Answer Guide To Test Questions - Third Anatomy Exam - 10/06/97

Note: This is an outline of items to discuss -- NOT the "Answer"

The Pennsylvania State University College of Medicine - Human Gross Anatomy

The Structural Basis of Medical Practice
This site has been accessed times since October 9, 1997
(Copyright Protected - L.A. Evey, Ph.D.)

Part II. Answer in the space provided. (22 pts)

  1. Discuss the elbow anastomis. Include key relations for each artery directly contributing to this anastomosis. (8 pts)
    1. superior ulnar collateral a.
      1. branch of the brachial a.
      2. courses toward ulnar groove with the ulnar nerve
      3. passes posterior to humeral epicondyle
    2. posterior ulnar recurrent a.
      1. branch of ulnar a.
      2. lateral to humeral head of flexor carpi ulnaris
      3. medial to ulnar head of flexor carpi ulnaris
      4. passes posterior to medial humeral epicondyle
    3. inferior ulnar collateral a.
      1. branch of brachial a.
      2. medial to brachialis and lateral to humeral head of pronator teres
      3. crosses elbow anterior to medial humeral epicondyle
    4. anterior ulnar recurrent a.
      1. branch of ulnar a.
      2. medial to brachialis and lateral to humeral head of pronator teres
      3. anterior to medial humeral epicondyle
    5. middle collateral a.
      1. terminal branch of profunda brachii
      2. courses toward posterior aspect of lateral humeral epicondyle
      3. relation to medial head of triceps
    6. interosseous recurrent a.
      1. branch of posterior interosseous a. (usually)
      2. on posterior surface of oblique ligament deep to anconeus
      3. passes posterior to lateral humeral epicondyle
    7. radial collateral a.
      1. terminal branch of profunda brachii
      2. pierces lateral intermuscular septum with radial n.
      3. coursed anterior to lateral humeral epicondyle
      4. lateral to brachialis and medial to brachioradialis
    8. radial recurrent a.
      1. branch of radial a.
      2. medial to brachioradialis and lateral to biceps tendon
      3. crosses anterior to lateral humeral epicondyle
  2. The suprascapular nerve is severed proximal to the transverse scapular ligament. Discuss the course (relations) of the suprascapular nerve distal to the transverse scapular ligament. Discuss compensation for the loss of functions specific to this injury. (6 pts.)
    1. The suprascapular n. enters the supraspinous fossa through foramen formed by suprascapula notch and transverse scapular ligament.
      1. innervates the supraspinatus - pure abductor (supraspinous fossa to greater tubercle)
      2. first 15 deg of abduction - there no direct compensation for this loss
      3. a "hip flick" or leaning over the lesion could effect the first 15 deg abduction
    2. The nerve courses laterally and then inferiorly around the great scapular notch (aka, spinoglenoid notch or fossa, inferior scapular notch) to enter the infraspinous fossa
      1. innervates the infraspinatus - pure lateral rotator (infraspinous fossa to greater tubercle)
      2. compensation by teres minor and posterior deltoid (axillary n.).
  3. Contrast the course of the deep radial nerve into the posterior compartment of the forearm to that of the posterior interosseous artery. Where is the deep radial nerve susceptible to entrapment? (4 pts)
    1. The deep radial nerve is a terminal branch of the radial n.
      1. branch occurs between brachioradialis (lateral) and brachialis (medial)
      2. courses posteriorly and inferiorly toward the superior free edge of the supinator as this muscle circles the radius
      3. courses laterally around the the radius deep to the supinator muscle
      4. emerges in posterior compartment inferior to the inferior free edge of the supinator
      5. entrapment might occur within the supinator muscle
    2. The posterior interosseous artery is a branch of the common interosseous a. from the ulnar a.
      1. This artery leaves the anterior compartment of the arm by passing into the posterior compartment through a gap defined by the superior free edge of the interosseous membrane and the inferior free edge of the oblique cord
  4. Discuss the relations of the ulnar artery beginning from the wrist and continuing distally. (4 pts)
    1. enters hand anterior to flexor retinaculum and lateral to flexor carpi ulnaris tendon
    2. lateral to pisiform bone
      1. canal of Guyon
    3. deep branch occurs medial to the hook of the hamate bone
      1. passes dorsally between the abductor digiti minimi and flexor digiti minimi brevis
    4. superficial branch contributes to the superficial palmar arch
      1. common palmar digital aa arise from this arch