Sept 11 - Upper Extremity Flashcards
What do the olecranon fossa and coronoid fossa do?
They allow the other pieces of the arm to lock in place
What is a fossa?
A fossa is an opening
Describe the ulna
It’s on the little finger side
The proximal end is shaped like a wrench
The inner part of the wrench is the olecranon fossa/trochlear notch
The lower lip of the wrench is the coronoid process
Distal “head” is small and terminates as the ulnar styloid process medially
Describe the radius
Thumb side of the forearm
Articulates directly with the wrist
The proximal end is the small rounded head
Distal end is larger and ends as the radial styloid process laterally
What is the radius responsible for?
Supination (asking for money) and pronation (tap on the head)
Describe the carpel bones
8 short bones arranged in 2 rows in the proximal aspect of hand
Allow for mobility of the hand and opposition (unique to humans)
Name the 4 carpel bones in the proximal row of the wrist, from lateral to medial
Scaphoid, Lunate, Triquetrum and Pisiform
Name the 4 carpel bones in the distal row of the wrist, from lateral to medial
Trapezium, Trapezoid, Capitate and Hamate
Describe the metacarpels
5 metacarpals make up the palm of the hand. They are numbers 1 to 5 (1 = thumb). They consist of the base, shaft and distal head. The middle metacarpal should be the highest
Describe the phalanges
Fingers of the hand. The thumb has two phalanges (distal and proximal). The remaining fingers have 3 phalanges (proximal, middle and distal).
Describe the elbow joint
Hinge type synovial joint, allows flexion/extension. During flexion, the trochlear notch of the ulna articulates with the trochlear surface of the humerus and the radial head glides on the capitulum
What is the carrying angle? What creates the carrying angle?
It’s a 15° angle of the forearm. It is greater in females to accommodate pelvic girdle (wider hips). The ulna migrates laterally because the trochlea is thicker medially.
Describe the proximal radioulnar joint
The pivot joint between the proximal radius and ulna.
Describe the position of the radius in relation to the ulna
Proximally, the radius and ulna are always side-by-side, but distally, the radius crosses over the ulna during pronation. This happens because the ulna is attached to the humerus, however the radius is only attached by a ligment
What comprises the wrist joint?
It is comprised of the distal end of the radius and the proximal row of carpel bones (the ulna is separated by a fibro-cartilagenous disc and does not contribute to the wrist joint).
In between each carpel is a joint, but globally referred to as the wrist joint.
It is a condyloid synovial joint
Name the function of the metacarpal-phalangeal joints
Aka MCPs
MCPs allow for flexion/extension, abduction/adduction (the middle finger is used as the point of reference to describe abduction and adduction
What makes the 1st MCP unusual?
It’s a saddle type synovial joint between the trapezium and the base of the first metacarpal and it allows for opposition, in addition to flexion/extension and abduction/adduction (opposition is a very limited type of rotation)
What are PIPs and DIPs?
Proximal interphalangeal joints and distal interphalangeal joints. They are hinge joints (flexion/extension, abduction/adduction
Name the three muscles of the biceps. Where are they located?
Biceps brachii (crosses both the shoulder and eblow)
Brachialis (crosses the elbow)
Coracobrachialis (crosses the shoulder)
Describe the biceps brachii
Superficial, 2 headed anterior arm muscle
Crosses the shoulder and the elbow (2 joints)
What is the functions of the biceps brachii
Forearm supination (opens a door, opens a twist-off beer) Secondary movements: elbow flexion (against resistance), shoulder flexion, shoulder adduction
Describe the brachialis
Flat thin muscle, deep to biceps brachii.
What is the function of the brachialis
Elbow flexion
Describe the coracobrachialis
Located deep to pectoralis major, pectoralis minor and deltoid.
What are the functions of the coracobrachialis?
Shoulder flexion, shoulder adduction
What nerve innervates the three muscles of the biceps?
The musculocutaneous nerve
Describe the triceps brachii
3 headed muscle on posterior arm (brachium) Long head (crosses shoulder joint)/lateral head/medial head
What nerve innervated the triceps brachii
Radial nerve
What is the function of the triceps brachii?
All involved in powering elbow extension (above the head, not towards the ground)
Describe the anterior compartment of the forearm
Arises from the medial epicondyle
Involves flexors
Involves pronators
Describe the posterior compartment of the forearm
Arises from the lateral epicondyle
Involves extensors
Involves supinators
Describe the compartments of the forearm
Each compartment contains a superficial and a deep region
All forearm muscles are termed as “extrinsic muscles” of the hand
Involved in power movements of the wrist, thumb and fingers
Name the movements of the anterior compartment of the forearm
Flexion (wrist and fingers) Ulnar deviation (adduction) Radial deviation (abduction) Pronation Thumb Flexion
Name the movements of the posterior compartment of the forearm
Extension (wrist and fingers) Ulnar deviation (adduction) Radial deviation (abduction) Supination Thumb extension Thumb abduction
Name the common attachment points of the compartments of the forearm
The flexors are pushed medially to medial epicondyle of the humerus
The extensors are pushed laterally to lateral epicondyle of the humerus
Name the five muscles of the superficial layer of the anterior compartment of the forearm
Pronator teres Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Flexor digitorum superficialis
Name the three muscles of the deep layer of the anterior compartment of the forearm
Flexor digitorum profondus
Flexor pollicis longus
Pronator quadratus
What is flexor retinaculum
It creates the carpal tunnel
Each tendon of the wrist is held in place by a thick connective tissue sheath called the flexor retinaculum. Ensure the wrist is thin and efficient
Name the five muscles of the superficial layer of the posterior compartment of the forearm
Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris
Name the five muscles of the deep layer of the posterior compartment of the forearm
Supinator Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis
What is the brachioradialis
At “top” of forearm (beer drinking muscle)
It does not cross the wrist joint so technically is not considered a member of either the flexor or extensor group of forearm muscles
Powers elbow flexion in semi-pronation
Innervated by the radial
What is the function of brachioradialis?
Powers elbow flexion in semi-pronation
What nerve innervates the brachioradialis?
The radial nerve
What is the thenar
It is the fleshy prominence on the palm
It’s comprised of 3 muscles that act on the thumb
What is the rule of three, in regards to the muscles of the hand?
Three compartments, each with comprised of 3 muscles and the compartments are innervated by three nerves
Name the three compartments of the hand muscles
Thenar
Hypothenar
Central
Name the three nerves that innervate the compartments of the hand muscles
Radial
Ulnar (hypothenar group)
Median (thenar group)
Describe the thenar muscle group of the hand
It is the fleshy prominence on the radial side of the palm
Describe the hypothenar muscle group of the hand
It is the fleshy prominence on the ball of the little finger
Describe the central compartment of the hand
Muscles between hypothenar and thenar eminences
Muscles are more prominent on palmar surface
Name the three muscles the comprise the central compartment and their function
Inter-ossei (abduction/adduction)
Lumbricals (flexion of the MCPs)
Adductor pollicis
What is the palmar aponeurosis
It connects skin to underlying structures of the hand
It helps with holding objects
Where do the nerves that innervate your arm muscles come from?
Every one of the muscles receives innervation from nerves that come from you neck, more specifically from the lower cervical (C5-C8) and ending at the upper thoracic level (T1)
Name the 5 terminal nerves of the arms
Musculocutaneous Axillary Radial Median Ulnar
Name the root blood takes from the heart to the arm
Heart - (brachiocephalic - subclavian artery)/common carotid artery - axillary artery - exits shoulder/armpit region - brachial artery - ulnar and radial artiery
