Session 4.1: Overview of the Upper Limb & Pectoral Region

The upper limb is divided into four major segments. What are they?

- Shoulder

- Arm

- Forearm

- Hand

These segments of the upper limb can be further subdivided into regions for precision.

What are the main regions of the upper limb?

Regions of Transition of Upper Limb

What is the region of transition here?

Axilla

Regions of Transition of Upper Limb

What is the region of transition here?

Cubital fossa

Regions of Transition of Upper Limb

What is the region of transition here?

Carpal tunnel

Movements of the Upper Limb

What movement is this?

Abduction (away from midline)

Adduction (towards midline)

What bone is highlighted here?

Clavicle

What bone is highlighted here?

Scapula

What is highlighted here?

Acromion

What is highlighted here?

Glenoid cavity

What bone is highlighted here?

Humerus

What bone is highlighted here?

Ulna

Whbat bone is highlighted here?

Radius

Movements of the Upper Limb

What movement is this?

Flexion (red arrow)

Extension (blue arrow)

Movements of the Upper Limb

What movement is this?

Medial rotation (towards midline)

Lateral rotation (away from midline)

Movements of the Upper Limb

What movement is this?

A = Retraction

B = Protraction

Movements of the Upper Limb

What movement is this?

A = Pronation

B = Supination

Movements of the Upper Limb

What movement is this?

Orange arrow = Flexion

Blue arrow = Extension

Movements of the Upper Limb

What movement is this?

Purple arrow = Abduction

Green arrow = Adduction

Movements of the Upper Limb

What movement is this?

Blue arrow = Extension

Orange arrow = Flexion

Movements of the Upper Limb

What movement is this?

Blue arrow = Extension

Orange arrow = Flexion

Movements of the Upper Limb

Movements of the thumb

What types of muscles can be mainly found in the anterior section of the upper limb?

Anterior = mostly flexor

What types of muscles can be mainly found in the posterior section of the upper limb?

Posterior = mostly extensor

The ___ ___ encloses the muscles of the upper limb.

The deep fascia encloses the muscles of the upper limb.

The ___ ___ arise from the deep fascia and separate the upper limb into discrete compartments.

Anterior → mainly flexor

Posterior → mainly extensor

The intermuscular septa arise from the deep fascia and separate the upper limb into discrete compartments.

Anterior → mainly flexor

Posterior → mainly extensor

Fascial planes

Potential spaces used by surgeons to separate deep structures

Does deep fascia allow for expansion?

No

Escharotomy

An incision made into the necrotic tissue resulting from a severe burn.

Full thickness incision through eschar, exposing subcutaneous fat.

Fasciotomy

A surgical incision through the fascia to relieve tension or pressure.

Incision through skin, fat and muscle fascia, exposing the underlying muscle compartment.

Compartment syndrome

Swelling in a confined anatomical space that produces dangerous pressure; may comprise blood supply leading to ischemia.

This can lead to...

- Temporary/permanent damage to muscles/nerves

Give an example of an acute cause of compartment syndrome

Fracture

Give an example of a chronic cause of compartment syndrome

Exercise

Symptoms of compartment syndrome

Early Findings

Paresthesias

Pain

Pulse deficit

Pallor

Late Findings

Paralysis

Treatment for compartment syndrome

Fasciotomy (fascial release)

Osteology of the upper limb

- Shoulder girdle (scapula & clavicle)

- Arm

- Forearm (radius - lateral & ulna - medial)

- Hand

Clavicle

Collar bone

The clavicle articulates with the ____ and ___ costal cartilage medially.

The clavicle articulates with the ____ ____ of the ____ laterally.

The clavicle articulates with the STERNUM and 1ST costal cartilage medially.

The clavicle articulates with the ACROMION PROCESS of the STERNUM laterally.

Clavicle function

Transmits mechanical force from the upper limb to the trunk. Transmits force to axial skeleton.

Clavicle acts as a strut that keeps the limb away from the trunk so that it has maximum freedom of movement.

The scapula

Shoulder blade

The humerus

Upper arm bone

What is this labelled area of the scapula & humerus area?

Coracoid process

Palpable below the lateral clavicle

What is this labelled area of the scapula & humerus area?

Acromion

Palpable bony shelf above the shoulder

What is this labelled area of the scapula & humerus area?

Greater tubercle

What is this labelled area of the scapula & humerus area?

Lesser tubercle

Attachment points for rotator cuff muscles, injury to which causes pain & tenderness

What is this labelled area of the scapula & humerus area?

Acromion

What is this labelled area of the scapula & humerus area?

Spine of the scapula

What is this labelled area of the scapula & humerus area?

Supraspinous fossa

What is this labelled area of the scapula & humerus area?

Infraspinous fossa

Infraspinatus muscle attachment point

What joint is highlighted here?

Acromioclavicular (AC) joint

- Joint line passes from anterior to posterior

- Dislocation can result in shoulder separation & visible deformity

What joint is highlighted here?

Sternoclavicular joint

- Only joint between the upper limb and axial skeleton

- Supported by the costoclavicular ligaments

What ligament is highlighted here?

Coracoacromial ligament

- Supports shoulder joint superiorly

- Can be ruptured by superiorly directed forces

- Can impinge on supraspinatus/subacromial bursa

What ligament is highlighted here?

Coracoclavicular ligament

Can be torn by AC (acromioclavicular) joint dislocation

What joint is this?

Acromioclavicular (AC) joint

What joint is this?

Sternoclavicular joint

What type of joint is the acromioclavicular (AC) joint?

Synovial plane joint

Dislocation is possible

What type of joint is the sternoclavicular joint?

Saddle type synovial joint that functions as a ball & socket

Dislocation is rare

Acromioclavicular (AC) joint dislocation can lead to rupture of the ___ ligaments

Acromioclavicular (AC) joint dislocation can lead to rupture of the coracoclavicular ligaments

Clavicular fractures are most likely in what 1/3 of the clavicle?

Middle 1/3 > Lateral 1/3 > Medial 1/3

The weakest point of the clavicle is what junction?

The weakest point of the clavicle is the junction between the middle and lateral thirds of the clavicle

Risk of a clavicular fracture can occur from what type of fall?

Fall onto the outstretched limb or onto the lateral shoulder

Pectoral girdle muscles - which muscle is shown here?

Pectoralis major

- Adducts & medially rotates shoulder

- Accessory breathing muscle

- Innervated by medial & lateral pectoral nerve

- Attaches to clavicle, sternum & adjacent costal cartilages and lateral lip of intertubercular groove (humerus)

Pectoral girdle muscles - which muscle is shown here?

Pectoralis minor

- Depresses & protracts scapula

- Divides axillary artery into 3 parts

- Innervated by medial pectoral nerve

- Attaches to ribs 3-5 and coracoid process

Pectoral girdle muscles - which muscle is shown here?

Serratus anterior

- Protracts scapula & holds it close to thoracic wall

- Attaches to ribs 1-8 anteriorly & medial scapula border

- Innervated by long thoracic nerve

Pectoral girdle muscles - which muscle is shown here?

Deltoid muscle

- Brings about all shoulder movement except adduction

- Innervated by axillary nerve

- Attaches to lateral clavicle, acromion, scapula spine & humerus

Causes of deltoid muscle damage?

- Shoulder dislocation

- Surgical neck of humerus fracture

- Intramuscular injection

Name the circled pectoral girdle muscle

Levator Scapulae

- Elevates & rotates scpula

- Innervated by dorsal scapula nerve & C3-4

Name the circled pectoral girdle muscle

Rhomboids (rhomboid minor and rhomboid major)

- Retract and fix position of scapula

- Innervated by dorsal scapula nerve

Name the circled pectoral girdle muscle

Teres major

- Adduction & medial rotation of humerus

- Innervated by lower subscapular nerve

Name the circled pectoral girdle muscle

Trapezius

- Elevates, retracts & depresses scapula

- Innervated by accessory nerve (CN XI)

Name the circled pectoral girdle muscle

Latissimus Dorsi

- Extends, adducts & medially rotates humerus

- Can raise trunk to arm e.g., dips/climbing

- Innervated by thoracodorsal nerve

The major artery, vein & nerves of the upper limb pass between the thorax and limb by travelling via which structures?

- Over rib 1

- Under clavicle

- Through the axillary inlet

The upper limb is almost entirely innervated by the nerves of the ___ plexus

The upper limb is almost entirely innervated by the nerves of the brachial plexus

- Formation of brachial plexus begins in the neck

- Moves into the axilla, arm, forearm and hand

- Plexus originates from cervical & thoracic spinal cord levels = C5, C6, C7, C8 and T1

Spinal nerve basics

What are the main nerves of the upper limb?

musculocutaneous, median, radial, ulnar, axillary

Blood supply to the upper limb

Subclavian, axillary, brachial, radial and ulnar

Deep veins of the upper limb

Brachial, axillary, subclavian

Superficial veins of the upper limb

Basilic vein, median cubital vein, cephalic vein, venous palmar arch

Superficial veins of the upper limb (e.g., cephalic) are clinically important and used for what?

- Venipuncture

- Blood transfusion

- Cardiac catheterization

Lymphatic drainage of the upper limb

Lymph drains into superficial and deep lymph nodes associated with superficial and deep veins

- Eventually they drain to axillary lymph nodes which drain to subclavian trunk (empties into R/L lymphatic ducts)

- Axillary lymph nodes also receive superficial lymph nodes of the anterior thoracic wall and upper quadrant of anterior abdominal wall

Lymph nodes

Bean shaped nodular aggregates of lymphoid tissue which act as filters with immune function.

Located along lymphatic vessels throughout the body & filters for lymph before it rejoins the venous bloodstream.

Lymph

Tissue fluid & plasma proteins

Lymphoid tissue

Forms aggregations at body entrances e.g., tonsils, adenoids

Axillary lymph nodes

Concentrated in armpit, receive lymph from upper limb and female breast

Lymphoedema

Abnormal collection of protein-rich fluid in the intrstitium due to obstruction of lymphatic drainage, resulting in painful swelling.

Primary causes (genetics)

Secondary causes (surgery, radiotherapy or infection)

Removal of nodes can lead to lymphoedema of a limb

Describe how the clavicle plays a role in weight transmission and explain the site where the clavicle is typically fractured & why?

- Clavicle acts as a strut

- Main bone that links appendicular to axial skeleton

- Main bone to transmit entire weight of upper limb to axial skeleton

Typically fractures occur at junction of medial 2/3 to later 1/3. This is because the curvature changes and thus forces impact more at this point, causing fractures here.

The part of the clavicle that articulates with the manubrium is the...

a) Acromial end

b) Sternal end

c) Shaft

d) Coracoid process

b) Sternal end

Regarding scapula; the part/feature that lies between the spine and superior border of the scapula is the...

a) Glenoid cavity

b) Superior angle

c) Suprascapular notch

d) Supraspinous fossa

d) Supraspinous fossa

The three muscles have their origin at the coracoid process are...

a) Long head of biceps, coracobrachialis, pec minor

b) Short head of biceps, pec minor, corachobrachialis

c) Short head of biceps, long head of biceps, corachobrachialis

d) Corachobrachialis, pec major, short head of biceps

b) Short head of biceps, pec minor, corachobrachialis

The structure that is an extension of the spine of the scapula is called...

a) Glenoid cavity

b) Coracoid process

c) Supraglenoid tubercle

d) Acromion process

d) Acromion process

The short, hook-like bony process of the scapula that is palpable in living subject just below the lateral third of clavicular shaft is called...

a) Glenoid fossa

b) Acromial process

c) Coracoid process

d) Suprasternal notch

c) Coracoid process

A 54 year old lady is diagnosed with cancer in her right breast. She undergoes staging and it is found that the breast tumour has invaded locally into the muscle below, as well as having positive lymph nodes.

Which muscle will the tumour have first invaded into?

Pectoralis major

Where is the most common site for a clavicular fracture to occur?

Middle third of the clavicle

What artery passes behind the middle of the clavicle and becomes named something different once crossing rib 1?

Subclavian artery

a) Identify the artery labelled X

b) Name the site at which the clavicle typically fractures

a) Axillary artery

b) Junction of its two curves (medial 2/3 & lateral 1/3)

Damage to the long thoracic nerve (which innervates serratus anterior) in breast surgery with axillary node clearance leads to what observable sign?

Scapula winging