Anatomy of the Upper Limbs Flashcards
Which neck of the humerus is more commonly damaged? The surgical neck or the anatomical neck?
The surgical neck is more commonly damaged.
What are the compartments of the shoulder and arm region?
There are 5 compartments in this region.
Anterior and posterior pectoral girdle muscles.
Intrinsic shoulder muscles
Anterior and posterior compartments of the arm.
Which muscles comprise the anterior pectoral girdle muscles?
Pectoralis major and minor, subclavius and serratus anterior.
N.B. the serratus anterior runs between the anterior and posterior pectoral girdle compartments.
Describe the pectoralis major muscle.
Medial attachment is the medial 1/3 of the clavicle, sternum and costal cartilages.
Lateral attachment is the lateral lip of the intertubercular sulcus.
Action: adducts and medially rotates the humerus.
Describe the pectoralis minor muscle.
Lies deep to pectoralis major.
Medial attachment is anterior surface of ribs 2-5.
Lateral attachment is coracoid process of scapula.
Protracts and depresses scapula.
Describe the action of the subclavius.
Anchors the clavicle to the 1st rib.
Describe the serratus anterior muscle.
Runs from medial border of scapula to the anterior attachments of the ribs.
Supplied by long thoracic nerve.
Protracts medial border of scapula. Rotates scapula upward by laterally rotating inferior angle.
Which muscles form the posterior pectoral girdle muscle compartment?
Trapezius, latissimus dorsi, levator scapulae and the rhomboids.
Describe the trapezius muscle.
Attaches ligamentum nuchae and spinous processes (to T12) to the spine of the scapula, acromion and clavicle.
Innervated by accessory nerve (CNXI) - N.B. this upper limb muscle is innervated by a cranial nerve.
Has major actions on the scapula.
Has ascending and descending parts.
Describe the latissimus dorsi.
Medial attachment is the thoracolumbar fascia (T8 and below).
Lateral attachment is the floor of the intertubercular groove of humerus.
Supplied by thoracodorsal nerve.
Extends, adducts and rotates humerus. Important in rowing and climbing.
Describe the levator scapulae.
Medial attachments are the transverse processes of C1-4.
Lateral attachment is superior angle of scapula.
Elevate and rotate scapula.
Supplied by dorsal scapular nerve.
Describe the rhomboids.
Medial attachments are the spinous processes of C7-T5.
Lateral attachment is the medial border of the scapula.
Retracts, rotates and fixes scapula.
Supplied by dorsal scapular nerve.
Which muscles comprise the intrinsic shoulder muscles?
Deltoid, teres major and rotator cuff muscles.
Which muscles form the rotator cuff muscles, and what is the role of this group?
Supraspinatus, infraspinatus, teres minor and subscapularis.
These work together to fix the head of the humerus in the glenoid fossa. The supraspinatus is important in initiating abduction of the arm for the first 15 degrees, then the deltoid takes over.
The supraspinatus, infraspinatus and teres minor fix the humerus superoposterioly and the subscapularis stabilises it anteriorly, meaning the main direction of dislocation is inferiorly.
The supraspinatus inserts into the superior facet on the greater tubercle; the infraspinatus into the middle facet and the teres minor into the inferior facet.
Subscapularis inserts into lesser tubercle. Medial rotation.
Describe the deltoid muscle.
Proximal attachment is acromion of scapula.
Distal attachment is deltoid tuberosity of humerus.
Supplied by axillary nerve.
Abducts arm.
Describe the action, attachments and innervation of the teres major muscle.
Action: adducts and medially rotates arm.
Innervated by lower subscapular nerve.
Medially attached to the dorsal surface of the inferior angle of the scapula.
Laterally attached to the medial lip of the intertubercular sulcus.
Which muscles comprise the anterior compartment of the arm? Which nerve supplies all of these?
Biceps, brachialis and coracobrachialis.
All supplied by musculocutaneous nerve.
Describe the biceps (biceps brachii).
The biceps has 2 heads.
The common distal attachment is the radial tuberosity as the biceps tendon. Also becomes biceps aponeurosis and blends with fascia.
The short head’s proximal attachment is the coracoid process.
The long head’s proximal attachment is the supraglenoid tubercle. It runs through the intertubercular sulcus.
Give the attachments of the coracobrachialis and brachialis muscles.
Coracobrachialis:
Proximal = coracoid process.
Distal = shaft of humerus.
Flexes ARM.
Brachialis: proximal is the shaft of humerus, distal is the coronoid process of ulna.
Flexes FOREARM.
Which muscles comprise the posterior compartment of the arm and which nerve supplies them?
Triceps and anconeus, supplied by radial nerve.
Describe the anconeus muscle.
Proximal attachment is the lateral epicondyle of the humerus.
Distal attachment is the shaft of the ulna.
Describe the triceps (triceps brachii).
Distal attachment is the olecranon process of the ulna, as the triceps tendon.
Proximal attachments: lateral and medial heads attach to the shaft of the humerus.
The long head attaches to the infraglenoid tubercle of the scapula.
Which joints are present in the pectoral girdle?
The sterno-clavicular joint, the acromioclavicular joint, the gleno-humeral (shoulder) joint and the scapula-thoracic joint (referred to often as a virtual or physiological joint).
Describe the gleno-humeral joint.
The gleno-humeral joint is a ball-and-socket joint. The glenoid fossa is shallow, but slightly deepened by a cartilaginous labrum. The rotator cuff group is required for stability. It holds the humeral head within the glenoid fossa. The rotator cuff group depresses the humeral head.
Describe the main arterial supply of the shoulder and arm region.
The subclavian artery passes over the first rib to become the axillary artery. At the lower border of the teres major it becomes the brachial artery. The brachial artery gives off a larger branch: profunda brachii.
At the level of the elbow, the brachial artery divides into ulnar and radial arteries.
Describe the main venous drainage of the shoulder and arm region.
The cephalic vein runs up the lateral border of the arm: the basilic runs up the medial border.
The basilic veins join venae comitantes to from the axillary vein.
The cephalic vein joins the axillary vein in the axilla.
Becomes the subclavian vein at the level of the first rib.
Describe the principal lymph drainage of the shoulder and arm region.
Lymph vessels, like veins, arranged in a superficial and deep system. Run along veins.
Main groups of nodes: cubital lymph nodes, delto-pectoral lymph nodes, axillary lymph nodes and subclavian lymph nodes.
How can breast cancer treatment lead to lymphoedema of the arm, forearm and hand?
Since the axillary lymph nodes are very important in draining the breast, removing axillary lymph nodes in breast cancer can lead to lymphoedema.
Describe how the brachial nerve plexus is divided into ‘zones’.
Roots - formed by anterior rami. Trunks Divisions Cords Terminal branches (peripheral nerves).
Give some features of the clavicles which would help you orientate it into its anatomical position.
Its superior surface is smooth; it’s inferior surface is rough.
It is flattened laterally (acromial end) and is s-shaped, with its lateral 1/3 being concave anteriorly, and medial 2/3 convex anteriorly.
Briefly, how do you test the trapezius muscle’s function - and what is its innervation?
Ask the patient to raise both shoulders against resistance.
Nerve supply is accessory nerve and C3,4.
Which muscle is palpable in the anterior axillary fold and how do you test it and its innervation?
Pectoralis major.
Ask the patient to adduct the abducted arm against resistance.
Nerves = lateral and medial pectoral.
Which muscles are palpable in the posterior axillary fold and how do you test it and its innervation?
Teres major and latissimus dorsi.
The teres major is tested by asking the patient to adduct the arm against resistance.
Nerve = lower subscapular.
Latissimus dorsi is tested by adducting the arm against resistance. (Or abduct and flex 45 degrees each way and then adduct).
Nerve = thoracodorsal.
How do you test the serratus anterior muscle and what is its innervation?
Ask the patient to outstretch both arms with their palms flat against a wall. Press forward strongly.
Nerve = long thoracic.
How do you test the deltoid muscle? What is its innervation?
Ask the patient to abduct the arm against resistance.
Nerve = axillary.
Name the carpal bones which comprise the proximal and distal rows.
Scaphoid, lunate, triquetrum and pisiform = proximal row.
Trapezium, trapezoid, capitate and hamate = distal row.
Describe the elbow joint.
A complex joint involving three separate articulations which share a common synovial cavity.
The joints between the trochlear notch of the ulna and the trochlea of the humerus and between the head of the radius and the capitulum of the humerus are primarily involved with hinge-like flexion and extension of the forearm.
The joint between the head of the radius and the radial notch of the ulna is involved with pronation and supination of the forearm. Typically considered a separate joint, the PROXIMAL RADIO-ULNAR joint.
What are the borders and contents of the cubital fossa?
A triangular depression between two forearm muscles: the brachioradialis muscle and pronator teres muscle. The base is an imaginary horizontal line between the medial and lateral epicondyles. The bed is formed by the brachialis muscle.
Major contents are the tendon of the biceps brachii, the brachial artery and the median nerve.
Bifurcation of the brachial artery normally occurs in the apex of the fossa.
