The ulna

Question 1

Ulna Structure

Answer 1

• Proximal Epiphysis: Features the olecranon, trochlear notch (incisura trochlearis), and coronoid process (proc. coronoideus).
• Body: The shaft of the ulna, which is relatively straight.
• Distal Epiphysis: Contains the head of the ulna and the styloid process (proc. styloideus).

Question 2

Ulna Joints

Answer 2

. Elbow Joint (Articulatio Cubiti):
- The ulna articulates with the humerus at the humero-ulnar joint (trochlea of the humerus with the trochlear notch of the ulna).
- It also forms part of the humero-radial joint (capitulum of the humerus with the head of the radius) and the proximal radio-ulnar joint (circumferentia articularis of the radius with the radial notch of the ulna).

2. Distal Radio-Ulnar Joint:
   - The ulna articulates with the radius at the distal end, allowing for pronation and supination of the forearm

Question 3

Ulna Muscles

Answer 3

1. Flexors:
   - Muscles that originate from the medial epicondyle of the humerus and insert on the ulna include:
   - Flexor carpi ulnaris (innervated by the ulnar nerve).
   - Flexor digitorum profundus (partially innervated by the ulnar nerve).
2. Extensors:
   - Muscles that originate from the lateral epicondyle and insert on the ulna include:
   - Extensor carpi ulnaris (innervated by the radial nerve).

Question 4

Ulna Ligaments

Answer 4

1. Collateral Ligaments of the Elbow:
   - Ulnar Collateral Ligament: Stabilizes the medial aspect of the elbow.
   - Radial Collateral Ligament: Stabilizes the lateral aspect of the elbow.
   - Annular Ligament: Encircles the head of the radius, allowing for rotation during pronation and supination.
2. Interosseous Membrane:
   - A fibrous sheet connecting the ulna and radius along their lengths, providing stability and serving as an attachment site for muscles

Question 5

Ulna Nerves

Answer 5

1. Ulnar Nerve:
   - Innervates the muscles of the hypothenar eminence, interossei, and the ulnar half of the flexor digitorum profundus. It runs posterior to the medial epicondyle of the humerus, often referred to as the “funny bone” area.
2. Median Nerve:
   - While it primarily innervates the flexor muscles of the forearm (except for the ulnar half of the flexor digitorum profundus and flexor carpi ulnaris), it also provides sensory innervation to parts of the hand.
3. Radial Nerve:
   - Innervates the extensor muscles of the forearm and provides sensory innervation to the posterior aspect of the arm and forearm.

Question 6

The blood supply of ulna

Answer 6

The blood supply to the ulna is primarily provided by the ulnar artery, which is one of the two major branches of the brachial artery. Here are the key points regarding the blood vessels associated with the ulna:

1. Ulnar Artery:
   - The ulnar artery branches off from the brachial artery in the upper arm and travels down the forearm, running along the medial side of the forearm.
   - It supplies blood to the muscles and structures in the anterior compartment of the forearm, as well as the hand.
2. Branches of the Ulnar Artery:
   - Anterior Ulnar Recurrent Artery: Supplies the elbow region.
   - Common Interosseous Artery: This artery branches into the anterior and posterior interosseous arteries, which supply the deep muscles of the forearm and the interosseous membrane.
   - Palmar and Dorsal Carpal Branches: These branches contribute to the blood supply of the wrist and hand.
3. Ulnar Veins:
   - The deep veins accompany the ulnar artery and include the ulnar veins, which drain blood from the forearm and ultimately converge into the brachial veins, leading back to the subclavian vein.
4. Superficial Venous Drainage:
   - The basilic vein runs along the medial side of the forearm and drains into the axillary vein, which is also associated with the ulnar region.