Mod 2: Lecture 3 - Arm, Elbow and Cubital Region Flashcards Preview

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Flashcards in Mod 2: Lecture 3 - Arm, Elbow and Cubital Region Deck (30)
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1

Cubital means

elbow

2

Distal Humerus

- Condyles: articulating surfaces
---- Capitulum: articulates with the radius
---- Trochlea: articulates with the ulna
- Epicondyles
---- Two: Medial and Lateral
---- primarily sites of muscle attachment
- Fossae
---- Three: radial, coronoid, olecranon

3

Radius and Ulna
1. proximal ends
2. distal ends

1. - both articulate with the distal humerus
- ulna is longer proximally
- end of ulna is much bigger, has a hook
-end of radius is a flat little cap
2. - radius is longer distally
- radius has a slanted triangular end
- ulna has a little bumpy end

4

Radius and Ulna
1. rotation
2. joined by

1. - radius rotates around the ulna
---- supination and pronation
2. - they are joined by interosseus membrane
---- syndesmosis joint
- proximal and distal radial-ulnar joints

5

Features of the Radius

1. Head: little flat cap
2. Neck: short, skinny area under the head
3. Radial Tuberosity: bump right under the neck, site of biceps attachment
4. Shaft of Radius
5. Styloid Process: the tip of the triangular distal end, pointed projection
6. Ulnar notch: the tip of the other side of the distal radius, where the radius meets the ulna

6

Features of the Ulna

1. Olecranon Process
2. Trochlear (Semilunar) Notch
3. Coronoid Process
4. Tuberosity
5. Radial Notch
6. Shaft of Ulna
7. Head of Ulna
8. Styloid Process

7

Features of the Ulna:
1. Olecranon Process
2. Trochlear Notch
3. Coronoid Process

1. the superior tip of the hook at the proximal end
2. the inside curve of the hook, where the ulna joins the trochlea of the humerus
3. the inferior tip of the hook at the proximal end

8

Features of the Ulna:
4. Tuberosity
5. Radial Notch

4. a bump a little below the hook on the same side as it, site of attachment for the brachialis muscle
5. bump on the lateral side (in anatomical position), right underneath the hook, where the radius meets the ulna on the proximal ends

9

Features of the Ulna:
6. Shaft
7. Head
8. Styloid Process

6. the long middle part
7. the distal end
8. the little pointy bump off of the distal end

10

Articulations

- Three which share a joint capsule
---- Humeroulnar
---- Humeroradial
---- Proximal Radioulnar
- Distal Radioulnar

11

1. Humeroulnar Joint
2. Humeroradial Joint
3. Proximal Radioulnar

- these three share a joint capsule
1. - Hinge
- Flexion/Extension of the elbow
- medial side
2. - Modified hinge
- flexion/extension
- supination/pronation - some spinning of radial head
- lateral side
3. - Pivot
- supination/pronation
- between the radius and ulna on the proximal ends

12

Distal Radioulnar

- Pivot
- supination/pronation
- between the radius and ulna on the distal ends

13

Arthrokinematics of the Elbow
1. In extension...
2. In flexion...

1. the olecranon process is in close approximation to the distal humerus in the olecranon fossa
2. the olecranon process pulls away from the distal humerus, as the coronoid process and radius approach their respective fossae
--- the radius and coronoid process get closer to the the humerus

14

Arthrokinematics: supination/pronation

- Supination occurs as the radial head spins on the capitulum of the humerus
- the radius rotates around the ulna
- the radius is the only bone that moves, the ulna is fixed
- includes these joints:
---- humeroradial
---- proximal and distal radioulnar

15

Supporting Structures: Elbow Region - Annular Ligament

- Encircles the head of the radius
---- forms 4/5 of a circle
---- the radial notch of the ulna forms the other 1/5
- Attaches to the margins of the radial notch
- Holds the head of the radius against the ulna
- Protects against the distal dislocation of the radius
---- holds the radius up so it stays in its place at the joint
---- distal dislocation is down toward the wrist
- Stabilizes the proximal radioulnar joint
---- holds the radius to the ulna

16

Supporting Structures: Lateral Collateral Ligament

- From the lateral epicondyle of the humerus to the annular ligament of the radius
- Protects against varus (medial) deviation of the forearm
- taut in full extension

17

Supporting Structures: Medial Collateral Ligament

- From the medial epicondyle of the humerus to the coronoid process and olecranon process of the ulna
- Protects against valgus (lateral) deviation of the forearm
- Posterior fibers taut in flexion
- Transverse (oblique) fibers from olecranon to coronoid process deepen socket for trochlea

18

Muscles Acting on the Elbow: Flexion/Extension

- Anterior Compartment:
---- Biceps Brachii
---- Brachialis
---- Nerve: Musculocutaneous
- Posterior Compartment:
---- Triceps Brachii
---- Anconeus
---- Brachioradialis
---- Nerve: Radial

19

Biceps Brachii
1. Attachments
2. Action
3. Innervation

1. - both heads: radius via bicipital aponeurosis
- short head: coracoid process of the scapula
- long head: supraglenoid tubercle
2. - flexes elbow (flex humerus)
- supinates the forearm
3. musculocutaneous nerve

20

Brachialis
1. Attachments
2. Action
3. Innervation

- deep to the biceps muscle
1. - distal, anterior humerus
- coronoid process of the ulna
2. flexes the forearm
3. musculocutaneous nerve

21

Triceps Brachii
1. Attachments
2. Action
3. Innervation

1. - all heads: olecranon of the ulna
- long head: infraglenoid tubercle
- lateral head: posterior superior humerus
- medial head (deep): posterior inferior humerus
2. extend elbow (LH-ext in shoulder)
3. radial nerve

22

Anoconeus
1. Attachments
2. Action
3. Innervation

1. - lateral epicondyle of humerus
- olecranon of ulna
2. extends the forearm and aids in pronation of the forearm
3. radial nerve

23

Brachioradialis
1. Attachments
2. Action
3. Innervation

1. - lateral supracondylar ridge of distal humerus
- lateral, distal radius
2. flexes elbow
3. radial nerve
- originates in the posterior compartment and shares the innervation of the posterior compartment, but rotates to the front of the muscle so its action is similar to the muscles of the anterior compartment

24

Muscles Acting on the Radioulnar Joints

- Supinators
---- Supinator Muscle
---- Biceps Brachii
- Pronators
---- Pronator Teres
---- Pronator Quadratus

25

Supinator Muscle
1. Attachments
2. Action
3. Innervation

1. - lateral epicondyle of humerus, crest of ulna
- anterior, lateral, and posterior surface of radius
2. supinates the forearm
3. radial nerve

26

Pronator Teres
1. Attachments
2. Action
3. Innervation

1. - coronoid process and medial epicondyle
- lateral surface of radius
2. pronates and flexes the forearm
3. median nerve

27

Cubital Fossa

- triangular hollow area on the anterior aspect of the elbow

28

Boundaries of the Cubital Fossa

- superiorly: an imaginary line connecting the medial and lateral epicondyles
- medially: pronator teres
- laterally: brachioradialis

29

Cubital Fossa:
1. Floor
2. Roof

1. formed by the brachialis and supinator
2. formed by deep fascia, subcutaneous tissue, and skin of the anterior elbow

30

Contents of the Cubital Fossa

- terminal part of the brachial artery
- (deep) accompanying veins of the arteries
- biceps brachii tendon
- median nerve