Tissues, Fascia, and Fascial Compartments - Upper Extremity

Question 1

Thoracolumbar Fascia

Answer 1

Gives origin to Latissimus Dorsi

Ensheaths deep intrinsic back muscles

Question 2

Ligamentum Nuchae

Answer 2

Fibroelastic connective tissue extending from the external occipital protuberance to the vertebral prominence (C7)

Question 3

Breast

Answer 3

Modified sweat gland developed for milk production

Developed entirely in subcutaneous tissue

Extend vertically from ribs 2-6

Internal composition:
Connective tissue creates septa that separate the tissue of the breast into lobules.
Lobules give rise to lactiferous ducts (there are 15 to 20 of them)
Lobules are connected to ducts that empty at the nipple.

Question 4

Pectoral Fascia

Answer 4

Deep Fasia

Extends from clavicle to sternum

Invests Pec Major

Continuous with Fascia of the anterior abdominal wall and the axillary fascia

Question 5

Clavipectoral Fascia and its Named Areas

Answer 5

Deep Fascia

Descends from the clavicle and coracoid process to the axilla

Encloses subclavius and pec minor

Named Areas

1. Costocoracoid membrane - superior part; deep to pec major and superficial to pec minor; pierced by a neurovascular bundle that includes the thoracoacromial artery and cephalic vein
2. Suspensatory Ligament - inferior part; deep to pec minor

Question 6

Brachial Fascia

Answer 6

Deep Fascia in the Arm

From the Deep surface of the brachial fascia, 2 projections called INTERMUSCULAR SEPTA run from the deep surface of the fascia to the supracondylar ridges of the humerus (1 medial septum and 1 lateral septum) The septa separate the arm into anteiror and posterior compartments

Brachial fascia is continuous with the pectoral and axillary fascia proximally and the antebrachial fascia distally, attaches to the olecranon of the ulna and medial and lateral epicondyles of the humerus distally

Question 7

Anterior compartment of the Arm

Answer 7

Contents:

Contains more vascular and neural elements than posterior compartment
Muscles: elbow flexors
Artery: Brachial Artery
Nerves:
MC -> supplies all muscles in the anterior compartment
Median -> just passing through
Ulnar -> just passing through
Medial brachial Cutaneous - sensory to the medial arm; often joins with T1/T2
Medial antebrachial cutaneous -> just passing through
Radial - supplies muscles in the posterior compartment of the arm; comes into the anterior compartment distally between brachioradialis and brachialis just proximal to the elbow
Axillary nerve before it winds around the head of the humerus and goes into the quadrangular space

Question 8

Posterior Compartment

Answer 8

Contents:

Muscles: elbow extensors
Artery: Profunda brachii (and radial collateral and middle collateral branches)
Nerves:
Ulnar - passes into the posterior compartment when it runs posterior to the medial epicondyle of the humerus
Axillary - wraps around the surgical neck of the humerus with the posterior circumflex humeral artery
Radial - runs in the radial groove with the profunda brachii artery

Question 9

Antebrachial Fascia

Answer 9

deep fasical sheath covering the forearm continuous proximally with the brachial fascia and distally with the retinacula that surround the wrist

attached posteriorly to the olecranon and posterior border of the ulna

Dives deep as the LATERAL INTERMUSCULAR SEPTUM attached to the anterior border of the radius

Question 10

Palmar carpal ligament

Answer 10

Proximal and superficial to the flexor retinaculum

Holds down the tendons of the superficial muscles in the anterior compartment

Question 11

Flexor Retinaculum

Answer 11

Anterior thickening of the antebrachial fasica

Creates the Carpal Tunnel

Maintians Position of Flexor Tendons

Question 12

Extensor Retinaculum

Answer 12

Distal Thickening of the antebrachial fascia on the posterior side of the hand

Continuous with palmar carpal ligament anteriorly

Maintains position of extensor tendons and divides into 6 tunnels

Question 13

What is the border between the anterior and posterior compartments of the forearm?

Answer 13

Ulna (attached to antebrachial fascia), interosseous membrane, radius, lateral intermuscular septum

Question 14

Anterior compartment of the forearm

Answer 14

Contents:

Muscles: flexor and pronator muscles (all but 1.5 innervated by median N.)
Nerves: median nerve, anterior interosseous nerve, ulanr nerve
arteries: ulnar artery, common interosseous artery, anterior interosseous artery, radial artery

Question 15

Posterior Compartment of the Forearm

Answer 15

Contents:

Muscles: extensors and supinators (all innervated by the radial nerve)
Nerves: deep and superficial branches of the radial nerve and posterior interosseous nerve
Artery: posterior interosseous artery

Question 16

Palmar Fascia - Superficial

Answer 16

Composed by lobulated fat pads that are organized differently from elsewhere in the body. Fibrous septa anchor everything down so that the fat in this region does not jiggle, enabling us to grip

Palmaris brevis muscle sits in the fascia on the medial side of the palm. It is entirely subcutaneous

Question 17

Palmar Fascia - Deep

Answer 17

Split in sections:

Hypothenar: over the muscles of the 5th digit

Thenar: over the muscles of the thumb

Palmar Aponeurosis: very thick; continuous with the flexor retinaculum; overlies the flexor tendos in the central palm; distally, it forms 4 longitudinal bands that become continuous with the fibrous digital sheaths on the digits

Adductor interosseous fascia: deep layer that overlies the muscles of the same name (adductor pollicis and interossei)

Question 18

Dorsal Fascia of the Hand

Answer 18

Consists of a thin superficial layer and a thin deep layer

Lots of room on the dorsum of the hand so that is where fluid tends to collect in case of injury

Question 19

Palmar Fascia of the Digits

Answer 19

Consists of Fibrous Digital Sheaths that are:

Continuous with the palmar aponeurosis
extend from the heads of the metacarpals to the bases of the distal phalanges

Attach allong the sides of the bones, creating tunnels for the flexor tendons (FDS splits at the middle phalanx to allow FDP to continue through the tunnel)

Lined by synovial sheaths to allow for gliding of tendons

Enclose FDS and FDP tendons on the medial 4 digits and FPL on the thumb

Question 20

Fascia of the Dorsum of the Digits

Answer 20

Extensor expansions:

At the base of the extensor expansion is a triangular aponeurosis called the HOOD that wraps around the dorsum and sides of the metacarpal and the proximal phalanx

Divides into one medial band that goes to the middle phalanx and two lateral bands that go to the distal phalanx

Holds the extensor tendons in place

Question 21

Central compartment of the palm

Answer 21

Between the palmar aponeurosis and the intermuscular septum

Contents:
FDS, FDL and FDP tendons coming through the Carpal Tunnel
Lumbrical Mucles
Palmar arterial arches and their branches
Median Nerve
Ulnar Nerve

Question 22

Thenar Compartment of the Palm

Answer 22

Located at the base of the thumb

Contents:
Tendon of FPL
Thenar Muscles (except Adductor Pollicis)
Recurrent Branch of the Median Nerve

Question 23

Hypothenar Compartment of the Palm

Answer 23

Located over the 5th metacarpal

Contents:
Deep Branch of Ulnar Nerve
Hypothenar Muscles

Question 24

Adductor Interosseous Compartment

Answer 24

This is the DEEP Compartment
Includes muscles that make up the deep palm and dorsum of the hand (Adductor Pollicis, Palmar Interossei, Dorsal Interossei)

Question 25

Dorsum of the Hand

Answer 25

Thin superficial layer of fascia

Deep layer of fascia contains the dorsal venous network

Contents:
Extensor Tendons
Dorsal Carpal Arch and its branches