STUDY GUIDE N - UNIT 3

Question 1

What joint has the greatest range of motion and is most frequently dislocated?

Answer 1

Glenohumeral joint.

Question 2

What deepens the glenoid cavity?

Answer 2

Glenoid labrum (fibrocartilage).

Question 3

What provides most strength to the shoulder joint?

Answer 3

Rotator cuff muscles.

Question 4

What is the weakest part of the shoulder joint?

Answer 4

Inferior portion—lacks rotator cuff support.

Question 5

Structural classifications:

Answer 5

1. Glenohumeral: Ball-and-socket
2. Elbow: Hinge
3. Radioulnar: Pivot
4. Intercarpal: Plane
5. Carpometacarpal (thumb): Saddle
6. MCP: Condylar
7. IP: Hinge

Question 6

What are the two articulations of the elbow?

Answer 6

Humeroulnar (hinge), Humeroradial (hinge).

Question 7

Key ligaments of the elbow?

Answer 7

Ulnar collateral, radial collateral.

Question 8

What ligament holds the radial head in place?

Answer 8

Anular ligament.

Question 9

Shape of smooth muscle cells?

Answer 9

Fusiform (spindle-shaped).

Question 10

Source of Ca²⁺ in smooth muscle?

Answer 10

Mostly from interstitial fluid (not much SR).

Question 11

Are smooth muscles striated?

Answer 11

No—lack sarcomeres/Z-discs.

Question 12

Contraction shape of smooth muscle?

Answer 12

Corkscrew twist.

Question 13

Smooth vs. skeletal muscle contraction?

Answer 13

Smooth = slower, longer, more fatigue-resistant.

Question 14

Smooth muscle control?

Answer 14

Autonomic nervous system, hormones, stretch (myogenic), local factors.

Question 15

Single-unit vs. multi-unit smooth muscle?

Answer 15

A. Single-unit: Most common, contracts in unison, has varicosities.
B. Multi-unit: Contracts individually, fine motor control (e.g., eye, arrector pili).

Question 16

What muscles protract the scapula?

Answer 16

Serratus anterior, pectoralis minor.

Question 17

What muscle elevates the scapula?

Answer 17

Levator scapulae.

Question 18

What muscles retract scapula?

Answer 18

Rhomboid major/minor, middle trapezius.

Question 19

What muscle depresses scapula?

Answer 19

Inferior trapezius.

Question 20

Actions of pectoralis major?

Answer 20

Flexes, adducts, medially rotates arm.

Question 21

Actions of latissimus dorsi?

Answer 21

Extends, adducts, medially rotates arm.

Question 22

Parts of deltoid and actions?

Answer 22

1. Anterior: flex/medially rotate
2. Middle: abduct
3. Posterior: extend/laterally rotate

Question 23

What do rotator cuff muscles do?

Answer 23

1. Stabilize the glenohumeral joint.
2. Mnemonic: SITS – Supraspinatus, Infraspinatus, Teres minor, Subscapularis.

Question 24

Anterior arm muscles?

Answer 24

Biceps brachii (also flexes shoulder), brachialis (main flexor), coracobrachialis.

Question 25

Posterior arm muscles?

Answer 25

Triceps brachii (main extensor, extends shoulder), anconeus.

Question 26

Where does triceps insert?

Answer 26

Olecranon of ulna.

Question 27

Forearm pronators?

Answer 27

Pronator teres, pronator quadratus.

Question 27

Muscle aiding in supination?

Answer 27

Supinator (assists biceps brachii).