Arm, forearm and hand I week 3 Flashcards
What is the group function of muscles in the anterior compartment of the arm? What nerve are they innervated by?
group function: flexion of the arm at the glenohumeral joint and/or flexion of the forearm at the elbow joint
innervation: musculocutaneous nerve (C5, C6)
What is the origin, insertion, function, and innervation of the biceps brachii?
origin:
long head: supraglenoid tubercle (on glenoid fossa of scapula) (passes through the bicipital/intertubercular groove which is covered by transverse humeral ligament)
short head: coracoid process of the scapula
insertion: radial tuberosity; fascia of the forearm
function: flexes the elbow and supinates forearm at proximal radio-ulnar joint. the long head can flex the arm at the glenohumeral joint
innervation: musculocutaneous nerve (C5, C6)
What is the origin, insertion, function, and innervation of the coracobrachialis?
origin: coracoid process of scapula
insertion: medial surface of the humerus
function: adducts and flexes the arm at the glenohumeral joint (is a weak flexor)
innervation: musculocutaneous nerve (C5, C6)
What is the origin, insertion, function, and innervation of the brachialis?
origin: anterior surface of the humerus
insertion: anterior surface of the ulna
function: flexes the elbow
innervation: musculocutaneous nerve (C5, C6)
What is the origin, insertion, function, and innervation of the triceps brachii?
origin:
long head: infraglenoid tubercle of glenoid fossa
lateral and medial heads: posterior surface of the humerus
insertion: olecranon process of the ulna
function: all heads can extend the forearm at the elbow joint. only the long head can extend the arm at the glenohumeral joint
innervation: radial nerve
Identify the branches of the axillary and brachial arteries.
Identify these veins.
Identify these nerves.
lateral epicondylitis
inflammation of the common tendinous origin of extensor muscles that originate at lateral epicondyle of humerus. is associated with overuse that not only affects tennis players but is associated with occupational overuse of extensor muscles in the forearm
carpal tunnel syndrome
caused by entrapment of median nerve as it passes under the flexor retinaculum (through the carpal tunnel) with the long flexor tendons of the hand
What is significant about scaphoid bone fractures?
one of the most frequently broken bones in a fall onto an outstretched hand-its location and shape make it susceptible to fracture. can go undiagnosed as sx can be mild. may need surgery. the scaphoid can easily disconnected from its blood supply and avascular necrosis can result
mallet finger
finger that does not straighten at the tip (DIP joint) due to trauma that results in overstretching or tearing of the extensor tendon
trigger finger
results when inflammation develops in the flexor tendons or their associated digital sheaths. the sheath or tendon may thicken or nodules may form resulting in decreased ability of the tendon to glide through the sheath during finger movement
What are the boundaries of the cubital fossa? What structures are contained in the cubital fossa?
The cubital fossa is the area of transition btwn the arm and forearm. It lies btwn the brachioradialis and the pronator teres muscle. The floor is formed mainly by the brachialis muscle and the roof is formed by superficial fascia and skin.
Major contents from lateral to medial: TAN
tendon of biceps brachii
brachial artery
median nerve
note: the radial nerve also passes through the cubital fossa
the brachial artery and median nerve are covered by the bicipital aponeurosis. contained within the roof the cubital fossa is the median cubital vein which connects the cephalic vein (lateral) and the basilic vein (medial)
What is the bicipital aponeurosis? What structures does it provide protection to?
the bicipital aponeurosis is a flattened extension of the biceps brachii tendon. is superficial to the brachial artery and median nerve and provides some protection to these structures during blood draws
Where do the cephalic and basilic veins terminate? What vein are they connected by?
cephalic (more lateral superficial vein): terminates in subclavian vein
basilic (more medial vein): terminates in axillary vein
are connected by the median cubital vein
Where does the radial nerve travel in the forearm and generally, what structures does it innervate?
The radial nerve lies just deep to the brachioradialis and gives off superficial and deep branches. The superficial branch continues into the forearm on the deep surface of the brachioradialis and is entirely cutaneous. It innervates the dorsal surface of the hand and digits
the deep branch pierces the supinator msucle and supplies the muscles of the posterior forearm and contributes to innervation of the elbow
Where does the ulnar nerve travel in the forearm?
It does not pass through the cubital fossa! It passes posterior to the medial epicondyle (funny bone). It is held down tightly by connective tissue which serves as a potential site of entrapment.
The gateway for structures passing between the arm and forearm is the ____ ____. The gateway for structures passing between the foreamr and hand is the ____ ____.
- cubital fossa
- carpal tunnel
Muscles in the anterior (flexor) compartment of the forearm are generally divided into what 3 layers? What are their general functions?
- superficial, intermediate, and deep
- movements of wrist joint, flexions of fingers including the thumb, and pronation of the forearm
What are the muscles of the superficial layer of the forearm? What is their common origin?
- from lateral to medial: pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris
- all originate on the medial epicondyle of the humerus
The muscles of the anterior compartment of the forearm are innervated by the ____ nerve with the exception of what muscles? What are those muscles innervated by?
- median nerve
- the flexor carpi ulnaris and the medial half of the flexor digitorum profundus are innervated by the ulnar nerve
What is the origin, insertion, function, and innervation of the pronator teres?
origin: medial epicondyle of humerus, ulna
insertion: lateral surface of radius
function: pronates forearm at distal radioulnar joint
innervation: median nerve
What is the origin, insertion, function, and innervation of the flexor carpi radialis?
origin: medial epicondyle of humerus
insertion: base of 2nd or 3rd metacarpal
function: flexes and abducts the wrist
innervation: median nerve