Brachial Plexus

Division of brachial plexus

3 anterior, 3 posterior divisons

Branches of brachial plexus that emerge from trunks

Both from superior trunk Suprascapular n. (C5, C6) Nerve to subclavius muscle

Muscles for lateral rotation of shoulder

C5 Infraspinatus Teres minor Posterior deltoid

Muscles for shoulder abduction

C5 Lateral deltoid Supraspinatus

Muscles for flexion of shoulder

C5 anterior deltoid coracobrachialis pect. major (clavicular head) biceps brachii

Muscles for adduction of shoulder

C6-C8 Pect. major Latissimus dorsi Teres major

Muscles for extension of shoulder

C6-C8 Posterior deltoid Latissimus dorsi Teres major Triceps, long head Pect. major (sternocostal portion)

Muscles for medial rotation of shoulder

C6-C8 Subscapularis Pect. major Teres major Latissimus dorsi Anterior deltoid

Branches of brachial plexus that emerge from roots

Dorsal scapular n. (C5) Long thoracic n. (C5, C6, C7)

Upper brachial plexus injuries often result in

Erb-Duchenne palsy. "waiter's tip". Occurs when shoulder and neck are violently separated, causing paralysis of muscles in shoulder and arm supplied by C5 and C6)

Lower brachial plexus injuries (C8 and T1) results in

Klumpe paralysis. "claw hand". Occurs when upper limb is suddenly pulled superiorly, injuring inferior trunk of brachial plexus.

Branches of brachial plexus that emerge from lateral cord

Lateral pectoral nerve (C5, C6, C7) Musculocutaneous nerve (C5-C7) Lateral head of median nerve (C6, C7)

Which artery supplies muscles of chest wall?

Lateral thoracic a.

Klumpe paralysis is caused by

Lower brachial plexus injuries. Occurs when upper limb is suddenly pulled superiorly, injuring inferior trunk of brachial plexus.

Branches of brachial plexus that emerge form medial cord

Medial pectoral nerve (C8, T1) Medial cutaneous nerve of arm (C8, T1) Medial cutaneous nerve of forearm (C8, T1) Medial head of medial nerve (C8, T1) Ulnar nerve (C8, T1)

Branches of brachial plexus that emerge from divisions

NONE

Which artery supplies deltoid muscle and glenohumeral joint?

Posterior circumflex humeral arteries

Brachial plexus is divided into which 5 parts

Root Trunk Division Cords Branches

Rotator cuff muscles

SITS: Supraspinatus Infraspitantus Teres minor Subscapularis

Which branch of axillary a. is located below the pect. minor?

Subscapular a. (scapular circumflex, thoracodorsal) Anterior/posterior circumflex humeral a.

Which rotator cuff muscle attaches to lesser tubercle of humerus?

Subscapularis

Which branch of axillary a. is located above the pect. minor?

Superior thoracic a.

6 branches of axillary artery

Superior thoracic a. (above pect. minor) Thoracoacromial a. (behind pect minor) Lateral thoracic a. (behind pect. minor) Subscapular a. (below pect.minor) Anterior and posterior circumflex humeral a. (below pect. minor, divides into scapular circumflex a. & thoracodorsal a.)

Trunks of brachial plexus

Superior= C5+C6 roots Middle= C7 root Inferior trunk= C8+T1

Cutaneous innervation of shoulder region

Supraclavicular c. (C3-4) Superior lateral cutaneous of arm- branch from axillary n. Intercostobrachial n. (T2)

Which rotator cuff muscle attach to greater tubercle of humerus?

Supraspinatus Infraspinatus Teres minor

Which branches of axillary a. is located behind the pect. minor?

Thoracoacromial a. Lateral thoracic a.

Which artery supplies muscles of anterior shoulder?

Thoracoacromial artery

Which artery supplies muscles of posterior axillary wall?

Thoracodorsal branch of subscapular artery

Branches of brachial plexus that emerge from posterior cord

ULTRA: Upper subscapular nerve (C5) Lower subscapular nerve (C6) Thoracodorsal nerve (C6, C7, C8) Radial nerve (C5-T1) Axillary (C5, C6)

Brachial plexus derives from ___ of spinal nerve.

anterior primary rami

Roots of brachial plexus derive from ___.

anterior primary rami of cervical spinal nerve C5, C6, C7, C8, T1

Posterior circumflex humeral artery passes

around the posterior aspect of the surgical neck

Which artery passes behind pect. minor?

axillary artery

Anterior deltoid is innervated by

axillary n.

Teres minor is innervated by

axillary n.

Lateral thoracic artery supplies

chest wall, and gives rise to lateral mammary branches

Rotator cuff injury may occur from

chronic wear and tear or an acute fall on an outstretched arm, producing instability of glenohumeral joint. Often the tendon of the supraspinatus is ruptured due to inflammation and calcification of the tendon, producing pain during abduction of arm.

Thoracic outlet syndrome is caused by

compression of neurovascular structures passing through the cervico-axillary canal (thoracic outlet), often involving inferior trunk. The compression occurs as a result of cervical ribs or abnormal insertions or size of the anterior and middle scalene muscles. Compression of subclavian artery can result in ischemic muscle pain.

Which ligament form an arch above the shoulder joint?

coracoacromial lig.

Branches from the infraclavicular part of the plexus arise from

cord of the plexus

Axillary nerve innervates

deltoid teres minor skin of shoulder

Posterior circumflex humeral artery supplies

deltoid muscle and glenohumeral joint

Median nerve innervates

forearm flexor muscles

Injury to Axillary nerve can be caused by

fracture of surgical neck of humerus or inferior dislocation of the humerus

which two ligaments strengthen the glenohumeral joint?

gelnohumeral lig. coracohumeral lig.

Glenohumeral joint involves articulation of which structures?

humerus and glenoid cavity of scapula

Subscapular artery supplies

lateral border of scapula (scapular circumflex a.) muscles of posterior axillary wall (thoracodorsal a.-latissimus dorsi)

Anterior circumflex humeral artery passes

laterally around the front of the surgical neck of humerus

Erb duchenne has what characteristic posture?

limb hanging by the side of the body (adduction) in medial rotation.

What marks the transition from subclavian to axillary artery?

lower border of first rib

What marks the transition from axillary to brachial artery?

lower border of teres major

Teres major is innervated by

lower subscapular n.

Ulnar nerve innervates

majority of hand muscles

Pect. major is innervated by

medial and lateral pectoral n.

Musculocutaneous nerve innervates

muscles of anterior compartment of arm, skin of lateral forearm

Thoracoacromial artery supplies

muscles of anterior shoulder

Biceps brachii is innervated by

musculocutaneous n.

Coracobrachialis is innervated by

musculocutaneous n.

Cords of brachial plexus

named after their relationship to axillary artery. Lateral- formed from anterior division of superior and middle trunk. Medial- formed from anterior division of inferior trunk Posterior- formed from posterior divisions of all three trunks

Symptoms of thoracic outlet syndrome

pain, numbness, tingling, or weakness and fatigue in upper limb.

Axillary artery passes behind what muscle?

pectoralis minor. Axillary artery is divided into the part above the muscle, behind the muscle, below the muscle.

Radial nerve innervates

posterior compartment muscles and skin of arm and forearm

Rotator cuff muscle function

provide major support for shoulder joint and form a musculotendinous cuff around the joint

Triceps long head is innervated by

radial nerve

Nerve branches from the supraclavicular part of the plexus are derived from

roots (2 branches) superior trunk (2 branches)

Axillary artery is a direct continuation of

subclavion artery

Lower subscapular nerve innervates

subscapularis teres major

Upper subscapular nerve innervates

subscapularis muscle

Infraspinatus is innervated by

suprascapular n.

Supraspinatus is innervated by

suprascapular n.

Suprascapular nerve innervates

supraspinatus and infraspinatus

Rotator cuff injury often produce rupture of ___ tendon.

supraspinatus due to inflammation of the tendon. Produces pain during abduction of arm.

Subscapularis is innervated by

upper and lower subscapular n.

Erb-Duchenne palsy results from

upper brachial plexus injuries. Occurs when shoulder and neck are violently separated, causing paralysis of muscles in shoulder and arm supplied by C5 and C6)

Erb duchenne is due to

upper brachial plexus injury that damages C5 muscles responsible for abduction and lateral rotation. So muscles responsible for adduction and medial rotation act unopposed.

Injury to axillary nerve can result in

weakness of lateral rotation and abduction of the arm at the glenohumeral point