Antebrachium Flashcards
What are the compartments of the antebrachium?
Anterior and posterior
What is the antebrachial fascia continuous with?
The brachial fascia
What type of joint is the interosseous membrane?
Syndesmoses (Long fibers)
Describe the difference between long fibers and short fibers in a syndesmoses
Longer fibers have greater flexibility than shorter fibers
What does the antibrachium have instead of medial intramuscular septum?
Interosseous membrane between the radius and the ulna
What is the purpose of the fascia retinaculum?
Hold down the long tendon during flexing so the muscles don’t bow string
What is the retinaculum?
It is extension of the fascia
What are the 2 retinaculums?
- Flexor retinaculum
- Extensor retinaculum
What is the main movement of the radius and the ulna?
-Pronation and Supination
What are the 2 articulations of the radius and the ulna?
- Head of the radius articulates with the radial notch of the ulna
- Head of the ulna articulates with the ulnar notch of the radius
Where is the radial head located (proximal/distal)
Proximal
Where is the ulnar head located (proximal/distal)
Distal- near the styloid process of the ulna
Describe a dinner fork deformity
- The distal radius is drivin posteriorly
- Commonly seen in Colles fracture
Describe Colles fracture
- Occurs in the distal 2 cm of the radius
- Usually occurs in older people
- Occurs when you fall and your hand is out- causing an extension force
- The distal part bends posteriorly and its usually communited fracture
Are the styloid processes of the radius and ulna proximal or distal?
Both are distal
What type of joint is the proximal radioulnar joint?
Synovial–> pivot
What articulates at the radioulnar joint?
The head of the radius and the radial notch on the ulna
What ligament holds the head of the radius on to the surface of the ulna?
The anular ligament
During supination and pronation, what bone stays steady and what bone moves?
The ulna stays steady
-The radius moves
Describe subluxation at the elbow
AKA nurse maids elbow
- the radial head pulls out of between the anular ligament and the ulna and pinches the anular ligament
- To fix you have to forcefully supinate/extend to cause the head to go back
How do the fibers of the interosseous membrane influence the movement of the radius and ulna?
They are long so they permit more movement and this allows for supination and pronation
Describe the distal radioulnar joint?
Synovial–> Pivot Joint
What 2 things articulate in the distal radioulnar joint?
The head of the ulna and the ulnar notch of the radius
What can you compare the distal radioulnar joint to?
Tetherball- one end it stabilized and the other can move
What is the name of the articular disc of the radius and ulna?
The dorsal radioulnar ligament
-“Triangular Ligament”
What are the 2 ligaments at the distal radioulnar joint?
- Anterior Ligament
- Posterior Ligament
How many bones does the carpus consist of?
8 (Pisiform, Triquetrum, Lunate, Scaffoid, Trapezium, Trapezoid, Capitate, Hamate)
Describe the radiocarpal joint
Synovial –> Condyloid
What movement does the radiocarpal joint allow?
-Flex/Ex/Ab/Ad/Circumduct
What are the 4 bones that participate in the radiocarpal joint?
Radius, Scaffoid, Lunate, and Triquetrum
Does the ulna play a role in the radiocarpal joint?
No!
What are the ligaments of the radiocarpal joint?
- Radial Collateral
- Ulnar Collateral
- Anterior Lig
- Posterior Lig
What does the radial collateral ligament limit?
Adduction
What does the ulnar collateral ligament limit?
Abduction
What does the anterior ligament do?
Pulls the hand to follow in suppination
What does the posterior ligament do?
Allows the hand to follow in pronation
Characteristics of the Radial Artery
- Recurrent
- Continues as deep palmar arch (anastomoses across the wrist)
Characteristics of the Ulnar Artery
- Recurrents
- Continues as superficial palmar arch
Describe the common interosseous artery
- Supplies the deepest structures
- Has 3 parts
What are the 3 parts of the interosseous artery
- Anterior
- Posterior
- Recurrent
Describe the alan test
To check for perfusion across radial and ulnar arteries from the wrist
What are signs of a median nerve injury?
You cant flex your thumb and 1st and 2nd digits
What occurs at an ulnar nerve injury
The pinky and ring finger do not flex (stay straight)
- can still flex the wrist
- not a good grip
What make up the floor of the anatomical snuff box (4)
- Scaphoid
- Trapezium
- Base of 1st metacarpal
- Radial styloid
How do you tighten your anatomical snuff box?
Abduct the thumb and the tendons tighten
What does the roof of the anatomical snuff box consist of?
The radial artery and nerve
What happens if your scaphoid is fractured?
- Causes stiffness
- May not show up for days,
- Heals slowly and poorly because of poor blood flow
What does the musculocutaneous nerve innervate?
- Muscles of the anterior compartment of the arm
- Lateral skin over the lateral forearm (post Cubital fossa)
What does the median nerve travel to and from?
Runs lateral to the brachial artery
-At midarm- it crosses to the medial side of the artery
Where does the ulnar nerve travel to and from?
Runs medial into medial intermuscular septum and posterior to the medial epicondyle
What are the boundaries of the anatomical snuff box (3)
- Extensor pollicis longus
- Extensor pollicis brevis
- Abductor pollicis longus
