A: Pectoral region, back, arm Flashcards
Trapezius (origin, insertion, action, nerve supply)
- Occipital bone of skull, ligament over vertebrae of neck, spine of 7th cervical and all thoracic vertebrae
- lateral 1/3 clavicle, acromion of scapula, spine of scapula
- Elevates shoulder, retracts scapula on thoracic wall, upwards rotation of scapula
- Motor = accessory nerve. Sensory = upper cervical nerves
Levator sculpae
- Upper cervical vertebrae
- Medial border of scapula above root of scapular spine
- Elevates scapula
- Cervical nerves
Rhomboid minor
- Lower cervical + upper thoracic vertebrae
- Medial margin of scapula at root of scapular spine
- Retracts and elevates scapula
- Brachial plexus
Rhomboid major
- Upper thoracic vertebrae
- Medial border of scapula below root of scapular spine
- Retracts and elevates scapula
- Brachial plexus
Serratus anterior
- Slips from lateral surface of 1st to 8th ribs
- Medial border of scapula
- Protracts scapula, rotates scapula upwards, holds medial border of scapula against thoracic wall
- Long thoracic nerve from brachial plexus
Pectoralis minor
- Anterior surface of upper ribs
- Coracoid process of scapula
- Protracts scapula
- Medial pectoral nerve of brachial plexus
Subclavius
- 1st rib
- Inferior surface of clavicle
- Pulls clavicle towards sternum, stabilizes sternoclavicular joint
- Nerve to subclavius from brachial plexus
Pectoralis major
- Medial clavicle, sternum, upper ribs, aponeurosis of external oblique muscle of abdomen
- Bicipital groove
- Shoulder joint: adduction, medial rotation, flexion, extends flexed arm.
- Medial + lateral pectoral nerves
Latissimus dorsi
- Spinous processes of lower thoracic vertebrae, lower ribs, lumbodorsal fascia, iliac crest.
- Bicipital groove
- Adduction, extension, medial rotation
- Thoracodorsal nerve
Deltoid
- lateral 1/3 clavicle, acromion of scapula, spine of scapula
- Deltoid tuberosity of humerus
- Abduction, flexion and medial rotation, extension, lateral rotation
- Axillary nerve
Supraspinatus
- Supraspinous fossa of scapula
- Blend with capsule of shoulder joint and greater tubercle of humerus.
- Stabilization of shoulder joint, initiates of arm
- Brachial plexus
Infraspinatus
- Infraspinous fossa of scapula
- Blend with capsule of shoulder joint and greater tubercle of humerus.
- Stabilization of shoulder joint, lateral rotation
- Brachial plexus
Teres minor
- Posterior surface scapula near lateral border
- Blend with capsule of shoulder joint and greater tubercle of humerus.
- Stabilization of shoulder joint, lateral rotation
- Axillary nerve
Subscapularis
- Anterior surface of scapula
- Blend with capsule of shoulder joint and lesser tubercle of humerus.
- Stabilization of shoulder, medial rotation
- Brachial plexus
Teres major
- Posterior surface inferior angle of scapula
- Bicipital groove
- Adduction, extension, medial rotation
- Brachial plexus
Axillary nerve journey
- Exits axilla with posterior cirumflex humeral artery, passes through quadrangular space.
Passes posteriorly around surgical neck of humerus deep to deltoid. Supplies deltoid, teres minor and skin over upper part of lateral arm.
How can axillary nerve be damaged
Inferior dislocation of head of humerus or fracture of surgical neck of humerus.
Quadrangular space syndrome
Compression of axillary nerve as it passes through, can occur from enlargement of muscles bounding space.
Causes weakness in teres minor and deltoid.
Cubital fossa boundaries
Superior = Imaginary line connecting medial and lateral epicondyles
Lateral = brachioradialis muscle
Medial = pronator teres
Floor = brachialis and supinator
Roof = bicipital aponeurosis
Contents of cubital fossa
TAN
Brachii Tendon
Brachial Artery
Median nerve
Bicep long head
Supraglenoid tubercle of scapula
Radial tuberosity
Flexion of elbow, supination, flexion of arm
Musculocutaneous
Bicep short head
Coracoid process
Radial tuberosity
Flexion of elbow, supination, flexion of arm
Musculocutaneous
Coracobrachialis
Coracoid process
Medial side of middle of humeral shaft
Flexion of arm at shoulder joint
Musculocutaneous
Brachialis
Distal half of anterior surface of humerus
Coronoid process & tuberosity of ulna
Flexion of forearm at elbow
Musculocutaneous
Tricep long head
Infraglenoid tubercle of scapula
Olecranon process of ulna
Extension of forearm, extension + adduction arm.
Radial
Resists dislocation of humerus
Tricep lateral head
Posterior surface of humerus superior to spinal groove
Olecranon process of ulna
Extension of forearm, extension + adduction arm.
Radial
Tricep medial head
Posterior surface of humerus inferior to spinal groove
Olecranon process of ulna
Extension of forearm, extension + adduction arm.
Radial
Musculocutaneous nerve path
Leaves axilla passes through coracobrachialis
Passes distally between biceps + brachialis
Supplies BBC
Emerges on lateral aspect of tendon of biceps brachii and continues as lateral cutaneous nerve
Median nerve
Leaves axilla and passes through anterior compartment
Lies lateral to brachial artery in proximal arm
Lies medial to brachial artery in distal arm
Passes through cubital fossa
Ulnar nerve
Leaves axilla and passes through anterior compartment medial to brachial artery
In middle of arm, pierces medial intermuscular septum and enters posterior compartment
Passes posterior to medial epicondyle of humerus + then into anterior compartment
Radial nerve
In axilla, posterior to axillary artery
Enters posterior compartment medial to humerus between long head of triceps and brachial artery
Goes from medial to lateral and enters spiral groove
When reaches lateral border of humerus, it enters anterior compartment of arm and lies deep to brachioradialis
Divides anterior to lateral epicondyle into terminal branches
Supracondylar fracture of humerus
- Transverse fracture of distal humerus above two epicondyles
- Distal bone fragment displaced posteriorly, damaging cubital fossa contents
- Brachial artery may be obstructed
Consequences of loss of function of trapezius
Drooping of shoulder (shoulder held in lower position than opposite) Unable to shrug shoulder (raise tip of shoulder)
Difficulty raising arm above the head / abduction above horizontal
(rotating scapulae upwards)
Difficulty retracting shoulder (retraction of scapula)
Identify this bony feature
Suprascapular notch of right scapula
