Week 1 Conceptual

Question 1

Demonstrate on a partner (palpate) the muscles of the rotator cuff. (Origin, Insertion, Innervation, and Action

Answer 1

• Subscapularis
• Supraspinatus
• Infraspinatus
• Teres Minor

Question 2

Demonstrate on a partner (palpate) the muscles of the Pectoral Girdle and Axilla. (Origin, Insertion, Innervation, and Action

Answer 2

• Pectoralis Major
• Pectoralis Minor
• Subclavius
• Serratusa Anterior

Question 3

Demonstrate on a partner (palpate) the muscles posterior shoulder girdle. (Origin, Insertion, Innervation, and Action)

Answer 3

• Teres Major
• Infraspinatus
• Teres Minor
• Deltoid (posterior fibers)

Question 4

Discuss Erb’s or Erbs-Duchenne palsy

Answer 4

Erb’s or Erbs-Duchenne Palsy is most commonly the result of trauma. Forceful side flexion of the neck away with depression of the scapula produces sudden tension on the C5/C6 ventral rami and upper trunk of the brachial plexus. Due to the significant contribution of C5 and C6 to the shoulder girdle and elbow, there is weakness of the glenohumeral abductors and external rotators; scapular retractors; elbow flexors and forearm supinators (i.e. biceps brachii). The head waiter’s tip hand is a sign of Erb’s palsy.

Question 5

Discuss the process of segmentation and innervation of the limb buds.

Answer 5

How well would you rate your ability to explain it?

Question 6

Demonstrate on a partner (palpate) of the muscles of the superficial Muscles of Anterior Neck. (Origin, Insertion, Innervation, and Action

Answer 6

• Platysma
• Sternocleidomastoid

Question 7

Draw the brachial plexus

Answer 7

Question 8

Discuss Klumpke’s Palsy

Answer 8

Klumpke’s Palsy is due to trauma in many cases. Force hyper abduction (arm-trunk separation) produces considerable tension on the lower trunk of the brachial plexus and C8/T1 ventral ramil. C8 and T1 contribute to the ulnar, medial brachial cutaneous, and medial antebrachial cutaneous nerves. Injury causes atrophy and weakness to many of the intrinsic hand muscles, resulting in ulnar claw-hand deformity. Additionally, sensory changes occur along the area of the dermis receiving cutaneous innervation from C8 and T1. A classic sign associated with Klumpke’s palsy is the sign of Benediction upon transitioning from a closed fist to open hand position. Klumpke’s palsy can be the result of a Pancoast tumor which compresses on the lower trunk of the brachial plexus (ventral rami C8 and T1), along with the inferior cervical ganglion located at the cervicothoracic junction.

Question 9

Discuss Saturday Night Palsy

Answer 9

Saturday Night Palsy is due to prolonged compression under the armpit (axilla). A common cause is ill-fitting or poor habits when using axillary crutches. In some rare cases, it is due to passing out with the arm slump over a chair… after drinking too much on a Saturday night. The result is prolonged compression on the posterior cord of the brachial plexus, in particular, the radial nerve branch. The presence of wrist drop and the inability to extend the elbow fully are classic signs of this condition.

Question 10

Discuss Suprascapular nerve palsy

Answer 10

Suprascapular nerve palsy is often caused by a traction injury (Erb’s palsy) or excessive stress from overhead throwing. A full-thickness tear of the supraspinatus tendon with retraction could compromise the nerve as well. In addition, the suprascapular nerve can be compressed between anterior and middle scalene muscles, or within the suprascapular notch or spinoglenoid notch. The former affects both the supraspinatus and infraspinatus muscle. Look for signs of atrophy and motor weakness of the supraspinatus and infraspinatus. However, entrapment of the nerve within the spinoglenoid notch only affects the infraspinatus muscle.

Question 11

Discuss Dorsal Scapular nerve palsy

Answer 11

Dorsal scapular nerve palsy can be due to traction injury of the C5 ventral rami. The dorsal scapular nerve is also vulnerable to compression as it passes between the middle and posterior scalene muscles, enroute to rhomboids. Paresis of the rhomboid muscles is associated with dorsal scapular nerve palsy, which causes winging and excessive protraction of the scapula.

Question 12

Discuss Thoracic outlet syndrome

Answer 12

“Thoracic Outlet Syndrome” can be neurological, vascular, or both. Refer to entrapment sites listed above. The correct term should be the “brachial inlet”. However, individuals with thoracic outlet syndrome often complain of paresthesia - a tingling sensation in the hand and fingers. In many cases of thoracic outlet syndrome the lower trunk is affected due to elevation of the 1st rib. In addition, the subclavian artery and axillary artery can become occluded temporarily with arm-trunk elevation (i.e. reaching overhead). The clinician appreciates a diminished radial pulse during provocation testing. Other potential causes include cervical rib syndrome (see subsequent section).

Question 13

Draw the anatomy of a spinal nerve with its central connections.

Answer 13

Question 14

Discuss Long Thoracic nerve palsy

Answer 14

Long thoracic nerve palsy can be due to forceful depression of the shoulder girdle, or blunt force trauma to the outer surface of the serratus anterior muscle. The nerve is vulnerable to traction injury where it courses over the first rib. In addition, radiation treatment or surgical procedures such as breast mastectomy can injure the nerve. Look for the presence of scapular winging during arm flexion. Performing a push-up is extremely difficult due to serratus anterior weakness and excessive scapular winging.

Question 15

Demonstrate on a partner (palpate) the muscles of the superficial back and intermediate back layer. (Origin, Insertion, Innervation, and Action

Answer 15

• Trapezius
• Latissimus dorsi
• Rhomboid Minor
• Rhomboid Major
• Levator Scapula
• Serratus posterior superior
• Serratus posterior inferior