Session 2: Shoulder and arm

Levator scapulae: attachments, innervation and action

- attaches to superior angle of scapula and transverse processes C1-C4 -Action: elevates and rotates the scapula

Pectoralis minor proximal and distal attachments

- originates from coracoid process -gives off digits that articulate with 3rd, 4th, 5th ribs, near their cartilages

Subclavius

-Attaches to R1 and middle or slightly lateral part of clavicle. -Helps anchor the clavicle.

Contents of the axilla

1. Arteries - the axillary artery and its branches 2. Veins - the axillary vein and its tributaries 3. Lymphatic vessels and lymph nodes - axillary lymph nodes (important) 4. Nerves - the infraclavicular part of the brachial plexus, long thoracic and intercostobrachial nerves

Main bones of pectoral girdle and arm

1. The scapula 2. The clavicle 3. The humerus

What muscles form the rotator cuff?

1. supraspinatous 2. infraspinatous 3. teres minor 4. subscapular SITS Supraspinatus, infraspinatus, teres MINOR (teres means straight)=all attach across. Subscapularis: deeper in relation to the others. Broad attachment to the deep surface (thoracic surface) of the scapula. Fibres converge and cross over.

Testing action of latissimus dorsi

Abduct arm to 90 degrees, then adduct against resistance See and palpate the muscle in the posterior axillary fold Nerve: thoracodorsal C6,7,8

Testing action of deltoid

Abduct the upper arm against resistance Nerve: axillary C5,6

Testing action of pectoralis major

Adduct the abducted arm against resistance. Nerves: lateral and medial pectoral- C5,6,7,8,T1

Testing action of teres major

Adduct the arm against resistance. See and palpate the muscle in the posterior axillary fold. Nerve: lower subscapular C5,6

Where does axillary vein become the subclavian vein?

At the level of the first rib

Where can you palpate the coracoid process?

Below lateral 1/3 of clavicle

Prime movers for flexion at elbow joint

Biceps, brachialis, brachioradialis (pronator teres)

What is the set of nerves serving the upper limb?

Brachial plexus

What is opposition and where does it take place?

Bringing the pad of the thumb towards the pad of another digit Between thumb and any of the digits of the same hand.

Function of the rotator cuff muscles

Coming off scapula. Cross the shoulder joint and attach around the head of the humerus. Fix the head of humerus in the glenoid fossa

Prime movers for extension at shoulder joint

Deltoid (posterior fibres)

What movements are possible at elbow joint?

Flexion Extension

Muscles producing extension at gleno-humeral joint

Latissimus dorsi

What muscles are in posterior axillary fold?

Latissimus dorsi Teres major

Where is the olecranon fossa?

Posterior aspect of the humerus

Where does pronation and supination take place?

Pronation: Rotation of the forearm along its long axis so that the palm faces posteriorly Supination: Rotation of the forearm along its long axis so that the palm faces anteriorly At forearm and hand at the radio-ulnar joint

What is protraction and retraction- where?

Protraction: anterior movement of body part Retraction: posterior movement of body part Scapula on thoracic wall

Prime movers for retraction at scapulo-thoracic joint

Rhomboids, midline trapezius, latissimus dorsi

Where does elevation and depression take place?

Shoulder

Muscles producing internal rotation at gleno-humeral joint

Subscapularis

Prime movers for internal rotation at shoulder joint

Subscapularis

Superior angle of scapula

T2

Medial end of scapular spine

T3

Inferior angle of scapula

T7

Function of the axilla?

The axilla is a passageway for the nerves, blood and lymph vessels to enter / leave the upper limb.

Significance of thoracoepigastric vein

The thoracoepigastric vein connects the superficial epigastric vein to the lateral thoracic vein (which connects with the axillary vein) and can act as a shunt for blood if the portal system develops hypertension or blockage, e.g. by tumour.

Define the muscular compartments of the shoulder and arm. a) shoulder: anterior, posterior and intrinsic compartments b) arm: anterior and posterior compartments

a) shoulder: -anterior: pec major, pec minor, subclavius, serratus anterior -posterior: trapezius, latissimus dorsi, rhomboids, levator scapulae -intrinsic: deltoids, rotator cuff, teres major b) Arm -anterior: biceps, coracobrachialis, brachialis -posterior: triceps, anconeus (?)

Testing action of SCM

turn head left/right against resistance - spinal accessory, CN XI , C3, C4.

What is a bursa?

A bursa is a fluid-filled sac which forms under the skin, usually over the joints, and acts as a cushion between the tendons and bones. eg subacromial bursa Clinically: inflammation leads to bursitis

What is circumduction and where does it take place?

A combination of flexion/extension and abduction/adduction so that the distal part of the upper limb moves in a circle

Prime movers for external rotation at shoulder joint

Infraspinatus

Rhomboids: attachments, innervation and action

-attach to medial border of scapula and spinous processes -supplied by DORSAL SCAPULAR NERVE -Action: retracts, rotates and fixes scapula

What are the largest nerves of the brachial plexus and what spinal roots are they formed from?

1. Axillary nerve (C56) 2. Musculocutaneous nerve (C567) 3. Ulnar nerve (C8, T1) 4. Median nerve (C678, T1) 5. Radial nerve (C5678, T1)

Intrinsic shoulder muscles

1. Deltoid 2. Teres Major 3. The Rotator Cuff Muscles a) supraspinatus b) infraspinatus c) teres minor d) subscapularis

Ligaments associated with gleno-humeral joint

1. The gleno-humeral ligaments : these strengthen the anterior portion of the shoulder capsule 2. The coraco-humeral ligament : strengthens the capsule superiorly 3. The transverse humeral ligament - holds the tendon of the long head of biceps in the inter-tubercular groove

Joints of the pectoral girdle and arm region

1. The sterno-clavicular joint (SCJ) 2. The acromio-clavicular joint (ACJ) 3. The gleno-humeral joint (shoulder joint) 4. The scapulo-thoracic joint (sometimes referred to as a "virtual" or "physiological" joint) 5. The elbow joint -->The pectoral girdle = SCJ + ACJ + GHJ + STJ The pectoral girdle works as a unit and if any one component is injured or pathological the function of the whole unit is impaired.

Two other extensions of the capsule of the shoulder joint (in addition to glenoid-->humeral head)

1. The subacromial bursa - the capsule extends above the humeral head to form a bursa between the humeral head and the overlying acromial process - this is often the site of pathology in impingement of the gleno-humeral joint. 2. An extension around the long head of biceps as it lies within the inter-tubercular grove of the humerus.

3 parts of the deltoid

1. anterior/clavicular part 2. middle part 3. spinal/posterior part

Articulations of the humerus

1. glenoid cavity of scapula 2. capitulum (radius) 3. trochlea (ulnar).

Muscles producing external at gleno-humeral joint

1. infraspinatus 2. teres minor

What are 4 principle nerves of the upper limb?

1. musculocutaeous 2. ulnar 3. median 4. radial

Muscles producing adducton at gleno-humeral joint

1. pec major 2. latissimus dorsi

Which joints can extension take place at?

1. shoulder 2. elbow 3. wrist 4. digits/hand

What can you palpate in the supraclavicular fossa?

1. subclavian artery pulse: just above and behind medial end of clavicle 2. trunks of brachial plexus: may cause discomfort

Testing action of serratus anterior

Both arms of the subject are outstretched with the palms against a wall and asked to press forward strongly Nerve: long thoracic- C5,6

Prime movers for flexion at shoulder joint

Pectoralis major (clavicular head) Deltoid (anterior fibres)

Prime movers for adduction at shoulder joint

Pectoralis major, latissimus dorsi

What is the delto-pectoral groove?

The delto-pectoral groove is a triangle bounded by the clavicle superiorly, the deltoid laterally and the pectoralis major medially.

How do the great vessels pass from neck to the upper limb?

The great vessels and nerves (brachial plexus) pass from the neck to the upper limb behind the convex medial aspect of the clavicle.

Which muscles form the anterior compartment of the arm? Which nerve innervates all these muscles?

1. biceps 2. brachialis 3. coracobrachialis MUSCOLOCUTANEOUS NERVE

Serratus anterior

*lies deep to the scapula -runs from medial border of the scapula -attaches to ribs 1-9 -supplied by long thoracic nerve

Triceps: attachments, innervation, action

-3 heads: long, lateral, medial -long head: attaches to INFRAGLENOID TUBERCLE of scapula -lateral head: attaches to shaft of humerus -medial head: attaches to shaft but deeper (covered by long and lateral heaD) -Together the heads merge to form the triceps tendon which crosses to olecranon process of the ulna -action: extension of elbow joint -innervation: radial nerve

Deltoid: attachments, innervation and action

-Goes over shoulder joint from scapula (front and back) and forms a delta shape muscle. -Fibres converge and attach to deltoid tuberosity on lateral side of shaft of the humerus. Innervation: axillary nerve Action: abducts arm

What is the coraco-acromial arch?

-The coraco-acromial arch lies above the gleno-humeral joint - it consists of the acromion, the coracoid process and a strong ligament running between the two, the coraco-acromial ligament. -This arch prevents the humerus from rising superiorly against the acromion. -Beneath the arch is the subacromial bursa and the supraspinatus tendon (part of the rotator cuff). -This is typically he site of the pathology of impingement of the shoulder, probably the commonest shoulder problem in clinical practice.

What forms the axillary vein (deep vein)?

-formed as the basilic vein (superficial vein running on medial side of forearm) passes through deep fascia to join the VENAE COMINTANTES of brachial artery (brachial veins) at level of lower border of teres major -tributaries: cephalic vein, lateral thoracic vein

Ulnar nerve

-is one of the nerves that supplies the anterior compartment of the forearm but is mainly the nerve of the hand. -It has no branches in the arm and passes though the arm in the anterior compartment initially but more distally in the posterior compartment. -It lies posterior to the medial epicondyle of the elbow and is at risk there.

musculocutaneous nerve

-is the nerve of the anterior compartment of the arm (coracobrachialis, brachialis and biceps). -It continues as the lateral cutaneous nerve of the forearm. -It lies close to the subscapularis tendon anterior to the shoulder and is at risk during surgery to the anterior gleno-humeral joint.

Structure of the clavicle + main features

-one end attaches to sternum and one end to acromion process of the scapula. -Pivot point is at sternoclavicular joint. -Orientate via the "flat" lateral end at the acromion of the scapula and the circular sternal end at the sternum/1st CC (superior smooth). _____ Identify - conoid tubercle (LATERAL end on INFERIOR surface), trapezoid line, subclavian groove (for subclavius MUSCLE) and costo-clavicular ligament groove. Reference points: -medial/sternal end=broad -lateral/acromial end=flat -superior surface=smooth -inferior surface=rough -medial 2/3=convex -lateral 1/3=concave

Describe the biceps, brachialis and coracobrachialis

1. Biceps -two heads- one long and one short -long head (lateral) has longer tendon which goes up and across shoulder joint, attaches to SUPRAGLENOID TUBERCLE (above glenoid fossa). -tendon of the long head runs in the bicipital groove -short head: attaches to coracoid process of the scapula -fibres of 2 heads merge distally to form two attachments a) radial tuberosity (bony) b) biceps aponeurosis 2. Coracobrachialis - Can see it once you remove the biceps - Comes from coracoid process -Attaches to medial side of shaft of the humerus -Involved in adduction and some flexion 3. Brachialis -deepest muscle -attaches to anterior portion of shaft of humerus -Crosses elbow joint and attaches to coranoid process of ulna -Important flexor of the elbow (in addition to biceps brachii)

Main articulations of the scapula

1. Gleno-humoral joint - humerus with glenoid cavity. 2. Acromio-clavicular joint. 3. Scapulo-thoracic joint - this is a "gliding" physiological joint with the chest wall (via serratus anterior) - long thoracic nerve damage causes "winging" of the scapula

Important nerves of brachial plexus in the pectoral and arm region

1. Long Thoracic Nerve - supplies serratus anterior 2. Suprascapular Nerve - supplies supraspinatus and infraspinatus 3. Medial and Lateral pectoral nerves - supply pectoralis major 4. Thoracodorsal nerve - latissimus dorsi 5. The axillary nerve - supplies teres minor and then deltoid as well as an area of skin over the deltoid. 6. The musculocutaneous nerve 7. The ulnar nerve 8. The median nerve 9. The radial nerve

What are the anterior pectoral girdle muscles?

1. Pectoralis major 2. Pectoralis minor 3. Subclavius 4. Serratus anterior (runs between anterior and posterior)

Which muscles are invovled in resisting dislocation at the gleno-humeral joint?

1. Rotator cuff muscles - hold the humeral head against the glenoid cavity 2. deltoid 3. coracobrachialis 4. short head of biceps 5. long head of biceps *dislocation is more likely downwards- important for neurological reasons

Groups of muscles in pectoral girdle and arm region

1. The anterior pectoral muscles 2. The posterior pectoral muscles 3. The intrinsic shoulder muscles 4. The anterior compartment of the arm 5. The posterior compartment of the arm

Muscles producing abduction at glenohumeral joint

1. supraspinatus (first 15 degrees) 2. central fibres of deltoid (after 15 degrees)

Posterior pectoral girdle muscles

1. trapezius 2. latissimus dorsi 3. levator scapulae 4. rhomboids

Which joints can rotation take place at? Rotation=revolving a body part along its longitudinal axis Internal rotation=Bringing the anterior surface of a body part closer to the midline External rotation=Taking the anterior surface of a body part away from the midline

1. upper limb

What is a prime mover?

A prime mover (or an agonist) is the main muscle responsible for producing a specific movement of the body part.

What is the brachial plexus formed from? What are the levels of branching?

Formed from the anterior primary rami of C5-T1. 1. roots formed in the neck from the spinal nerve roots 2. trunks formed from the roots in the posterior triangle of the neck 3. divisions formed from the trunks behind the clavicle 4. cords formed from the divisions in the axilla in close proximity to the axillary artery 5. branches the peripheral nerves supplying the upper limb itself.

Structure of the scapula+main features

Glenoid cavity- forms the socket of shoulder joint. Spines: posterioly you have the spine of the scapula, whose lateral end is the acromion process. Acromion process: projecting laterally Coracoid process: looks like a crow Scapula is the hub for muscles that act between the trunk and upper limbs.

Shape of axilla

It is shaped like a truncated pyramid and consequently has a base, apex and four walls: 1. the base is composed of skin, subcutaneous tissue and fascia extending from the arm to the chest 2. the apex lies between the first rib, the clavicle and the superior border of the subscapularis muscle 3. the anterior wall is formed by pectoralis major and pectoralis minor 4. the posterior wall is formed by the scapula and subscapularis (superiorly) and the teres major and latissimus dorsi (inferiorly) 5. the medial wall is formed by the chest wall (1st to 4th ribs) and the serratus anterior 6. the lateral wall is formed by the intertubercular groove of the humerus

What muscles are in anterior axillary fold?

Pectoralis major- sternocostal head

Prime movers for rotation down at scapulo-thoracic joint

Pectoralis minor, latissimus dorsi, rhomboids, levator scapulae

Prime movers for protraction at scapulo-thoracic joint

Pectoralis minor, serratus anterior

Pectoralis major: proximal and distal attachments + action

Proximal attachment: on the medial 1/3rd of the clavicle, the sternum and costal cartilages. Distal attachment: lateral lip of the intertubercular sulcus (groove). Action: adduction and medial rotation of the humerus. Stabilisation of the scapula. *medial rotation=punching muscle

Prime movers for rotation at scapulo-thoracic joint

Superior trapezius, inferior trapezius, serratus anterior

Prime movers for elevation at scapulo-thoracic joint

Superior trapezius, levator scapulae, rhomboids

Action of supraspinatous muscle

Supraspinatus important in initiating abduction of arm for first 15°, then deltoid takes over.

Prime movers for abduction at shoulder joint

Supraspinatus initially then central deltoid

Risk of axillary lymph node sampling

The axillary lymph nodes are frequently dissected and "sampled" in patients with carcinoma of the breast. There are two nerves in close relation to the axillary lymph node region. These are; 1. the long thoracic nerve - supplies the serratus anterior muscle. 2. The thoracodorsal nerve - supplies the latissimus dorsi muscle These nerves may be are at risk during axillary lymph node dissections. Section of the thoracodorsal nerve surprisingly does not produce too much disability but section of the long thoracic nerve causes paralysis of the serratus anterior muscle and as a result, winging of the scapula.

General principle of muscle function test

To test muscle action, ask the subject to bring about movement that causes contraction of muscle whilst the examiner resists the movement which makes the muscle belly to stand out and readily palpable. e.g. to test the biceps, the subject is asked to flex the elbow whilst the examiner applies an opposing force against the flexion.

Prime movers for extension at elbow joint

Triceps (anconeus)

Nerve contact of the humerus

o Axillary nerve - winds around surgical neck of humerus and can be damaged in shoulder dislocation. o Radial nerve - runs in radial groove and can be damaged by humoral shaft fractures. o Ulnar nerve - runs posterior to medial epicondyle (funny bone) and is damaged in fractures and dislocations of the elbow joint. o Median nerve - runs anterior to distal humerus and can be damaged by supracondylar fractures of humerus and dislocations of the elbow joint.

Muscles of the pectoral girdle and arm region

o Back - Trapezius, latissimus dorsi. o Scapular - Deltoid, rotator cuff, teres major, serratus anterior, rhomboids, levator scapulae. o Pectoral - Pectoralis major, pectoralis minor, subclavius, serratus anterior. o anterior (flexor) compartment of the arm: coracobrachialis, brachialis, biceps brachii o posterior (extensor) compartment of the arm: triceps

Blood supply to the region: general overview

♣ Subclavian--> axillary-->brachial artery. ♣ Note the brachial artery and its branches: o Circumflex humoral arteries. o Deep branch (profunda brachii artery) ♣ The axillary artery has 3 parts with branches off: o 1 - superior thoracic artery. o 2 - thoraco-acromial, lateral thoracic artery. o 3 - subscapular, anterior & posterior humoral circumflex arteries.

Latissimus dorsi: attachments+action+innervation

- attachments down in pelvic region (down to iliac crest) -fibres come most superiorly from T8 -Fibres converge and form a strap-like muscles and tendon that twists slightly as it comes. Attaches in the FLOOR of the intertubercular groove. Action: -extends, adducts and rotates the humerus -pulls body up during climbing+important in rowing

Describe the venous drainage of the pectoral girdle+arm region

-In limbs, venous return is via superficial and deep vessels -Cephalic vein (superficial) runs up lateral border of arm and terminates by passing deep in DELTO-PECTORAL GROOVE (to join axillary vein) -Basilic vein (superficial) runs up the medial border of forearm and arm -Basilic veins passes deep halfway, join venae comitantes (of the brachial artery) to form the axillary vein in the arm -Axillary vein becomes the subclavian vein at the level of the first rib

Median nerve

-Is one of the nerves that supplies the anterior compartment of the forearm and hand. -It has no branches in the arm. -It passes through the arm in the anterior compartment. -At the level of the elbow it lies alongside the brachial artery and is at risk in supracondylar fractures of the humerus.

Describe the lymphatic drainage of the pectoral girdle+arm

-Superficial and deep systems: run with veins a) lymph drains from hand via superficial lymphatics which run alongside cephalic and basilic veins -some lymphatics pass directly and superficially up the arm but there are also some CUBITAL LYMPH NODES at elbow -also some DELTO-PECTORAL LYMPH NODES alongside CEPHALIC VEIN -->ultimately lymph from superficial system drains into axillary lymph nodes (important!) b) Deep lymphatics -run alongside deep veins -also terminate in axillary lymph nodes -Axillary lymph nodes: significant clinical importance in relation to breast carcinoma, as lymphatic drainage of breast includes these lymph nodes. (removal can lead to lymphoedema!!) 5 groups: 1. apical 2. pectoral 3. subscapular 4. humeral 5. central -->all groups drain via apical lymph nodes which then drain into SUBCLAVIAN LYMPHATIC TRUNK, then into RIGHT LYMPHATIC DUCT (right side) or THORACIC DUCT (left side)

Sternoclavicular joint

-The SCJ is a synovial joint composed of two portions separated by a fibrocartilage articular disc. -It is a very strong joint and this strength arises from the very strong sterno-clavicular ligaments. However these are sometimes injured, resulting in sterno-clavicular subluxation and dislocation. -The sternal end of the clavicle not only articulates with the sternum (manubrium); it also articulates with the first costal cartilage. -The SCJ is the only connection of the pectoral girdle to the the axial skeleton and it allows movement of the clavicle (and therefore the girdle) in 3 planes).

What is the gleno-humeral joint?

-The gleno-humeral joint is the joint between the glenoid cavity of the scapula and the head of the humerus. -It is a synovial ball and socket joint. -It allows for great mobility, but at the expense of stability. -The stability of the joint derives not from the shape of the bony articulation itself, but rather from the muscles, ligaments and capsular attachments around it.

How is the gleno-humeral joint stabilised?

-The glenoid cavity forms a very shallow socket. - It is deepened by the glenoid labrum, which is clinically important. -The humeral head lies within the glenoid and its labrum. -To a significant extent the head stays within the socket not because of the shape of the bony articulation, but because of the active tone of the rotator cuff muscles (subscapularis, suprasinatus, infraspinatus and teres minor.

Scapulo-thoracic joint and movements invovled

-When describing movements of the pectoral girdle, it is crucial to realise that movement is not only occurring at the sterno-clavicular joint, movement also occurs at the scapulo-thoracic 'joint'. -The scapulo-thoracic 'joint' is essentially a theoretical concept, but represents the 'articulation' between the scapula and the chest wall. -The main movements of the scapula at the scapulo-thoracic 'joint' are: a) Elevation and depression of the scapula b) Protraction of the scapula i.e. forward and lateral movement of the scapula against the chest wall c) Retraction of the scapula i.e. backward and medial movement of the scapula against the chest wall d) Rotation of the scapula.

Muscles in posterior compartment of the arm What nerve supplies these?

1. Triceps 2. Anconeus RADIAL NERVE

Muscles producing flexion at gleno-humeral joint

1. clavicular head of pectoralis major 2. anterior fibres of deltoid 3. coracobrachialis 4. biceps

Movements possible at scapulo-thoracic joint

1. elevation 2. depression 3. protraction 4. retraction 5. rotation 6. rotation up 7. rotation down

Movements possible at shoulder joint

1. flexion 2. extension 3. abduction 4. adduction 5 .internal rotation 6. external rotation 7. circumduction

Movements at gleno-humeral joint

1. flexion 2. extension 3. abduction 4. adduction 5. internal rotation 6. external rotation 7. circumduction (combination of movements)

Which joints can abduction take place at? Abduction=Moving the distal part away from the midline in the coronal plane. NB: the "midline" of the hand is the middle finger, and in the foot is the second toe.

1. shoulder 2. wrist 3. digits/hand

Which joints can adduction take place at? Adduction=Moving the distal part towards the midline in the coronal plane

1. shoulder 2. wrist 3. digits/hand

Which joints can flexion take place at? Flexion=bending or decreasing angle between bones or parts of the body

1. shoulder (raise arm up, keeping elbow straight) 2. elbow 3. wrist 4. digits/hand

Trapezius

Proximal attachment: spinous processes Distal attachment: scapula and clavicle _______________ (wiki) 1. superior or upper (or descending) fibers of the trapezius originate from the spinous process of C7, the external occipital protuberance, the medial third of the superior nuchal line of the occipital bone (both in the back of the head), and the ligamentum nuchae. -From this origin they proceed downward and laterally to be inserted into the posterior border of the lateral third of the clavicle. 2. The middle fibers, or transverse of the trapezius arise from the spinous process of the seventh cervical (both in the back of the neck), and the spinous processes of the first, second, and third thoracic vertebrae. They are inserted into the medial margin of the acromion, and into the superior lip of the posterior border of the spine of the scapula. 3. The inferior or lower (or ascending) fibers of the trapezius arise from the spinous processes of the remaining thoracic vertebrae (T4-T12). From this origin they proceed upward and laterally to converge near the scapula and end in an aponeurosis, which glides over the smooth triangular surface on the medial end of the spine, to be inserted into a tubercle at the apex of this smooth triangular surface.

Structure of the humerus

Proximal end: -Head of humerus has ball of the ball and socket joint. -Has two necks- anatomical neck and surgical neck (more commonly damaged that anatomical neck.) -Greater tubercle (lateral) and lesser tubercle (medial), wth inter-tubercular (bicipital) groove. Body: -Less than halfway down you have the deltoid tuberosity which attaches to the deltoid. Distal end: -medial and lateral supracondylar ridges -medial and lateral epicondyles -capitulum (LATERAL) for articulation with RADIUS and trochlea (MEDIAL) for articulation with ULNRA. -coranoid fossa -olecranon fossa -radial fossa **biceps brachi does NOT insert/attach to the humerus **NB: deltoid tuberosity and radial groove (posterior side)

Testing action of trapezius

Raise both shoulders against resistance - spinal accessory, CN XI, C3, C4.

What are the venae comitante of the brachial artery?

Venae comitantes of the brachial artery - these are (usually) a pair of veins that closely accompany an artery in such a manner that pulsations of the artery aid venous return.

Acromioclavicular joint -ligaments involved -clinical points

-The ACJ is also a synovial joint between the acromial end of the clavicle and the acromion process of the scapula Ligaments: 1. The acromio-clavicular ligament 2. The coraco-clavicular ligament : runs from the coracoid process of the scapula to the clavicle. There are two main sections to this ligament, the conoid and the trapezoid ligaments. 3. The coraco-acromial ligament ; this is not particularly strong, but it is clinically important in that it is often a cause of impingement of the gleno-humeral joint. -The ACJ is frequently injured by falls onto the outstretched hand. More minor dislocations occur when the acromio-clavicular ligament alone is torn. More severe dislocations occur when the coraco-clavicular ligaments are also torn.

Teres major: attachments and action

-Attaches to inferior angle of the scapula + floor and medial lip of intertubercular sulcus of humerus. -Teres major (not rotator cuff) adducts and medially rotates arm. -Innervated by lower subscapular nerve

Anconeus: attachments, innervation, action

-Attachment to lateral epicondyle of humerus and upper part of shaft of ulna -Stabilises elbow joint -innervated by radial nerve

Radial nerve

-supplies the posterior compartment of the arm as well as the posterior compartment of the forearm. -It lies on the humerus in the radial groove and is at risk in humeral shaft fractures. -Just proximal to the elbow, it divides into the superficial radial nerve (sensory) and the posterior interosseous nerve (motor).

Describe the arterial supply of the pectoral girdle+arm region

1. subclavian artery: - arises from the right brachiocephalic artery (right side) or the aorta (left side) in the chest. -runs towards the axilla in the root of the neck. -passes over first rib to give AXILLARY ARTERY 2. Axillary artery -It passes through the axilla to become the brachial artery at the inferior border of the teres major muscle. -The axillary artery is divided into three parts according to its relation to the pectoralis minor muscle (superior, deep, inferior) and gives off a number of branches in the axilla. -There is an extensive collateral circulation in this region around the scapula. 3. Brachial artery (continuation of axillary artery at inferior border of teres major) -the main artery to the arm. -It ends by dividing at the elbow into the radial and ulnar arteries. -In the distal part of the arm it runs alongside the median nerve. -In the course of its passage through the arm, the brachial artery gives off a number of muscular branches, the largest of which is the profunda brachii artery, which follows the radial nerve. 4. Radial and ulnar arteries *There is an extensive arterial anastomosis at the elbow.

Prime movers for depression at scapulo-thoracic joint

Inferior trapezius, pectoralis minor, serratus anterior

Major nerves of brachial plexus

o Radial posterior arm muscles. o Musculocutaneous anterior arm muscles. o Ulnar & median ---. o Axillary deltoid & teres minor. o Thoracodorsal latissimus dorsi. o Long thoracic serratus anterior. o Lateral/medial pectoral pectoralis major/minor. o Suprascapular & subscapular rotator cuff.