injury for 6-8 weeks to keen tendon immobile while it heals
- Crutches to reduce weight bearing
- Pain-relief/anti-inflammatories e.g. NSAIDs
Describe surgical treatment of tendon ruptures
- Often done if active/young/athlete
- Depends on where tendon is ruptured (e.g. if achilles tendon is ruptured at or above the point at which the tendon meets the calf muscle surgery may not be possible)
- Open surgery - one long incision to reach tendon and repair it
- Limited open surgery - make a single incision but it will be shortened
- Percutaneous surgery - number of small incisions to reach tendon and repair it
- Tendon is stitched together to allow more efficient healing
- Chance tendon will rupture again after surgery
How are muscles attached to bones?
Directly via tendons, indirectly via aponeurosis
Describe the macrostructure of a muscle
Origin -> belly -> insertion
(From smallest to largest structure)
- Myofilaments (proteins responsible for muscle contraction)
- Myofibrils (tubes of proteins)
- Muscle fibres (muscle cells)
- Muscle fascicles
- Skeletal muscle
Describe the function of muscles
Able to:
- Contract
- Respond to stimulation from nervous system
- Stretch beyond normal resting length
- Revert to normal resting length
List the layers of connective tissue found in muscles
- Endomysium
- Perimysium
- Epimysium
Endomysium
- Thin layer of connective tissue
- Surrounds each muscle fibre (cell)
Perimysium
- Thick connective tissue
- Groups muscle fibres into fascicles
- Protects fascicles from damage, contains capillaries + nerve fibres - allows nutrient transfer
Epimysium
- Thick connective tissue
- Surrounds whole skeletal muscle
- May continue beyond muscle belly as tendon and become continuous with periosteum of bone
- Separates muscle from surrounding tissues and organs
List the components of skeletal muscle fibres (cells)
- Nuclei
- Sarcoplasm
- Myofibrils
- Terminal cisternae
- Sarcoplasmic reticulum
- Transverse tubules
- Sarcolemma
What is the sarcolemma of a muscle fibre?
- Plasma membrane of a muscle fibre
- Invaginated to from transverse tubules
What are the transverse tubules of a muscle fibre?
- Sarcolemma is invaginated to form transverse tubules (T tubules)
- Penetrate through the fibre, conduct electrical stimuli from sarcolemma
Nuclei of muscle fibres
- Each cell contains multiple flattened nuclei
- Lie beneath sarcolemma
Describe the sarcoplasmic reticulum of a muscle fibre
- Type of smooth endoplasmic reticulum
- Only found in skeletal muscle cells
- Large, concentrated store of calcium