Brachial Plexus
- Somatic plexus formed by the anterior rami of C5-C8 and T1
- Originates in the neck, passes laterally and inferiorly over rib I and enters the axilla
- All major nerves that innervate the upper limb originate from the brachial plexus
- Branches of the Brachial Plexus
- Dorsal scapular
- Origin: C5 root
- Spinal Segment: C5
- Function: Motor
- Innervates: Rhomboid major, Rhomboid minor
- Long Thoracic
- Origin: C5 to C7 roots
- Spinal Segment: C5-C7
- Function: Motor
- Innervates: Serratus anterior
- Suprascapular
- Origin: Superior trunk
- Spinal Segment: C5,C6
- Function: Motor
- Innervates: Supraspinatus, Infraspinatus
- Nerve to subclavius
- Origin: Superior trunk
- Spinal Segment: C5,C6
- Function: Motor
- Innervates: Subclavius
- Lateral pectoral
- Origin: Lateral cord
- Spinal Segment: C5 to C7
- Function: Motor
- Innervates: Pectoralis Major
- Musculocutaneous
- Origin: Lateral cord
- Spinal Segment: C5 to C7
- Function: Motor, Sensory
- Innervates: Motor to Biceps brachii, Brachialis, Coracobrachialis. Sensory to skin on lateral side of forearm
- Medial pectoral
- Origin: Medial cord
- Spinal Segment: C8,T1
- Function: Motor
- Innervates: Pectoralis major, Pectoralis minor
- Medial brachial cutaneous
- Origin: Medial cord
- Spinal Segment: C8,T1
- Function: Sensory
- Innervates: Skin on medial side of distal 1/3rd of arm
- Medial antebrachial cutaneous
- Origin: Medial cord
- Spinal Segment: C8, T1
- Function: Sensory
- Innervates: Skin on medial side of forearm
- Median
- Origin: Medial and lateral cords
- Spinal Segment: C5 to T1
- Function: Motor, Sensory
- Innervates: Motor to all muscles in anterior compartment of forearm (except flexor carpi ulnaris and medial half of flexor digitorum profundus), Thenar muscles (Flexor pollicis brevis, Abductor pollicis brevis, Opponens pollicis) , 2 lateral lumbricals. Sensory to skin over the palmar surface of the lateral 3 1/2 digits, lateral side of palm and middle wrist
- Ulnar
- Origin: Medial cord
- Spinal Segment: C8, T1
- Function: Motor, Sensory
- Innervates: Motor to all intrinsic muscles in the hand except for the thenar muscles and and 2 lateral lumbricals, flexor carpi ulnaris, and medial half of flexor digitorum profundus
- Upper subscapular
- Origin: Posterior cord
- Spinal Segment: C5,C6
- Function: Motor
- Innervates: Subscapularis
- Thoracodorsal
- Origin: Posterior cord
- Spinal Segment: C6 to C8
- Function: Motor
- Innervates: Latissimus dorsi
- Lower subscapular
- Origin: Posterior cord
- Spinal Segment: C5, C6
- Function: Motor
- Innervates: Subscapularis, Teres major
- Axillary
- Origin: Posterior cord
- Spinal Segment: C5,C6
- Function: Motor, Sensory
- Innervates: Motor to Deltoid and Teres minor, Sensory to skin over deltoid
- Radial
- Origin: Posterior cord
- Spinal Segment: C5,T1
- Function: Motor, Sensory
- Innervates: Motor to all muscles in posterior compartments of arm and forearm, Sensory to skin on posterior aspects of arm and forearm, lower lateral surface of the arm, and the dorsal lateral surface of the hand
- Dorsal scapular
- Axillary artery
- Branches: Screw The Lawyers, Save a Patient
- Superior thoracic artery - anastamoses with intercostal arteries and internal thoracic artery
- Thoracoacromial trunk
- Clavicular - supplies sternoclavicular joint, subclavius
- Acromial - supplies deltoid
- Deltoid - supplies pectoralis major, deltoid
- Pectoral - supplies pectoralis major, pectoralis minor
- Lateral thoracic artery - supplies pectoralis major, serratus anterior
- Subscapular artery - supplies latissimus dorsi
- Anterior circumflex humeral - anastamoses with v
- Posterior circumflex humeral - anastamoses with ^ - supplies deltoid
- Branches: Screw The Lawyers, Save a Patient
- Brachial artery
- Branches
- Deep brachial artery - SIMR PAIR anastamoses
- Middle collateral artery - interosseus recurrent
- Radial collateral artery - radial recurrent
- Superior ulnar collateral artery - posterior ulnar recurrent
- Inferior ulnar collateral artery - anterior ulnar recurrent
- Radial artery
- Radial recurrent artery - radial collateral
- Palmar carpal branch of radial artery
- Superficial palmar branch of radial artery
- Princeps pollicis artery
- Radialis indicis - radial artery of index finger
- Deep palmar arch
- Ulnar artery
- Anterior ulnar recurrent artery - inferior ulnar recurrent
- Posterior ulnar recurrent artery - superior ulnar recurrent
- Common interosseous artery
- Posterior interosseus artery
- Interosseus recurrent artery - middle collateral
- Anterior interosseus artery
- Posterior interosseus artery
- Superficial palmar arch
- Deep brachial artery - SIMR PAIR anastamoses
- Branches
- Axillary spaces
- Quadrangular space
- Borders:
- Medial: long head of triceps
- Lateral: humeral shaft
- Superior: teres minor
- Inferior: teres major
- Contents
- Axillary nerve
- Posterior humeral circumflex artery
- Borders:
- Triangular space
- Borders
- Lateral: long head of tricpes
- Superior: teres minor
- Inferior: teres major
- Contents
- Scapular circumflex artery
- Borders
- Triangular interval
- Borders
- Lateral: lateral head of triceps
- Medial: long head of triceps
- Superior: teres major
- Contents
- Radial nerve, deep brachial artery
- Borders
- Quadrangular space
- Cubital Fossa
- Borders
- Lateral: brachioradialis muscle.
- Medial: pronator teres muscle.
- Superior: an imaginary line from the medial and lateral epicondyles.
- Contents from Lateral to Medial: Really Need Beer To Be At My Nicest
- Radial Nerve
- Biceps Tendon
- Brachial Artery
- Median Nerve
- Borders
- Carpal Tunnel
- Borders
- Contents
- Flexor digitorum profundus tendons (4)
- Flexor digitorum superficialis tendons (4)
- Flexor pollicis longus (1)
- Median nerve
- Anatomical Snuff Box
- Borders
- Medial: Tendon of extensor pollicis longus
- Lateral: Tendons of extensor pollicis brevis and abductor pollicis longus
- Floor: Scaphoid and part of trapezium
- Contents
- Radial artery
- Cephalic vein
- Radial nerve
- Borders
- Glenohumeral joint
- Action: Abduction and adduction, flexion and extension, internal and external rotation of humerus
- Bones: Scapula, clavicle, humerus
- Ligaments
- Superior glenohumeral ligament -tight when arm is at 0 deg.
- Middle glenohumeral ligament - tight when arm is at 90 deg.
- Inferior glenohumeral ligament - tight when arm is at 180 deg.
- Coracohumeral ligament - From coracoid process to glenohumeral capsule
- Acromioclavicular joint
- Action: Allows for arm to be raised over the head
- Bones: Scapula, clavicle
- Ligaments
- Acromioclavicular ligament
- Trapezoid ligament
- Conoid ligament
- Elbow joint
- Action: Allows for extension of the elbow, as well as supination and pronation of the forearm
- Bones: Humerus, ulna, radius
- Ligaments
- Annular ligament - Nursemaid elbow - annular ligament displacement
- Radial collateral ligament
- Ulnar collateral ligament
- Others (link to med.umich)
- Humerus fractures
- Surgical neck fracture
- Potential structure damage
- Axillary artery
- Posterior circumflex humeral artery
- Potential structure damage
- Midshaft humerus fracture
- Potential structure damage
- Radial nerve
- Deep brachial artery
- Potential structure damage
- Supracondylar fracture
- Potential structure damage
- Median nerve
- Brachial artery
- Potential structure damage
- Surgical neck fracture
- Nursemaid elbow
- Common in young children
- Dislocation of radius from annular ligament
- Usually due to pulling
- Winged scapula
- Damage to the long thoracic nerve inhibits the function of the serratus anterior
- Results in winging of the scapula
- Compartment syndrome
- Increased pressure within one of the body’s compartments, which contain muscles and nerves
- Most common in legs and arms
- Symptoms
- Pain
- Paresthesia
- Paralysis of limb
- Treatment
- Acute – fasciotomy
- Chronic – rest, anti inflammatories, manual decompression, faschiotomy
- Ulnar claw
- Distal ulnar nerve damage/lesion
- Patient presents with physical sign
- Pope’s blessing
- Proximal median nerve damage/lesion
- Patient must be asked to make a fist before physical sign is seen
- Distal median nerve injury
- Inability to extend 2nd and 3rd fingers
- Ape hand
- Inability to abduct the thumb
- Caused by damage to proximal median nerve
Muscles of the Upper Limb
Shoulder Muscles
Muscle |
Origin |
Insertion |
Function |
|
Inferior edge of spine of scapula, lateral margin of acromion, lateral 1/3rd of clavicle |
Deltoid tuberosity of humerus |
Axillary n. |
Major abductor of arm (past initial 15 deg.) flexion and extension of arm |
|
|
Supraspinatus fossa of the scapula, deep fascia that covers the muscle |
Superior part of greater tubercle of humerus |
Suprascapular n. |
Initial abduction from 0-15 deg. of arm |
Infraspinatus fossa of the scapula, deep fascia that covers the muscle |
Middle facet of the posterior part of greater tubercle of humerus |
Suprascapular n. |
Rotator cuff muscle Lateral rotation of arm at gleno-humeral joint |
|
Middle part of the lateral (axillary) border of the scapula. |
Inferior aspect of greater tubercle of humerus. |
Axillary n. |
Rotator cuff muscle Lateral rotation of arm at gleno-humeral joint |
|
Posterior surface of inferior angle of scapula |
Anterior surface of humerus |
Lower subscapular n. |
Medial rotation and extension of arm at gleno-humeral joint |
|
Medial 2/3rds of subscapular fossa |
Lesser tubercle of humerus |
Upper and lower subscapular nerves |
Rotator cuff muscle Medial rotation of arm at gleno-humeral joint |
Anterior
wall of Axilla (and Serratus Anterior)
Muscle |
Origin |
Insertion |
Function |
|
Medial half of clavicle, anterior surface of sternum, first 7 ciostal cartilages, aponeuosis of external oblique |
Lateral interbercular sulcus of humerus |
Medial and lateral pectoral nerves |
Flexion adduction and medial rotation of arm at glenohumeral joint, flexion of extended arm, extension of flexed arm |
|
Ribs 3,4,5 deep fascia overlying those ribs |
Coracoid process of scapula |
Medial pectoral nerve |
Pulls tip of shoulder down, protracts scapula |
|
First rib |
Middle 1/3rd of clavicle |
Subclavius n. |
Pulls tip of shoulder down, pulls clavicle medially |
|
Lateral surface of upper 8-9 ribs |
Costal surface of medial border of scapula |
Long thoracic nerve |
Protraction and rotation of scapula, keeps scapula in place |
Upper Arm
Muscles
Muscle |
Origin |
Insertion |
Function |
|
Apex of Coracoid process |
Medial midshaft humerus |
Musculocutaneous n. |
Flexes arm at glenohumeral joint |
|
Long head – supraglenoid tubercle of scapula. Short head – Apex of coracoid process |
Musculocutaneous n. |
Flexor of forearm at elbow joint, supinator of forearm |
||
Anterior medial aspect of humerus |
Musculocutaneous n. |
Flexor of forearm at elbow joint |
||
LH- infraglenoid tubercle of scapula MH- posterior surface of humerus LatH- Posterior surface of humerus |
Olecranon |
Radial n. |
Extension of forearm at elbow joint. Extension and adduction of arm at shoulder joint. |
Anterior
compartment of the forearm
Muscle |
Origin |
Insertion |
Function |
|
Medial epicondyle of humerus, olecranon/posterior border of ulna |
Ulnar nerve |
Flexes and adducts wrist joint |
||
Medial epicondyle of humerus |
Palmar aponeurosis |
Median nerve |
Flexes wrist joint |
|
Medial epicondyle of humerus |
Base of metacarpals II and III |
Median nerve |
Flexes and abducts writs |
|
Medial epicondyle, medial side of coronoid process |
Lateral midshaft radius |
Median nerve |
Pronation |
|
Medial epicondyle of humerus, adjacent coronoid process, oblique line of radius |
4 tendons attach to palmar surfaces of the middle phalanges of the fingers |
Median nerve |
Flexes proximal interphalangeal joints |
|
Anterior/medial surfaces of ulna and medial half of interosseous membrane |
4 tendons attach to palmar surfaces of the distal phalanges of the fingers |
Lateral half median n. (ant. Interosseous) Medial half ulnar n. |
Flexes distal interphalangeal joints |
|
Anterior surface of radius, radial half of interosseous membrane |
Plamar surface of distal phalanx of thumb |
Median nerve (anterior interosseous nerve) |
Flexes interphalangeal joint of the thumb |
|
Linear ridge of distal anterior surface of ulna |
Distal anterior surface of radius |
Median nerve (anterior interosseous nerve) |
Pronation |
Superficial
Posterior Compartment of Forearm
Muscle |
Origin |
Insertion |
Function |
|
Lateral supraepicondylar ridge of humerus |
Lateral surface of distal end of radius |
Radial nerve |
Flexor of elbow when forearm is midpronated |
|
Distal lateral supraepicondylar ridge of humerus |
Dorsal surface of base of metacarpal II |
Radial nerve |
Extends and abducts wrist |
|
Lateral epicondyle of humerus |
Dorsal surface of base of metacarpal II, III |
Deep branch of radial nerve |
Entends and abducts wrist |
|
Lateral epicondyle of humerus |
4 tendons, dorsal aspects of middle and distal phalanges (II-V) |
Posterior interosseus nerve (deep radial after piercing supinator) |
Extends index, middle, ring, little fingers, extends wrist |
|
Lateral epicondyle of humerus |
Extensor hood of little finger |
Posterior interosseus nerve |
Extends little finger |
|
Lateral epicondyle of humerus, posterior border of ulna |
Tubercle on base of medial side of metacarpal V |
Posterior interosseus nerve |
Extends adducts wrist |
|
Lateral epicondyle of humerus |
Olecranon/posterior surface of ulna |
Radial nerve |
Abduction of ulna in pronation, extensor of elbow joint |
Deep
Posterior Compartment of Forearm
Muscle |
Origin |
Insertion |
Function |
|
Lateral epicondyle of humerus, radial collateral and annular ligaments. Supinator crest of ulna |
Lateral surface of radius |
Posterior interosseus nerve |
Supination |
|
Posterior surfaces of radius and ulna |
Lateral side of base of metacarpal I |
Posterior interosseus nerve |
Abducts carpometacarpal joint of thumb, extensor of thumb |
|
Posterior surface of radius |
Dorsal surface of base of proximal phalanx of the thumb |
Posterior interosseus nerve |
Extends metacarpo-phalangeal joint of the thumb |
|
Posterior surface of ulna |
Dorsal surface of base of distal phalanx of the thumb |
Posterior interosseus nerve |
Extends interphalangeal joint of the thumb |
|
Posterior surface of ulna |
Extensor hood of index finger |
Posterior interosseus nerve |
Extends index finger |
Non-(Hypo)Thenar Intrinsic Muscles of
the Hand
Muscle |
Origin |
Insertion |
Function |
|
Palmar aponeurosis and flexor retinaculum |
Dermis of skin on medial margin of the hand |
Superficial branch of ulnar nerve |
Improves grip |
|
Adjacent sides of metacarpals |
Extensor hoods/base of proximal phalanges of index, middle, and ring fingers |
Deep branch of ulnar nerve |
Abduction of index, middle, and ring finger at metacarpo-phalangeal joints |
|
Sides of metacarpals |
Extensor hoods of the thumb, index, ring, and little fingers |
Deep branch of ulnar nerve |
Abduction of thumb, index, ring, and little finger at metacarpo-phalangeal joints |
|
Metacarpal III, Capitate and bases of metacarpals II, and III |
Base of proximal phalanx and extensor hood of thumb |
Deep branch of ulnar nerve |
Adducts thumb |
|
Tendons of flexor digitorum profundus |
Extensor hoods of fingers |
Medial 2, ulnar, lateral 2, median |
Flexes metacarpo-phalangeal joints while extending interphalangeal joints |
Thenar and Hypothenar Muscles of
the Hand
Muscle |
Origin |
Insertion |
Function |
|
Tubercle of trapezium and flexor retinaculum |
Lateral margin and adjacent palmar surface of metacarpal I |
Recurrent branch of median nerve |
Medially rotates thumb |
|
Tubercles of scaphoid and trapezium, adjacent retinaculum |
Proximal phalanx and extensor hood of thumb |
Recurrent branch of median nerve |
Abducts thumb at metacarpo-phalangeal joint |
|
Tubercle of trapezium and flexor retinaculum |
Proximal phalanx of thumb |
Recurrent branch of median nerve |
Flexes thumb at metacarpo-phalangeal joint |
|
Hook of hamate, flexor retinaculum |
Medial aspect of metacarpal V |
Deep branch of ulnar nerve |
Laterally rotates metacarpal V |
|
Pisiform, pisohamate ligament, tendon of flexor carpi ulnaris |
Proximal phalanx of little finger |
Deep branch of ulnar nerve |
Abducts little finger at metacarpo-phalangeal joint |
|
Hook of hamate and flexor retinaculum |
Proximal phalanx of little finger |
Deep branch of ulnar nerve |
Flexes little finger at metacarpo-phalangeal joint |