Brachial Plexus Overview Quiz

Questions and Answers

Which spinal roots primarily contribute to the formation of the brachial plexus?

C4 to T2

C5 to T5

C1 to C3

C5 to T1 (correct)

The upper trunk of the brachial plexus is formed by nerve roots C5 and C7.

False

What mnemonic helps to remember the components of the brachial plexus?

Mar mu

The _________ Nerve supplies muscles in the anterior forearm and some hand muscles.

Median Signup and view all the answers

Match the nerves to their corresponding primary muscles or functions:

Musculocutaneous Nerve = Biceps brachii Axillary Nerve = Deltoid Ulnar Nerve = Medial side of hand Radial Nerve = Elbow extension Signup and view all the answers

What forms the posterior cord of the brachial plexus?

Posterior divisions of all trunks Signup and view all the answers

The long thoracic nerve helps in scapular elevation.

False Signup and view all the answers

Which minor nerve supplies the subclavius muscle?

Nerve to Subclavius Signup and view all the answers

Which muscle is primarily responsible for extending the elbow joint?

Triceps brachii Signup and view all the answers

The lower trunk of the brachial plexus is formed by nerve roots _________ and T1.

C8 Signup and view all the answers

What is the function of the dorsal scapular nerve?

Scapular retraction and elevation Signup and view all the answers

The pectoralis major is responsible for adducting the shoulder.

True Signup and view all the answers

Name the nerve responsible for supplying the muscle that flexes and adducts the shoulder.

Musculocutaneous nerve Signup and view all the answers

The __________ extends the fingers.

extensor digitorum Signup and view all the answers

Match the following nerves with their primary functions:

Radial nerve = Supplies extensor muscles of the forearm Median nerve = Innervates flexor muscles and provides sensation to the palm Ulnar nerve = Supplies hypothenar muscles and provides sensation to the medial hand Axillary nerve = Innervates skin over the deltoid Signup and view all the answers

What is the main function of the teres major muscle?

Extends and adducts the shoulder Signup and view all the answers

The ulnar nerve innervates the thenar muscles.

False Signup and view all the answers

What syndrome can occur due to compression of the median nerve?

Carpal tunnel syndrome Signup and view all the answers

The primary muscles in the anatomical snuffbox are the abductor pollicis longus, extensor pollicis brevis, and __________.

extensor pollicis longus Signup and view all the answers

Which nerve provides cutaneous sensation to the dorsal hand?

Radial nerve Signup and view all the answers

Which nerve is primarily responsible for motor function in the biceps brachii?

Musculocutaneous Nerve Signup and view all the answers

The lateral cord of the brachial plexus is formed by the anterior division of the lower trunk.

False Signup and view all the answers

What muscles does the axillary nerve supply?

Deltoid and teres minor Signup and view all the answers

The posterior cord of the brachial plexus is formed from the __________ divisions of the trunks.

posterior Signup and view all the answers

Match the following minor nerves with their functions:

Dorsal Scapular Nerve = Supplies rhomboids and levator scapulae Long Thoracic Nerve = Aids in scapular protraction Suprascapular Nerve = Supplies muscles for shoulder movements Nerve to Subclavius = Supplies subclavius muscle to depress the clavicle Signup and view all the answers

The musculocutaneous nerve supplies the __________.

Forearm flexors Signup and view all the answers

The median nerve mainly supplies muscles in the posterior forearm.

False Signup and view all the answers

What is the function of the long thoracic nerve?

Aids in scapular protraction Signup and view all the answers

The __________ nerve supplies skin over the deltoid muscle.

axillary Signup and view all the answers

Which of the following trunks is formed by the spinal root C7?

Middle Trunk Signup and view all the answers

What is the primary function of the triceps brachii?

Extend the elbow joint Signup and view all the answers

The musculocutaneous nerve innervates the skin over the deltoid.

False Signup and view all the answers

Which nerve runs through the carpal tunnel and is prone to compression?

Median nerve Signup and view all the answers

The __________ muscles are responsible for thumb adduction and are innervated by the ulnar nerve.

hypothenar Signup and view all the answers

Match each muscle to its corresponding function:

Pectoralis Major = Flexes and adducts the shoulder Coracobrachialis = Flexes and adducts the shoulder Teres Major = Extends and medially rotates the shoulder Latissimus Dorsi = Extends, adducts, and medially rotates the shoulder Signup and view all the answers

Which muscle specifically extends the little finger?

Extensor digiti minimi Signup and view all the answers

The radial nerve primarily supplies motor branches to flexor muscles in the forearm.

False Signup and view all the answers

What is the primary action of the extensor carpi radialis longus?

Extend the wrist Signup and view all the answers

The __________ nerve provides sensory innervation to the dorsal surface of the hand.

radial Signup and view all the answers

Which muscle assists the triceps brachii in extending the elbow?

Anconeus Signup and view all the answers

Which muscle is responsible for flexing and adducting the shoulder?

Coracobrachialis Signup and view all the answers

The medial nerve runs through the carpal tunnel and can cause carpal tunnel syndrome upon compression.

True Signup and view all the answers

What is the primary action of the triceps brachii?

Extends the elbow joint Signup and view all the answers

The long thoracic nerve assists in __________ elevation.

scapular Signup and view all the answers

Match the following muscles with their corresponding functions:

Brachioradialis = Flexes the elbow Extensor digitorum = Extends the fingers Supinator = Supinates the palm Anconeus = Assists in elbow extension Signup and view all the answers

Which nerve supplies the extensor muscles in the forearm?

Radial nerve Signup and view all the answers

The ulnar nerve provides sensory innervation primarily to the lateral third of the hand.

False Signup and view all the answers

Name the primary muscle responsible for protracting the scapula.

Pectoralis Minor Signup and view all the answers

The __________ muscles innervated by the ulnar nerve contribute to pinky dexterity.

hypothenar Signup and view all the answers

Match each nerve to its primary sensory function:

Musculocutaneous nerve = Lateral forearm sensation Axillary nerve = Skin over deltoid Median nerve = Ventral palm and digits two and three Ulnar nerve = Medial third of the hand Signup and view all the answers

Which nerve primarily supplies the deltoid muscle?

Axillary Nerve Signup and view all the answers

The brachial plexus consists of five trunks.

False Signup and view all the answers

Name the nerve responsible for innervating the rhomboids.

Dorsal Scapular Nerve Signup and view all the answers

The upper trunk of the brachial plexus is formed by the spinal roots __________ and C6.

C5 Signup and view all the answers

Match the following nerves with their primary functions:

Musculocutaneous Nerve = Flexes the elbow Median Nerve = Innervates the anterior forearm Ulnar Nerve = Innervates the medial forearm and hand Radial Nerve = Extends the elbow and wrist Signup and view all the answers

Which nerve aids in scapular protraction?

Long Thoracic Nerve Signup and view all the answers

The posterior cord of the brachial plexus is formed exclusively from the anterior divisions of the trunks.

False Signup and view all the answers

What is the primary function of the teres minor muscle?

Shoulder external rotation Signup and view all the answers

The __________ nerve supplies the skin of the lateral forearm.

Musculocutaneous Signup and view all the answers

Match the nerves with their respective muscles:

Axillary Nerve = Deltoid Median Nerve = Flexor muscles in the forearm Ulnar Nerve = Intrinsic hand muscles Radial Nerve = Extensor muscles of the arm Signup and view all the answers

Which muscle group is responsible for extending the elbow joint?

Triceps brachii Signup and view all the answers

The radial nerve supplies motor branches to the extensor muscles in the forearm.

True Signup and view all the answers

What is the primary function of the pectoralis minor muscle?

Protracts the scapula. Signup and view all the answers

The _________ nerve innervates the hypothenar muscles.

ulnar Signup and view all the answers

Match the following muscles with their actions:

Brachioradialis = Flexes the elbow Extensor carpi radialis = Extends the wrist Supinator = Supinates the palm Anconeus = Assists the triceps brachii in elbow extension Signup and view all the answers

Which nerve is primarily responsible for sensation in the lateral forearm?

Musculocutaneous nerve Signup and view all the answers

The axillary nerve supplies the skin over the abdomen.

False Signup and view all the answers

Which muscle specifically targets the index finger for extension?

Extensor indicis. Signup and view all the answers

The anatomical snuffbox contains the _________, which are key for thumb function.

abductor pollicis longus, extensor pollicis brevis, and extensor pollicis longus Signup and view all the answers

Match the following nerves with their sensory functions:

Median nerve = Ventral and lateral palm and digits two and three Ulnar nerve = Ventral and dorsal surfaces of the medial third of the hand Radial nerve = Dorsal hand Musculocutaneous nerve = Lateral forearm sensation Signup and view all the answers

Which nerve is responsible for supplying muscles in the anterior forearm?

Median Nerve Signup and view all the answers

The lateral cord of the brachial plexus is formed solely by the anterior division of the upper trunk.

False Signup and view all the answers

What is the main function of the dorsal scapular nerve?

It supplies the rhomboids and levator scapulae, assisting in scapular retraction and elevation. Signup and view all the answers

The __________ nerve supplies the deltoid muscle.

Axillary Signup and view all the answers

Match the following nerves to their primary function:

Musculocutaneous Nerve = Flexes the elbow Radial Nerve = Extends the elbow Median Nerve = Flexes the wrist Ulnar Nerve = Adducts the fingers Signup and view all the answers

What forms the medial cord of the brachial plexus?

Anterior division of the lower trunk Signup and view all the answers

The suprascapular nerve supplies muscles responsible for shoulder movements.

True Signup and view all the answers

Which nerve provides sensory innervation to the skin over the lateral forearm?

Musculocutaneous Nerve Signup and view all the answers

The __________ nerve is known to be prone to compression in the carpal tunnel.

Median Signup and view all the answers

Which of the following trunks is formed by the spinal roots C5 and C6?

Upper Trunk Signup and view all the answers

Which nerve is responsible for supplying the deltoid muscle?

Axillary Nerve Signup and view all the answers

The medial cord is formed by the anterior divisions of the upper and lower trunks.

False Signup and view all the answers

Name one function of the long thoracic nerve.

Aids in scapular protraction. Signup and view all the answers

The _________ nerve provides cutaneous sensation to the lateral forearm.

Musculocutaneous Signup and view all the answers

Match the following nerves with their primary functions:

Radial Nerve = Supplies elbow extension Median Nerve = Supplies anterior forearm muscles Ulnar Nerve = Supplies hand muscles on medial side Suprascapular Nerve = Supplies shoulder muscles Signup and view all the answers

What is the main function of the musculocutaneous nerve?

Supplies flexor muscles in the arm Signup and view all the answers

C5 and C6 nerve roots combine to form the lower trunk of the brachial plexus.

False Signup and view all the answers

What muscle does the axillary nerve innervate?

Deltoid Signup and view all the answers

The _________ nerve aids in scapular retraction.

Dorsal Scapular Signup and view all the answers

Match the trunks with their corresponding spinal roots:

Upper Trunk = C5 and C6 Middle Trunk = C7 Lower Trunk = C8 and T1 Signup and view all the answers

What is the primary action of the latissimus dorsi muscle?

Extends, adducts, and medially rotates the shoulder Signup and view all the answers

The radial nerve supplies motor branches to all extensor muscles in the forearm.

True Signup and view all the answers

What muscle assists in flexing and adducting the shoulder?

Coracobrachialis Signup and view all the answers

The __________ nerve provides cutaneous sensation to the medial third of the hand.

ulnar Signup and view all the answers

Match the following muscles with their primary actions:

Triceps Brachii = Extends the elbow Anconeus = Assists in elbow extension Brachioradialis = Flexes the elbow Extensor Digitorum = Extends the fingers Signup and view all the answers

Which of the following muscles is NOT associated with thumb movement?

Flexor Carpi Ulnaris Signup and view all the answers

The median nerve is responsible for innervating most of the forearm flexors.

True Signup and view all the answers

Identify the nerve that runs through the carpal tunnel.

Median nerve Signup and view all the answers

The __________ muscles are innervated by the ulnar nerve and are crucial for pinky dexterity.

hypothenar Signup and view all the answers

Match the nerves to their corresponding sensory regions:

Musculocutaneous nerve = Lateral forearm Axillary nerve = Skin over deltoid Radial nerve = Dorsal hand Ulnar nerve = Ulnar half of palm Signup and view all the answers

Study Notes

Brachial Plexus Overview

The brachial plexus originates primarily from spinal roots C5 to T1.
C5 and C6 nerve roots combine to form the upper trunk; C7 forms the middle trunk; C8 and T1 join to form the lower trunk.

Key Mnemonics

"Mar mu" represents:
- R: Root
- T: Trunk
- D: Division
- C: Cord
- B: Branch

Structure of the Brachial Plexus

Trunks:
- Upper Trunk: Formed by C5 and C6.
- Middle Trunk: Formed by C7.
- Lower Trunk: Formed by C8 and T1.
Each trunk divides into anterior and posterior divisions.

Cords Formation

Posterior Cord: Formed from all posterior divisions of the trunks.
Lateral Cord: Formed from the anterior divisions of the upper and middle trunks.
Medial Cord: Formed from the anterior division of the lower trunk.

Major Nerves from Brachial Plexus

Musculocutaneous Nerve:
- Supplies lateral forearm (cutaneous) and muscles: coracobrachialis, brachialis, biceps brachii (motor).
Axillary Nerve:
- Supplies skin over deltoid (cutaneous) and muscles: deltoid and teres minor (motor).
Radial Nerve:
- Supplies a large area of the arm and dorsal surface of the hand (cutaneous), numerous muscles (motor) including those for elbow extension and wrist/hand movement.
Median Nerve:
- Supplies muscles in the anterior forearm and some hand muscles.
Ulnar Nerve:
- Supplies muscles in the forearm and hand, particularly on the medial side.

Minor Nerves and Their Functions

Dorsal Scapular Nerve: Supplies rhomboids and levator scapulae, involved in scapular retraction and elevation.
Long Thoracic Nerve: Supplies serratus anterior, aiding in scapular protraction.
Suprascapular Nerve: Supplies supraspinatus and infraspinatus for shoulder movements.
Nerve to Subclavius: Supplies subclavius muscle to depress the clavicle.
Lateral Pectoral Nerve: Supplies pectoralis major.
Medial Pectoral Nerve: Supplies pectoralis major and minor.

Important Muscle Functions

Pectoralis Major:
- Flexes, adducts, and medially rotates the shoulder.
Pectoralis Minor:
- Protracts the scapula.
Latissimus Dorsi:
- Extends, adducts, and medially rotates the shoulder.
Teres Major:
- Similar function as latissimus dorsi.
Coracobrachialis:
- Flexes and adducts the shoulder.

Cutaneous Innervations Summary

Lateral forearm: Musculocutaneous nerve.
Skin over deltoid: Axillary nerve.
Dorsal hand: Radial nerve (distal portion).
Anterior forearm and hand: Median and Ulnar nerves cover specific regions.

Summary of Functional Dynamics

The brachial plexus is essential for upper limb motor and sensory innervation, affecting shoulder and arm movements.
Knowledge of its structure and branches is crucial for understanding upper limb anatomy and function.### Muscles of the Posterior Arm and Forearm
Triceps brachii consists of three heads and primarily extends the elbow joint.
Anconeus assists the triceps brachii in extending the elbow.
Brachioradialis, located in the forearm, flexes the elbow.
Extensor carpi radialis longus and brevis extend the wrist and are positioned adjacent to the brachioradialis.
Extensor digitorum extends the fingers, while extensor indicis specifically targets the index finger.
Extensor digiti minimi extends the little finger, enhancing dexterity.
Extensor carpi ulnaris aids in wrist extension.
Anatomical snuffbox region contains abductor pollicis longus, extensor pollicis brevis, and extensor pollicis longus, key muscles for thumb function.
Supinator, located beneath brachioradialis, is crucial for supination of the palm.

Nerve Supplies and Branches

Radial nerve supplies motor branches to nearly all extensor muscles in the forearm.
Median nerve has cutaneous branches, providing sensation to the ventral and lateral palm and digits two and three.
Median nerve runs through the carpal tunnel, and compression can lead to carpal tunnel syndrome.
Motor branches of the median nerve innervate multiple forearm flexors including pronator teres, quadratus, palmaris longus, flexor carpi radialis, flexor digitorum superficialis, and flexor digitorum profundus.
Supplies second and third lumbricals, enabling complex hand movements.
Thenar muscles innervated by median nerve include opponens pollicis, flexor pollicis brevis, and abductor pollicis brevis.

Ulnar Nerve Functionality

Ulnar nerve provides cutaneous branches supplying the ventral and dorsal surfaces of the medial third of the hand.
Motor branches of the ulnar nerve supply deeper muscles, including flexor carpi ulnaris and ulnar half of flexor digitorum profundus.
Hypothenar muscles innervated by ulnar nerve consist of opponens digiti minimi, flexor digiti minimi, and abductor digiti minimi, contributing to pinky dexterity.
Adductor pollicis is also supplied by the ulnar nerve, facilitating thumb adduction.

Brachial Plexus Overview

Originates from spinal roots C5 to T1.
Composed of upper trunk (C5-C6), middle trunk (C7), and lower trunk (C8-T1).

Key Mnemonics

"Mar mu" helps remember the order:
- R: Root
- T: Trunk
- D: Division
- C: Cord
- B: Branch

Structure of the Brachial Plexus

Trunks:
- Upper trunk is C5 and C6.
- Middle trunk is C7.
- Lower trunk is C8 and T1.
- Each trunk branches into anterior and posterior divisions.

Cords Formation

Posterior Cord: Formed by posterior divisions of all trunks.
Lateral Cord: Anterior divisions of upper and middle trunks.
Medial Cord: Anterior division of lower trunk.

Major Nerves from Brachial Plexus

Musculocutaneous Nerve:
- Innervates lateral forearm and flexor muscles (coracobrachialis, brachialis, biceps brachii).
Axillary Nerve:
- Supplies deltoid skin and muscles (deltoid, teres minor).
Radial Nerve:
- Covers a large area of the arm and dorsal hand; innervates extensors.
Median Nerve:
- Innervates forearm flexors and some hand muscles.
Ulnar Nerve:
- Supplies forearm and hand muscles, especially on the medial side.

Minor Nerves and Their Functions

Dorsal Scapular Nerve: Supplies rhomboids and levator scapulae for scapular movements.
Long Thoracic Nerve: Innervates serratus anterior for scapular protraction.
Suprascapular Nerve: Supplies supraspinatus and infraspinatus for shoulder movement.
Nerve to Subclavius: Innervates subclavius muscle, assisting in clavicle depression.
Lateral and Medial Pectoral Nerves: Supply pectoralis major and minor.

Important Muscle Functions

Pectoralis Major: Flexes, adducts, medially rotates shoulder.
Pectoralis Minor: Protracts scapula.
Latissimus Dorsi & Teres Major: Extend, adduct, medially rotate shoulder.
Coracobrachialis: Flexes and adducts the shoulder.

Cutaneous Innervations Summary

Lateral Forearm: Musculocutaneous nerve.
Deltoid Skin: Axillary nerve.
Dorsal Hand: Radial nerve (distal).
Anterior Forearm & Hand: Median and ulnar nerves cover specific areas.

Summary of Functional Dynamics

Brachial plexus is vital for motor and sensory innervation of the upper limb.
Understanding structure and branches is essential for grasping upper limb anatomy.

Muscles of the Posterior Arm and Forearm

Triceps Brachii: Extends elbow joint with three heads.
Anconeus: Assists in elbow extension.
Brachioradialis: Flexes elbow in the forearm.
Extensors (carpi and digitorum): Facilitate wrist and finger movements.
Anatomical Snuffbox: Contains muscles important for thumb function (abductor pollicis longus, extensor pollicis brevis/longus).
Supinator: Critical for palm supination, placed beneath brachioradialis.

Nerve Supplies and Branches

Radial Nerve: Innervates most extensors in the forearm.
Median Nerve: Provides cutaneous sensation to palm and parts of digits; runs through carpal tunnel, where compression leads to carpal tunnel syndrome.
Motor Functions of Median Nerve: Innervates flexors and lumbricals for advanced hand movements.
Thenar Muscles: Innervated by median nerve for thumb movement.

Ulnar Nerve Functionality

Cutaneous Distribution: Supplies the medial third of the hand, both ventral and dorsal.
Motor Branches: Innervate deeper forearm muscles and hypothenar muscles for pinky dexterity.
Adductor Pollicis: Also supplied by ulnar nerve for thumb adduction.

Brachial Plexus Overview

Originates from spinal roots C5 to T1.
Composed of upper trunk (C5-C6), middle trunk (C7), and lower trunk (C8-T1).

Key Mnemonics

"Mar mu" helps remember the order:
- R: Root
- T: Trunk
- D: Division
- C: Cord
- B: Branch

Structure of the Brachial Plexus

Trunks:
- Upper trunk is C5 and C6.
- Middle trunk is C7.
- Lower trunk is C8 and T1.
- Each trunk branches into anterior and posterior divisions.

Cords Formation

Posterior Cord: Formed by posterior divisions of all trunks.
Lateral Cord: Anterior divisions of upper and middle trunks.
Medial Cord: Anterior division of lower trunk.

Major Nerves from Brachial Plexus

Musculocutaneous Nerve:
- Innervates lateral forearm and flexor muscles (coracobrachialis, brachialis, biceps brachii).
Axillary Nerve:
- Supplies deltoid skin and muscles (deltoid, teres minor).
Radial Nerve:
- Covers a large area of the arm and dorsal hand; innervates extensors.
Median Nerve:
- Innervates forearm flexors and some hand muscles.
Ulnar Nerve:
- Supplies forearm and hand muscles, especially on the medial side.

Minor Nerves and Their Functions

Dorsal Scapular Nerve: Supplies rhomboids and levator scapulae for scapular movements.
Long Thoracic Nerve: Innervates serratus anterior for scapular protraction.
Suprascapular Nerve: Supplies supraspinatus and infraspinatus for shoulder movement.
Nerve to Subclavius: Innervates subclavius muscle, assisting in clavicle depression.
Lateral and Medial Pectoral Nerves: Supply pectoralis major and minor.

Important Muscle Functions

Pectoralis Major: Flexes, adducts, medially rotates shoulder.
Pectoralis Minor: Protracts scapula.
Latissimus Dorsi & Teres Major: Extend, adduct, medially rotate shoulder.
Coracobrachialis: Flexes and adducts the shoulder.

Cutaneous Innervations Summary

Lateral Forearm: Musculocutaneous nerve.
Deltoid Skin: Axillary nerve.
Dorsal Hand: Radial nerve (distal).
Anterior Forearm & Hand: Median and ulnar nerves cover specific areas.

Summary of Functional Dynamics

Brachial plexus is vital for motor and sensory innervation of the upper limb.
Understanding structure and branches is essential for grasping upper limb anatomy.

Muscles of the Posterior Arm and Forearm

Triceps Brachii: Extends elbow joint with three heads.
Anconeus: Assists in elbow extension.
Brachioradialis: Flexes elbow in the forearm.
Extensors (carpi and digitorum): Facilitate wrist and finger movements.
Anatomical Snuffbox: Contains muscles important for thumb function (abductor pollicis longus, extensor pollicis brevis/longus).
Supinator: Critical for palm supination, placed beneath brachioradialis.

Nerve Supplies and Branches

Radial Nerve: Innervates most extensors in the forearm.
Median Nerve: Provides cutaneous sensation to palm and parts of digits; runs through carpal tunnel, where compression leads to carpal tunnel syndrome.
Motor Functions of Median Nerve: Innervates flexors and lumbricals for advanced hand movements.
Thenar Muscles: Innervated by median nerve for thumb movement.

Ulnar Nerve Functionality

Cutaneous Distribution: Supplies the medial third of the hand, both ventral and dorsal.
Motor Branches: Innervate deeper forearm muscles and hypothenar muscles for pinky dexterity.
Adductor Pollicis: Also supplied by ulnar nerve for thumb adduction.

Brachial Plexus Overview

Originates from spinal roots C5 to T1.
Composed of upper trunk (C5-C6), middle trunk (C7), and lower trunk (C8-T1).

Key Mnemonics

"Mar mu" helps remember the order:
- R: Root
- T: Trunk
- D: Division
- C: Cord
- B: Branch

Structure of the Brachial Plexus

Trunks:
- Upper trunk is C5 and C6.
- Middle trunk is C7.
- Lower trunk is C8 and T1.
- Each trunk branches into anterior and posterior divisions.

Cords Formation

Posterior Cord: Formed by posterior divisions of all trunks.
Lateral Cord: Anterior divisions of upper and middle trunks.
Medial Cord: Anterior division of lower trunk.

Major Nerves from Brachial Plexus

Musculocutaneous Nerve:
- Innervates lateral forearm and flexor muscles (coracobrachialis, brachialis, biceps brachii).
Axillary Nerve:
- Supplies deltoid skin and muscles (deltoid, teres minor).
Radial Nerve:
- Covers a large area of the arm and dorsal hand; innervates extensors.
Median Nerve:
- Innervates forearm flexors and some hand muscles.
Ulnar Nerve:
- Supplies forearm and hand muscles, especially on the medial side.

Minor Nerves and Their Functions

Dorsal Scapular Nerve: Supplies rhomboids and levator scapulae for scapular movements.
Long Thoracic Nerve: Innervates serratus anterior for scapular protraction.
Suprascapular Nerve: Supplies supraspinatus and infraspinatus for shoulder movement.
Nerve to Subclavius: Innervates subclavius muscle, assisting in clavicle depression.
Lateral and Medial Pectoral Nerves: Supply pectoralis major and minor.

Important Muscle Functions

Pectoralis Major: Flexes, adducts, medially rotates shoulder.
Pectoralis Minor: Protracts scapula.
Latissimus Dorsi & Teres Major: Extend, adduct, medially rotate shoulder.
Coracobrachialis: Flexes and adducts the shoulder.

Cutaneous Innervations Summary

Lateral Forearm: Musculocutaneous nerve.
Deltoid Skin: Axillary nerve.
Dorsal Hand: Radial nerve (distal).
Anterior Forearm & Hand: Median and ulnar nerves cover specific areas.

Summary of Functional Dynamics

Brachial plexus is vital for motor and sensory innervation of the upper limb.
Understanding structure and branches is essential for grasping upper limb anatomy.

Muscles of the Posterior Arm and Forearm

Triceps Brachii: Extends elbow joint with three heads.
Anconeus: Assists in elbow extension.
Brachioradialis: Flexes elbow in the forearm.
Extensors (carpi and digitorum): Facilitate wrist and finger movements.
Anatomical Snuffbox: Contains muscles important for thumb function (abductor pollicis longus, extensor pollicis brevis/longus).
Supinator: Critical for palm supination, placed beneath brachioradialis.

Nerve Supplies and Branches

Radial Nerve: Innervates most extensors in the forearm.
Median Nerve: Provides cutaneous sensation to palm and parts of digits; runs through carpal tunnel, where compression leads to carpal tunnel syndrome.
Motor Functions of Median Nerve: Innervates flexors and lumbricals for advanced hand movements.
Thenar Muscles: Innervated by median nerve for thumb movement.

Ulnar Nerve Functionality

Cutaneous Distribution: Supplies the medial third of the hand, both ventral and dorsal.
Motor Branches: Innervate deeper forearm muscles and hypothenar muscles for pinky dexterity.
Adductor Pollicis: Also supplied by ulnar nerve for thumb adduction.

Brachial Plexus Overview

Originates from spinal roots C5 to T1.
Composed of upper trunk (C5-C6), middle trunk (C7), and lower trunk (C8-T1).

Key Mnemonics

"Mar mu" helps remember the order:
- R: Root
- T: Trunk
- D: Division
- C: Cord
- B: Branch

Structure of the Brachial Plexus

Trunks:
- Upper trunk is C5 and C6.
- Middle trunk is C7.
- Lower trunk is C8 and T1.
- Each trunk branches into anterior and posterior divisions.

Cords Formation

Posterior Cord: Formed by posterior divisions of all trunks.
Lateral Cord: Anterior divisions of upper and middle trunks.
Medial Cord: Anterior division of lower trunk.

Major Nerves from Brachial Plexus

Musculocutaneous Nerve:
- Innervates lateral forearm and flexor muscles (coracobrachialis, brachialis, biceps brachii).
Axillary Nerve:
- Supplies deltoid skin and muscles (deltoid, teres minor).
Radial Nerve:
- Covers a large area of the arm and dorsal hand; innervates extensors.
Median Nerve:
- Innervates forearm flexors and some hand muscles.
Ulnar Nerve:
- Supplies forearm and hand muscles, especially on the medial side.

Minor Nerves and Their Functions

Dorsal Scapular Nerve: Supplies rhomboids and levator scapulae for scapular movements.
Long Thoracic Nerve: Innervates serratus anterior for scapular protraction.
Suprascapular Nerve: Supplies supraspinatus and infraspinatus for shoulder movement.
Nerve to Subclavius: Innervates subclavius muscle, assisting in clavicle depression.
Lateral and Medial Pectoral Nerves: Supply pectoralis major and minor.

Important Muscle Functions

Pectoralis Major: Flexes, adducts, medially rotates shoulder.
Pectoralis Minor: Protracts scapula.
Latissimus Dorsi & Teres Major: Extend, adduct, medially rotate shoulder.
Coracobrachialis: Flexes and adducts the shoulder.

Cutaneous Innervations Summary

Lateral Forearm: Musculocutaneous nerve.
Deltoid Skin: Axillary nerve.
Dorsal Hand: Radial nerve (distal).
Anterior Forearm & Hand: Median and ulnar nerves cover specific areas.

Summary of Functional Dynamics

Brachial plexus is vital for motor and sensory innervation of the upper limb.
Understanding structure and branches is essential for grasping upper limb anatomy.

Muscles of the Posterior Arm and Forearm

Triceps Brachii: Extends elbow joint with three heads.
Anconeus: Assists in elbow extension.
Brachioradialis: Flexes elbow in the forearm.
Extensors (carpi and digitorum): Facilitate wrist and finger movements.
Anatomical Snuffbox: Contains muscles important for thumb function (abductor pollicis longus, extensor pollicis brevis/longus).
Supinator: Critical for palm supination, placed beneath brachioradialis.

Nerve Supplies and Branches

Radial Nerve: Innervates most extensors in the forearm.
Median Nerve: Provides cutaneous sensation to palm and parts of digits; runs through carpal tunnel, where compression leads to carpal tunnel syndrome.
Motor Functions of Median Nerve: Innervates flexors and lumbricals for advanced hand movements.
Thenar Muscles: Innervated by median nerve for thumb movement.

Ulnar Nerve Functionality

Cutaneous Distribution: Supplies the medial third of the hand, both ventral and dorsal.
Motor Branches: Innervate deeper forearm muscles and hypothenar muscles for pinky dexterity.
Adductor Pollicis: Also supplied by ulnar nerve for thumb adduction.

Brachial Plexus Overview

Originates from spinal roots C5 to T1.
Composed of upper trunk (C5-C6), middle trunk (C7), and lower trunk (C8-T1).

Key Mnemonics

"Mar mu" helps remember the order:
- R: Root
- T: Trunk
- D: Division
- C: Cord
- B: Branch

Structure of the Brachial Plexus

Trunks:
- Upper trunk is C5 and C6.
- Middle trunk is C7.
- Lower trunk is C8 and T1.
- Each trunk branches into anterior and posterior divisions.

Cords Formation

Posterior Cord: Formed by posterior divisions of all trunks.
Lateral Cord: Anterior divisions of upper and middle trunks.
Medial Cord: Anterior division of lower trunk.

Major Nerves from Brachial Plexus

Musculocutaneous Nerve:
- Innervates lateral forearm and flexor muscles (coracobrachialis, brachialis, biceps brachii).
Axillary Nerve:
- Supplies deltoid skin and muscles (deltoid, teres minor).
Radial Nerve:
- Covers a large area of the arm and dorsal hand; innervates extensors.
Median Nerve:
- Innervates forearm flexors and some hand muscles.
Ulnar Nerve:
- Supplies forearm and hand muscles, especially on the medial side.

Minor Nerves and Their Functions

Dorsal Scapular Nerve: Supplies rhomboids and levator scapulae for scapular movements.
Long Thoracic Nerve: Innervates serratus anterior for scapular protraction.
Suprascapular Nerve: Supplies supraspinatus and infraspinatus for shoulder movement.
Nerve to Subclavius: Innervates subclavius muscle, assisting in clavicle depression.
Lateral and Medial Pectoral Nerves: Supply pectoralis major and minor.

Important Muscle Functions

Pectoralis Major: Flexes, adducts, medially rotates shoulder.
Pectoralis Minor: Protracts scapula.
Latissimus Dorsi & Teres Major: Extend, adduct, medially rotate shoulder.
Coracobrachialis: Flexes and adducts the shoulder.

Cutaneous Innervations Summary

Lateral Forearm: Musculocutaneous nerve.
Deltoid Skin: Axillary nerve.
Dorsal Hand: Radial nerve (distal).
Anterior Forearm & Hand: Median and ulnar nerves cover specific areas.

Summary of Functional Dynamics

Brachial plexus is vital for motor and sensory innervation of the upper limb.
Understanding structure and branches is essential for grasping upper limb anatomy.

Muscles of the Posterior Arm and Forearm

Triceps Brachii: Extends elbow joint with three heads.
Anconeus: Assists in elbow extension.
Brachioradialis: Flexes elbow in the forearm.
Extensors (carpi and digitorum): Facilitate wrist and finger movements.
Anatomical Snuffbox: Contains muscles important for thumb function (abductor pollicis longus, extensor pollicis brevis/longus).
Supinator: Critical for palm supination, placed beneath brachioradialis.

Nerve Supplies and Branches

Radial Nerve: Innervates most extensors in the forearm.
Median Nerve: Provides cutaneous sensation to palm and parts of digits; runs through carpal tunnel, where compression leads to carpal tunnel syndrome.
Motor Functions of Median Nerve: Innervates flexors and lumbricals for advanced hand movements.
Thenar Muscles: Innervated by median nerve for thumb movement.

Ulnar Nerve Functionality

Cutaneous Distribution: Supplies the medial third of the hand, both ventral and dorsal.
Motor Branches: Innervate deeper forearm muscles and hypothenar muscles for pinky dexterity.
Adductor Pollicis: Also supplied by ulnar nerve for thumb adduction.

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Description

This quiz covers the anatomy and structure of the brachial plexus, detailing its origins, trunks, and major nerves. Learn key mnemonics to help remember the divisions and cords formed from the brachial plexus. Test your knowledge on the critical components of this important neural network.