Upper limb 1+2 anatomy Flashcards
consolidate knowledge of anatomy
What is the axilla?
Pyramidal space below shoulder joint providing passage for vessels/nerves to upper limb
What makes up the following walls of axilla?
- Anterior wall
- Posterior wall
- Medial wall
- Lateral wall
Anterior: pectoralis major/minor
Posterior: scapularis muscle
Medial: thoracic wall and serratus anterior
Lateral: intertubular sulcus of humerus
The axillary artery is a continuation of what artery?
Subclavian artery
What anatomical point does axillary artery begin?
Midpoint of clavicle
What anatomical point does axillary artery become brachial artery?
Lower border of teres major
What ventral rami form the brachial plexus?
C5-T1
What nerve roots form the superior trunk of brachial plexus?
C5 and 6
What is Erbs point?
Point where C5 and 6 join together. Injury here (eg at birth/from fall on shoulder) results in Erbs palsy, which can result in biceps brachii/brachialis/coracobrachialis/brachioradialis/deltoid being affected
What segmental roots form inferior (medial) trunk of brachial plexus?
C8 and T1
Injury to the inferior trunk of brachial plexus results in Klumpke’s palsy. What is the injury cause and what muscles are affected?
Undue abduction of arm is cause.
Intrinsic muscles of hand and ulnar flexors of wrist/fingers are affected
What is the superior/middle/inferior trunks of the brachial plexus when named by their respective cords?
- Lateral cord (C5 and 6)
- Posterior cord (C7)
- Medial cord (C8 and T1)
What are the branches of the lateral cord of brachial plexus?
- Lateral pectoral nerve
- Lateral root of median nerve
- Musculocutaneous nerve
What are the branches of the posterior cord of brachial plexus?
- Thoracodorsal nerve
- Axillary nerve
- Ulnar nerve
- Subscapular nerve
What are the branches of the medial cord of brachial plexus?
- Medial pectoral nerve
- Radial nerve
- Medial branch of median nerve
- Medial cutaneous nerve of arm
- Medial cutaneous nerve of forearm
How does the veins of the hand form from the dorsal venous arch?
- Basilic vein forms laterally from dorsal venous arch
- Cephalic vein forms medially from dorsal venous arch
Where do lymphatic vessels from upper limb drain into?
Axillary lymph nodes`
Could infection around umbilicus spread to both axillary and superficial inguinal groups of both sides? If so why?
Yes - lymphatic system drains up and down around umbilicus
What is the function of pectoral/shoulder girdle?
Connect upper limb to axial skeleton on each side
What is the only articulating joint between the upper limb and pectoral girdle? What type of joint is this?
Acromioclavicular joint. Synovial plane joint
Where is weakest point point of the clavicle and is most commonly broken during a fall with an outstretches hand?
1/3 from acromial end. Thinnest part of clavicle
What type of joint is the sternoclavicular joint?
Synovial saddle
Where does the head of humerus attach to the scapula bone?
Glenoid cavity
What muscles are responsible for ELEVATION of the scapula?
- Levator scapulae
- Upper fibres of trapezius
What muscles are responsible for DEPRESSION of the scapula?
- Pectoralis minor
- Lower fibres of trapezius
- Subclavius
- Latissimus dorsi
What muscles are responsible for PROTRACTION (forward movement) of the scapula?
- Serratus anterior
- Pectoralis major
- Pectoralis minor
What muscles are responsible for RETRACTION (backward movement) of the scapula?
- Trapezius (middle fibres)
- Rhomboid major
- Rhomboid minor
What muscles are responsible for LATERAL ROTATION (elevating glenoid cavity) of the scapula?
- Infraspinatus
- Teres minor
What muscles are responsible for MEDIAL ROTATION (depressing glenoid cavity) of scapula?
- (Gravity)
- Levator scapulae
- Rhomboid major
- Rhomboid minor
- Pectoralis minor
What type of joint is the glenohumeral joint (shoulder joint)?
Synovial ball and socket
What is the rim of cartilage surrounding the glenoid cavity? What is its function?
Glenoid labrum. Acts to deepen the joint helping to keep it in place
What are the ligaments of the shoulder? What do they attach to?
-Joint capsule - Attaches to head of humerus and superior part of the rim of glenoid cavity. Surrounds joint
Coracohumeral ligament - attaches to head of humerus and coracoid process
Coracoclavicular ligament - attaches to coracoid process and clavicle
Coracoacromial ligament - attaches to acromion and coracoid process
Glenohumeral ligament - attaches to head of humerus and glenoid cavity
Transverse humeral ligament - attaches in intertubercular sulcus of humerus
What do the glenohumeral ligaments do?
Act to strengthen the inferior aspect of joint capsule
What does the coracohumeral ligament do?
Act to strengthen superior aspect of joint capsule
What is the coracoacromial arch made up of and what does it prevent?
- Acromion and coracoid process of scapula, and coracoacromial ligament
- Acts to prevent superior displacement of humeral head
What part of the shoulder joint capsule is weakest due to not being protected by ligaments and muscles? therefore what type of shoulder dislocation is most common?
Beneath head of humerus on anterior side. Therefore ANTERIOR dislocation is most common
What is the function of bursa at joints?
Provide cushioning via their fluid filled interior
What bursa communicates with joint cavity?
Subscapular bursa. Seen when looking at coronal view of glenoid cavity. Surrounds it
What is the role of the subacromial bursa?
Facilitate gliding of tendons over the bone
What common sporting injury damages the subacromial bursa?
Subacromial bursitis
What are the rotator cuff muscles?
- Subscapularis (anterior side)
- Supraspinatus
- Infraspinatus
- Teres minor
The rotator cuff muscles extend from the scapula to humerus. What movements of the glenohumeral joint do they evoke? Is there any other functions at this joint the muscles have?
Internal/external rotation. Stablising joint
Where does the deltoid insert?
From the lateral spine of the scapula, across acromion, to lateral third of clavicle
The deltoid has anterior, middle and posterior fibres, with different movements for each set of fibres. What are the movements each of these evoke?
Anterior: flexes and medially rotates at shoulder joint
Middle: abduct at shoulder joint
Posterior: extends and laterally rotates
What nerve innervates the deltoid?
Axillary nerve (C5, C6)
What nerve innervates teres minor?
Axillary nerve (C5, C6)
What nerve innervates subscapularis, supraspinatus and infraspinatus?
- Subscapularis: subscapular nerves
- Supraspinatus: suprascapular nerve
- Infraspinatus: suprascapular nerve
What common shoulder injury leads to the axillary nerve becoming trapped?
Shoulder dislocation
Where do the fibres of the pectoralis major originate?
Medial third of clavicle, sternum and ribs
What is the action(s) of the pectoralis major at the glenohumeral (shoulder) joint?
Adduction and internal rotation
What is the action(s) of serratus anterior?
Protraction of scapula. Stabilise scapula during limb movements
What nerve innervates the serratus anterior?
Long thoracic nerve (C5, C6, C7)
What clinical sign can arise if injury to long thoracic nerve (and therefore paralysing serratus anterior) occurs?
Winged scapula (retracted scapula position)
During what procedure is long thoracic nerve commonly injured?
Mastectomy
The trapezius has superior, middle and inferior fibres. What do each of these do?
Superior fibres: elevate scapula
Middle fibres: retract scapula
Inferior fibres: depress scapula
What nerve innervates trapezius?
Accessory nerve (CN XI)
What are the action(s) of teres major on shoulder joint?
- Adduction
- Internal rotation
What are the action(s) of latissimus dorsi on shoulder joint?
- Adduction
- Extension
- Internal rotation
What muscles are involved in FLEXION of shoulder joint?
- Anterior part of deltoid
- Coracobrachialis
- Pectoralis major
- Biceps brachii
What muscles are involved in EXTENSION of shoulder joint?
- Long head of triceps brachii
- Posterior part of deltoid
- Latissimus dorsi
What muscles are involved in ADDUCTION of shoulder joint?
- Subscapularis
- Teres major
- Latissimus dorsi
- Pectoralis major
What muscles are involved in ABDUCTION of shoulder joint?
- Middle part of deltoid
- Supraspinatus
What muscles are involved in INTERNAL ROTATION of shoulder joint?
- Subscapularis
- Latissimus dorsi
- Pectoralis major
- Teres major
What muscles are involved in EXTERNAL ROTATION of shoulder joint?
- Teres minor
- Infraspinatus
What are the three important muscles of the anterior compartment of the forearm?
- Biceps brachii
- Coracobrachialis
- Brachialis
The biceps brachii has two heads arising from the scapula, uniting at the distal third of upper arm, forming a a short tendon. Which of the two heads (long and short head) arise from the coracoid process along with coracobrachialis?
Short head
Which head of the biceps brachii arises from supraglenoid tubercle (above glenoid cavity) and runs in bicipital groove of humerus?
Long head
Which bony process of radius does tendon of biceps attach distally?
Radial tuberosity
What is the action of biceps brachii on:
- Shoulder and elbow joint
- Superior radio-ulnar joint?
- Shoulder and elbow joint: Abduction
- Superior radio-ulnar joint: Supination
What is the nerve supply to biceps brachii?
Musculocutaneous nerve
What segmental fibres mainly innervate biceps brachii?
C5-C7
From which cord of brachial plexus does musculocutaneous nerve arise?
Lateral cord
What is the insertion for the coracobrachialis?
From tip of coracoid process to medial margin of humerus at about its middle
What is the action of coracobrachialis on the shoulder joint?
Adduction
What nerve supplies the coracobrachialis?
Musculocutaneous nerve
What is the insertion of the brachialis?
Arises from front of the distal half of humerus shaft and inserts into coronoid process of ulna
What is the main action of brachialis on elbow joint?
Flexion
What nerve supplies the brachialis?
Musculocutaneous nerve
The musculocutaneous nerve is the main nerve of the anterior arm compartment. What is the course of this nerve in the arm?
Perforates coracobrachialis and descends between biceps and brachialis
What does the musculocutaneous nerve continue as after supplying the anterior arm muscles?
Lateral cutaneous nerve of forearm
What is the segmental root value of the musculocutaneous nerve?
C5-C7
List the 3 muscles supplied by musculocutaneous nerve
- Biceps brachii
- Coracobrachialis
- Brachialis
If someone sustained an injury via a weapon to the axilla area, what would be the result of the injury to musculocutaneous nerve?
- Paralysis of biceps brachii, coracobrachialis, brachialis
- Loss of sensation to lateral aspect of forearm
When does the subclavian artery become the axillary artery?
Outer border of first rib
When does axillary artery become brachial artery?
Lower border of teres major
Where does brachial artery divide into radial and ulnar artery?
In cubital fossa close to neck of radius
What is one of the main arteries branching off the brachial artery?
Profunda brachii (deep artery of arm)
What two cords does the median nerve arise from?
Lateral and medial cords
How does the median nerve travel in the arm?
Descends along lateral side of axillary artery and upper part of brachial artery, and in middle of arm it crosses to medial side of brachial artery entering cubital fossa
Does the median nerve supply any muscles in arm?
No, supplies muscles in hand
What cord of brachial plexus does ulnar nerve arise from?
Medial cord
How does the ulnar nerve descend in the arm?
Descends along medial side of brachial artery and enters posterior compartment of arm through intermuscular septum. Runs along medial head of triceps and to back of medial epicondyle
Does ulnar nerve innervate any muscles in arm?
- Flexor carpi ulnaris
- Medial half of flexor digitorum profundus
What are 3 common sites on the humerus where damage to these three nerves are likely due to fracture?
- Radial nerve
- Ulnar nerve
- Axillary nerve
- Radial nerve: radial groove
- Ulnar nerve: medial epicondyle
- Axillary nerve: surgical neck
How do you tell if you are looking at the left or right arm using brachial artery/biceps tendon/median cubital vein?
-Brachial artery is more medial than biceps tendon. Also median cubital vein points diagonally away from the body to the lateral side where the cephalic vein is
What is the pulse that can be felt medial to the tendon of biceps brachii?
Brachial pulse (of brachial artery)
What is the base of the cubital fossa made up of?
Imaginary line made up by two epicondyles
What muscle makes up the medial border of the cubital fossa?
Pronator teres
What muscle makes up lateral border of cubital fossa?
Brachioradialis
What are the contents of the cubital fossa?
- Terminal part of brachial artery and commencement of radial/ulnar arteries
- Biceps brachii tendon
- Median nerve
- Radial nerve +superficial/deep branches
Where is the brachial artery in relation to the median nerve and biceps brachii tendon in the cubital fossa?
In between them both. Median nerve runs medially to the brachial artery
The triceps has a long head and two shorter heads (lateral and medial). Where do each of these heads arise from?
- Long head: infraglenoid tubercle of scapula
- Lateral and medial heads: humerus
Where does the common tendon of triceps insert into?
Olecranon process of ulna
What is the main action of triceps on elbow joint?
Extension
What is the action of the anconeus muscles on the elbow joint?
Extension, stabilisation of joint
What type of muscles does the radial nerve innervate of the arm?
All extensor muscles of elbow and wrist joint
The radial nerve is a terminal branch of what cord of brachial plexus?
Posterior cord
Where does radial nerve enter the arm?
Anterior to long head of triceps, running with profunda femoris artery (deep artery of arm), curving around midshaft region of humerus in radial groove WITH the deep brachial artery
What is the root value of radial nerve?
C5-T1
What would the characteristic sign of a radial nerve injury be and where is the most common place for fracture?
Midshaft humeral fracture, can’t straighten arm
What type of joint is the elbow joint?
Synovial hinge
List the articular parts of the elbow joint
Trochlea, capitulum, trochlear notch, coronoid process, olecranon process, head of radius
What movements occur at elbow joint?
Flexion, extension
How are the ligaments of the elbow formed?
Thickening of the fibrous layer of joint capsule on medial and lateral side
What are the two collateral ligaments of the elbow?
- Radial collateral ligament
- Ulnar collateral ligament
What ligament holds the head of radius?
Annular ligament
What are the flexors of the elbow joint?
- Brachialis
- Biceps brachii
- Brachioradialis
What are the extensors of the elbow joint?
- Triceps brachii
- Anconeus
What is olecranon bursitis otherwise known as?
Student elbow
What type of joint are the proximal and distal radioulnar joints?
Synovial pivot joint
What movements occur at the radioulnar joints?
Supination, pronation
What is subluxation?
Partial dislocation of joint
What are the main muscles in supination at radio-ulnar joint?
- Supinator
- Brachioradialis
What are the main muscles in pronation at radioulnar joint?
- Pronator teres
- Pronator quadratus
What are muscles that assist in supination other than supinator/brachioradialis?
- Extensor pollicis longus
- Extensor carpi radialis longus
- Biceps brachii (long head)
What are muscles that assist in pronation other than pronator teres/quadratus?
- Flexor carpi radialis
- Palmaris longus
- Brachioradialis
What is the strongest supinator and pronator of arm?
- Supinator: supinator muscle
- Pronator: Pronator teres
What is the innervation of teres minor?
Axillary nerve
What movement of shoulder occurs when infraspinatus contracts?
Lateral rotation
What is the action of serratus anterior?
Protraction of scapula
What nerve innervates serratus anterior?
Long thoracic nerve
What are two actions of long head of biceps brachii?
- Flexion at shoulder
- Supination at radioulnar joint
What nerve innervates biceps brachii?
Musculocutaneous nerve
What type of joint is acromioclavicular joint?
Synovial plane
What muscles insert into greater tubercle of humerus?
- Supraspinatus
- Infraspinatus
- Teres minor
What nerve is closely related to medial epicondyle?
Ulnar nerve
What are the actions of latissimus dorsi on shoulder joint?
- Extension
- Medial rotation
- Adducts
What are the actions of the middle fibres of deltoid?
Abduct scapula
What spinal segments innervate deltoid?
C5 and C6
The subacromial bursa is associated with with muscle?
Supraspinatus
