Anatomy - AUL COPY COPY Flashcards
Describe the clavicle:
-Slender
-S-shaped bone
-Easily palpable
-Commonly fractured
Where does the clavicle articulate?
-Sternum at its medial end (sternoclavicular joint)
-Acromion of scapula at its lateral end (acromioclavicular joint)
-BOTH SYNOVIAL
-Holds limb away from trunk so it can move freely
Label this diagram:
Describe the scapula:
-Mostly flat
-Some important bony projections
-Some parts can be palpated
What does the posterior surface of the scapula bear and what is its significance?
-Ridge of bone called spine
-Lateral end of spine expands to form acromion
-Articulates with lateral end of clavicle
Label this diagram:
What does the clavicle, scapula and attached muscles form?
Pectoral girdle
What important structure is on the lateral aspect of the scapula?
-Gleniod fossa
-Articulates with proximal humerus to form shoulder (glenohumeral joint)
-Shallow making it a poor fit for humerus
-Increases range of movement but low stability
What is this?
Glenoid fossa
What are superior and inferior to the glenoid fossa?
-Supraglenoid tubercle
-Infraglenoid tubercle
-Important sites for muscle attachment
Label this diagram:
Describe the humerus:
-Long bone in the arm
-Shaft and expanded proximal and distal ends
What part of the humerus is this and what does it articulate with?
-Head
-Articulates with glenoid fossa of scapula
-Bears groove called anatomical neck
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What does the proximal humerus bear laterally?
-Projection of bone called greater tubercle
-Smaller anterior projection called lesser tubercle
-Important sites for muscle attachment
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What happens just distal to the tubercles?
-Bone narrows and becomes continuous with shaft
-Region is called surgical neck
-Commonly fractured especially in elderly due to fall
-Axillary nerve runs close to region and can be damaged by fractures of surgical neck or dislocation of humeral head
Label this diagram:
What is this?
-Deltoid tuberosity
-Site for attachment of deltoid muscle
What is this?
-Radial groove
-Marks path of radial nerve over posterior aspect of upper humeral shaft
-Runs very close and can be damaged in mid-shaft humeral fractures
Movement of what bone is vital for normal movement of the shoulder joint?
Scapula
What articulation is there between the scapula and the posterior thoracic wall?
-NONE
-Lies on posterior chest wall
-Surrounded by muscle and so no bony articulation between posterior thoracic wall and scapula
What are the 5 movements of the scapula?
-Protraction - extends upper limb
-Retraction - squaring shoulders
-Elevation - shrugging shoulders
-Depression - lowering shoulders
-Rotation - tilts glenoid fossa cranially to elevate upper limb
Label this diagram:
What movement of the scapula is very important?
-Rotation
-When raising arm above head, for every 2o of abduction of the shoulder, scapula rotates 1o
What is the scapula attached to posteriorly and by what?
-Vertebral column
-By muscles
-Attachment point of muscles and orientation of muscle fibres determine direction scapula moves
What is the key muscle involved in protraction of the scapula?
Serratus anterior
What are the muscles of the anterior pectoral girdle?
-Pectoralis major
-Pectoralis minor
-Serratus anterior
What are the two large superficial muscles of the posterior pectoral girdle?
-Trapezius
-Latissimus dorsi
Label this diagram:
Describe the trapezius and latissimus dorsi:
What is different about the latissimus dorsi?
-Large flat muscles
-Extensive attachments to vertebral column (trapezius to skull)
-Latissimus dorsi attaches to anterior aspect of proximal humerus not scapula
What are the 3 smaller, deeper muscles of the posterior pectoral girdle?
-Levator scapulae
-Rhomboid major
-Rhomboid minor
ATTACH MEDIAL BORDER OF SCAPULA TO VERTEBRAL COLUMN
Label this diagram:
Label this diagram:
Describe how each of these muscles move the scapula:
What is the origin and insertion of Trapezius?
-Origin - Skull, cervical and thoracic vertebrae
-Insertion - Clavicle and scapula (spine and acromnion)
What is the origin and insertion of latissimus dorsi?
-Origin - Lower thoracic vertebrae
-Insertion - Humerus - upper anterior
What is the origin and insertion of levator scapulae?
-Origin - upper cervical vertebrae
-Insertion - scapula - medial border
What is the origin and insertion of rhomboid minor?
-Origin - C7 and T1
-Insertion - Scapula - medial border
What is the origin and insertion of rhomboid major?
-Origin - Thoracic vertebrae
-Insertion - Scapula - medial border
What are most of the muscles of the posterior pectoral region innervated by?
Which muscle is an outlier?
-Branches that arise from brachial plexus
-Complex network of nerves that innervate upper limb
-Does not innervate trapezius
What innervates the trapezius?
-Cranial nerve XI - accessory nerve
What innervates latissimus dorsi?
-Branch of brachial plexus
-Thoracodorsal nerve
What movements are possible at the shoulder joint? (7)
-Flexion
-Extension
-Abduction
-Adduction
-Medial rotation
-Lateral rotation
-Circumduction
Label this diagram:
Act all of these on yourself: Shoulder
-Flexion
-Extension
-Abduction
-Adduction
-Medial rotation
-Lateral rotation
-Circumduction
What is the fit like of the scapula and humerus?
-Poor fit
-Glenoid fossa of scapula and head of humerus
-Extensive mobility of joint
-Most commonly dislocated
What six muscles connect the scapula to the humerus?
-Deltoid
-Supraspinatus
-Infraspinatus
-Subscapularis
-Teres major
-Teres minor
Label this diagram:
What do the six muscles connecting the scapula to the humerus do?
What is the significance of their position?
-Move and stabilise shoulder joint
-All except deltoid lie deep to posterior scapula muscles
What is the rotator cuff?
-Four muscles work together to provide vital stability to the shoulder joint
-Supraspinatus
-Infraspinatus
-Subscapularis
-Teres minor
Label this diagram:
Where does the deltoid connect?
-Large muscle over lateral shoulder
-Attaches humerus to lateral part of clavicle and spine of scapula
-Gives shoulder its rounded contour
Where does the deltoid insert?
Deltoid tuberosity
What is the action of deltoid muscle?
-Powerful abductor of shoulder
-Cannot initiate abduction - another muscle initiates first 20o before it takes over
-Anterior and posterior deltoid fibres contribute to flexion and extension
What innervates the deltoid muscle?
-Major branch of brachial plexus
-Axillary nerve
-Injury of nerve can cause atrophy and weakness of deltoid
What is the attachment of the teres major?
-Arises from posterior aspect of scapula
-Inserts onto anterior aspect of humerus
What is the action of teres major?
-Medial rotator and adductor of shoulder joint
What is common among the muscles of the rotator cuff?
-All move shoulder joint
-Short muscles which attach the scapula to the tubercles of the humerus
What 3 rotator cuff muscles can be grouped together and why?
-Supraspinatus
-Infraspinatus
-Teres minor
-Originate from posterior scapula surface and insert onto greater tubercle
-Tendons fuse with fibrous capsule that surrounds shoulder joint
What is this?
What is the quadrilateral space?
-Square shaped space bound by:
-Teres minor above
-Teres major below
-Long head of triceps medially
-Surgical neck of humerus laterally
What passes through the quadrilateral space and where does it travel to?
-Axillary nerve
-Enter posterior scapula region and innervate deltoid and teres minor
Label this diagram:
Where does subscapularis originate and insert?
-Originates anterior surface of scapula
-Inserts onto lesser tubercle of the humerus
What is the action, origin and insertion of deltoid?
-Action - Abduction beyond 20 degrees
-Origin - Spine and acromion (plus clavicle)
-Insertion - deltoid tuberosity
What is the action, origin and insertion of teres major?
-Action - Medial rotation, Adduction
-Origin - Posterior surface, inferior part of lateral border
-Insertion - Anterior humerus
What is the action, origin and insertion of supraspinatus?
-Action - First 20 degrees of abduction
-Origin - Supraspinous fossa
-Insertion - Greater tubercle - superior facet
What is the action, origin and insertion of infraspinatus?
-Action - Lateral rotation
-Origin - Infraspinous fossa
-Insertion - Greater tubercle - middle facet
What is the action, origin and insertion of teres minor?
-Action - Lateral rotation
-Origin - Lateral border of scapula
-Insertion - Greater tubercle - inferior facet
What is the action, origin and insertion of subscapularis?
-Action - medial rotation
-Origin - subscapular fossa
-Insertion - Lesser tubercle
what is a painful arc a sign of?
-Tendon of supraspinatus becomes inflamed as it is pinched between acromion and humerus
-Called impingement
As a group, what provides vital stability to the shoulder joint?
-Four rotator cuff muscles
-Contraction holds the head of the humerus in the shallow glenoid
-Rotator cuff tendons fuse with the capsule of the shoulder joint
What three other structures contribute to glenohumeral joint stability?
-Glenoid labrum
-Reinforced by ligaments
-Tendons of biceps brachii
What is the glenoid labrum?
-Rim of fibrocartilage around the margin of the glenoid fossa
-Deepens the shallow glenoid fossa and aids stability
What separates the arm into posterior and anterior components?
-Intermuscular septa
-Extends from deep brachial fascia surrounding arm
What is the single muscle in the posterior compartment of the arm?
Describe it:
-Triceps brachii
-Three muscle bellies
-All converge via a common tendon onto single insertion point - Olecranon of ulna
Label this diagram:
What is the insertion point of the triceps brachii?
What does it do on contraction?
-Olecranon of the ulna
-Crosses posterior elbow joint
-Extends elbow on contraction
Label this diagram:
Where does the long head of triceps brachii originate?
-Infraglenoid tubercle of scapula
-Most medial part of triceps
Where does the lateral head of triceps brachii originate?
-Posterior humerus
-Proximal to radial groove
Where does the medial head of the triceps brachii originate?
-Posterior humerus
-Distal to radial groove
What can the long head of triceps brachii contribute to and why?
-Extension of shoulder joint
-Because of its attachment to scapula
What innervates the three parts of triceps?
-Radial nerve
-Major terminal branch of brachial plexus
What is the path of the radial nerve in the posterior arm?
Winds around posterior aspect of humerus in radial groove between medial and lateral heads of triceps
What does the shaft of the humerus expand to form distally?
-Bony prominences called medial and lateral epicondyles
-Distal humerus bears trochlea and capitellum
Label this diagram:
What do the trochlea and capitellum of the humerus articulate with?
-Trochlear notch of the ulna
-Head of radius
At elbow joint
Describe the axilla:
-Anatomical term for armpit - space between trunk and upper arm
-Pyramid shaped
-Six boundaries
What are the 6 boundaries of the axilla?
- Anterior wall – pectoralis major and minor
- Posterior wall – subscapularis, teres major and latissimus dorsi
- Lateral wall – upper humerus
- Medial wall – serratus anterior and chest wall
- Apex – first rib, clavicle and scapula. It is the passage between the neck and the axilla
- Base – skin and fascia between the chest wall and arm
Label this diagram:
What does it show?
The boundaries and structures that form the axilla
What 5 structures does the axilla contain?
-Fat
-Lymph nodes - upper limb, chest, abdo to umbilicus
-Axillary artery - upper limb
-Axillary vein
-Brachial plexus - upper limb
How many groups of lymph nodes are there in the axilla?
What do they drain?
-5 groups
-Drain upper limb, breast, chest wall, scapular region and abdominal region as far as umbilicus
Which axillary lymph nodes receive lymph from all of the others?
-Apical nodes
-Often involved in the spread of cancer (metastasis)
What is the path and branching of the subclavian artery?
-Travels under clavicle and into axilla
-Axillary artery is continuation of subclavian
-Axillary artery continues into arm as brachial artery
Label this diagram:
What branches does the axillary artery give?
-Several branches
-One above pectoralis minor
-Two behind it and three below it
What vein drains the upper limb?
-Axillary vein (large vein)
-Continuous with subclavian vein
-Alongside artery
Label this diagram:
How is the axillary vein formed?
Union of the deep veins of the arm with the basilic vein
What is the brachial plexus?
Network of nerves that provides motor and sensory innervation to the upper limb
What forms the brachial plexus?
-Spinal nerves that leave lower cervical spinal cord segments and first thoracic
-C5-8 and T1
How is the brachial plexus most often described?
-Roots
-Trunks
-Divisions
-Cords
-Branches
Label the sections of the brachial plexus:
Label these nerves of the brachial plexus:
What are the roots of the brachial plexus and where are they found?
-Five spinal nerves (C5-T1)
-Found in neck
What are the trunks of the brachial plexus?
-C5 and C6 combine to form superior trunk
-C7 continues as middle trunk
-C8 and T1 combine to form inferior trunk
What are the divisions of the brachial plexus?
Each trunk divides into an anterior and posterior division under the clavicle
What are the cords of the brachial plexus?
-Named relative to position around second part of axillary artery
-Anterior divisions of superior and middle trunk combine = lateral cord
-Posterior divisions of all trunks = posterior cord
-Anterior division of inferior trunk continues as medial cord
What are the branches of the brachial plexus?
-Axillary - branch of posterior cord
-Radial - continuation of posterior cord
-Musculocutaneous - branch from lateral cord
-Ulnar - branch from medial cord
-Median - branches of lateral and media cords
Other than the 5 main terminal branches, what other nerves arise from the brachial plexus?
-Different segments give rise to other nerves
-Innervate the shoulder and pectoral muscles
What does the axillary nerve innervate?
-Deltoid muscle
-Teres minor
-Small region of skin over upper lateral arm
Describe the axillary nerve path:
-Branch of posterior cord
-Contains fibres from C5 and C6
-Runs down to surgical neck of humerus
What nerve is this?
Axillary nerve
What does the radial nerve innervate?
-Triceps in posterior arm
-All muscles in posterior compartment of forearm - extensors of wrist and digits
-Regions of skin over arm, forearm and hand
Describe the radial nerve path:
-Continuation of posterior cord
-Contains fibres from C5-T1
-Runs along radial groove on posterior surface of humerus
What nerve is this?
Describe the pathway of the musculocutaneous nerve:
-Arises from lateral cord
-Contains fibres from C5-7
-Continues as sensory nerve that innervates skin region over forearm
Describe the pathway of the musculocutaneous nerve:
-Arises from lateral cord
-Contains fibres from C5-7
-Continues as sensory nerve that innervates skin region over forearm
-innervates biceps
What nerve is this and what does it arise from?
What do the median and ulnar nerves innervate in the arm?
-They do not
-They innervate muscles in the anterior forearm and the hand
Describe the median nerve pathway;
-Formed from contributions from both lateral and medial cords
-Contains fibres from C6-T1
-Crosses anterior aspect of elbow in cubital fossa
What nerve is this?
Median nerve
What does the median nerve innervate?
-Most of the muscles of the anterior forearm - flexors of wrist and digits
-Small muscles of thumb
-Skin over lateral aspect of palm of hand and lateral digits
Describe the pathway of the ulnar nerve:
-Formed from continuation of the medial cord after it has given a contribution to median nerve
-Contains fibres from C8-T1
-Lies superficial to medial epicondyle
What does the ulnar nerve innervate?
-Most of small muscles of hand and therefore vital for fine movement of digits
-Skin over medial aspect of hand and medial digits
What is the most catastrophic type of brachial plexus injury?
-All five roots are injured
-Denervates whole of upper limb
-Injuries to different parts results in different clinical presentations
What 3 muscles does the anterior compartment of the arm contain?
-Biceps brachii
-Brachialis
-Coracobrachialis
What are common among the 3 muscles of the anterior arm?
-All act as flexors
-All innervated by musculocutaneous nerve
Label this diagram:
Describe the biceps brachii proximally:
-Lies most superficial in anterior arm
-Two muscle bellies - long and short head
-Both attached to scapula
-Long head - supraglenoid tubercle
-Short head - coracoid process
-Long head tendon pierces shoulder capsule to stabilise joint
Describe the biceps brachii laterally:
Two muscle bellies converge via common tendon onto radial tuberosity of radius
What is the action of the biceps brachii on the elbow and shoulder joints?
-Flexor of elbow joint
-Crosses shoulder joint so can contribute to flexion of shoulder joint
What is the action of biceps brachii on the forearm?
-Powerful supinator
-When the elbow is flexed
-Power to turn screwdriver very tightly
What is the attachment of the brachialis?
-Deep to biceps
-Proximally, anterior aspect of lower half of humerus shaft
-Crosses elbow joint to insert distally upon ulnar tuberosity
What is the action of brachialis?
-Powerful flexor of elbow joint
-Does not cross shoulder so doesn’t act on it
What is the attachment of the coracobrachialis?
-Smaller muscle
-Attaches proximally to coracoid process of scapula
-Distally to medial aspect of middle humerus
What is the action of coracobrachialis?
-Crosses shoulder
-Weak flexor
What is the cubital fossa?
-Region anterior to elbow joint
-Clinically - antecubital fossa ACF
Describe the borders of the cubital fossa:
-Lateral border - brachioradialis
-Medial border - pronator teres
-Superior border - Line drawn between medial and lateral epicondyles of the humerus
Label the borders of the cubital fossa:
What can be traced into the cubital fossa as it travels to its insertion point?
-Tendon of biceps brachii
-Travels to insertion point on radial tuberosity
-Easily palpated when flexed elbow
What extension of the biceps tendon exists in the cubital fossa and what is its significance?
-Bicipital aponeurosis
-Fascial extension of biceps tendon
-Separates superficial veins from deeper structures in fossa - brachial artery and median nerve
What is the pathway of the brachial artery into the cubital fossa?
-Lies medial to biceps tendon
-Bifurcates into its terminal branches in the cubital fossa - radial and ulnar arteries
Label this diagram:
What is the pathway of the median nerve in the arm and what does it innervate here?
-Medial to brachial artery
-Does not innervate any muscles in the arm
-Travels through anterior component and cubital fossa to anterior forearm and hand
What is the pathway of the radial nerve in the arm?
-Passes through lateral aspect of cubital fossa
-Deep to brachioradialis
What is the clinical significance of the superficial veins of the cubital fossa and where are they?
-Subcutaneous tissue over cubital fossa
-Venepuncture
-Intravenous access
-Must not mistake median nerve or brachial artery
What are the two bones of the forearm and what are they connected by?
-Radius and ulna
-Connected by interosseous membrane
What is the articulation of the humerus with the two bones of the forearm?
-Ulna + radius articulate at proximal ends with humerus
-Trochlea notch of ulna + trochlea of humerus
-Radial head + capitellum