Upper Limb Part 3

Question 1

Superficial muscles of the back

Answer 1

Teres major
Latissimus dorsi
Both muscles travel from the posterior aspect of the body to the anterior humerus- so both adduct and medially rotate the humerus

Trapezius

Question 2

Intermediate muscles of the back

Answer 2

Elevator scapulae
Rhomboid minor
Rhomboid major
All three muscles attach to the medial border of the scapula

Question 3

Deltoid muscle

Answer 3

Posterior, middle and anterior muscle fibers- the multiple attachment sites of the deltoid muscle allow it to perform several actions, including some that are antagonistic

Question 4

Anterior shoulder muscles

Answer 4

Subscapularis

Supraspinatus-can see a portion of it*

Question 5

Posterior shoulder muscles

Answer 5

Supraspinatus
Infraspinatus
Teres minor
Teres major
Triceps brachii

Question 6

Attachments/actions of the teres muscles

Answer 6

Keep in mind the different humeral attachment sites of the teres muscles. The posterior humeral attachment of the teres minor muscle allows it to laterally rotate the arm, while the anterior attachment of the teres major muscle will medially rotate the arm

Question 7

Rotator cuff muscles

Answer 7

Supraspinatus, infraspinatus, teres minor and subscapularis- “SITS” muscles
Function to hold the humeral head in the glenoid cavity during shoulder movement. Injury can occur with overuse- pitchers, swimmers, etc.

Question 8

The long head of the triceps brachii muscle passes:

Answer 8

Posterior/on top of the teres major and anterior/beneath the teres minor

Question 9

Spaces and neurovasculature of upper limb/shoulder

Answer 9

Crossing the teres muscles and the long head of the triceps brachii creates 3 bounded spaces

1) quadrangular space- axillary nerve and posterior circumflex humeral artery
2) triceps hiatus- radial nerve and deep artery of the arm
3) triangular space- circumflex scapular artery

Question 10

Upper limb- posterior arm muscles

Answer 10

Triceps brachii- long, lateral and medial head

Distal attachment site is the olecranon process of ulna

Question 11

Upper limb- posterior forearm muscles

Answer 11

Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis

Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris

Question 12

Upper limb posterior forearm muscles- deep view

Answer 12

Supinator
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Extensor indicis

Question 13

The axillary artery can be clamped or have an occlusion proximal to what artery and blood can still reach the arm and forearm

Answer 13

Subscapular artery

Question 14

Scapular anastomoses

Answer 14

The dorsal scapular artery (off of the subclavian a) anastomoses with the circumflex scapular artery (off of the subscapular artery) and the suprascapular artery. All 3 of these arteries also have another point that all anastomose together

The circumflex scapular artery and the subscapular artery also have their own separate point of anastomoses

Question 15

Sternoclavicular joint

Answer 15

Costoclavicular ligaments
Anterior sternoclavicular ligaments
Manubrium
Articular disc

It is the ONLY bony attachment of the upper limb complex to the thorax. It is so strong, yet so mobile, that is is more common for forceful trauma to fracture the clavicle than to injure this joint (via dislocation or a tear)

Question 16

‘Shoulder’ joint is composed of several joints

Answer 16

Acromioclavicular joint
Glenohumeral joint
Coracoacromial joint
Scapuloclavicular joint

Question 17

Acromioclavicular joint

Answer 17

Synovial
Upper limb attached to the clavicle via acromion: the acromioclavicular ligament
And via the coracoid process: coracoclavicular ligament (made up of the trapezoid ligament and the conoid ligament) stabilizes the acromioclavicular joint, even though it is not part of the joint itself (‘extra-articular’)
There is also a coracoacromial ligament

Question 18

Glenohumeral joint

Answer 18

Ball and socket, synovial joint
Very mobile and very unstable
It is stabilized by some ligaments, 1 ring of fibrocartilage, and a variety of muscles
There are a variety of bursar associated with the glenohumeral joint, which contain synovial fluid and help lubricate structures that move over a bony feature.

Question 19

Glenohumeral stabilizers

Answer 19

Coracoacromial arch- prevents superior movement, limits abduction of humerus unless it is rotated laterally
Capsule of the glenohumeral joint- attaches to the humerus and glenoid fossa, reinforced by glenoid labrum (fibrocartilage ring around glenoid fossa) and the glenohumeral ligaments (its inferior portion is thickened, and is the strongest deterrent to anterior dislocation of the humeral head)
Rotator cuff muscles- tonic muscles that stabilize the humeral head and keep it from slipping inferiorly and posteriorly

Question 20

The tendon of the long head of the biceps brachii muscles travels
This tendon is held in place by

Answer 20

In the intertubercular sulcus and through the glenoid capsule on its path to attach on the Supra glenoid tubercle

Held in place by the transverse humeral ligaments, if this is ruptured, the tendon of the long head of biceps brachii can becomes displaced.

Question 21

Glenohumeral bursae

Answer 21

Subacromial bursa (subdeltoid) facilitates movement of deltoid and supraspinatus muscles

Question 22

Glenohumeral-vasculature

Answer 22

Posterior humeral circumflex artery is the main blood supply to the glenohumeral joint capsule
*runs with the axillary nerve- appear posteriorly in the quadrangular space

Question 23

Elbow joint

Answer 23

Synovial joint is actually composed of multiple bony articulation
Vasculature- no primary blood supply, instead all collateral and recurrent elbow vessels are involved equally
Ligaments: ulnar collateral ligament (has several parts) and radial collateral ligament)

Question 24

Elbow bursae

Answer 24

Olecranon bursae posterior to the ulna (cutaneous), deep to the triceps brachii (subtendinous), and within the triceps brachii tendon (intratendinous)
Protect the triceps brachii and the olecranon process
Can become inflamed due to repetitive use, acute injury, etc

Question 25

Radio-ulnar joints

Answer 25

Allow supination and pronation
The proximal-ulnar joint is stabilized by the anular ligament, which keeps the radial head in place as it rotates during supination/pronation
The radio-ulnar joint is also stabilized by an interosseus ligament (syndesmosis) between the shafts of the bones

Question 26

Radio-ulnar/radio-carpal joints

Answer 26

The distal radio-ulnar joint is synovial
The ulna is relatively fixed (distally) and the radius moves around it
The articular disc of the distal radio-ulnar joint unites the radius and ulna
The wrist joint is reinforced by radiocarpal ligaments anteriorly and posteriorly

Question 27

The wrist joint

Answer 27

Radiocarpal joints*, in which the radius articulates with the scaphoid and lunate, the articular disc and the triquetrum (the proximal carpal bone except the pisiform)
It is stabilized by a radial and ulnar collateral ligament and a variety of fibrous ligaments (radiocarpal ligs)
The intercarpal joints are stabilized by the interosseous ligaments

Both the wrist and intercarpal joints are synovial joints

Question 28

1st carpometacarpal joint

Answer 28

The thumb has a saddle-shaped joint at the carpometacarpal junction, which permits biaxial movement and circumduction all to about the same degree
There are carpometacarpal ligaments that stabilize this joint that are hard to distinguish from other carpometacarpal intercarpal ligaments

Question 29

Metacarpophalangeal joints

Answer 29

Condylar in shape, which permits movement in two planes: flexion/extension AND abduction and adduction
Abduction and adduction must be limited (when this joint is flexed into a fist) so that the proximal phalanx doesn’t fall off of the metacarpal

Medial and lateral collateral ligaments restrict abduction. They are fan shaped so that they are lax when the digit is extended, but when the digit is flexed, the collateral ligaments become taut making it more difficult to adduct and abduct during flexion

Question 30

Interphalangeal joints

Answer 30

Hinge joints, permitting flexion and extension
The joints are stabilized by medial and lateral collateral ligaments, which further restrict other motions outside of flexion and extension

Question 31

Sheaths vs. potential spaces

Answer 31

Sheaths surround tendons and allow smooth movement- common flexor tendon sheath, flexor pollicis longus sheath
Both communicate with carpal tunnel

Potential spaces- areas usually filled with CT- thenar space, midpalmar space

Question 32

Spaces and sheaths can be sources of

Answer 32

Infection- tenosynovitis
Infection can be contained by CT, but can also spread since some spaces and structures connect:

infection can spread from the midpalmar space through the carpal tunnel into the forearm
Infection in the 5th digital synovial sheath can spread to the common flexor sheath through the carpal tunnel to the forearm
Infection of the flexor pollicis longus sheath can spread directly to the carpal tunnel and then to the forearm

Question 33

Anatomical snuff box boundaries and contents

Answer 33

Medial boundary- tendon of extensor pollicis longus
Lateral boundary- tendon of extensor pollicis brevis and tendon of abductor pollicis longus

Contains the radial artery- radial pulse can be felt here
And the scaphoid bone- pain in this area when bone is fractured