Upper Extremity Week 1 Learning Objectives

Question 1

Distinguish between the extrinsic and intrinsic back muscles

Answer 1

Extrinsic:

• Superficial (limb movement, “axioappendicular”)
• Intermediate (respiration/proprioception)

Intrinsic:
- Deep (vertebral column movement, stabilization)

Question 2

List the intermediate extrinsic back muscles

Answer 2

Serratus posterior superior
Serratus posterior inferior

Responsible for respiration/proprioception

Innervation: Anterior (ventral) rami of spinal nn., intercostal nn.

Question 3

List the intrinsic back muscles

Answer 3

Superficial layer:
(Splenius)
Splenius capitis
Splenius cervicis

Intermediate layer:
(Erector spinae)
Spinalis
Longissimus
Iliocostalis

Deep layer:
(Transversospinales)
Semispinales
Multifidus and rotatores

Responsible for vertebral column movement and stabilization.

Innervation: posterior (dorsal) rami of spinal nn.

Question 4

Describe the location and contents of the following neurovascular tracts: quadrangular space, medial border of scapula, and scapular notch

Answer 4

Quandrangular space:

• Content: axillary n., posterior circumflex a.
• Location: bordered by teres major, teres minor, triceps brachii long head, and humerus

Medial border of scapula:

• Content: dorsal scapular n., dorsal scapular a.
• Location: medial border of scapula

Scapular notch:

• Content: suprascapular n., suprascapular a.
• Location: nerve passes inferiorly to the transverse scapular ligament, through the scapular notch. artery passes superiorly to the transverse scapular ligament.

Question 5

Describe the following injuries and relate anatomical structures to each: shoulder separation.

Answer 5

Shoulder separation:

• MOI FOOSH (falling on outstretched hand) or landing on shoulder
• Severe cases: Both AC and coracoclavicular ligaments are torn.
• Complete tear of coracoclavicular ligament causes the clavicle to move over the acromion
• Free moving acromion can move inferiorly to damage GH joint

Question 6

Describe the following injuries and relate anatomical structures to each: shoulder dislocation.

Answer 6

Shoulder dislocation:

• GH joint most frequently dislocated
• Inferior joint capsule not reinforced by rotator cuff muscles or ligaments
• Vulnerable to dislocation when arm is in abducted position (downward force)
• 95% of shoulder dislocations are anterior dislocations (inferiorly dislocated, then head of humerus moves anteriorly to GH space)

Question 7

Describe the location and contents of the subacromial space.

Answer 7

Location: inferior to the acromion
Contents: Supraspinatus m., subacromial bursa, subdeltoid bursa, subtendinous bursa of subscapularis (WHAT ELSE?)

Question 8

Predict what neurovascular structures would be injured based on bone fracture located at the medial border of the scapula.

Answer 8

Dorsal scapular nerve and dorsal scapular artery (runs parallel to the medial border of the scapula)

Anastomoses with intercostal arteries? (connected to dorsal scapular artery

SEE DIAGRAM OF SCAPULAR ANASTOMOSIS/ARCADE

Question 9

Describe the location and function of the bursae of the scapular region.

Answer 9

Composition:

• lined by synovial membrane
• filled with synovial fluid

Function:

• cushion
• reduces friction between bone and tendon

Location:

• subacromial (inferior to acromion, superior to supraspinatus)
• subdeltoid (lateral, deep to deltoid)
• subtendinous of subscapularis (superficial to subscapularis)

Question 10

Identify the joints of the pectoral (shoulder) girdle and provide their synovial classification on the Structure Information List.

Answer 10

Sternoclavicular: sellar or saddle

Acromioclavicular: plane or gliding

Glenohumeral: ball and socket

Scapulothoracic: pseudo-joint necessary for full glenohumeral function