MSK 2 Flashcards
What are the three main functions of the clavicle?
- Connects the upper limb to the trunk
- Protects underlying neurovascular structures supplying upper limb
- Transmits force from upper limb to axial skeleton
What are the medial and lateral attachments of the clavicle?
Medially to sternum - Sternoclavicular joint
Laterally to the acromion - Acromioclavicular joint
What is the most common fracture of the clavicle?
Junction of the medial 2/3 and lateral 1/3
How is the clavicle most commonly displaced during a fracture and why?
Lateral end is displaced inferiorly by weight of arm and medially by pectoralis major
Medial end is pulled superiorly by sternocleidomastoid muscle
What are the nerves that could be at risk during a clavicular fracture?
Suprascapular nerves by upwards movement (they innervate the lateral rotator cuff muscles)
What is the purpose of the glenoid fossa on the scapula?
Articulates with humerus to form glenohumeral joint
What is the purpose of the supraglenoid tubercle and infraglenoid tubercle respectively?
Supraglenoid tubercle - Attachment for the long head of biceps brachii
Infraglenoid tubercle - Attachment for the long head of triceps brachii
When is a scapula fracture usually seen?
Severe chest trauma - hight speed road collisions, crushing injuries, sports injuries
What causes winging of the scapula?
Damage to the long thoracic nerve - as it innervates serratus anterior which attaches to costal face of scapula pulling it against ribcage
What does the proximal region of the humerus form?
Glenohumeral joint with glenoid fossa of scapula
What are the bony landmarks of the proximal region of the humerus?
Head Anatomical neck Greater tubercle Lesser tubercle Intertubercular sulcus Surgical neck
What attaches to the greater tubercle of the humerus?
3 rotator cuff muscles:
Supraspinatus, infraspinatus, teres minor
What attaches to the lesser tubercle of the humerus?
Subscapularis
What sits in the intertubercular sulcus of the humerus?
Tendon of long head of biceps brachii
What attaches to the lips of the intertubercular sulcus of the humerus?
Pectorialis major
Teres major
Latissimus dorsi
What are the common fractures of the humerus?
Surgical neck of humerus caused by falling on an outstretched hand
Mid-shaft fracture
Supraepicondylar fracture - falling on flexed elbow
Medial epicondyle
What neurovascular structures are at risk during a surgical neck fracture of the humerus?
Axillary nerve
Posterior circumflex artery
What does damage to the axillary nerve result in?
Paralysis of deltoid and teres minor muscles - patient will not be able to abduct their arm
Sensory innervation of regimental badge area will also be lost
What bony landmarks are found on the shaft of the humerus?
Deltoid tuberosity
Radial groove
What other muscles attach to the humerus shaft?
Anteriorly - Corocobrachilais, deltoid, brachialis, brachioradialis
Posteriorly - Medial and lateral heads of triceps
What neurovascular structures are at risk during a mid-shaft fracture of the humerus?
Radial nerve and prrofunda brachii artery - bound in radial groove
What would be seen in radial nerve damage in a mid-shaft fracture of humerus?
Wrist drop - Radial nerve innervates extensors of the wrist, so damage will lead to paralysis giving unopposed flexion
Sensory loss over dorsal surface of the hand and proximal ends of lateral 3 and a half fingers dorsally
What are the bony landmarks of the distal region of the humerus?
From lateral to medial: Lateral epicondyle Capitulum Radial fossa Trochlea Coronoid fossa Medial epicondyle
What is the role of the trochlea of the humerus?
Articulates with ulna
What is the role of the capitulum of the humerus?
Articulates with the radius
Where does the ulnar nerve run at the distal region of the humerus?
Posteriorly to the medial epicondyle
What neurovascular structures are at risk during a distal region fracture of the humerus?
Supraepicondylar fracture - Brachial artery
Medial epicondyle fracture - Ulnar nerve
What could ulnar nerve damage due to medial epicondyle fracture result in?
Ulnar claw - Flexion of medial two fingers & loss of sensation on both dorsal and palmar surfaces
What is the function of the ulna?
Stabilising bone of forearm
What are the bony landmarks of the proximal ulna?
Olecranon
Trochlear notch
Coronoid process
Radial notch
What are the bony landmarks of the distal ulna?
Rounded head with ulnar styloid process
What is the common cause of a ulna only fracture and where on the ulna does this occur?
Ulna being hit by an object
Shaft of ulna
What is the role of the radius?
Pivots around ulna to produce movement
What are the four articulations of the radius?
Elbow joint - head of radius and capitulum of humerus
Proximal radioulnar joint - articulation between radial head and radial notch of the ulna
Wrist joint - articulation between distal end of radius and carpal bones
Distal radioulnar joint - articulation between ulnar notch and head of ulna
What are the bony landmarks of the proximal region of the radius?
Head
Neck
Radial tuberosity
What are the bony landmarks of the distal region of the radius?
Styloid process
Ulnar notch
Two facets for articulation with scaphoid and lunate carpal bones
What is a Colles’ fracture?
Most common type of radial fracture - falling on an outstretched hand
Fracture of distal radius causing hand and wrist to be displaced posteriorly - ‘dinner fork deformity’
How does the fracturing of the radius cause a fracture of the ulna and what are the two common fractures?
The force is transmitted across to the other bone via the interosseous membrane
Monteggia’s fracture
Galeazzi’s fracture
What is Monteggia’s fracture?
Caused from force behind the ulnar. Proximal shaft of ulna is fractured and the head of radius dislocates anteriorly at the elbow
What is Galeazzi’s fracture?
Fracture to distal radius with ulna head dislocating at the distal radio-ulnar joint
What are the three groups of bones in the hand?
Carpal bones
Metacarpals
Phalanges
What are the eight carpal bones?
Scaphoid Lunate Triquetrum Pisiform Trapezium Trapezoid Capitate Hamate
Which are the two carpel bones that are most commonly fractured?
Scaphoid and lunate
What is the clinical signpost for a fractured scaphoid?
Tenderness in anatomical snuffbox
What is the long term consequence of an untreated scaphoid fracture?
Can cut off blood supply to proximal part of the bone causing avascular necrosis
What are the common metacarpal fractures?
Boxer’s fracture - fracture of neck of 5th metaa
carpal, usually caused by clenched fist striking hard object
Bennett’s fracture - fracture of 1 metacarpal close to carpometacarpal joint caused by hyperabduction of thumb
What are the two superficial extrinsic shoulder muscles?
Trapezius
Latissimus dorsi
What are the attachments, innervations and actions of trapezius?
Attachment
Axial skeleton, skull - T12 and attach to posterior surface of scapula and clavicle
Innervation
Motor is accessory nerve, sensory is from C3 and C4 spinal roots
Action
Upper: elevate scapula & rotate during abduction of arm
Middle: retract scapula
Lower: pulls scapula inferiorly
What are the attachments, innervations and actions of latissimus dorsi?
Attachment
Thoracic spine, iliac crest and inferior 3 ribs and converges to a tendon that attaches to intertubecular sulcus of humerus
Innervation
Thoracodorsal nerve
Action
Extension of arm at shoulder, adduction at shoulder and medial rotation of arm
What are the three deep extrinsic should muscles?
Levator scapulae
Rhomboid major
Rohmboid minor
What are the attachments, innervations and actions of levator scapulae?
Attachment
Originates from transverse processes of C1-C4 and attaches to medial broder of scapula
Innervation
Dorsal scapular nerve
Action
Elevates scapula and rotates scapula to tilt glenohumeral joint inferiorly
What are the attachments, innervations and actions of rhomboid major and minor?
Attachment
C7-T5 vertebrae to medial border of scapula
Innervation
Dorsal scapula nerve
Action
Retracts scapula and rotates scapula to tilt glenohumeral joint inferiorly
What are the scapulohumeral muscles?
Deltoid
Teres major
What are the attachments, innervations and actions of deltoid?
Attachment
Scapula and clavicle and attaches to deltoid tuberosity
Innervation
Axillary nerve
Action
Anterior - Flex arm at shoulder
Middle - Major abductor (after first 15 degrees)
Posterior - Extend arm at shoulder
What are the attachments, innervations and actions of teres major?
Attachment
Inferior angle of scapula and attaches to intertubecular groove on humerus
Innervation
Lower subscapular nerve
Action
Adducts shoulder and medially rotates
What are the four rotator cuff muscles?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
What is the function of the rotator cuff muscles?
Pull humerus head into glenoid fossa, therefore giving stability to glenohumeral joint
Broadly, where do the rotator cuff muscles originate and attach to?
Scapula and greater tubercle of humerus, teres minor attaches to lesser tubercle of humerus
What is the innervation of the rotator cuff muscles?
Supraspinatus - Suprascapular nerve
Infraspinatus - Suprascapular nerve
Teres minor - Axillary nerve
Subscapularis - Upper and lower subscapular nerve
What is the action of the rotator cuff muscles?
Supraspinatus - Adbuction of first 15 degrees
Infraspinatus and teres minor - Lateral rotation
Subscapularis - Medial rotation
What is rotator cuff tendonitis?
When arm is abducted the tendon of supraspinatus rubs against coraco-acromial arch (friction reduced by subacromial bursa)
Repetitive use can cause degenerative changes of subacromial bursa and supraspinatus tendon leading to painful arc (pain in middle of abduction, when affected area comes into contact with acromion) - leads to inflammation
What are the four muscles of the arm?
Biceps brachii
Brachialis
Coracobrachialis
Triceps brachii
What innervates the muscles of the arm?
Musculocutaneous nerve - Biceps brachii, brachialis, coracobrachialis
Radial nerve - Triceps brachii
Where do the two heads of biceps brachii originate from?
Long head - supraglenoid tubercle, passes through the intertubercle sulcus
Short head - coracoid process
Where on the hip bone does the femur attach?
Acetabulum
What is the main function of the femur?
To transmit forces from tibia to the hip joint
What are the bony landmarks of the proximal region of the femur?
Head Neck Greater & lesser trochanter Intertrochanteric line Intertrochanteric crest
What are the bony landmarks of the shaft of femur?
Linea aspera splitting into the medial and lateral supraepicondylar line
Gluteal tuberosity
What are the bony landmarks of the distal region of the femur?
Medial and lateral condyles
Medial and lateral epicondyles
Intercondylar fossa
What is the function of the tibia?
Weight bearing
What are the bony landmarks at the proximal end of the tibia?
Medial and lateral condyles
Tibial tuberosity
Intercondylar emimance
What are the borders of the shaft of the tibia?
Anterior, posterior and lateral
What are the bony landmarks of the distal tibia?
Medial malleolus
Fibular notch
Which end of the tibia is most vulnerable to damage?
Proximal end
What fractures are common of the tibia?
Condyles
Medial malleolus
What is the main action of biceps brachii?
Supranation of forearm and flexion of arm at elbow
What is given off from the biceps brachii as it enters the forearm?
Bicipital aponeurosis
What does the bicipital aponeurosis do?
Forms roof of cubital fossa
What is the most common injury of biceps brachii?
Complete rupture of long head tendon - popeye sign (upon flexion at the elbow)
What are the attachments and action of coracobrachialis?
Coracoid process to medial side of humerus at the level of the deltoid tubercle
Action: flexion of arm at shoulder
What are the attachments and action of brachialis?
Medial/lateral surfaces of humeral shaft to ulna tuberosity
Action: flexion at the elbow
Where do the three heads of triceps originate?
Long head: infraglenoid tubercle
Lateral head: humerus, superior to radial groove
Medial head: humerus, inferior to radial groove
Where does triceps brachii attach?
Olecranon of ulna
What are the actions and innervation of triceps brachii?
Extension of arm at elbow
Radial nerve
What are the 3 muscles of the pectoral region?
Pectoralis major
Pectoralis minor
Serratus anterior
What are the attachments and innervation of pectoralis major?
Intertubecular groove of humerus and then clavicle and sternum/ribs
Medial and lateral pectoral nerves
What are the attachments and innervation of pectoralis minor?
Coracoid process and ribs 3-5
Medial pectoral nerve
What are the attachments and innervation of serratus anterior?
Medial border of scapula and ribs 2-8
Long thoracic nerve
What are the actions of pectoralis major?
Adducts and medially rotates
What are the actions of pectoralis minor?
Depresses shoulder
What are the actions of serratus anterior?
Rotates scapula and holds it against ribcage
What causes a winged scapula?
Damage to the long thoracic nerve, paralyses serratus anterior. Scapula no longer held against ribcage
What makes up the lateral border of the axilla?
Intertubecular sulcus
What makes up the posterior border of the axilla?
Latissimus dorsi, teres major, subscapularis
What makes up the medial border of the axilla?
Serratus anterior and thoracic wall
What makes up the anterior border of the axilla?
Pectoralis major and minor
What makes up the apex border of the axilla?
Lateral border of 1st rib, superior border of scapula and posterior border of clavicle
What makes up the base border of the axilla?
Skin
What are the contents of the axilla?
Long head of biceps brachii Coracobrachialis Brachial Plexus Axillary artery Axillary vein
What are the three passageways exiting the axilla?
Inferiorly & laterally into the upper limb
Quadrangular space - Gap in posterior wall of axilla (axillary nerve & posterior circumflex artery leave here)
Clavipectoral triangle - Gap in anterior wall (cephalic vein and lateral pectoral nerve leave here)
What are the roots of the musculocutaneous nerve?
C5, C6, C7
Which muscles does the musculocutaneous nerve supply motor innervation to?
Anterior compartment of arm (‘BBC’)
Biceps brachii
Brachialis
Coracobrachialis
Where does the musculocutaneous nerve provide sensory innervation to?
Lateral surface of forearm
What are the roots of the median nerve?
C6, C7, C8, T1
Which muscles does the median nerve supply motor innervation to?
Flexors of the forearm
Thenar muscles at lateral 2 lumbricals
Where does the median nerve provide sensory innervation to?
Lateral palm and lateral 3 1/2 fingers on anterior side
What are the roots of the radial nerve?
C5, C6, C7, C8, T1
Which muscles does the radial nerve supply motor innervation to?
Triceps brachii
Extensors of forearm
What does the radial nerve supply sensory innervation to?
Lateral arm (below deltoid)
Posterior surface of arm
Posterior forearm
Dorsal of lateral 3 1/2 fingers
What are the roots of the ulnar nerve?
C8, T1
Which muscles does the ulnar nerve supply motor innervation to?
Muscles of the hand (excluding thenar and lateral 2 lumbricals
What does the ulnar nerve supply sensory innervation to?
Anterior and posterior of medial 1 1/2 fingers & associated palm
What are the roots of the axillary nerve?
C5, C6
Which muscles does the axillary nerve supply motor innervation to?
Teres minor
Deltoid
- Abductors of the arm
What does the axillary nerve supply sensory innervation to?
Lower deltoid (Regimental badge area)
