Upper Limb 2 Flashcards
What are the main muscles of the anterior compartment of the arm (shoulder to elbow)
What is their action on the elbow joint
- biceps brachi
- brachialis
- Coracobrachialis
Flexion
Where does the short head of the biceps brachii arise from
Short arises from the coracoid process of the scapula
Where does the long head of the biceps brachii arise from
The supraglenoid process of the scapula
What is the distal attachment of the biceps brachii
The radial tuberosity
What is the main action of the biceps brachii
- Supination of the forearm
- also flexion of the arm at the elbow and shoulder
Which nerve innervates all the muscles in the anterior compartment of the arm
The musculocutaneous nerve
Tapping the biceps tendon tests which spinal nerve
C6
From which cord of the brachial plexus does the musculocutaneous nerve arise
Lateral
Where is the Coracobrachialis muscle in relation to the biceps brachii
Deep to the biceps brachii
What is the origin of the Coracobrachialis muscle
The coracoid process of the scapula
What is the insertion of the Coracobrachialis muscle
The medial margin of the humerus
What is the main action of the Coracobrachialis muscle
Flexion of the arm at the shoulder
Which muscle forms the base of the cubital fossa
The brachialis muscle
Where does the brachialis muscle originate
Medial and lateral surfaces of the humeral shaft
Where does the brachialis muscle insert
The tuberosity of the ulna just distal to the elbow joint
What is the main action of the brachialis muscle
Flexion of the elbow
Describe the path of the musculocutaneous nerve
Arises from the lateral cord of the brachial plexus, enters the arm by perforating the Coracobrachialis muscle and descends between the biceps and brachialis. After supplying the muscles it continues as the lateral cutaneous nerve of the forearm
Sensory functions of the musculocutaneous nerve
Gives rise to the lateral cutaneous nerve of forearm - it innervates the skin on the lateral aspect of the forearm
An injury to the musculocutaneous nerve would cause
- paralysis of the biceps brachii, brachialis and Coracobrachialis
- loss of sensation from lateral aspect of the forearm
At what anatomical point does the brachial artery begin
The inferior border of the teres major muscle
What muscles does the median nerve supply
The flexor muscles of the anterior compartment of the forearm (except the flexor Capri ulnaris and part of the flexor digitorum profundus which are innervated by the ulnar nerve) also supplies the the arm muscles and lateral 2 lumbricals in the hand
What is the sensory function of the median nerve
Gives rise to the palmar cutaneous branch which innervates the lateral part of the palm, and the digital cutaneous branch which innervates the lateral 3 and a half fingers on the palmar surface of the hand
Which artery does the median nerve cross in the arm
Brachial artery
Which group of muscles atrophies in carpal tunnel syndrome
Thenar eminence
Which deformity occurs when the median nerve is damaged at the elbow
Hand of benediction - only the little and ring fingers can flex completely when patient tries to make a fist
What muscles of the forearm are innervated by the ulnar nerve
- Flexor Capri ulnaris
- medial half of digitorum profundus
Sensory functions of the ulnar nerve
Innervates the anterior and posterior surfaces of the medial one and a half fingers, and the associated palm area
Which nerve passes posteriorly to the medial epicondyle
The ulnar nerve
Where does the ulnar nerve travel in relation to the flexor retinaculum
Superficial to the flexor retinaculum
Which muscles of the hand are innervated by the ulnar nerve
- The hypothenar muscles - flexor digiti minimise brevis, adductor digiti minimise, opponens digiti minimi
- medial 2 lumbricals
- adductor pollicis
- interossei of the hand
What is the most common site that the radial nerve could be damaged
The radial groove of the humerus - on the centre of the lateral border of the humerus
What is the most common site that the ulnar nerve could be damaged
The medial epicondyle of the humerus
What is the most common site the axillary nerve could be damaged
Surgical neck of the humerus
What muscle forms the medial border of the cubital fossa
Pronator teres
What muscle formed the lateral border of the cubital fossa
Brachioradialis
What forms the superior border of the cubital fossa
An imaginary line between the medial and lateral epicodyles of the humerus
Contents of the cubital fossa
- radial nerve
- biceps tendon
- brachial artery (bifurcates into radial and ulnar)
- median nerve
Really Need Beer To Be at My Nicest (from lateral to medial contents)
Where is the median cubital vein in relation to the cubital fossa
Within the roof - in the fascia
What forms the floor of the cubital fossa
Supinator and brachialis muscle
What muscle is the posterior compartment of the arm
Triceps
Where do the heads of the triceps muscle originate from
- Long head - infraglenoid tubercle
- Lateral head - humerus, superior to radial groove
- Medial head - humerus, inferior to radial groove
Where does the common tendon of the triceps insert
The olecranon process of the ulna
What is the action of the triceps brachii
Extension of the arm at the elbow
Innervation of the triceps
Radial nerve
Which spinal segment does a tap on the triceps tendon test
C7
Which head of the triceps brachii lies deeper than the other 2
The medial head
What is the action of the aconeus muscle
Helps triceps extend the forarm and abduct the ulna during pronation
Sensory innervation of the radial nerve
Most of the skin on the posterior side of the forearm and the dorsal surface of the lateral side of the palm, and lateral 3 and a half digits
Motor innervation of the radial nerve
- Innervates the triceps brachii
- Deep branch innervates the muscles in the posterior compartment of the forearm (extend at the wrist and finger joints)
What is the characteristic clinical sign of damage to the radial nerve
Wrist drop
- due to not being able to extend the wrist using the posterior muscles of the forearm
Which nerve is most at risk from a midshaft humeral fracture
Radial nerve
What kind of joint is the elbow
Synovial hinge
Which landmark of the humerus marks the course of the radial nerve
The radial groove
How many cutaneous branches does the radial nerve give off
4
What are the 2 separate articulations of the elbow joint
- Trochlea of humerus and trochlear notch of ulna
- Capilutulum of humerus and head of radius
What movements are permitted at the elbow joint
Flexion and extension
What joint allows pronation and supination
Radioulnar joints
Which ligament holds the radius in the radial notch of the ulna
Annular ligament of the radius
What is the name for the fibrous thickening of the joint capsule extending from the lateral epicondyle of the humerus to the annular ligament
Radial collateral ligament
Where does the ulnar collateral ligament extend from
The medial epicondyle of the humerus to the coronoid process and olecranon of the ulna
Which muscles flex the elbow
- Biceps brachii
- brachioradialis
- brachialis
Which muscles extend the elbow
- Triceps brachii
- Anconeus
What is the common flexor origin
Medial epicondyle
What is the common extensor origin
Lateral epicondyle
Which bursa is commonly affected by “students elbow”
Subcutaneous olecranon bursa
What kind of joint is the radio ulnar joint
What movements are permitted at this joint
- Pivot type synovial
- Pronation and supination
Which muscles produce pronation at the radio-ulnar joints
- pronator quadratus
- pronator teres
Which muscles produce supination of the radio-ulnar joints
- supinator
- biceps brachii
What is the name of the connective tissue which joins the radius and ulna between the radio ulnar joints
Interosseus membrane - holds radius and ulna together, acts a as a site of attachment for muscles, transfers forces from the radius to the ulna
Why are children more prone to subluxation and dislocation of the radio-ulnar joint
They have a weak annular ligament
Which muscles attach to the greater tubercle of the humerus
- the infraspinatus
- the supraspinatus
- teres minor
Innervation of the deltoid is
Axillary nerve
Actions of the deltoid muscle
- anterior fibres flex the arm at the shoulder
- posterior fibres extend the arm at the shoulder
- middle fibres are the major abductor of the arm
Where does the deltoid muscle originate and attach to
Originates from the scapula and clavicle and attaches to the deltoid tuberosity on the lateral surface of the humerus
Where is the origination and attachments of the teres major
The posterior surface of the inferior angle of the scapula and attaches to the intertubercular groove of the humerus
Innervation of the teres major
Lower scapular nerve
Actions of the teres major
Adducts at the shoulder and medially rotates the arm
What is the action of the supraspinatus
Abducts the arm and assists the deltoid
What is the individual action of the infraspinatus
Laterally rotates the arm
What is the individual action of the subscapularis muscle
Medially rotates the arm
What is the action of the teres minor
Laterally rotates the arm
Which nerve innervates the rhomboids and levator scapulae
Dorsal scapular nerve
Which nerve innervates the supraspinatus
The suprascapular nerve
Which nerve innervates the teres minor
Axillary nerve
