Table of Contents
- 1 Where does the ulna and humerus meet?
- 2 What type of joint is formed when the humerus radius and ulna meet at the elbow?
- 3 Which injury is the most common forearm fracture?
- 4 Which joint is the most complex diarthrosis in the body?
- 5 What muscles insert on the humerus?
- 6 What part of the body is the ulna?
Where does the ulna and humerus meet?
Elbow
The elbow is where the two bones of the forearm – the radius on the thumb side of the arm and the ulna on the pinky finger side – meet the bone of the upper arm — the humerus. The lower end of the humerus flares out into two rounded protrusions called epicondyles, where muscles attach.
What type of joint is formed when the humerus radius and ulna meet at the elbow?
hinge joint
The elbow joint is a complex hinge joint formed between the distal end of the humerus in the upper arm and the proximal ends of the ulna and radius in the forearm.
What type of joint does the humerus have?
ball and socket joint
The most proximal portion of the humerus is the head of the humerus, which forms a ball and socket joint with the glenoid cavity on the scapula. [1] Just inferior to the head of the humerus is the anatomical neck of the humerus, which divides the head of the humerus from the greater and lesser tubercles.
What muscles insert on the ulna?
Muscle attachments
| Muscle | Direction |
|---|---|
| Brachialis muscle | Insertion |
| Pronator teres muscle | Origin |
| Flexor carpi ulnaris muscle | Origin |
| Flexor digitorum superficialis muscle | Origin |
Which injury is the most common forearm fracture?
What are the different types of forearm fractures?
- Galeazzi facture: Most often a displaced fracture in the radius and a dislocation of the ulna at the wrist, where the radius and ulna come together.
- Monteggia fracture: Most often a fracture in the ulna and the top (head) of the radius is dislocated at the elbow joint.
Which joint is the most complex diarthrosis in the body?
the knee
The most complex diarthrosis in the body is the knee.
What kind of joint allows the arm to move freely in all directions?
There are six types of freely movable diarthrosis (synovial) joints: Ball and socket joint. Permitting movement in all directions, the ball and socket joint features the rounded head of one bone sitting in the cup of another bone. Examples include your shoulder joint and your hip joint.
What is the most distal feature of the humerus?
The distal end of the humerus has two articulation areas, which join the ulna and radius bones of the forearm to form the elbow joint. The more medial of these areas is the trochlea, a spindle- or pulley-shaped region (trochlea = “pulley”), which articulates with the ulna bone.
What muscles insert on the humerus?
The pectoralis major, teres major, and latissimus dorsi insert at the intertubercular groove of the humerus. They work to adduct and medially, or internally, rotate the humerus. The infraspinatus and teres minor insert on the greater tubercle, and work to laterally, or externally, rotate the humerus.
What part of the body is the ulna?
forearm
The ulna is one of two bones that make up the forearm, the other being the radius. It forms the elbow joint with the humerus and also articulates with the radius both proximally and distally. It is located in the medial forearm when the arm is in the anatomical position. It is the larger of the two forearm bones.
What movement does the ulna allow?
The main function of the ulna, along with the radius, is to assist with rotation. This rotation allows for the maximal function of the wrist and hand due to the increased range of motion. The sole motion of the elbow joint is flexion and extension, otherwise known as bending and straightening the arm.
How do you tell if your ulna is broken?
Symptoms
- Severe pain, which might increase with movement.
- Swelling.
- Bruising.
- Deformity, such as a bent arm or wrist.
- Inability to turn your arm from palm up to palm down or vice versa.