Arm and Fossa Flashcards
What is the arm technically
- divided into and by what
Shoulder to elbow
It is divided into anterior (or flexor), and posterior (or extensor) compartments by medial and lateral intermuscular septa.
These septa are attached to the medial and lateral supracondylar ridges (or lines) of the humerus and are continuous with the deep fascia.
What makes up the bulk of the anterior compartment of arm -innervated by?
- coracobrachialis
2.biceps brachii
3.brachialis
all innervated by the musculocutaneous nerve. This nerve pierces coracobrachialis and then lies on brachialis (under biceps brachii)
Origins of all 3 bulky muscles of anterior compartment
Coracobrachialis and the short head of biceps take origin from the coracoid process and are partially attached to each other
The long head of biceps originates from the supraglenoid tubercle
brachialis from the front of the humerus
Insertions and origins of all 3 bulky muscles of anterior compartment
Coracobrachialis
O= Coracoid process
I= medial aspect of the humerus opposite the deltoid tuberosity
Brachialis
O= Anterior aspect of distal humerus
I= tuberosity of the ulna
Biceps
O Long Head: Supraglenoid fossa
O Short head: Coracoid process
i= radial tuberosity
Describe the flow of the veins/arteries in the arm from top to bottom
The axillary artery becomes the brachial at the lower border of teres major and passes into the arm with the median nerve on its anterolateral side and the ulnar nerve behind.
The ulnar nerve passes behind the medial intermuscular septum in the lower third of the arm to accompany the superior ulnar collateral artery. The ulnar nerve then passes behind the medial epicondyle of the humerus to enter the forearm between the two heads of flexor carpi ulnaris (a forearm flexor muscle).
Neither the median nerve (which passes straight down the arm on brachialis, accompanied by the brachial artery and vena comitantes), nor the ulnar nerve, have any branches in the arm
What are the main muscles in the following regions of arm
- Pectoral girdle to arm
- Pectoral girdle to forearm
- Arm to forearm
- Pectroal girdle to arm
Deltoid
Teres major Coracobrachialis
Rotator cuff muscles:
Supraspinatus Infraspinatus Teres minor Subscapularis
- Pectoral girdle to forearm
Biceps Brachii
Triceps brachii - long head - Arm to forearm
Brachialis
Triceps - lateral head
- medial head
Deltoid can be divided into
show on diagram
The deltoid can be divided into three parts, anterior, posterior and middle fibres.
Lecture slide
What nerve is assosicated with deltoid
Axillary nerve
(Deltoid) What does posterior fibres do?
(unipennate)
-extend shoulder
-externally rotate arm
- abduct / adducts arm with post. fibres (depending on shoulder posi- tion)
(deltoid) What does middle fibres do?
-abducts arm (very strong)
(deltoid) What does anterior fibres do? (unipennate)
-flex shoulder
-internally rotate arm
- abduct / adducts arm with post. fibres (depending on shoulder position)
Posterior compartment:
Triceps brachii has how many heads
3 heads (long, lateral and medial, with the medial head occurring under the other two)
Describe the location of each head of Triceps brachii
- Origin
- Insertion
-movement
long: infraglenoid tubercle
The lateral: back of the humerus
Medial head: Medial distal end of posterior humerus
and all three heads merge and have a strong, tendinous INSERTION into the olecranon of the ulna, therefore extensors of the elbow
Triceps brachii nerve supply and blood supply
They are supplied, like all the muscles of the extensor compartment of the limb, by the radial nerve, and are supplied with blood from branches of the profunda brachii artery.
What gaps form at back of shoulder
At the back of the shoulder 3 spaces
1. a quadrangular space on the lateral side (between teres major inferiorly, teres minor superiorly and the humerus laterally)
- posterior circumflex of humeral artery and vein, axillary nerve
- triangular space on the medial side (teres minor and major above and below respectively).
- Circumflex of scapula artery - Triangular interval - below quadrangular and lateral to triangular space (Radial nerve, profunda brachii arterty)
Blood and nerve supply in gaps of shoulder
Through the quadrangular space passes the axillary nerve and posterior humeral circumflex artery. Through the triangular space passes a branch of the circumflex scapular artery.
Cubital fossa:
Location
A triangular region whose medial boundary is formed by pronator teres, lateral boundary by brachioradialis, floor by brachialis (and supinator laterally), roof by deep fascia of the forearm, and upper border by a line joining the epicondyles of the humerus
Label Anterior elbow (deep)
Lecture Slide
Label the Anterior view of the bones of the arm and forearm
Lecture Slide
Arm in x-section showing compartments as you move down the arm
Lecture Slide
Label the 3 diagrams (cross sections) as you move down the arm
Lecture Slide
Label the arms three main muscles
-assosicated nerve
movements
Biceps brachii
- Musculocutaneous n.
–supinator
- elbow flexor
Brachialis
- Musculocutaneous n.
- main elbow flexor
Coracobrachialis
-Musculocutaneous n
–adduction of shoulder
- flexion of shoulder
Lecture Slide
Label the main muscle in posterior arm
-associated nerve
-movement
Triceps brachii
-Radial n.
- elbow extensor
- shoulder adductor - shoulder extensor
Label the nerves on the arm Posterior and Anterior views
Musculocutaneous
Radial
Lateral cutaneous nerve of forearm
Median nerve
Ulnar nerve
Lecture Slide
** when determining if muscocut or median- the median RUNS with ulna
Draw the schematic view of the axilia
Lecture Slide
Arteries of the Arm and Elbow
Need to know:
Axiliary artery
Profunda brachii artery
Radial artery
Ulnar artery
Brachial artery
What is the cubital fossa
triangular area on front of elbow
Label the key area of the cubital fossa
Lecture Slide
Veins of the Arm and Elbow
Lecture Slide
have more venous drainage than arterial supply deep veins (smaller) run paired twisting around we
· artery (same name)
superficial veins don’t run w/ arteries (bigger
Area for blood draw
main C2superficial veins (cephalic a basilic) are linked together by a vein at the cubital fossa (Medial cubital vein)
- target for drawing blood
