Anatomy Shoulder & Arm 🩸 Flashcards
What are the 3 heads of the triceps?
- Long head (most medial).
- Lateral head.
- Medial head.
Which head of the triceps lies deepest?
The medial head - cannot be seen unless the lateral and long are dissected away.
What is the insertion of triceps?
Olecranon of the ulna.
What is the innervation of triceps?
The radial nerve.
Which rotator cuff muscle is most likely to be affected in rotator cuff tendinitis?
Supraspinatus - tendon passes through a tight gap between the humerus and acromium of the scapula and so is prone to inflammation. ‘Painful arc’.
Name the 4 rotator cuff muscles.
- Supraspinatus.
- Infraspinatus.
- Teres minor.
- Subscapularis.
What is the function of the rotator cuff muscles?
To stabilise the shoulder joint.
What is the action of supraspinatus?
Abduction.
What is the action of infraspinatus?
External rotation.
What is the action of teres minor?
External rotation.
What is the action of subscapularis?
Internal rotation.
What is the innervation of the deltoid muscle?
Axillary nerve
What is the insertion of the deltoid muscle?
Deltoid tuberosity of humerus.
What is the action of deltoid?
Abduction of the arm!
What type of muscles fibres make up deltoid?
Multi-pennate fibres - these fibres are powerful.
What is the function of latissiums dorsi?
Adduction!
What is the action of triceps?
Extension of the forearm.
Name 5 things contained wihin the axilla.
- Fat.
- Lymph nodes.
- Axillary artery.
- Axillary vein.
- Brachial plexus.
What spinal nerve roots form the brachial plexus?
C5 - T1.
What are the 5 main branches of the brachial plexus?
- Musculocutaneous.
- Axillary.
- Median.
- Radial.
- Ulnar.
What are the nerve roots for the musculocutaneous branch?
C5, 6, 7.
What muscle does the musculocutaneous nerve enter?
Coracobrachialis.
What are the nerve roots for the axillary branch?
C5, 6.
What are the nerve roots for the median branch?
C6, 7, 8, T1.
What are the nerve roots for the radial branch?
C5, 6, 7, 8, T1.
What are the nerve roots for the ulnar branch?
C8, T1.
What does the musculocutaneous nerve give motor innervation to?
Anterior flexors - brachialis, biceps brachii and coracobrachialis - BBC.
What does the musculocutaneous nerve give sensory innervation to?
Lateral forearm.
What would be the effect of damage to the musculotaneous nerve?
Flexion at the shoulder and elbow would be affected. Loss of sensation to the lateral forearms.
What does the axillary nerve give motor innervation to?
Abductors of the arm at the shoulder - teres minor, long head of triceps and deltoid.
What does the axillary nerve give sensory innervation to?
Innervates the skin over the lower deltoid.
What would be the effect of damage to the axillary nerve?
Unable to abduct the arm 15-90 degrees. Loss of sensation over the lower deltoid region.
What does the median nerve give sensory innervation to?
Lateral palm of the hand and the lateral 3.5 fingers.
What does the median nerve give motor innervation to?
Flexors in the anterior forearm, the thenar muscles and the lateral two lumbricals in the hand.
What would be the effect of damage to the median nerve?
Flexion of the forearm would be weakened, thenar muscle atrophy, unable to make a fist with their hands - only the little and ring fingers can flex completely. Loss of sensation over the lateral palm and lateral 3.5 fingers.
What does the radial nerve give motor innervation to?
Triceps brachii, responsible for extension at the elbow. It also innervates extensor muscles in the posterior compartment of the forearm.
What does the radial nerve give sensory innervation to?
Skin on the posterior side of the forearm and the posterior aspect of the hand.
What would be the effect of damage to the radial nerve?
Unable to extend the forearm, wrist and fingers. Unopposed flexion of the wrist: ‘wrist drop’. Loss of sensation over the posterior forearm and hand.
What would be the effect of damage to the ulnar nerve?
Unable to abduct and adduct the fingers. Movement of the little and ring fingers is reduced. A hand deformity called ‘ulnar claw’ will develop long term. Loss of sensation to the medial 1.5 fingers and medial palm.
What does the ulnar nerve give sensory innervation to?
Medial 1.5 fingers and the medial palm.
What does the ulnar nerve give motor innervation to?
Muscles of the hand, flexor carpi ulnaris (flexes and adducts the hand at the wrist) and medial half of the flexor digitorum profundus (flexes the fingers).
What is the cubital fossa?
An area of transition between the arm and forearm.
What muscle forms the medial border of the cubital fossa?
Pronator teres muscle.
What muscle forms the lateral border of the cubital fossa?
Brachioradialis muscle.
What are the contents of the cubital fossa lateral to medial?
- Biceps tendon.
- Brachial artery.
- Median nerve.
(TAN)
Does the median nerve lie lateral or medial to the brachial artery in the upper arm?
Laterally. It crosses to the medial side as it descends through the arm.
What is the origin of brachialis? What is the insertion of brachialis?
o- Lower half of the anterior humerus.
i- Coronoid process of the ulna.
What is the action of brachialis?
Flexion of the elbow joint.
What muscle does brachialis lie deep to?
Biceps brachii.
Biceps brachii: what is the origin of the long head?
Supraglenoid tubercle of the scapula.
Biceps brachii: what is the origin of the short head?
Coracoid process of the scapula.
Where does the biceps tendon insert?
The tuberosity of the radius.
What is the action of biceps?
Flexion of the elbow joint and supination of the forearm.
What is the origin of deltoid?
Clavicle, acromion of scapula, spine of scapula
Name 3 nerves closely related to the humerus.
- Radius.
- Ulnar.
- Axillary.
Transection of which cord of the brachial plexus produces paralysis of the biceps, brachialis and coracobrachialis?
Lateral cord.
What is the main muscle to abduct the shoulder 0-15 degrees?
Supraspinatus.
What is the main muscle to abduct the shoulder 15-90 degrees?
Deltoid.
What are the main muscle(s) that abduct the shoulder greater than 90 degrees?
Trapezius and serratus anterior.
Name 4 superficial muscles in the anterior compartment of the forearm?
- Pronator teres.
- Flexor carpi radialis.
- Palmaris longus.
- Flexor carpi ulnaris.
Where do the superficial muscles in the anterior compartment of the forearm originate from
The common tendon which arises from the medial epicondyle of the humerus.
What nerve innervates flexor carpi ulnaris?
What is the action of flexor carpi ulnaris?
Ulnar nerve (C8-T1). Flexion and adduction at the wrist.
What is the action of flexor carpi ulnaris?
Flexion and adduction at the wrist.
What nerve innervates palmaris longus?
Median nerve (C6-T1).
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What is the action of palmaris longus?
Flexion at the wri
st.
What nerve innervates flexor carpi radialis?
Median nerve (C6-T1).
What is the action of flexor carpi radialis?
Flexion and abduction at the wrist.
What nerve innervates pronator teres?
Median nerve (C6-T1).
What is the action of pronator teres?
Pronation of the forearm.
What nerve innervates brachioradialis?
Radial nerve (C5-T1).
What is the action of brachioradialis?
Flexion of the elbow.
What artery is the brachial artery a continuation of?
The axillary artery.
What arteries does the brachial artery branch into?
The radial and ulnar arteries.