Upper Extremity Mega Study Guide

Vocabulary practice flashcards covering upper extremity anatomy, osteology, joints, kinematics, muscle OIAN, and clinical injuries.

Pectoralis Major

• O: Clavicular head: anterior medial clavicle; Sternocostal head: anterior sternum and costal cartilages 1–6; Abdominal part: rectus sheath

• I: Lateral lip of humeral intertubercular groove (crest of greater tubercle)

• A: Adducts and internally rotates GH joint; clavicular head flexes and horizontally adducts; sternocostal head extends humerus from flexed position

• N: Lateral and medial pectoral nerves ($\text{C5--T1}$)

Pectoralis Minor

• O: Anterior surfaces of ribs 3–5

• I: Coracoid process of scapula

• A: Scapular depression and protraction/abduction

• N: Medial pectoral nerve

Serratus Anterior

• O: External surfaces of lateral ribs 1–8
• I: Anterior surface of medial border of scapula
• A: Protracts and upwardly rotates scapula; stabilizes scapula against thoracic wall
• N: Long thoracic nerve

Upper (Descending) Trapezius

• O: External occipital protuberance, medial third superior nuchal line, ligamentum nuchae, and $\text{C7}$ spinous process
• I: Lateral third of clavicle and acromion of scapula
• A: Elevates and upwardly rotates scapula; extends neck bilaterally; produces same-side lateral flexion and opposite-side rotation of neck
• N: Spinal accessory nerve (CN XI)

Middle Trapezius

• O: Spinous processes of $\text{T1--T5}$
• I: Medial margin of acromion and spine of scapula
• A: Retracts (adducts) scapula
• N: Spinal accessory nerve (CN XI)

Lower (Ascending) Trapezius

• O: Spinous processes of $\text{T6--T12}$
• I: Tubercle at apex of scapular spine
• A: Depresses and upwardly rotates scapula
• N: Spinal accessory nerve (CN XI)

Rhomboid Major

• O: Spinous processes of $\text{T2--T5}$
• I: Medial border of scapula between spine and inferior angle
• A: Retracts, elevates, and downwardly rotates scapula
• N: Dorsal scapular nerve

Rhomboid Minor

• O: Spinous processes of $\text{C7--T1}$
• I: Medial border of scapula at level of scapular spine
• A: Retracts, elevates, and downwardly rotates scapula
• N: Dorsal scapular nerve

Levator Scapulae

• O: Transverse processes of $\text{C1--C4}$
• I: Superior angle and upper medial border of scapula
• A: Elevates and downwardly rotates scapula; extends neck bilaterally and produces same-side lateral flexion and rotation
• N: Dorsal scapular nerve

Latissimus Dorsi

• O: Spinous processes of $\text{T6--T12}$, lower ribs, thoracolumbar fascia, and posterior third of iliac crest
• I: Floor of humeral intertubercular groove
• A: Extends, adducts, and internally rotates GH joint
• N: Thoracodorsal nerve

Deltoid

• O: Lateral third of clavicle, acromion, and spine of scapula
• I: Deltoid tuberosity of humerus
• A: Abducts GH joint (all fibers); anterior fibers flex, internally rotate, and horizontally adduct; posterior fibers extend, externally rotate, and horizontally abduct
• N: Axillary nerve ($\text{C5--C6}$)

Teres Major

• O: Posterior surface of inferior angle of scapula
• I: Medial lip of humeral intertubercular groove (crest of lesser tubercle)
• A: Internally rotates, adducts, and extends GH joint
• N: Lower subscapular nerve ($\text{C5--C6}$)

Supraspinatus

• O: Supraspinous fossa of scapula
• I: Superior facet of greater tubercle of humerus
• A: Initiates and assists the first $15^\circ\text{--}30^\circ$ of GH abduction; stabilizes humeral head in glenoid cavity
• N: Suprascapular nerve ($\text{C4--C6}$)

Infraspinatus

• O: Infraspinous fossa of scapula
• I: Middle facet of greater tubercle of humerus
• A: Externally rotates GH joint; stabilizes humeral head
• N: Suprascapular nerve ($\text{C5--C6}$)

Teres Minor

• O: Middle portion of lateral border of scapula
• I: Inferior facet of greater tubercle of humerus
• A: Externally rotates GH joint; stabilizes humeral head
• N: Axillary nerve ($\text{C5--C6}$)

Subscapularis

• O: Subscapular fossa of scapula
• I: Lesser tubercle of humerus
• A: Internally rotates GH joint; stabilizes humeral head
• N: Upper and lower subscapular nerves ($\text{C5--C6}$)

Biceps Brachii

• O: Short head: coracoid process tip; Long head: supraglenoid tubercle of scapula and glenoid labrum
• I: Radial tuberosity and antebrachial fascia via bicipital aponeurosis
• A: Supinates forearm, flexes elbow (most effectively in supination), and assists GH flexion
• N: Musculocutaneous nerve ($\text{C5--C6}$)

Coracobrachialis

• O: Tip of coracoid process of scapula
• I: Middle third of medial surface of humerus
• A: Flexes and adducts GH joint
• N: Musculocutaneous nerve

Brachialis

• O: Distal half of anterior surface of humerus
• I: Coronoid process and ulnar tuberosity
• A: Primary elbow flexor across all forearm positions
• N: Musculocutaneous nerve (small lateral slip receives radial nerve)

Triceps Brachii

• O: Long head: infraglenoid tubercle; Lateral head: posterior humerus superior to radial groove; Medial head: posterior humerus inferior to radial groove
• I: Proximal olecranon of ulna and antebrachial fascia
• A: Primary elbow extensor; long head assists GH extension and adduction
• N: Radial nerve ($\text{C6--C8}$)

Pronator Teres

• O: Humeral head: medial epicondyle (common flexor tendon); Ulnar head: coronoid process of ulna
• I: Midshaft lateral surface of radius
• A: Forearm pronation; assists elbow flexion
• N: Median nerve ($\text{C6--C7}$)

Flexor Carpi Radialis (FCR)

• O: Medial epicondyle of humerus via common flexor tendon
• I: Base of second metacarpal
• A: Wrist flexion and radial deviation (abduction)
• N: Median nerve ($\text{C6--C7}$)

Palmaris Longus

• O: Medial epicondyle of humerus via common flexor origin
• I: Flexor retinaculum and palmar aponeurosis
• A: Tenses palmar aponeurosis; assists wrist flexion
• N: Median nerve ($\text{C7--C8}$)

Flexor Carpi Ulnaris (FCU)

• O: Humeral head: medial epicondyle; Ulnar head: olecranon and posterior border of ulna
• I: Pisiform, hook of hamate, and base of fifth metacarpal
• A: Wrist flexion and ulnar deviation (adduction)
• N: Ulnar nerve ($\text{C7--T1}$)

Flexor Digitorum Superficialis (FDS)

• O: Humeroulnar head: medial epicondyle, UCL, and coronoid process; Radial head: anterior oblique line of radius
• I: Shafts of middle phalanges of digits 2–5
• A: Flexes proximal interphalangeal (PIP) joints of digits 2–5; assists MCP and wrist flexion
• N: Median nerve ($\text{C8--T1}$)

Flexor Digitorum Profundus (FDP)

• O: Proximal three-quarters of anterior/medial ulna and interosseous membrane
• I: Palmar bases of distal phalanges of digits 2–5
• A: Flexes distal interphalangeal (DIP) joints of digits 2–5; assists PIP, MCP, and wrist flexion
• N: Median nerve (digits 2–3) and ulnar nerve (digits 4–5) ($\text{C8--T1}$)

Flexor Pollicis Longus (FPL)

• O: Anterior midshaft of radius and interosseous membrane
• I: Base of distal phalanx of thumb
• A: Flexes interphalangeal (IP) joint of thumb; assists thumb MCP, CMC, and wrist flexion
• N: Median nerve ($\text{C7--C8}$)

Pronator Quadratus

• O: Distal fourth of anterior surface of ulna
• I: Distal fourth of anterior surface of radius
• A: Forearm pronation
• N: Median nerve

Brachioradialis

• O: Proximal two-thirds of lateral supracondylar ridge of humerus
• I: Lateral distal radius proximal to styloid process
• A: Elbow flexion, strongest when forearm is in neutral position
• N: Radial nerve ($\text{C5--C7}$)

Extensor Carpi Radialis Longus (ECRL)

• O: Lateral supracondylar ridge of humerus, lateral intermuscular septum, and common extensor tendon
• I: Dorsal surface of base of second metacarpal
• A: Wrist extension and radial deviation; assists elbow flexion
• N: Radial nerve ($\text{C6--C7}$)

Extensor Carpi Radialis Brevis (ECRB)

• O: Lateral epicondyle of humerus via common extensor tendon
• I: Dorsal surface of base of third metacarpal
• A: Wrist extension; assists radial deviation
• N: Radial nerve ($\text{C7--C8}$)

Extensor Digitorum

• O: Lateral epicondyle of humerus via common extensor tendon
• I: Extensor expansions of digits 2–5
• A: Extends MCP, PIP, and DIP joints of digits 2–5; assists wrist extension
• N: Radial nerve ($\text{C7--C8}$)

Extensor Digiti Minimi

• O: Lateral epicondyle of humerus via common extensor tendon
• I: Extensor expansion of fifth digit
• A: Extends fifth digit at MCP, PIP, and DIP joints; assists wrist extension and fifth-digit abduction
• N: Radial nerve ($\text{C7--C8}$)

Extensor Carpi Ulnaris (ECU)

• O: Lateral epicondyle of humerus via common extensor tendon and posterior border of ulna
• I: Dorsal surface of base of fifth metacarpal
• A: Wrist extension and ulnar deviation
• N: Radial nerve ($\text{C7--C8}$)

Supinator

• O: Lateral epicondyle of humerus, radial collateral ligament, annular ligament, and supinator crest of ulna
• I: Lateral surface of proximal third of radius
• A: Forearm supination
• N: Radial nerve (posterior interosseous branch) ($\text{C6--C7}$)

Extensor Indicis

• O: Distal third of posterior surface of ulna and interosseous membrane
• I: Extensor expansion of index finger (digit 2)
• A: Extends MCP joint of digit 2; assists wrist extension
• N: Radial nerve ($\text{C7--C8}$)

Abductor Pollicis Longus (APL)

• O: Posterior shafts of ulna and middle third radius, and interosseous membrane
• I: Radial base of first metacarpal
• A: Thumb abduction and extension at carpometacarpal (CMC) joint
• N: Radial nerve ($\text{C7--C8}$)

Extensor Pollicis Brevis (EPB)

• O: Posterior distal third of radius and interosseous membrane
• I: Dorsal base of proximal phalanx of thumb
• A: Extends MCP joint of thumb; assists CMC extension and abduction
• N: Radial nerve ($\text{C7--C8}$)

Extensor Pollicis Longus (EPL)

• O: Posterior middle third of ulna and interosseous membrane
• I: Dorsal base of distal phalanx of thumb
• A: Extends IP joint of thumb; assists CMC/MCP extension and radial deviation
• N: Radial nerve ($\text{C7--C8}$)

Opponens Pollicis

• O: Tubercles of scaphoid and trapezium, and flexor retinaculum
• I: Lateral border of first metacarpal
• A: Opposes thumb by drawing first metacarpal toward center of palm with medial rotation
• N: Recurrent branch of median nerve ($\text{C8--T1}$)

Abductor Pollicis Brevis (APB)

• O: Tubercles of scaphoid and trapezium, and flexor retinaculum
• I: Lateral base of proximal phalanx of thumb
• A: Thumb abduction at CMC and MCP joints; assists opposition
• N: Recurrent branch of median nerve ($\text{C8--T1}$)

Flexor Pollicis Brevis (FPB)

• O: Tubercles of scaphoid and trapezium, and flexor retinaculum
• I: Lateral base of proximal phalanx of thumb
• A: Flexes MCP joint of thumb
• N: Superficial head: recurrent branch of median nerve; Deep head: deep branch of ulnar nerve ($\text{C8--T1}$)

Adductor Pollicis

• O: Oblique head: bases of metacarpals 2–3 and capitate; Transverse head: palmar surface of third metacarpal shaft
• I: Medial base of proximal phalanx of thumb
• A: Adducts thumb toward middle finger
• N: Deep branch of ulnar nerve ($\text{C8--T1}$)

Opponens Digiti Minimi

• O: Hook of hamate and flexor retinaculum
• I: Medial border of fifth metacarpal
• A: Draws fifth metacarpal into opposition toward thumb
• N: Deep branch of ulnar nerve ($\text{C8--T1}$)

Abductor Digiti Minimi

• O: Pisiform bone and tendon of flexor carpi ulnaris
• I: Medial base of proximal phalanx of fifth digit
• A: Abducts fifth digit; assists proximal phalanx flexion
• N: Deep branch of ulnar nerve ($\text{C8--T1}$)

Flexor Digiti Minimi Brevis

• O: Hook of hamate and flexor retinaculum
• I: Medial base of proximal phalanx of fifth digit
• A: Flexes proximal phalanx of fifth digit at MCP joint
• N: Deep branch of ulnar nerve ($\text{C8--T1}$)

Lumbricals (Hand)

• O: Tendons of flexor digitorum profundus (1–2 unipennate from lateral tendons; 3–4 bipennate from adjacent tendons)
• I: Lateral extensor expansions of digits 2–5
• A: Flex MCP joints while extending IP joints of digits 2–5 (tabletop position)
• N: Lumbricals 1–2: median nerve; Lumbricals 3–4: deep branch of ulnar nerve ($\text{C8--T1}$)

Dorsal Interossei (Hand)

• O: Adjacent sides of metacarpals 1–5 (bipennate)
• I: Bases of proximal phalanges and extensor expansions of digits 2–4
• A: Abduct digits 2–4 away from axial midline of digit 3; assist MCP flexion and IP extension (DAB)
• N: Deep branch of ulnar nerve

Palmar Interossei (Hand)

• O: Palmar shafts of metacarpals 2, 4, and 5 (unipennate)
• I: Bases of proximal phalanges and extensor expansions of digits 2, 4, and 5
• A: Adduct digits 2, 4, and 5 toward axial midline of digit 3; assist MCP flexion and IP extension (PAD)
• N: Deep branch of ulnar nerve ($\text{C8--T1}$)