Ps2017 - Cga - Lab 6 (The Forearm & Dorsum Of The Hand)

Front 1

Radial Artery (source, course, branches)

Back 1

Source: One of the two terminal branches of the brachial artery

Course: The radial artery runs on the lateral side of the anterior compartment of the forearm, it is deep to the brachioradialis muscle and is accompanied by the superficial branch of the radial nerve; as the radial artery approaches the wrist it runs to the dorsal surface of the forearm; it then goes through the anatomical snuffbox to reach the first dorsal interosseous muscle which it pierces through to reach a deep palmar compartment changing its name to the deep palmar arterial arch.

Branches: Radial reccurent - A branch that runs parallel to the brachial artery, it anastomoses with collateral arteries from sources superior to the elbow joint thereby providing an alternate pathway for blood in the event that brachial artery becomes compromised.
Superficial branch - A branch near the wrist that runs superficial to the thenar eminence and may connect to the superficial palmar arterial arch

Front 2

Ulnar Artery (source, course, branches)

Back 2

Source: One of the two terminal branches of the brachial artery

Course: The ulnar artery runs on the medial side of the anterior compartment of the forearm in a place between the superficial and deep flexor muscles, and is accompanied by the ulnar nerve; after crossing the wrist the ulnar artery passes superficial to the flexor retinaculum (it does NOT go through the carpal tunnel; within the hand it becomes the superficial palmar arterial arch)

Front 3

Common interosseous artery (source, course)

Back 3

Source: A branch of the ulnar artery near its origin

Course: This artery bifurcates quickly into the anterior interosseous and posterior interosseous arteries that supply the deep parts of the anterior and posterior compartments of the forearm, respectively

Front 4

Anterior interosseous artery (source, course - from Wikipedia since no glossary entry)

Back 4

Source: A terminal branch of the common interosseous artery

Course: Passes down the forearm on the palmar surface of the interosseous membrane, goes deep near the at the upper border of the pronator quadratus muscle & joins the dorsal carpal network

Front 5

Pronator teres muscle (attachments, innervation, action)

Back 5

Proximal Attachments: Medial epicondyle of the humerus; coronoid process of the ulna

Distal Attachment: Lateral side of the radius approximately mid-shaft

Innervation: Median nerve

Actions: Flexion at the elbow joint and pronation at the radioulnar joints

Front 6

Pronator quadratus muscle (attachments, innervation, actions)

Back 6

Proximal Attachment: Anterior surface of the ulna; Anterior surface of the radius

Innervation: Median nerve

Action: Pronation at the proximal and distal radio-ulnar joints

Front 7

Flexor digitorum superficialis muscle (attachments, innervation, action)

Back 7

Proximal Attachments: Medial epicondyle of the humerus, anterior border of the radius

Distal Attachments: Middle phalanges of the index, middle, ring, and little fingers

Innervation: Median nerve

Actions: Flexion at the wrist joint, metacarpophalangeal (MP) joints and proximal interphalangeal (PIP) joints

Front 8

Flexor digitorum profundus muscle (attachments, innervation, actions)

Back 8

Proximal Attachments: Anterior surface of the ulna; interosseous membrane

Distal Attachments: Distal phalanges of the index, middle, ring, and little fingers

Innervation: Medial half - Ulnar nerve; Lateral half - Median nerve

Action: Flexion at the wrist joint, metacarpophalangeal (MP) joints, and proximal and distal (PIP and DIP) joints (this is the only muscle that can flex the DIP joint).

Front 9

Flexor pollicis longus muscle (attachments, innervation, actions)

Back 9

Proximal Attachments: Anterior surface of the radius, interosseous membrane

Distal Attachment: Distal phalange of the thumb

Innervation: Median nerve

Actions: Flexion at the wrist, and metacarpophalangeal (MP) and interphalangeal (IP) joints of the thumb (this is the only muscle that can flex the DIP joint); contributes to opposition at the carpometacarpal joint of the thumb and abduction (radial deviation) at the wrist

Front 10

Palmaris longus muscle (attachment, innervation, action)

Back 10

Proximal Attachment: Medial epicondyle of the humerus

Distal Attachment: Palmar aponeurosis

Innervation: Median nerve

Actions: Flexion at the wrist joint and tightening of the palmar aponeurosis during gripping

Front 11

Flexor carpi ulnaris muscle (attachments, innervation, action)

Back 11

Proximal Attachment: Medial epicondyle of the humerus

Distal Attachments: Medial carpal bones (pisiform, hook of hamate) and 5th metacarpal

Innervation: Ulnar nerve

Actions: Flexion and adduction (ulnar deviation) and wrist joint

Front 12

Flexor carpi radialis muscle (attachments, innervation, action)

Back 12

Proximal Attachment: Medial epicondyle of the humerus

Distal Attachment: 2nd metacarpal

Innervation: Median nerve

Actions: Flexion and abduction (radial deviation) at the wrist joint

Front 13

Brachioradialis muscle (attachments, innervation, action)

Back 13

Proximal Attachment: Lateral supraepicondylar ridge of the humerus

Distal Attachment: Lateral surface of the distal shaft of the radius

Innervation: Radial nerve

Action: Flexion at the elbow joint

Front 14

Extensor carpi radialis longus muscle (attachments, innervation, action)

Back 14

Proximal Attachment: Lateral supraepicondylar ridge of the humerus

Distal Attachment: 2nd metacarpal

Innervation: Radial nerve

Actions: Extension and abduction (radial deviation) at the wrist joint

Front 15

Extensor carpi radialis brevis muscle (attachments, innervation, action)

Back 15

Proximal Attachment: Lateral epicondyle of the humerus

Distal Attachment: 3rd metacarpal

Innervation: Radial nerve

Actions: Extension and abduction (radial deviation) at the wrist joint

Front 16

Extensor carpi ulnaris muscle (attachments, innervation, action)

Back 16

Proximal Attachment: Lateral epicondyle of the humerus

Distal Attachment: 5th metacarpal

Innervation: Radial nerve

Actions: Extension and adduction (ulnar deviation) at the wrist joint

Front 17

Extensor digitorum muscle (attachments, innervation, action)

Back 17

Proximal Attachment: Lateral epicondyle

Distal Attachment: Extensor expansion of the index, middle, ring, and little fingers (2nd through 5th digit)

Innervation: Radial nerve

Actions: Extension at the wrist joint, and metacarpophalangeal (MP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints of the index, middle, ring, and little fingers

Front 18

Extensor indicis muscle (attachments, innervation, actions)

Back 18

Proximal Attachment: Distal shaft of the ulna

Distal Attachments: Extensor expansion of the index finger (2nd digit)

Innervation: Radial nerve

Actions: Extension at the wrist joint, and metacarpophalangeal (MP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints of the index finger (2nd digit)

Front 19

Extensor digiti minimi muscle (attachments, innervation)

Back 19

Proximal Attachment: Lateral epicondyle of the humerus

Distal Attachment: Extensor expansion of the little finger

Innervation: Radial nerve

Action: Extension at the wrist joint; and metacarpophalangeal (MP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints of the little finger (5th digit); also contributes to adduction

Front 20

Extensor pollicis longus muscle (attachments, innervation, action)

Back 20

Proximal Attachment: Shaft of the ulna; interosseous membrane

Distal Attachment: Distal phalanx of the thumb

Innervation: Radial nerve

Actions: Extension and abduction (radial deviation) at the wrist joint; extension of the carpometacarpal (CMC), metacarpophalangeal (MP), interphalangeal (IP) joints of the thumb

Front 21

Extensor pollicis brevis muscle (attachments, innervation, actions)

Back 21

Proximal attachments: Distal shaft of the radius; interosseous membrane

Distal attachment: Proximal phalanx of thumb

Innervation: Radial nerve

Actions: Abduction (radial deviation) at the wrist joint, extension of the carpometacarpal (CMC) and metacarpophalangeal (MP) joints of the thumb

Front 22

Abductor pollicis longus muscle (attachments, innervation, actions)

Back 22

Proximal Attachments: Shaft of ulna and radius; interosseous membrane

Distal Attachment: 1st metacarpal

Innervation: Radial nerve

Actions: Abduction (radial deviation) at the wrist and carpometacarpal (CMC) joint of the thumb

Front 23

Supinator muscle (attachments, innervation, action)

Back 23

Proximal Attachments: Lateral epicondyle of the humerus; Ulna (proximal shaft)

Distal: Proximal half of the shaft of the radius

Innervation: Radial nerve

Actions: Supination at the proximal and distal radioulnar joints

Front 24

Ulnar nerve (origin, muscles innervated, skin innervated, path, named branches)

Back 24

Origin: One of the two terminal branches of the medial cord (the other being the medial head of the median nerve; contains axons from C8 & T1)

Muscles Innervated: Forearm - Flexor carpi ulnaris & medial half of the flexor digitorum profundus (to ring and little fingers); Hand - Hypothenar muscles (flexor digiti minimi brevis, abductor digiti minimi, opponens digiti minimi), palmaris brevis, adductor pollicis, medial 2 lumbricals & all interossei (both palmar and dorsal).

Skin Innervated: Skin of the medial half of the palm, dorsum of the hand & distal forearm, as well as the skin of the little finger and half the ringer finger

Path: Travels through the medial side of the anterior compartment of the arm with the brachial artery without giving off any muscular branches; it goes posterior to the medial epicondyle of the humerus entering the anterior compartment of the forearm by piercing through the flexor carpi ulnaris; within the forearm it lies between the flexor carpi ulnaris and flexor digitalis profundus muscles becoming superficial toward the wrist; just before the wrist, the nerve gives off a dorsal branch; the remainder of the nerve passes superficial to the flexor retinaculum (it DOES NOT go through the carpal tunnel) where it bifurcates into the superficial ulnar and deep ulnar nerves.

Named Branches (most branches to muscles are unnamed):
Dorsal branch - cutaneous innervation to the dorsum of the hand
Superficial ulnar - cutaneous innervation to the palm of the hand
Deep ulnar - innervates the hypothenar muscles (flexor digiti minimi brevis, abductor digiti minimi, opponens digiti minimi), palmaris brevis, adductor pollicis, medial 2 lumbricals, and interossei (both palmar and dorsal)

Front 25

Radial nerve (origin, muscles innervated, skin innervated, path)

Back 25

Origin: One of two terminal branches of the posterior cord (contains axons from C5, C6, C7, C8, and T1)

Muscles Innervated: Triceps brachii, brachioradialis, anconeous, supinator, extensors of the forearm & abductor pollicis longus (the last three items are innervated by the deep branch of the radial nerve following bifurcation).

Skin Innervated: Lateral arm, forearm, and hand (see green areas on image)

Path: Passes through the triangular interval and runs through the radial (spiral) groove of the humerus into the cubital fossa where it terminates by bifurcating into the deep radial and superficial radial nerves.

Front 26

Superficial branch of radial nerve (origin, muscles innervated, skin innervated, path)

Back 26

Origin: One of the terminal branches of the radial nerve (the other being the deep radial nerve)

Muscles Innervated: None

Skin Innervated: Lateral side of the dorsum of the hand as well as the proximal part of the dorsum of the thumb, index, middle and half of the ring fingers.

Path: The bifurcation of the radial nerve occurs in the cubital fossa; the superficial radial nerve runs on the deep surface of the brachioradialis muscle & becomes superficial near the wrist.

Front 27

Median nerve (origin, muscles innervated, skin innervated, path, named branches)

Back 27

Origin: A terminal branch of both the lateral and medial cords (contains axons from C6, C7, C8, and T1)

Muscles Innervated: Forearm - All forearm flexor muscles except flexor carpi ulnaris and the medial half of the digitorum profundus (ring and pinky fingers).

Skin Innervated: Skin of the lateral half of the palm and the ventral & distal dorsal skin of the thumb, index finger, middle finger, and half of the ring finger (see picture in glossary, remember the "ulnar cutaneous innervation as dipping in paint" analogy from SSN)

Front 28

Deep branch of radial nerve (origin, muscles innervated, skin innervated, path)

Back 28

Origin: One of the terminal branches of the radial nerve (the other being the superficial radial nerve)

Muscles Innervated: Supinator, Abductor pollicis longus, all extensors of the forearm (EXCEPT extensor carpi radialis longus)

Skin Innervated: None

Path: The bifurcation of the radial nerve occurs in the cubital fossa; the deep radial nerve pierces the supinator muscle & interosseous membrane to run in the posterior compartment of the arm.

Note: Change name to posterior interosseous nerve once it pierces the interosseous membrane; both names accepted on test

Front 29

Common flexor tendon (from Wikipedia)

Back 29

Attaches to the medial epicondyle of the humerus; provides the origin/proximal attachment for the superficial flexor muscles in the anterior compartment of the arm (pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor carpi ulnaris).

Front 30

Extensor retinaculum (from Wikipedia)

Back 30

Thickened fascia which holds the extensor muscles in place just proximal to the hand.

Front 31

Extensor expansion (definition)

Back 31

A widening of the extensor tendons that attaches to the middle and distal phalanges of the index, middle, ring, and little fingers. The extensors include the extensor digitorum for all fingers, and the extensor indicis for the index finger (2nd digit) and the extensor digiti minimi for the little finger (5th digit). The interossei and lumbricals have all attachments to the extensor expansion

Front 32

Anatomical snuffbox (from Wikipedia)

Back 32

The anatomical snuff box is a triangular deepening on the radial, dorsal aspect of the hand—at the level of the carpal bones, specifically, the scaphoid and trapezium bones forming the floor.

The boundaries:

The posterior border of the snuffbox is the tendon of the extensor pollicis longus.
The anterior border (closest to the edge of the hand) is a pair of parallel and intimate tendons, of the extensor pollicis brevis and the abductor pollicis longus.[1] (Accordingly, the anatomical snuffbox is most visible, having a more pronounced concavity, during thumb extension.)
The proximal border is formed by the styloid process of the radius
The distal border is formed by the approximate apex of the schematic snuffbox isosceles triangle.
The floor of the snuffbox varies depending on the position of the wrist, but both the trapezium and primarily the scaphoid can be palpated.