Arm Flashcards
Flexion and extension of the arm is done by what?
Elbow joint
Can you really extend the arm from anatomical position?
No , olecron process stops you
Which two bones have proximal heads?
Humerus and Ulna All other heads on bones are distal
how many movements can you do with the arm?
4
Which two joints are in the synovial cavity of the arm?
Elbow joint
Radioulnar joint
Muscles on the anterior side of the arm
Coracobrachialis
Biceps Brachii
Brachialis
Coracobrachialis (oblique muscle)
Origin: corociod process of the scapula process
Innervation: Musculocutaneous
Function: flex and suppinate forearm. adduct the arm at the shoulder joint;
Biceps Brachii
Origin: Short head - coracoid process of scapula; long head - superglenoid process of shoulder
Function: flex and supinate the forearm
Innervation: musculocutaneous nerve
Opposer of Biceps Brachii
Bicipital aponeurosis
Brachialis
Origin: humerus
Insertion: Ulnar
Function: Flex and supinate the forearm
Innervation: musculocutaneous nerve
Triceps Brachii (only posterior arm muscle)
Origin: Long head - shoulder/scapula Lateral and medial head - humerus Insertion: Electron process of the ulna
Function: extend the forearm. Long head can do a small extension of the arm
Innervation: radial nerve.
Which head of the triceps cross only one joint?
Lateral and medial (comes from humerus so only cross the elbow joint, the long head crosses the shoulder joint too)
Parts of the Humerus
Medial Epicondlye (bigger and more lateral)
Coronoid fossa (seen anteriorly)
Lateral Epicondyle
Capitulum - articulates with the head of the radius
Trochlea - articulates with the trochlear notch of the ulna
Olecron fossa (seen posteriorly) - articulates with olecron process on ulna
Spiral Groove - where radial nerve runs (posteriorly)
Which nerve is at more risk of injury by a fracture of the midshaft of the humerus?
Radial nerve
Major nerve of the upper limb
In the spiral groove and runs posteriorly
Which nerve is most at risk of injury by a fracture of the medial epicondyle of the humerus?
The ulnar nerve
Major nerve of the upper limb
runs anteriorly, goes posteriorly over the medial epicondyle of the humerus and then comes back anteriorly
Parts of the Radius
This bone is lateral
Head (proximal) - articulates with the radial notch of the ulna
Neck (proximal)
Radial Tuberosity
Oblique line (anterior)
Anterior Border/Surface
Ulnar notch (medial)
styloid process (lateral)
Torus fracture of distal radius
Bulking of cortical bone in distal radius
Greenstick fracture
Fracture of the midshaft of the radius
Fracture of the cortical bone on the lateral side of the shaft of the radius
Cortical Bone bent on medial side of the shaft of the radius
Colles’ Fracture
Fall on the hand in which the distal end of the radius is forced posteriorly and angulated
Parts of the ulna
This bone is medial
Olecron process
Trochlear notch
Radial Notch (Recieves the head of the humerus)
Tuberosity of Ulna
Anterior surface
Styloid process
Head is distal
What is the proximal radialulnar joint?
Articulation of the head of the radius with the radia notch of the ulna
What does the annular ligament do?
It is attached to the radial notch of the ulna posteriorly and anteriorlyas well as holds the radius in place
Head of the Radius not attached but suspended within the ligament
What is the distal radial ulnar joint?
An articular disc that connects to the stylodid process of the ulna and the ulna notch of the radius. Allows the head of ulna to articulate with the ulnar notch.
Supinaiton and pronation of the forearm is allowed by which joints?
The proximal and distal radialulnar joints
When a person is in anatomical postion is the forearm supinated or pronated?
Fully supinated
During pronation/supination which bones move mainly?
The radius uses the joint to cross over while the ulna stays in place
What is an injury that most commonly occurs in children?
Pulled elbow
What causes a pulled elbow?
Distal pull on upper limb while arm is extended and protonated resuts in a distal pull on the head of the radius away from the capitilum of the humerus.
What are the two things that can happen when the elbow is pulled?
- transverse tear in the annular ligament - upper part of the annular ligament slides up and partially pver the upper surface of the head of the radius
- A partial dislocation, subluxation - pulling of the head of the radius away from the capitilum
What are the results of a pulled elbow?
Annular ligament becomes pinched between capitulum and head of the radius
Child presents with a flexed, pronated forarm supported closely to the trunk of the body. He/she complains of pain around the head of the humerus.
What is the diagnosis?
Pulled Elbow
after rulling out fractures and dislocations
How do you reduce a pulled elbow?
stabilize the childs elbow and palpate the head of the radius with one hand and then slowly, but firmly, supinating and flesing the child’s forarm with the other hand
Why is it important to not only look at a lateral radiograph of the elbow when looking for a pulled elbow?
Lateral radiograph will not show any displacement of the head of the radius because, with a pulled elbow, it is the upper part of the annular ligament and not the head of the radius that is displaced at the time
Beside the radioulnar joint, what other joint holds the radius and ulnar together?
Interosseous membrane of the forearm
What are the layers of the arm?
Skin
Superficial fascia
Fat
Deep fascia
Muscle
Intermuscular septum
Biceps Brachii Reflex test
Assesses spinal cord reflex activity in the C5 and C6 spinal cord segment levels
flexion of the forearm at the elbow joint is mainly controled by which nerve fibers?
C6
Because the biceps brachi and brachialis (major flexors of the forearm)
Each recieve innervation from C5 and C6 nerve fibers
Triceps Brachi Reflex test
Asses spinal cord activity in the C7 and C8 spinal cord segment levels
This shows extension of the forearm
Erb’s Palsy
severe injury of the C5 and C6 roots, upper trunk, or the division of the upper trunk of the brachial plexus
mainly caused by upper brachial plexus injury - excessive traction on th eupper plexus
